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Volume 26 Supplement 1 2010 ISSN 0109-5641

Journal for Oral and Craniofacial Biomaterials Sciences

Abstracts of the Academy of Dental Materials Annual Meeting,

7–9 October 2010, Trieste, Italy

Official Publication of the Academy of Dental Materials


Editor-in-Chief

David C Watts PhD FADM, University of Manchester School of Dentistry, Manchester, UK.

North American Editor

Ronald Sakaguchi PhD FADM, OHSU School of Dentistry, Portland OR, USA.

E-mail: sakaguch@ohsu.edu

Editorial Advisor

Nick Silikas PhD FADM, University of Manchester School of Dentistry, Manchester, UK.

Editorial Assistant

Diana Knight, University of Manchester School of Dentistry, Manchester, UK.

E-mail: dentistry.dentmatj@manchester.ac.uk

Official Publication of the Academy of Dental Materials

Editorial Board

Joseph Antonucci

NIST Dental & Medical Materials,

USA

Kenneth Anusavice

University of Florida, USA

Roberto R Braga

University of São Paulo, BRAZIL

Stephen Bayne

The University of Michigan, USA

Pierre Colon

Université Denis Diderot, FRANCE

Brian Darvell

University of Kuwait, KUWAIT

Alvaro Della Bona

University of Passo Fundo, BRAZIL

George Eliades

University of Athens, Athens,

GREECE

Jack Ferracane

Oregon Health Sciences University,

USA

Marco Ferrari

University of Siena, ITALY

Garry J.P. Fleming

Trinity College Dublin, IRELAND

Alex S.L. Fok

The University of Minnesota, USA

Per Olof Glantz

University of Lund, SWEDEN

Jason A. Griggs

The University of Mississippi, USA

Satoshi Imazato

Osaka University, JAPAN

Klaus Jandt

Friedrich-Schiller Universität Jena,

GERMANY

J. Robert Kelly

University of Connecticut, USA

Karl-Heinz Kunzelmann

Ludwig-Maximilians University of

Munich, GERMANY

Paul Lambrechts

Katholieke Universiteit, Leuven,

BELGIUM

Charles Lloyd

University of Dundee, UK

Ulrich Lohbauer

University of Erlangen-Nuremberg,

Erlangen, GERMANY

Grayson W Marshall

University of California

San Francisco, USA

Sally Marshall

University of California,

San Francisco, USA

Jukka P. Matinlinna

University of Hong Kong, CHINA

John McCabe

University of Newcastle Upon Tyne,

UK

Bart van Meerbeek

Katholieke Universiteit, Leuven,

BELGIUM

Takashi Miyazaki

Showa University, JAPAN

Yasuko Momoi

Tsurumi University, Yokohama,

JAPAN

Will Pallin

University of Birmingham, UK

David Pashley

Medical College of Georgia, USA

Patricia N.R. Pereira

University of Brasilia, BRAZIL

John Powers

University of Texas at Houston, USA

Reinhard Hickel

Ludwig-Maximilians University,

GERMANY

N. Dorin Ruse

University of British Columbia

Vancouver, CANADA

Paulette Spencer

University of Kansas, USA

Jeffrey W. Stansbury

University of Colorado, USA

Michael Swain

University of Sydney,

AUSTRALIA

Burak Taskonak

Indiana University, USA

John E. Tibballs

Nordic Institute of Dental

Materials, NORWAY

Pekka K. Vallittu

University of Turku, FINLAND

John C Wataha

Medical College of Georgia, USA

Nairn H F Wilson

GKT Dental Institute, London, UK

Huakun (Hockin) Xu

The University of Maryland

Dental School, MD, USA

Spiros Zinelis

University of Athens, GREECE


Volume 26 Supplement 1 2010

ISSN 0109-5641

Contents

Official Publication of the

Academy of Dental Materials

www.academydentalmaterials.org

e1 1. Bond strength of izobuthyl and HEMA immersed resilient liner to denture base

H. Akin, F. Tugut, B. Mutaf, U. Guney, A.K. Ozdemir

e1 2. The effect of chlorhexidine pre-treatment on the bond strength of fiber posts

V. Angeloni, G. Marchesi, M. Cadenaro, A. Mazzoni, F.R. Tay, D.H. Pashley, L. Breschi

e2 3. Antibacterial activity and dentin bond strength in situ design

M. Bail, C.Z. Grande, A.D.L.M.C.S. Rastelli, S.M.G. Reinke, A. Reis, E.B. Santos

e2 4. Experimental HEMA-free self-etching adhesive: Effect of long-term water storage on bond strength

C.H. Zanchi, A. Bertacci, E.A. Münchow, F.A. Ogliari, E. Piva, F.F. Demarco, C. Pirani, S. Chersoni

e3 5. Failures of adhesion: Non-invasive and three-dimensional images using two-photon microscopy

A.K.S. Braz, A.S.L. Gomes, T.Y. Ohulchanskyy, P.N. Prasad

e3 6. Inhibition of dentinal proteolytic activity is dependent on CHX concentration

M.R. Carrilho, A. Mazzoni, F. Nato, F.D. Nascimento, C. Anauate-Netto, L. Tjäderhane, D.H. Pashley, L. Breschi

e4 7. The application of superficial treatments to improve bond strength to fiber posts

G. Casella

e4 8. Evaluation of the enamel etching pattern of self-etching adhesives

G. Castelli, L. Gallottini, G. Sotgiu, A. Lumbau, G. Gallina, E. Milia

e5 9. Replacing HEMA for surfactant dimethacrylate monomers in self-etching adhesive formulations

S. Chersoni, C.H. Zanchi, E.A. Münchow, F.A. Ogliari, C. Prati, M.G. Gandolfi, E. Piva, F.F. Demarco

e5 10. Effect of riboflavin on bond stability: A 1-year study

A. Cova, F. Nato, A. Mazzoni, A. Ruggeri, C. Prati, L. Breschi

e6 11. Durability of resin–dentin bonds using the ethanol bonding technique

A.G. Devito-Moraes, M.R. Carrilho, M. Akemi-Kikuti, M.N. Gomes, L.C. Yamasaki, L.M. Silva, C. Francci

e6 12. Synthesis and adhesive properties of acidic monomers for dental applications

M. Derbanne, V. Besse, S. Le Goff, J.P. Attal, T.N. Pham, M. Degrange

e7 13. Microtensile bond-strength of self-adhesive luting cements to chlorhexidine pre-treated dentin

V.D. Hipolito, P.H.P. D’alpino, F.B. Piveta, N. Silikas, F.P. Rodrigues, R. Alonso, M.F.D. Goes

e7 14. Microtensile bond strength of simplified and un-simplified adhesives

M. Diolosá, C.O. Navarra, E. Visintini, M. Cadenaro, R. Di Lenarda, L. Breschi

e8 15. Effect of chlorhexidine on 6-months bond strength of resin-glass-modified-ionomer to dentin

E. Dursun, J.P. Attal

e8 16. Bonding effectiveness of all-in-one adhesives

H.M. El-Damanhoury, N.A. El-Sahn, A.N. Habib, K.B. Moore

e8 17. Influence of surface pretreatment on the short term bond strength of composite resin to a zirconia-based material

G. Fazi, A. Vichi, M. Ferrari

e9 18. Bond strength of resin cements to dentin after water storage

T.R. Aguiar, C.B. Andre, L. Correr-Sobrinho, C.A.G. Arrais, G.M.B. Ambrosano, M. Giannini

e9 19. Immediate bond strength of various adhesives obtained by general practitioners

R. Guggenberger, I. Richter, A. Rumphorst, A. Bock, M. Wieland, C. Thalacker

e10 20. In vitro mutans Streptococci colonization of an Mdpb-containing adhesive system

A. Ionescu, L. Fadini, M. Gagliani, E. Brambilla

e10 21. Mechanical strength of dental adhesives cured by violet laser diode

A. Kameyama, J. Kato, H. Hatayama, J. De Munck, A. Haruyama, M. Yoshinari, M. Tsunoda, B. Van Meerbeek

e11 22. Effects of immersion time and frequency of water exchange on bond strength durability

A.D. Loguercio, L. Skovron, D. Kogeo, L. Gordillo, A. Reis

e11 23. Influence of ethanol on E-modulus of experimental adhesive blends

G. Marchesi, M. Cadenaro, R. Di Lenarda, F.R. Tay, D.H. Pashley, L. Breschi

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e12 24. Longevity of the bond created by 0.2% CHX-containing scotchbond 1XT

A. Mazzoni, F. Nato, C. Nucci, M. Carrilho, L. Tjäderhane, F.R. Tay, D.H. Pashley, L. Breschi

e12 25. Proprietary solvent enhances dentin wettability

P. Mehtälä, K. Agee, L. Breschi, D.H. Pashley, L. Tjäderhane

e13 26. The anti-MMP activity of benzalkonium chloride

M.M. Mutluay, A. Tezvergil-Mutluay, K.A. Agee, R.M. Carvalho, A. Manso, F.R. Tay, B.-Y. Suh, D.H. Pashley

e13 27. CHX-containing adhesive inhibits dentin MMPs: A zymographic assay

F. Nato, A. Mazzoni, P. Gobbi, M. Carrilho, G. Mazzotti, F.R. Tay, D.H. Pashley, L. Breschi

e14 28. Influence of dentin adhesive on bond strength of self-adhesive cements

F. Ozer, M.B. Blatz, A. Atlas, L. Daneshmehr, K. Kashyap, F. Mante

e14 29. Shear-bond strength of a new restorative material to primary dentin

E. Pacifici, A. Giovannetti, C. Goracci, A. Vichi, A. Polimeni, M. Ferrari

e15 30. Increased exposure times of simplified adhesives: Effects on degradation and quality of the polymer network

A. Reis, S.Q. Ferreira, T.R.F. Costa, A.D. Loguercio

e15 31. MTBS of dentin adhesives on primary dentin subjected to irradiation

K. Bekes, C. Rettig, J. Klinsmann, H.G. Schaller, C.R. Gernhardt

e15 32. Effects of aging on one-step self-etch adhesives

M. Taschner, F. Nato, A. Mazzoni, R. Di Lenarda, A. Petschelt, L. Breschi

e16 33. The inhibitory effect of carbodiimide on soluble and matrix-bound dentin MMPs

A. Tezvergil-Mutluay, M.M. Mutluay, L.S. Gu, K.A. Agee, T. Hoshika, M. Cadenaro, L. Breschi, F.R. Tay, D.H. Pashley

e16 34. Shear bond strength of an experimental adhesive to various substrates

C. Thalacker, H. Loll, R. Guggenberger

e17 35. Chlorhexidine release from adhesive resins after chewing simulation

G. Turco, G. Marchesi, A. Coslovi, M. Cadenaro, S. Paoletti, R. Di Lenarda, F.R. Tay, D.H. Pashley, L. Breschi

e17 36. QAM-based primers do not affect immediate bond strength of an etch-and-rinse adhesive

E. Visintini, M. Cadenaro, R. di Lenarda, F.R. Tay, D.H. Pashley, L. Breschi

e18 37. Influence of HAp-nanoparticle reinforcement on the adhesion to dentin

A. Wagner, R. Belli, C. Stoetzel, F.A. Mueller, A. Hilpert, A. Petschelt, U. Lohbauer

e18 38. Withdrawn

e18 39. Degree of conversion of nano- and micro-hybrid resin composites cured by different light sources

T.S. Jafarzadeh Kashi, H. Bagheri G, M. Behroozibakhsh, S.M. Fatemi, Y. Rezaei

e19 40. Prophylometric analysis of class-II cavities finished with four different methods

G. Ciampalini, F. Cerutti, N. Balzanelli, N. Barabanti, A. Cerutti

e19 41. The effect of temperature on the efficacy of polymerization of a dental resin composite

T.S. Jafarzadeh Kashi, M. Behroozibakhsh, S.M. Fatemi, M. Erfan, H. Bagheri G

e20 42. Time-dependent fracture toughness of conventional glassionomer cements

R. Belli, A. Petschelt, U. Lohbauer

e20 43. Bond strength to enamel and flexural strength of fiber-reinforced composites

M. Beloica, C. Goracci, N. Chieffi, A. Vichi, Z.R. Vulicevic, M. Ferrari

e21 44. Effect of resin shade and LED light intensity on microhardness

K. Tolidis, P. Gerasimou, C. Boutsiouki

e21 45. Temperature increase during composites polymerisation using two LED curing lights

E. Armellin, G. Bovesecchi, P. Coppa, G. Pasquantonio, L. Breschi, L. Cerroni

e22 46. Is pre-heated microhybrid composite effective as a inlay luting agent?

F. Cerutti, M. Gagliani, A. Cerutti

e22 47. Evaluation of polymerization stress correlated with the extent of polymerization of flowable composites

B. Codan, L. Breschi, E. de Stefano Dorigo, M. Cadenaro

e23 48. Experimental methodology to characterize volumetric changes of composite during photopolymerization

A. Joubert, C. Villat, P. Colon, B. Grosgogeat, N. Pradelle-Plasse

e23 49. Mould materials’ influence on degree of conversion of dental resins

R.B. Cornelio, H.M. Kopperud, J. Haasum, U. Gedde, U. Ørtengren

e23 50. Effect of photoactivation mode on cross-link density of resin composites

A.B. Correr, A.R. Costa, R.L.X. Consani, L. Correr-Sobrinho, M.A.C. Sinhoreti

e24 51. Influence of energy dose on the hardness, depth of polymerization and internal gap formation of methacrylate- and

silorane-based restorations

P.H.P. D’alpino, V.D. Hipolito, J. Bechtold, P.J. Santos, R.C.B. Alonso, F.P. Rodrigues, N. Silikas

e24 52. Effect of hydrogen peroxide topical applications on enamel and composite resin surfaces

M. D’Amario, G. Turco, M. Castronovo, M. Ciribe, R. Di Lenarda, M. Giannoni, M. Baldi

e25 53. Microhardness of a new flowable composite liner for posterior restorations

M. de Biasi, R.M. Calvi, D. Sossi, M. Maglione, D. Angerame

e25 54. Evaluation of surface roughness and filler characteristics of restorative composites

M. Di Francescantonio, R. Pacheco, R.R. Braga, M. Giannini

e26 55. Influence of curing time, overlay shade and thickness on Vicker’s hardness of light cured composites

L. Di Loreto, F. De Angelis, M. Vadini, M. D’amario, L. Merla Vitalone, C. D’arcangelo

e26 56. Roughness and microhardness of restorative materials submitted to erosive challenges

P.H. Dos Santos, A.P. Guedes, T.Y. Suzuki, S. Pavan, A.L. Briso, W.G. Assunção


e26 57. Effect of cavity configuration factor on nanoleakage of low-shrinkage composites

N.A. El-Sahn, H.M. El-Damanhoury, D. El-Kassas, O.M. Fahmy, H. Gomaa, J.A. Platt

e27 58. Can filler-size affect the colour and gloss of resin-composites?

H. Elbishari, J. Satterthwaite, N. Silikas

e27 59. Choosing the allocation method for clinical trials in restorative dentistry

H. Fron, P. Durieux, G. Chatellier, F. Gillaizeau, J.P. Attal

e27 60. Polishability of nanofilled resin-based composites

K. Hirata, J. Yamagawa, S. Geraldeli, F. Qian, S.R. Armstrong

e28 61. A novel test chip for measuring in situ degradation of dental composites using electrochemical impedance spectroscopy

S. Grego, J.R. Piascik, B. Brown, S.D. Wolter, B.R. Stoner

e29 62. Simulated clinical polishability of nanofilled resin-based composites

K. Hirata, J. Yamagawa, F. Qian, S.R. Armstrong

e29 63. Nanometer deformations of wet and dry composites determined by Speckle interferometry

N. Kachrimanis, P. Zaslansky, W.-D. Müller

e30 64. A new method to measure the linear polymerization shrinkage of composites with computer vision

I.-B. Lee, S.-H. Min

e30 65. Exposure reciprocity law: Influence of viscosity on different materials properties

J. Leprince, G. Springuel, W.M. Palin, J. Devaux, G. Leloup

e31 66. Polymerization of dental sealants: Influence of exposure times and curing-units

G. Liani, B. Codan, R. Di Lenarda, L. Breschi, M. Cadenaro

e31 67. Changes of microleakage using different composites and stratification techniques

A. Lizio, F. Lipari, S. Bertolami, C. Panarello, G. Lo Giudice

e32 68. Fracture toughness of GIC—A mechanistic approach on the nanoscale

B. Brandt, K. Durst, R. Belli, M. Goeken, U. Lohbauer

e32 69. Comparison of two self-adhesive composite flowables

R. Guggenberger, T. Luchterhandt, A. Stippschild

e32 70. Temperature stress distributions in posterior composite restorations: A 3D-FEA study

N.A. Manchorova

e33 71. SS-OCT as alternative to micro-CT for composites internal adaptation evaluation

J.R. Mayoral, A. Sadr, Y. Shimada, E. Cho, Y. Sumi, I. Krejci, L. Giner, M. Roig, J. Tagami

e33 72. Curing depth of restorative composites achieved with QTH and LED units

W.G.M. Jr, S.W. Kim, B. Pick, A.O. Lopes, F.A. Maeda

e34 73. Influence of fiber post on degree of conversion of a luting cement

C.O. Navarra, C. Goracci, G. Corciolani, A. Vichi, L. Breschi, M. Cadenaro, M. Ferrari

e35 74. Thermal evaluation of light-curing composites

M. Petrini, P. Trentini, G. Spoto, M. Ferrante

e35 75. Delayed gelation through chain-transfer reactions: Stress reduction in methacrylate networks

C.S. Pfeifer, N.D. Wilson, S. Lewis, Z.R. Shelton, J.W. Stansbury

e36 76. In vivo quantification of Streptococcus mutans in composite restored teeth

I. Piccinelli, F. Cerutti, L. Madini, N. Barabanti, A. Cerutti

e36 77. Energy delivered to a simulated restoration at the 2010 AADR meeting

R.B. Price, C.M. Felix

e37 78. Effect of modulated photoactivation methods on mechanical properties of composites with different loading systems

E.J. Souza-Junior, R.C.B. Alonso, L. Paulillo, C. Anauate-Neto, R.M. Puppin-Rontani

e37 79. Withdrawn

e37 80. Evaluation of depth of cure in nanohybrid composite: Scraping vs. Micro F-TIR analysis

R. Rota, N. Scotti, A. Venturello, D. Pasqualini, E. Berutti

e38 81. UK-GDPs’ knowledge of light curing of resin based composites materials

A. Santini, S. Turner

e38 82. Factors influencing depth of cure of nanohybrid composite: Micro F-TIR analysis

M. Scansetti, N. Scotti, A. Venturello, D. Pasqualini, E. Berutti

e39 83. 12-h Post-polymerization of a nanohybrid resin composite: Conversion degree’s evaluation

N. Scotti, A. Venturello, F. Pera, D. Pasqualini, E. Berutti

e39 84. Rugosimetric analysis of a microhybrid composite polished with four protocols

D. Angerame, D. Sossi, M. Cattaruzza, F. Spizzo, M. De Biasi

e39 85. Nanogel-modified composite materials: Route to low shrinkage and stress

J.W. Stansbury, R.R. Moraes, J.W. Garcia, M.D. Barros, S.H. Lewis, C.S. Pfeifer

e40 86. Coefficient of thermal expansion of different types of composite resins

K. Tolidis, T. Vaimakis, P. Gerasimou, C. Boutsiouki

e40 87. Manipulation of a dental composite resin using bovine enamel as reinforcing filler

J.T. Tribioli, D.P. Jacomassi, V.S. Bagnato, C. Kurachi

e41 88. Self-curing dental composition with improved cure temperature

M. Trujillo-Lemon, K. Esquibel, K. Ida, I. Ahmed, B. Gallagher, A. Sotiros, C. Bonner, C. Bracho-Troconis

e42 89. Colorimetric difference between two composites with the same shade

M.A. Verlicchi, F. Fazzi, G. Dondi Dall’orologio

e42 90. Restoration interface gap evaluation proposal by 3D-microtomography

F. Zuppante, L. Manzon, R. Pecci, R. Bedini


e43 91. Potential of cure of resin cements mixed with bonding agents

T.R. Aguiar, M. Oliveira, L. Correr-Sobrinho, C. Arrais, M. Giannini

e43 92. Effect of the incorporation of potassium titanate fibers on the strength of a dental porcelain

M.D. Araujo, R.B.P. Miranda, P.F. Cesar, H.N. Yoshimura

e44 93. CD117 expression in peri-implantitis soft tissues: An immunohistochemical study

S.D. Aspriello, A. Zizzi, F. Bambini, M. Lorenzi, C. Rubini, M. Piemontese

e44 94. Self-adhesive cement adhesion to zirconia ceramic: Effect of surface treatments

D. Augusti, D. Re, M. Ferrari, G. Augusti, F. Caimi

e45 95. Evaluation of the mechanical behavior of ceramic systems using fractographic analysis

M. Borba, K.A. Fukushima, H.N. Yoshimura, P.F. Cesar, J.A. Griggs, A. Della Bona

e45 96. Clinical performance of posterior three-unit zirconia-based fixed partial dentures: 63-Month prospective clinical study

B. Borelli, R. Sorrentino, G. De Simone, S. Tete’, F. Zarone

e46 97. Mechanical properties of particulate glass fiber-reinforced acrylic resins

R.G. Soares, A.L. Botelho, D. Cecchin, A.P. Farina, A.C. Reis, M.O. Mazzetto

e46 98. Effect of ceramic surface conditioning on resin-MTBS durability to leucite ceramic

M.A. Bottino, A. Amaral, L.F. Valandro

e46 99. Influence of cement color on final shade of all-ceramic restorations

M. Carrabba, A. Vichi, C. Goracci, M. Ferrari

e47 100. Effect of surface conditioning on bonding to zirconium-oxide ceramic

A. Casucci, C. Goracci, F. Monticelli, N. Chieffi, M. Sedda, M. Ferrari

e47 101. Effect of multiple sintering cycles on the translucency parameter of dental ceramics

P.F. Cesar, C.C. Gonzaga, C.F.S. Pereira, M.M. Pinto, H.N. Yoshimura

e48 102. Risks of ceramic veneer fracture under different occlusal loading conditions

Y. Chaiyabutr, J.C. Kois, V. Isvilanonda

e48 103. Shade match of two ceramic systems with 3D-Master Toothguide

G. Corciolani, A. Vichi, M. Sedda, C. Goracci, M. Ferrari

e49 104. Precision of different transfer impression techniques in multiple implants

F.L.G. Cruz, J.C.B. de Faria, F.P.P. Leite, A.P.P. Leite, M. Chaves, L.R.S. Concílio, A.C.C. Neves

e49 105. Effect of hydrothermal aging on zirconia crystal phases and strength

R. Dittmann, E. Mecher, A. Schmalzl, T. Kuretzky

e50 106. Fatigue lifetime prediction of dental implant using finite element analysis

Y. Duan, P.A. Kulkarni, J.A. Gonzalez, W.W. Nagy, J.A. Griggs

e50 107. Traditional and CAD/CAM generated metal-free restorations. 12-Month follow-up

A. Fabianelli, A. Vichi, M. Sedda, M. Ferrari

e51 108. Contraction stress of two self-adhesive cements

A. Frassetto, G. Marchesi, B. Codan, R. Di Lenarda, L. Breschi, M. Cadenaro

e51 109. Influence of surface finishing on flexural strength of veneered zirconia

J. Geis-Gerstorfer, C. Goldammer, C. Schille

e52 110. Comparison of Elastomeric Impression Materials’ Thixotropic Behavior

P. Gerasimou, K. Tolidis, C. Boutsiouki, D. Tortopidis

e52 111. Resin bond strength to alumina coated dental oxide ceramics

M. Golobič, A. Kocjan, T. Kosmač, P. Jevnikar

e53 112. Effect of tooth preparation on the fit of Y-TZP copings

R.I. Hmaidouch, P.E. Neumann, W.-D. Mueller

e53 113. Evaluation of newly developed experimental zirconia primer

S. Hotta, A. Arita, T. Kumagai, T. Sakuma

e54 114. Effect of light on the micro-mechanical properties of dual-cured self-adhesive resin cements

N. Ilie, A. Simon

e54 115. Effect of silane heat treatment on resin-cement and glass-ceramic adhesion

F.P.P. Leite, R.F. Carvalho, F.L.G. Cruz, M. Martins, J.R.C. Queiroz, A.D. Vanderlei, M. Ozcan

e55 116. Influence of veneer thickness on residual stresses in zirconia prostheses

A.K. Mainjot, G.S. Schajer, A.J. Vanheusden, M.J. Sadoun

e55 117. Identifying subsurface fatigue cracks in resin bonded ceramics subjected to cyclic compression

L.H. Mair, P. Padipatvuthikul

e56 118. Withdrawn

e56 119. Adhesion mechanisms at the interface between Y-TZP and veneering ceramics

C. Monaco, P. Cardelli, A. Tucci, L. Esposito, R. Scotti

e56 120. Fit and fracture behaviour of metal laser sintered posterior bridges

W.-D. Mueller, U.W. Stecher, R.I. Hmaidouch

e56 121. Different protocol for silane application on ceramic: A FTIR analyses

J.R.C. Queiroz, H.C. Garcia, L.F.C. Oliveira, C.E. Silva, M.P.C. Neto

e57 122. Clinical follow-up of direct adhesive bridges up to 7 years

M. Özcan

e57 123. Adhesive behaviour of resin-based sealer cements in thin and thick layers

E.S. Pane, J.E.A. Palamara, H.H. Messer

e58 124. Zirconium oxy-fluoride surface activation for improved bonding to zirconia substrates

J.R. Piascik, S.D. Wolter, B.R. Stoner


e58 125. Adhesion between zirconia and luting cements: Effect of surface treatments

M. Querzè, P. Baldissara, N. Scotti, L.F. Valandro, R. Scotti

e59 126. FIB/SEM analysis of metal- and zirconia- ceramic interfaces

R. Salvi, G. Merlati, P. Battaini, M. Sebastiani, F. Massimi, P. Menghini, E. Bemporad

e59 127. An in vitro fatigue resistance of CAD/CAM occlusal veneers

L.H. Schlichting, H.P. Maia, L.N. Baratieri, P. Magne

e60 128. Flexural strength and Weibull analysis of materials for CEREC CAD/CAM

M. Sedda, A. Vichi, F. Del Siena, A. Casucci, G. Corciolani, M. Ferrari

e60 129. Flexural strength of dental alumina ceramic systems reinforced by Al2O3 /GdAlO3 fibers

R. Sgura, I.S. Medeiros, A.C. Hernandes

e61 130. Effect of sintering and SiO2 deposition on core–veneer ceramic bonding

J.R.C. Queiroz, P. Benetti, S.F. Fissmer, M. Massi, A.M. Silva, L.N. Junior, A.D. Bona

e61 131. Effect of sintering temperature on three-point flexural strength of different zirconia materials

B. Stawarczyk, M. Özcan, M. Roos, A. Trottmann, C.H.F. Hämmerle

e62 132. Cementation strategy and mechanical-cycling effects on human-dentin and composite-inlays MTBS

L.F. Valandro, E.P. Prochnow, C. Bergoli, M. Amaral, G. Saavedra

e62 133. Microstructural changes on sandblasting Y-TZP before and after sintering

A. Verna, A. Tucci, L. Esposito, C. Monaco, P. Cardelli, R. Scotti, L.F. Valandro, P.F. Cesar, M. Oda

e62 134. Performance profile of different new self-adhesive resin cements

C.A. Wiedig, G. Raia, M. Ludsteck, R. Hecht

e63 135. Measurement of the phase transformation of 3Y-TZP in depth using Raman spectroscopy

C. Wulfman, N. Dupont, M. Sadoun, M.L.D.L. Chapelle

e64 136. Mechanical performance of self-adhesive resin cements

J.I. Zorzin, A. Petschelt, U. Lohbauer

e64 137. Self-etching cement–dentine interface: A macrostructural evaluation

P.A. Acquaviva, F. Cerutti, M. Gagliani, A. Cerutti

e64 138. Effective fluoride recharging protocols for various orthodontic adhesives

B.S. Lim, S.J. Lee, D.Y. Lee, S.J. Ahn

e65 139. Does the disk-specimen height impact the push-out bond strength results?

M. Amaral, C.D. Bergoli, L.F. Valandro

e65 140. MIH hypoplasic enamel treated with a novel bioactive light-curing calcium-silicate material: A pilot clinical study

C. Baroni, M.G. Gandolfi, C. Prati

e66 141. Reliability of fractal dimension analysis based on round-robin tests

A.A. Barrett, P.F. Cesar, S.S. Scherrer, J.A. Griggs, U. Lohbauer, K. Gopalakrishnan, C. Shen, J.J. Mecholsky Jr., K.J. Anusavice

e66 142. TiO2 , poly-l-lysine and hydroxyapatite differently affect osteoblastic differentiation and IL-6 production

E. Canciani, M. Frattini, S. Mele, B. Palazzo, L. Rimondini

e67 143. Effects of external bleaching agents on dental tissues and cement–enamel junction

M.G.A.M. Chaves, M. Oliveira, M.N. Pereira, M.R.S.P. Soares, H.D.M. Chaves Filho, F.P.P. Leite

e67 144. Solubility in water or DMEM of F-doped MTA cements with increasing F-content

A. Colin, C. Prati, G.A. Pelliccioni, M.G. Gandolfi

e67 145. In vivo, morphological and clinical effects of a desensitizing agent

E. Milia, E. Cotti, G. Sotgiu, G. Castelli, M. Masarin, A. Manunta, G. Gallina

e68 146. Increases of intracanal and root surface temperatures during the obturation of canal using the E&Q master system

and the system

E. Cumbo, R. Russo, E. Milia, G. Gallina

e68 147. Assessment of gutta-percha adaptation with different root canal obturation techniques

P. Cusimano, E.M. Cumbo, S. Provenzano, C. Goracci, G. Gallina, M. Ferrari

e69 148. In vitro loading curve of an orthodontic distalizing spring

D. Dalessandri, L. Laffranchi, F. Zotti, S. Bonetti, L. Visconti

e69 149. Intraradicular marginal integrity of fiber posts relined and fixed with composite resin

M.F. De Goes, A.C.R.L. Caiado, M.C. Alves, F. Souza-Filho

e70 150. Antimicrobial activity of a new endodontic irrigant against Enterococcus faecalis

C. Dettori, S. Pisu, E. Cotti

e70 151. In vitro resistance to sliding: Self-ligating bracket/archwire 0.014˝ using a customized typodont

P. Fontana, L. Laffranchi, D. Dalessandri, I. Tonni, L. Visconti

e71 152. Structural analysis of the enamel subjected to pre- and post-bleaching agents

C. Francci, M.N. Gomes, A.G. Devito-Moraes, F.P. Rodrigues, L.C. Yamazaki, L.M. Silva, N.R.G. Fróes-Salgado, A.C. Nishida

e71 153. Biomimetic dentine remineralization by a novel bioactive light-curing calcium-silicate composite

M.G. Gandolfi, F. Siboni, P. Taddei, E. Modena, C. Prati

e72 154. Post retention using a new resin-based-composite with low curing stress

A. Giovannetti, C. Goracci, A. Polimeni, E. Pacifici, M. Ferrari

e72 155. Varying PLA functionality and texture to influence osteoprogenitors

R. Lakhman, K. O’Brien, R. Kasi, R.A. Weiss, L.T. Kuhn, M. Mina, A.J. Goldberg

e73 156. Early in vitro mutans streptococci colonization on different experimental resins

M. Grassi, A. Ionescu, M. Gagliani, L. Breschi, M. Cadenaro, F.R. Tay, D.H. Pashley, E. Brambilla

e73 157. Assessment methods of tissue reactions around implants for orthodontic anchorage

K. Gritsch, N. Laroche, R. Al-Hity, L. Vico, P. Colon, B. Grosgogeat


e74 158. Mild-acidic HOCl solution as pretreatment for caries-affected dentin: A morphological study

S. Kunawarote, M. Nakajima, S. Ichinose, J. Tagami

e74 159. Chlorhexidine and fluoride: A reduction of Streptococcus mutans in orthodontic patients with special needs

L. Laffranchi, I. Casula, F. Luparia, E. Marchesini, D. Dalessandri, C. Paganelli

e75 160. Microhardness of MTA and SuperEBA in acid solutions

S. Loghi, D. Nicosia, M. De Biasi, D. Sossi, D. Angerame

e75 161. Mesenchymal stem cells and bovine bone mineral in sinus lift

R. Gutwald, M. Maglione, S. Sauerbier, R. Schmelzeisen

e75 162. Wetting behaviour of root canal sealers

A.M. Saleh, N. Silikas, D.C. Watts

e76 163. Angiogenesis in a bilateral maxillary sinus elevation with or without platelet-rich fibrin

G. Morandi, T. Stocca, M. Maglione, M. Bertolotto

e76 164. Effects of photoactivation in bleaching with hydrogen peroxide: Spectrophotometric evaluation

A. Velo, G. Pajno, G. Cervino, A. Artemisia, G.L. Giudice

e77 165. Characterization of bioscaffolds and grafted human bone by microcomputed tomography

R. Pecci, D. Meleo, R. Bedini, L. Pacifici

e77 166. Corrosion of NiTi instruments by contact with sodium hypochlorite in clinical simulated conditions: TOF-Sims analysis

E. Pedulla’, M. Cicciu’, A. Licciardello, E. Rapisarda

e78 167. Amalgam versus MTA as root and filling material in apicoectomyzed roots: A long term longitudinal study

G.A. Pelliccioni, M.R. Gatto, C. Prati

e79 168. Fatigue testing and fractographic analysis of a NiTi rotary instrument

C. Pirani, C. Prati, P.P. Cirulli, S. Chersoni, O. Ruggeri

e79 169. Bioinspired remineralization of dentine by designed light-curing calcium-silicate material

C. Prati, M.G. Gandolfi, F. Siboni, P. Taddei, E.D. De Stefano

e80 170. Effect of DLC film on C. albicans biofilm formation

J.R.C. Queiroz, S.F. Fissmer, C.Y.K. Ito, A.C.R.D. Salvia, M. Massi, L. Nogueira Junior

e80 171. Electrospun collagen/hyaluronic acid nanofibers improve osteoblastic differentiation onto titanium surfaces

I. Foltran, S. Mele, N. Roveri, L. Rimondini

e81 172. Instrumentation, post and mechanical cycling effects on fracture strength on roots

M.P. Rippe, M. Santini, C.A.S. Bier, L.F. Valandro

e81 173. Actual in vitro TEGDMA concentration used in cytotoxicity tests

V. Rivieccio, G. Nocca, L. Demartis, V. D’antò, S. Rengo, A. Lupi, G. Spagnuolo

e82 174. Influence of NaOCl and ACP-CPP on the color-parameters of teeth bleached with 35% hydrogen peroxide

M.N. Gomes, F.P. Rodrigues, C.L. Miyazaki, N. Silikas, D.C. Watts, C. Francci

e82 175. Withdrawn

e82 176. Bones regeneration with adult stem cells: Animal model

M. Maglione, E. Salvador, D. Angerame, M. Melato, M.E. Ruaro, R. Di Lenarda

e83 177. Bioactivity and marginal adaptation of a novel light-curing MTA cement

F. Siboni, M.G. Gandolfi, C. Prati

e83 178. Nickel–titanium orthodontic wire and load deflection

I. Tonni, L. Laffranchi, P. Fontana, F. Zotti, S. Bonetti

e83 179. Nanostructured hydroxyapatite-dextran composite scaffolds for tissue engineering

E. Varoni, E. Canciani, B. Palazzo, V. Betti, C. Dellavia, L. Rimondini

e84 180. Fluoride treatment of demineralization in patients following a vegan diet: Observational study

F. Zotti, L. Laffranchi, D. Dalessandri, P. Fontana, C. Paganelli

Paffenbarger Award finalists (in alphabetical order)

A COVA*, F NATO, A MAZZONI, A RUGGERI, C PRATI, L BRESCHI. Effect of Riboflavin on Bond Stability: a 1-year study. (Poster 10)

M GOLOBIČ *, A KOCJAN, T KOSMA , P JEVNIKAR. Resin Bond-Strength to Alumina Coated Dental Oxide Ceramics. (Poster 111)

P MEHTÄLÄ*, K AGEE, L BRESCHI, DH PASHLEY, L TJÄDERHANE. Proprietary Solvent Enhances Dentin Wettability. (Poster 25)

V ROSA*, RHM GRANDE, JE NÖR. Injectable Scaffolds Allow for the Engineering of Functional Dental Pulp. (Poster 175)

C WULFMAN*, N DUPONT, M SADOUN, M LAMY DE LA CHAPELLE. Measurement of the Phase Transformation of 3Y-TZP in Depth

Using Raman Spectroscopy. (Poster 135)


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dental materials 26S (2010) e1–e84

available at www.sciencedirect.com

journal homepage: www.intl.elsevierhealth.com/journals/dema

Abstracts of the Academy of Dental Materials Annual

Meeting, 7–9 October 2010, Trieste, Italy

1

Bond strength of izobuthyl and HEMA immersed resilient

liner to denture base

H. Akin ∗ , F. Tugut, B. Mutaf, U. Guney, A.K. Ozdemir

Cumhuriyet University, Faculty of Dentistry, Sivas, Turkey

Objectives: Bonding to the denture base surface is a significant

problem for resilient liner, especially for silicone-based

ones. The purpose of this study was to investigate the bonding

properties of denture base to silicone based soft denture liner

when immersed in izobuhyl and 2-hydroxyethyl methacrylate

(HEMA) for various times.

Materials and methods: Polymethyl methacrylate test

specimens were fabricated and then randomly assigned to 5

groups (n = 15), according to the treatments applied, untreated

(control, group 1), resilient liner immersed in izobuthyl for

1 min (group 2), resilient liner immersed in izobuthyl for 3 min

(group 3), resilient liner immersed in HEMA for 1 min (group

4), and resilient liner immersed in HEMA for 3 min (group 5).

The resilient liner specimens were processed between 2 polymethyl

methacrylate (PMMA) blocks. Bonding strength of the

liners to PMMA was compared by tensile test with the use of

universal testing machine at a crosshead speed of 5 mm/min.

The mean value and standard deviation of the specimens

were statistically evaluated by 1-way ANOVA and post hoc

Tukey–Kramer multiple comparisons tests (˛ = 0.05).

Results:

Groups Mean (N) SD

Group 1 25.25 a 2.09

Group 2 39.59 b 1.55

Group 3 56.85 c 2.24

Group 4 27.26 a 1.67

Group 5 33.73 d 2.46

n = 15, F = 582.184, and groups with same superscripted letters not significantly

different (p > 0.05). There was no statistical difference in

tensile bond strength between group 1 and group 4 (p = 0.063).

0109-5641/$ – see front matter

Conclusions: Immersion of silicon based soft denture liner

in Izobuthyl for 1 min increased tensile bond strength twice

between silicone soft liner and PMMA denture base materials.

doi:10.1016/j.dental.2010.08.009

2

The effect of chlorhexidine pre-treatment on the bond

strength of fiber posts

V. Angeloni 1 , G. Marchesi 1 , M. Cadenaro 1 , A. Mazzoni 2 ,

F.R. Tay 3 , D.H. Pashley 3 , L. Breschi 1

1 University of Trieste, Italy

2 University of Bologna, Italy

3 Medical College of Georgia, GA, USA

Objectives: The application of chlorhexidine (CHX) as a

therapeutic primer to dentin has been reported to reduce the

degradation of the hybrid layer over time. The aim of this

study was to evaluate the effect of CHX pre-treatment on bond

strength of fiber posts luted to intra-radicular dentin with a

self-adhesive cement immediately and after 1-year storage

in artificial saliva. The hypothesis tested was that CHX pretreatment

does not affect bond strength after aging.

Materials and methods: RelyX Fiber-Posts (3M ESPE, St

Paul, MN, USA) were luted with a self-adhesive cement (RelyX

Unicem, 3M ESPE) into roots of human incisor with or without

CHX pre-treatment of the intra-radicular dentin. 2% CHX

(Bisco Inc., Schaumburg, IL, USA) was applied for 1 min and

carefully air-dried before self-adhesive cement application.

Bonded specimens were sectioned in 1 mm-thick slabs and

either immediately submitted to push-out bond strength test

or stored in artificial saliva at 37 ◦C for 1 year prior testing. Data

were statistically analyzed with Kruskaal–Wallis test (p = 0.05).

Results: CHX pre-treatment did not affect push-out bond

strength of luted specimens, both immediately and after aging

in artificial saliva for 1 year (p > 0.05).

Means and standard deviations of push-out bond strength

expressed as MPa:


e2 dental materials 26S (2010) e1–e84

Time 0 1 year

RelyX Unicem without CHX 8.4 (4.1) a 8.0 (3.3) a

RelyX Unicem with CHX 8.0 (4.1) a 8.3 (3.4) a

Different superscript letters indicate statistical differences (p < 0.05).

Conclusions: The tested hypothesis was accepted. CHX

used as a therapeutic primer did not influence the bond

strength values of fiber posts luted with RelyX Unicem after

aging. The possibility to incorporate the CHX within the selfadhesive

cement formulation should be further investigated.

doi:10.1016/j.dental.2010.08.010

3

Antibacterial activity and dentin bond strength in situ design

M. Bail, C.Z. Grande, A.D. Loguercio M.C.S. Rastelli, S.M.G.

Reinke, A. Reis, E.B. Santos

State University of Ponta Grossa, Brazil

Objectives: Despite the monomer MDPB shows strong bactericidal

activity against oral bacteria (Imazato et al., J Dent Res

1994;73:1437), this property was observed in in vitro studies.

The present study assessed the application of dentin adhesive

system incorporating MDPB monomer in inhibiting oral bacteria,

and bond strength performance using an in situ design.

Materials and methods: Cavities (4 mm × 4mm× 2 mm)

prepared on bovine root dentin slabs were treated with

different adhesive systems (Clearfil SE bond [without MDPmonomer]

vs. Clearfil protect bond [with MDP-monomer]) and

then restored using a resin composite (Opallis/FGM). According

to the ethical guidelines, 14 volunteers were selected

to use an acrylic custom-made palatal device containing

the specimens tested (n = 4). Half of the specimens were

subjected to a cariogenic challenge using a 20% sucrose

solution twice a day. After 14 days, the biofilm formed on

the slabs was collected for microbiological analysis. The

restored slabs (immediate and after 14 days of in situ simulation),

fixed to the cutting machine ISOMET 1000 (Buehler, IL,

USA), were submitted to longitudinal and perpendicular cuts

obtaining 0.8 mm 2 rectangular area “sticks”. Each stick was

submitted to microtensile testing at a speed of 0.5 mm/min

(Kratos).

Results: Dental biofilm vs. material after 14-days.

Total streptococci

(×10 −5 CFU/mg)

Mutans streptococci

(×10 −5 CFU/mg))

Results: Microtensile dentin bond strength (MPa).

Material Immediate (n = 10) After 14 days (n = 14)

Clearfil

SE bond

Clearfil

protect

bond

Clearfil

SE bond

Lactobacilli

(×10 −5 CFU/mg)

Sucrose No sucrose Sucrose No sucrose Sucrose No sucrose

Clearfil

protect

bond

30.1 ± 5.7 28.2 ± 6.5 32.3 ± 7.1 29.4 ± 9.1

Conclusions: Microtensile dentin bond strength (�TBS) was

not influenced by the adhesive systems used. The use of adhesive

system with MDP-monomer significantly decreases the

amount of Total streptococci and Mutans streptococci in this in

situ study.

doi:10.1016/j.dental.2010.08.011

Clearfil SE bond 280.5 ± 164.5(b) 281.9 ± 173.2 (b) 97.9 ± 70.2 (A) 42.9 ± 22.1 (B) 18.6 ± 18.6(a) 20.1 ± 12.4 (a)

Clearfil protect

bond

185.2 ± 117.1(a) 221.1 ± 147.3 (a) 29.7 ± 31.4 (B) 9.0 ± 14.3 (C) 27.9 ± 23.7(a) 63.7 ± 39.6 (b)

4

Experimental HEMA-free self-etching adhesive: Effect of longterm

water storage on bond strength

C.H. Zanchi 1 , A. Bertacci 2 , E.A. Münchow 1 , F.A. Ogliari 1 ,E.

Piva 1 , F.F. Demarco 1 , C. Pirani 2 , S. Chersoni 2

1 Federal University of Pelotas, Brazil

2 University of Bologna, Italy

Objectives: To evaluate the influence of surfactant

dimethacrylates (SD) on the resin-to-dentin immediate and

long-term microtensile bond strength (�TBS) of the experimental

HEMA-free self-etching systems.

Materials and methods: Five experimental HEMA-free

two-step self-etching systems containing different surfactant

dimetacrylates (SD) (Bis-EMA 10, Bis-EMA 30, PEG 400,

PEG 1000, and PEG 400 UDMA) and a HEMA-containing system

(control) were formulated. Sixty bovine incisors had the

superficial coronal dentin exposed and were allocated into six

groups according to their SD or HEMA containing formulation.

The teeth were restored and sectioned to obtain sticks randomly

allocated into three storage periods: 24 h, 6 months, and

12 months. Thereafter, the specimens were subjected to the

�TBS test. Data (MPa) were analyzed by Kruskall–Wallis and

Dunn test (˛ = 0.05).


Results: Between the HEMA-free groups, the adhesive system

formulated with PEG 400 UDMA produced the highest

�TBS and was similar to HEMA-containing group. Specimens

stored for 24 h were statistically higher for all groups tested

when compared those after 6 and 12 months storage (p < 0.05).

Conclusions: The �TBS test showed that PEG 400 UDMA

could be considered satisfactory substitute for HEMA in adhesive

systems compositions.

doi:10.1016/j.dental.2010.08.012

5

Failures of adhesion: Non-invasive and three-dimensional

images using two-photon microscopy

A.K.S. Braz, A.S.L. Gomes, T.Y. Ohulchanskyy, P.N. Prasad

Federal University of Pernambuco, Brazil

Objectives: The purpose of this study was to examine

the two and three-dimensional morphological images

of the adhesive layer, hybrid layer and resin tags in a

non-destructive manner using a two-photon laser scanning

microscopy (TPLSM).

Materials and methods: Three bonding systems were evaluated:

Prime&Bond NT, Dentsply-Detrey; Heliobond, Ivoclar;

and Adhese, Ivoclar. Fifteen extracted intact human third

molars were randomly distributed among 3 groups corresponding

to the adhesive materials used. The occlusal

one-third and root of each tooth were removed by means

of a diamond saw. The teeth were cut perpendicularly to

the longitudinal axis into 1- to 1.5-mm-thick slices to obtain

superficial dentin. The dentin surfaces were polished with

600-grit SiC papers under running water to create a standardized

smear layer. The adhesives were doped with AF280

two-photon absorbing fluorescent dye and applied to the tooth

according to the manufacturers’ instructions, then, were lightcured

for 20 s (600 mW/cm 2 ) and promptly examined in a

two-photon laser scanning microscope without drying or fracturing

the specimens.

Results: TPLSM imaging enabled interfacial micromorphology

at submicrometer resolution and provided non-invasive,

two- and three-dimensional high-contrast images of bonded

dentin. This technique assessed the quality and distribution of

resin tags after a three-dimensional reconstruction, revealed

the occurrence of blisters into the adhesive layer and the

absence of hybrid layer and resin tags formation into the

dentin of some samples.

Conclusions: TPLSM provided high quality, highresolution,

non-invasive, two and three-dimensional images

of the bonded interfaces, allowing accurate analysis of the

structure and integrity of the adhesive layer, hybrid layer and

resin tags.

doi:10.1016/j.dental.2010.08.013

dental materials 26S (2010) e1–e84 e3

6

Inhibition of dentinal proteolytic activity is dependent on CHX

concentration

M.R. Carrilho 1 , A. Mazzoni 2 , F. Nato 2 , F.D. Nascimento 1 ,C.

Anauate-Netto 1 , L. Tjäderhane 3 , D.H. Pashley 4 , L. Breschi 5

1 UNIBAN, Brazil

2 University of Bologna, Italy

3 University of Oulu, Finland

4 Medical College of Georgia, GA, USA

5 University of Trieste, Italy

Objectives: The purpose of this study was to evaluate the

effect of different concentration of chlorhexidine (0.02–2.0%)

on the proteolytic activity of mineralized and demineralized

dentin.

Materials and methods: Thirty freshly extracted human

third molars had their enamel, cementum and pulp tissue

removed. After freezing in liquid nitrogen, dentin fragments

were reduced to powder in a mixer mill. Half of the dentin

powder was kept mineralized (MD), while the other half

was demineralized in phosphoric acid (DD). Both of dentin

samples, M and D, were equally divided into 4 groups and preincubated

for 1 h in: (1) HEPES buffer (control); (2) 0.02% CHX;

(3) 0.2% CHX or (4) 2% CHX. Then, all groups were incubated

in a CaCl2/ZnCl2-containing artificial saliva for 24 h. Total

protein concentration of all extracts was determined using

the Bradford assay. The collagenolytic/gelatinolytic activity of

human dentin was assessed by two methods: zymography

(ZM) and hydroxyproline assay (HYP) (wherein the degradation

of collagen is estimated from the concentration of released

hydroxyproline, an amino acid that particularize collagen).

Data obtained from HYP assay were analyzed by ANOVA and

Holm–Sidak tests at ˛ = 0.05.

Results: ZM data: No enzymatic activity was found in proteins

extracted from MD. Zymograms of DD extracts showed

multiple forms of gelatinolytic enzymes, with the 66-kDa as

MMP-2 active-form, a fainter band of 86 kDa corresponding

to the active form of MMP-9 and other minor gelatinolytic

bands with lower molecular weights. Treatment with 0.2% or

2% CHX solutions of both MD and DD showed complete inhibition

of both MMP-2 and -9 activity. Incubation of MD and

DD with 0.02% CHX showed a faint band at 66-kDa as MMP-

2 active-form. HYP data: proteolytic activity of MD was lower

than that observed for DD, regardless the sample treatment

(p < 0.05). For both MD and DD samples, the highest percentage

(%) of degraded collagen, resultant from the dentinal proteolytic

activity, was observed for the control groups (i.e. not

treated with CHX) (p < 0.05), followed by the groups that were

treated with 0.02% CHX, 0.2% CHX and 2% CHX. No difference

was observed in % of collagen degradation for groups treated

with 0.2 or 2% (p > 0.05).

Conclusions: Again, CHX has shown to decrease significantly

the endogenous proteolytic activity of human dentin.

Nevertheless, this inhibitory role of CHX showed to be dosedependent,

being less effective for concentrations of CHX as

low as 0.02%. This finding might have a clinical implication

if one tries to increase the durability of resin-–dentin bonds

using extremely low concentration of CHX.


e4 dental materials 26S (2010) e1–e84

Supported by FAPESP, Brazil #07/54618-4 and CNPq, Brazil

#300615/2007-8.

doi:10.1016/j.dental.2010.08.014

7

The application of superficial treatments to improve bond

strength to fiber posts

G. Casella

University of Catania, Italy

Objectives: The objective of the study was to understand

which, among the surface treatments recently proposed by literature,

is more useful in order to increase the adhesion of the

post-cement system. It was also evaluated if the same treatments

caused the same effects on all types of tested posts.

Materials and methods: The study analyzed the surface

micro-morphology and roughness of 6 different fiber posts.

4 samples of each group were immersed for 10 min in: (1) 10%

hydrogen peroxide; (2) 20% hydrogen peroxide; (3) 10% potassium

permanganate; (4) 10% sodium ethoxyde. 4 posts of each

type were treated for 1 min with 36% ortophosphoric acid. A

confocal microscope was used to evaluate the surface morphology

of the samples. The statistical analysis on the degree

of roughness measured on the post-surface was performed by

means of two-way ANOVA test; the level of significance was

set at 0.05.

Results: All the posts showed signs of surface changes after

the contact for 10 min with the four solutions and after 1 min

of treatment with 36%. ortophosphoric acid. The statistical

analysis underlined that hydrogen peroxide was more effective

on glass-fibre and carbon-fibre posts, while the treatment

with 36% orthophosphoric acid increased the surface roughness

of the glass-fibre reinforced composite posts (see Table).

10% hydrogen

peroxide

20% hydrogen

peroxide

10% potassium

pergamangate

10% sodium

etoxide

36% ortophosphoric

acid

Control group

Mean ± S.D. Mean ± S.D. Mean ± S.D. Mean ± S.D. Mean ± S.D. Mean ± S.D.

1 76.96 ± 3.44 73.59 ± 3.55 25.39 ± 1.29 34.38 ± 1.35 22.99 ± 1.28 15.23 ± 1.42

2 74.01 ± 5.30 65.61 ± 2.51 83.06 ± 1.74 83.96 ± 2.45 122.31 ± 1.76 34.23 ± 1.07

3 137.09 ± 2.68 119.12 ± 1.02 19.39 ± 1.38 14.70 ± 1.94 22.16 ± 1.17 18.33 ± 1.40

4 70.06 ± 6.40 39.29 ± 31.30 31.30 ± 1.29 15.36 ± 1.25 34.15 ± 1.39 22.24 ± 1.27

5 100.71 ± 4.50 113.05 ± 1.07 14.35 ± 1.43 20.15 ± 0.89 75.21 ± 1.33 13.18 ± 0.96

6 109.45 ± 2.49 90.18 ± 1.08 15.35 ± 1.24 25.38 ± 1.41 47.18 ± 1.07 17.33 ± 1.37

1 = Tech 2000 Xop; 2 = FRC Postec Plus; 3 = RelyX Fiber Post; 4 = DT Light-Post; 5 = Millenium Plus Conical Black; 6 = Glassix Glass Fiber Post.

Conclusions: When effective, the tested pre-treatments

create new sites of mechanical retention and improve the

post-cement composite interface, stabilizing the quality of the

adhesive bond over time.

doi:10.1016/j.dental.2010.08.015

8

Evaluation of the enamel etching pattern of self-etching

adhesives

G. Castelli 1 , L. Gallottini 2 , G. Sotgiu 1 , A. Lumbau 1 ,G.

Gallina 3 , E. Milia 1

1 University of Sassari, Italy

2 University of Roma, Italy

3 University of Palermo, Italy

Objectives: To evaluate the capacity of seven self-etching

adhesives (SEAs) to demineralize ground enamel in comparison

with traditional phosphoric acid etchant (PAE) using SEM

and statistical analysis.

Materials and methods: 80 caries-free extracted human

third molars were divided into 8 groups (n = 10). Enamel bur-cut

surfaces were prepared and, strictly following the manufacturers’

instructions, treated with three priming agents of

two-step self-etching adhesives: Aqua Resulcin Prime (Group

1); Peak TM (Group 2); Clearfil Protect Bond (Group 3); four

one-step self-etch (all-in-one) adhesives, G-Bond (Group 4);

Artegral One (Group 5); Clearfil S3 Bond (Group 6); Adper Easy

Bond (Group 7); and phosphoric acid etching (Control group).

The etch patterns for the SEA systems were determined by

rinsing off the material with water, acetone and alcohol. A

minimum of 15 specimens was used for each group. Morphology

matches were made between each SEA system and PAE

by means of ultrastructural SEM analysis and were computed

using the Kruskal–Wallis test (P < 0.05).

Results: SEM images showed that two-step-self-etching

adhesives (Groups 1–3) produced a regular pattern over a considerable

surface area and depth, not concerning, however,

the prismless layer of enamel in the fissure space; one-step

self-etch adhesives (Groups 4–7) demonstrated similar morphological

features; an uneven demineralization pattern was


observed in the PAE group with un-etched prismless enamel

in the depth of the fissures. The Kruskal–Wallis test demonstrated

no statistically significant difference among the groups

(P = 0.43).

Conclusions: Despite the enamel etching pattern being

similar for all SEAs used, two-step self-etching systems

containing phosphate derivative monomers were the most

efficient self-etching agents with a more homogeneous and

regular pattern of demineralization when compared to the

traditional PAE.

doi:10.1016/j.dental.2010.08.016

9

Replacing HEMA for surfactant dimethacrylate monomers in

self-etching adhesive formulations

S. Chersoni 1 , C.H. Zanchi 2 , E.A. Münchow 2 , F.A. Ogliari 2 ,C.

Prati 1 , M.G. Gandolfi 1 , E. Piva 2 , F.F. Demarco 2

1 University of Bologna, Italy

2 Federal University of Pelotas, Brazil

Objectives: To evaluate the influence of surfactant

dimethacrylates (SD) on the resin-to-dentin microtensile bond

strength (�TBS) and to characterize the interfacial micromorphology

of hybrid layer of the experimental HEMA-free

self-etching systems.

Materials and methods: Five experimental HEMA-free

two-step self-etching systems containing different surfactant

dimetacrylates (SD) (Bis-EMA 10, Bis-EMA 30, PEG 400, PEG

1000 and PEG 400 UDMA) and a HEMA-containing system

(control) were formulated. Sixty bovine incisors allocated into

six groups had their superficial coronal dentin exposed. Each

experimental adhesive system was applied and resin composite

restorations were incrementally built up. After 24 h,

restored teeth were sectioned to obtain 24 sticks per group

with cross-sectional area of 0.5 mm 2 . Thereafter, the specimens

were subjected to the �TBS test. Data (MPa) were

analyzed by one-way ANOVA and Tukey’s test. Analysis of the

adhesive–dentin interfaces was performed through scanning

electron microscopy (SEM).

Results: The adhesive system formulated with PEG 400

UDMA produced �TBS similar to the HEMA-containing group

and statistically higher than the HEMA-free groups. Additionally,

similar failure percentages were observed in the PEG 400

UDMA and the control group. The lowest �TBS was observed

with Bis-EMA 30 with predominance of the adhesive failures.

In the SEM analysis, all the adhesives systems presented similar

partially demineralized hybrid layer (1.5–3.0 �m thickness)

with well-formed resin tags.

Conclusions: All the adhesives systems presented similar

partially demineralized hybrid layer with well-formed resin

tags. All SD presented reasonable initial �TBS, with the PEG

400 UDMA being a promising monomer to be considered as a

HEMA substitute in adhesive systems compositions.

doi:10.1016/j.dental.2010.08.017

dental materials 26S (2010) e1–e84 e5

10

Effect of riboflavin on bond stability: A 1-year study

A. Cova 1 , F. Nato 2 , A. Mazzoni 1 , A. Ruggeri 1 , C. Prati 1 ,L.

Breschi 3

1 University of Bologna, Italy

2 University of Urbino, Italy

3 University of Trieste, Italy

Objectives: The stability of the dentin collagen network is

crucial for bonding effectiveness over time. Previous studies

reported the success of cross-linkers in adequately stabilize

the dentin collagen network preventing its degradation.

Thus, the aim of this study was to assay the stability of the

dentin/adhesive interface created by a 2-step etch-and-rinse

adhesive system applied with or without 0.1% riboflavin pretreatment.

Materials and methods: Middle/deep dentin was exposed

from human molars and etched with 35% phosphoric acid for

15 s. Specimens were then assigned to: Group 1, dentin was

treated with 0.1% riboflavin (water solution) and exposed to

ultraviolet type A radiation for 2 min, then XP Bond (Dentsply

DeTrey GmbH, Konstanz, German) was applied; Group 2, XP

Bond was applied on untreated etched dentin (control). Specimens

were processed for microtensile bond strength analysis

in accordance with the non-trimming technique and pulled

to failure after 24 h, 6 months or 1 year of storage in artificial

saliva at 37 ◦ C. Data were analyzed with two-way ANOVA and

Tukey post hoc test (p < 0.05). Interfacial nanoleakage evaluation

was performed at light microscope and TEM.

Results: The use of ultraviolet-activated riboflavin before

XP-Bond application increased immediate bond strength compared

to controls (Group 1: 44.4 ± 10.4 MPa vs. Group 2:

37.3 ± 10.3 MPa, respectively; p < 0.05). After storage (either 6

months or 1 year) riboflavin-treated specimens confirmed the

findings revealing higher bond strength compared to controls

(6 months: 35.6 ± 11.2 MPa vs. 22.0 ± 7.0 MPa, respectively,

p < 0.05; 1 year: 30.9 ± 12.2 MPa and 17.7 ± 9.1 MPa, respectively,

p < 0.05). Interfacial nanoleakage expression along XP-Bond

bonded interfaces decreased on riboflavin-treated specimens

compared to controls irrespective from storage.

Conclusions: The use of ultraviolet-activated riboflavin as

experimental cross-linker on etched dentin surfaces before

the application of a 2-step etch-and-rinse adhesive increased

bond strength and reduced interfacial nanoleakage expression

at 6 months and 1 year of artificial aging. These data can

be related to increased dentin collagen cross-linking due to

riboflavin application. Further studies are needed to support

the use of riboflavin in vivo.

doi:10.1016/j.dental.2010.08.018


e6 dental materials 26S (2010) e1–e84

11

Durability of resin–dentin bonds using the ethanol bonding

technique

A.G. Devito-Moraes 1 , M.R. Carrilho 2 , M. Akemi-Kikuti 1 , M.N.

Gomes 1 , L.C. Yamasaki 1 , L.M. Silva 1 , C. Francci 1

1 University of São Paulo, Brazil

2 University of Bandeirante de São Paulo, Brazil

Objectives: The aim of this study was to evaluate the durability

of adhesive interfaces that were obtained when using

the ethanol-bonding technique and hydrophobic adhesives.

Materials and methods: Twenty-eight molar teeth were

cut in order to expose a flat surface of middle dentin. Four

experimental groups were prepared: control for which the

three-step etch-and-rinse adhesive system (Scotchbond MultiPurpose,

3M ESPE) was applied to dentin as recommended

by the manufacturer (water–wet bonding technique); Experimental

1, for which dentin was saturated with ethanol and

hybridized only with the neat bonding resin (3rd step) of the

Scotchbond MultiPurpose system; Experimental 2 and 3, for

which dentin was saturated with ethanol and hybridized with

primers, containing 90 or 70% of the neat bonding resin of

Scotchbond MultiPurpose system with 10 or 30% of ethanol

(w/w%), respectively. After dentin hybridization a layer of

the neat bonding resin of Scotchbond MultiPurpose system

was added and photo-cured. All teeth were restored with a

nanohybrid resin composite (Filtek Z350, 3M ESPE). Microtensile

specimens (1 mm 2 ) were prepared and tested immediately

or after 6 months of storage in artificial saliva at 37 ◦ C. Extra

samples were prepared to characterize the adhesive interface

by scanning electron microscopy. The data were analyzed by

two-way ANOVA.

Results: For all groups, no decrease in bond strength was

observed after 6 months of storage. Moreover, no differences

were found between groups evaluated immediately or after 6

months of storage. The morphologic characteristics of hybrid

layers formed in ethanol-saturated dentin did not differ from

that obtained when using the conventional water–wet bonding

technique.

Conclusions: Durability of resin–dentin bonds formed

when using the ethanol-bonding technique was quite similar

to that obtained when using the “gold-standard” which

comprises the combination of the conventional water–wet

technique with a three-step etch-and-rinse adhesive system.

doi:10.1016/j.dental.2010.08.019

12

Synthesis and adhesive properties of acidic monomers for

dental applications

M. Derbanne 1 , V. Besse 2 , S. Le Goff 1 , J.P. Attal 1 , T.N. Pham 2 ,

M. Degrange 1

1 Université Paris Descartes, Montrouge, France

2 ENSICAEN, Caen, France

Objectives: The major shortcoming of modern dental adhesive

is their limited durability in vivo (Van Meerkeek et al.,

J Dent 1998;26:1). The purpose of this study was to inves-

tigate whether phosphonic acid monomers to be included

in self-etching adhesive provide a better bond to dental

substrate by providing interaction with hydroxyapatite. Additionally,

acrylamide polymerizing function was tested against

methacrylate function as it should provide better resistance to

hydrolysis (Moszner et al., V Macromol Mater Eng 2003;288:621).

Materials and methods: 6 two-steps self etching dental

adhesives were formulated using 3 different spacing chain

length (number of carbon atoms: 2, 6 and 10) and 2 different

polymerizing groups (acrylamide and methacrylate). Other

components of the formulations were a common bisacrylamide

monomer (DEBAAP) developed by Ivoclar-Vivadent,

camphorquinone, ethyl-4-dimethylamine benzoate as the initiation

system, stabilisator and solvents (Catel et al., J Polym

Sci A Polym Chem 2008;46:7074). Adhesion was assessed on 10

samples for each group at 24 h and 60 days of 37 ◦ C water

storage using SBS test at a crosshead speed of .5 mm min −1

on dentin and enamel. Data were analysed for correlation

between spacer length, polymerising group, substrate and SBS

(PASW). Additionally, SEM observation was conducted to provide

a better understanding of the results.

Results:

Spacer

length

Acrylamide

2 6 10

24 h 60

days

24 h 60

days

24 h 60

days

Dentin 13.97 12.46 15.17 14.17 16.15 15.31

Enamel 18.97 19.67 19.98 19.50 19.52 24.23

Spacer

length

Methacrylate

2 6 10

24 h 60

days

24 h 60

days

24 h 60

days

Dentin 18.40 16.31 17.87 14.86 15.10 16.34

Enamel 15.77 16.19 21.92 17.96 19.12 16.34

SBS values are expressed in Mpa; spacer length is expressed in number

of carbon.

Conclusions: Adhesion is improved on dentin when

increasing the length of the spacer group of the acidic

monomer while it remains stable after 60 days of water storage.

doi:10.1016/j.dental.2010.08.020


13

Microtensile bond-strength of self-adhesive luting cements to

chlorhexidine pre-treated dentin

V.D. Hipolito 1,2,3 , P.H.P. D’alpino 1 , F.B. Piveta 1 , N. Silikas 2 , F.P.

Rodrigues 1 , R. Alonso 1 , M.F.D. Goes 3

1 Bandeirante University of São Paulo -UNIBAN, Brazil

2 The University of Manchester, UK

3 University of Campinas, Piracicaba, Brazil

Objectives: To investigate the effect of chlorhexidine (CHX)

on the microtensile bond-strength (�TBS) of self-adhesive luting

cements (SLC) to dentin.

Material and methods: The occlusal enamel was removed

from 30 extracted sound human molars, exposed a flat

dentin. Resin-composite (Filtek Z250, 3M ESPE) discs (1.2 mm

in diameter, 6 mm in thickness) were cemented to the smearlayer-covered

dentin using the SLC [RelyX Unicem, 3M ESPE

(UN); Multilink Sprint, Ivoclar Vivadent (MS)] with/without

0.2% or 2% CHX solutions. Six groups were then created

according to the SLC and dentin pre-treatment (n = 5). After

24 h of water storage, restored teeth were sectioned into

beams with a cross-sectional area of approximately 0.9 mm 2

at the bonded interface, subsequently tested in tension with

a crosshead speed of 0.5 mm/min in a universal testing

machine. The fractured surfaces were examined with SEM.

Two-way ANOVA and Tukey’s test were performed (˛ = 0.05).

Nine additional teeth were processed for energy-dispersive Xray

(EDS) analysis using SEM of the dentin surface treated with

0.2 and 2% CHX solutions.

Results: Mean bond-strength values in MPa and standard

deviations are shown in the table below. Data with same letters

(uppercase for rows, lowercase for columns) are not significantly

different. Fracture analysis indicated that most failures

occurred cohesively in the SLC for the control groups (without

CHX). When the dentin was pre-treated with the CHX solutions,

there was a higher incidence of adhesive failures. The

EDS/SEM analysis detected a larger concentration of ions chlorine

on the dentin surface treated with 2% CHX compared to

that treated with 0.2% CHX.

dental materials 26S (2010) e1–e84 e7

Materials Baseline CHX 0.2% CHX 2%

UN 54.18 ± 5.24 aA 34.87 ± 7.24 aB 25.51 ± 5.27 aC

MS 31.80 ± 2.45 bA 20.50 ± 3.05 bB 21.50 ± 1.39 aB

Conclusions: Pre-treatment of dentin with CHX negatively

influences the bond-strength when associated with both SLCs,

irrespective of the concentration tested. So, the CHX pretreatment

does not suggest an improvement in the bonding

durability of SLCs to dentin as described for the total-etch

adhesives systems.

doi:10.1016/j.dental.2010.08.021

14

Microtensile bond strength of simplified and un-simplified

adhesives

M. Diolosá, C.O. Navarra, E. Visintini, M. Cadenaro, R. Di

Lenarda, L. Breschi

University of Trieste, Italy

Objectives: The purpose of this study was to assess

the immediate bond strength of different adhesives either

self-etch or etch-and-rinse. The hypothesis tested was that

simplified adhesives (two-step etch-and-rinse and one-step

self-etch) have lower bond strength than un-simplified

multi-step versions (three-step etch-and-rinse and two-step

self-etch).

Materials and methods: Two adhesives for each of the four

main classes were selected. Name and manufacturer are listed

in the Table. Forty human third molars were cut to expose

middle/deep dentin and equally and randomly assigned to one

bonding system (N = 5). All adhesives were applied according

to manufacturers’ instructions. Specimens were processed for

microtensile bond strength test in accordance with the nontrimming

technique.

Results: Means and standard deviations of microtensile

bond stregnth are reported:

Adhesive Manufacturer Class �TBS (MPa)

All Bond 3 Bisco Industries, Anaheim,

CA, USA

Gluma Solid

Bond

Haeraus Kulzer GmbH,

Hanau, Germany

Gluma Confort Haeraus Kulzer GmbH,

Hanau, Germany

Adper Scotchbond

1 XT

3M ESPE, St. Paul, MN,

USA

Sea2 3M ESPE, St. Paul, MN,

USA

Clearfil Protect

Bond

Kuraray Medical Inc.,

Tokyo, Japan

Clearfil S3 Kuraray Medical Inc.,

Tokyo, Japan

All Bond SE Bisco Industries, Anaheim,

CA, USA

3-Step etch-and-rinse 23 ± 8 abc

3-Step etch-and-rinse 15 ± 6 a

2-Step etch-and-rinse 40 ± 10 d

2-Step etch-and-rinse 41 ± 11 d

2-Step self-etch 35 ± 9 cd

2-Step self-etch 30 ± 10 bcd

1-Step self-etch 34 ± 11 cd

1-Step self-etch 20 ± 9 ab

Different superscript letter identify statistical differences (p < 0.05).

Conclusions: The tested hypothesis was rejected since

some simplified adhesives showed similar or higher microtensile

bond strength values than unsimplified versions. Further


e8 dental materials 26S (2010) e1–e84

in vivo studies are needed to clarify the clinical performance

of simplified adhesives.

doi:10.1016/j.dental.2010.08.022

15

Effect of chlorhexidine on 6-months bond strength of resinglass-modified-ionomer

to dentin

E. Dursun, J.P. Attal

University of Paris Descartes, France

Objectives: The purpose of this study was to investigate

the effect of chlorhexidine (CHX) on dentin bond strength of

resin-modified glass-ionomer (RMGI) after 24 h and 6 months

of water storage.

Materials and methods: 60 human teeth with a flat surface

of dentin were embedded in blocks of resin. 60 cylinders

of RMGI (Fuji LCII ® (GC)) were bonded on 60 teeth following

various modalities: 30 after polyalkenoic acid (ac pol) treatment,

30 after polyalkenoic acid treatment and an application

of 0.05% chlorhexidine (CHX). One subgroup (n = 15) was tested

after 24 h in water at 37 ◦ C and the other subgroup (n = 15)

after 6-month storage in water. A shear bond strength (SBS)

test was performed. The data (in MPa) were analyzed with

ANOVA and Tukey tests (p < 0.05). The type of bond failure

(mixed/adhesive/cohesive) was noted and analyzed with a chisquare

test (p < 0.05).

Results:

Dentin treatment, material and time Dentin SBS (MPa)

Ac Pol + RMGI 24 h 8 ± 1 (a)

AcPol+Chx+RMGI24h 9 ± 3 (a)

Ac Poly + RMGI 6 months 12 ± 4 (b)

Ac Pol + Chx + RMGI 6 months 9 ± 3 (a)

Letters in parentheses = homogeneous subsets.

After 24 h, there were no significant differences on dentin

SBS of RMGI with or without application of chlorhexidine.

After 6 months, the dentin SBS increased in the samples that

had not been treated with chlorhexidine, and did not increase

in those that had been treated with chlorhexidine.

No significant differences in debonding locations were

found between the various groups tested with 100% of adhesive

failures.

Conclusions: Chlorhexidine application does not seem to

disturb the dentin SBS of RMGI after 24 h. However, the dentin

SBS of RMGI seems to increase after 6 months and application

of chlorhexidine may inhibit this increase.

doi:10.1016/j.dental.2010.08.023

16

Bonding effectiveness of all-in-one adhesives

H.M. El-Damanhoury 1 , N.A. El-Sahn 2 , A.N. Habib 2 , K.B.

Moore 3

1 University of Sharjah, UAE

2 Cairo University, Egypt

3 Indiana University, IN, USA

Objectives: To evaluate the bonding effectiveness of

six all-in-one adhesives to dentin by testing micro-tensile

bond strength (�-TBS) and micrographic analysis of the

resin/adhesive interface.

Materials and methods: Flat occlusal dentin was exposed

in 128 extracted human molars. Teeth were equally divided

into 16 groups (8 teeth each). Two groups were randomly

assigned for each all-in-one adhesive and controls: Clearfil

S3 (S3-kuraray); G-Bond (GB-GC dental); iBond (IB-Heraeus

Kulzer); Xeno V (XB-Dentsply); Optibond All-in-one (OB-Kerr)

and Adper Easy Bond (AEB-3M ESPE). Adper ScotchBond SE

(ASE-3M ESPE) was used as two-bottle self-etch control and

Adper Single Bond Plus (SB-3M ESPE) as etch-and-rinse control.

Specimens were restored with Filtek Z250 Composite (3M

ESPE). One group for each material was thermocycled (TC). �-

TBS to dentin was measured in a universal testing machine.

Mode of failure of debonded beams was examined under SEM.

Micrographic analysis of the bonded interface of demineralized/deproteinized

samples was done using SEM. All data were

analyzed by one-way ANOVA and multiple comparisons was

done using Tukey’s test (p < 0.05).

Results: SB presented the highest �-TBS (58.17 ± 10.1 MPa)

and a reduction of 25.12% after TC, with resin tags >40 �m,

while GB (53.40 ± 9.6 MPa) showed the least reduction in �-TBS

after TC (14.71%). OB (48.40 ± 8.0 MPa) exhibited the highest

reduction in �-TBS (31.16%) and resin tags >40 �m. XB presented

the lowest �-TBS (25.88 ± 5.5 MPa) with reduction of

22.06% after TC. All-in-one adhesive showed mixed type of

failure, except for GB and XB, which failed cohesively within

the adhesive layer.

Conclusions: Etch and rinse adhesive systems remain as

the gold standard for bonding to dentin, meanwhile some of

the all-in-one adhesives demonstrate promising results concerning

the bond strength and durability after thermocyclying.

There is no direct relation between depth of infiltration in

dentin and bond strength of adhesives.

doi:10.1016/j.dental.2010.08.024

17

Influence of surface pretreatment on the short term bond

strength of composite resin to a zirconia-based material

G. Fazi, A. Vichi, M. Ferrari

University of Siena, Italy

Objectives: The purpose of the present study was to evaluate

the influence of sandblasting zirconia before and after

sintering on the bond strength between a zirconia core and a

composite resin material.


Materials and methods: Methods: 30 microsticks per group

for a total of 0 microsticks were obtained by 9 disks of Y-

TZP zirconia core divided in 3 groups according different

surface treatments: in group 1 Y-TZP zirconia at presintered

stage was sandblasted with 120 �m alumina oxide;

in group 2 sintered Y-TZP zirconia was sandblasted with

120 �m alumina oxide; in group 3 sintered Y-TZP zirconia

was not treated and thus served as control group. A

10-methacryloylooxydecyldihydrogenphosphate (MDP) containing

bonding agent and silane coupling agent mixture was

applied on all groups. Composite resin for indirect restorations

was incrementally layered in a plastic mold to a final

thickness of 3 mm. Specimens were sectioned under water

cooling to obtain microsticks 6 mm × 1mm× 1 mm in dimensions.

Microtensile bond strength test was conducted with a

universal testing machine. Fractured microsticks and sections

from each group were also examined by an optical microscope

and a scanning electron microscope to evaluate respectively

mode of failure and zirconia–composite interface. T test for

independent samples was applied to check for the significance

of the between-group differences. The level of significance was

set at p < 0.05.

Results: Microtensile bond strength (SD) in MPa and failure

mode of test groups. Different letters after the values indicate

statistical significant data.

Group 1

(pre-SB)

Bond strength

(MPa)

Type of failure 90% interfacial

Group 2

(post-SB)

dental materials 26S (2010) e1–e84 e9

Group 3

(control)

25.65 (7.23) a 24.65 (12.33) a 3.36 (4.17) b

92% interfacial

100%

interfacial

Conclusions: 1. Application of MDP containing bonding/silane

coupling agent mixture resulted in an adequate

composite resin bond to sandblasted Y-TZP substrate but

resulted in a poor bonding to untreated Y-TZP. 2. Sandblasting

performed either before or after sintering did not affect

zirconia-resin bond strength. The bond strength values measured

in the present study suggest a possible application of

indirect resin composite as veneering materials for Y-TZP

frameworks.

doi:10.1016/j.dental.2010.08.025

18

Bond strength of resin cements to dentin after water storage

T.R. Aguiar 1 , C.B. Andre 1 , L. Correr-Sobrinho 1 , C.A.G. Arrais 2 ,

G.M.B. Ambrosano 1 , M. Giannini 1

1 State University of Campinas, Brazil

2 University of Guarulhos, Brazil

Objectives: The aim of this study was to evaluate the bond

strength of cementing systems to dentin after water storage

for 24 h or 1 year.

Materials and methods: Occlusal dentin surfaces of 64

human third molars were exposed and flattened with SiC

paper (600) under water irrigation. Teeth were assigned to 8

groups (n = 8), according to two storage times and four cementing

systems: RelyX ARC/Scotchbond Multi-Purpose, 1 Clearfil

Esthetic Cement/DC Bond, 2 RelyX Unicem 3 and Clearfil SA

Cement. 4 All materials were used according to the manufacturers’

instructions. Resin luting cements were applied to

pre-polymerized resin discs (2 mm thick), which were subsequently

bonded to the prepared dentin surfaces. Restored

teeth were stored in water for 24 h or 1 year. Afterwards, they

were sectioned to obtain multiple bonded beams (1.0 mm 2 )

and tested in tension at a crosshead speed of 0.5 mm/min

until failure. Data (MPa) were analyzed by two-way ANOVA

and Tukey test (˛ = 0.05).

Results: Means (SD) of bond strength (MPa) are in the table

below.

Cementing systems 24 h 1 year

RelyX ARC 16.3 (2.0) Ab 15.7 (2.6) Ab

RelyX Unicem 18.3 (1.9) Aa 21.0 (3.8) Aa

Clearfil Esthetic Cement 12.6 (3.7) Ac 12.9 (3.8) Ac

Clearfil SA Cement 19.9 (2.4) Aa 21.1 (2.3) Aa

Values of groups having similar letters were not significantly different

(p ≤ 0.05). (uppercase letters = rows; lowercase letters = column).

Conclusions: The dentin bond strength of all cementing

systems was not reduced after 1 year of water storage. Clearfil

Esthetic Cement showed the lowest bond strength to dentin

in both storage times.

doi:10.1016/j.dental.2010.08.026

19

Immediate bond strength of various adhesives obtained by

general practitioners

R. Guggenberger, I. Richter, A. Rumphorst, A. Bock, M.

Wieland, C. Thalacker

3 M ESPE AG, Seefeld, Germany

Objectives: Aim of this study was to evaluate the immediate

shear bond strength (SBS) obtained by general practitioners for

their routinely used adhesive and an all-in-one adhesive.

Materials and methods: Bovine incisors were embedded in

cold-cure acrylic resin. The labial surface of each tooth was

ground to expose enamel (E) or dentin (D). A cylindrical button

of Filtek TM Supreme XT A2 (2.36 mm diameter, 2 mm height)

was cured on the tooth surfaces treated with the respective

self-etch (S) or total etch (T) adhesive by a total of 137 dentists.

A notched-edge shear method (Ultradent) was used to

measure the SBS.

Results: The table shows the SBS in MPa. The standard deviations

(SD) are given in parentheses. All data were analyzed

by ANOVA and multiple comparisons using Fisher’s LSD procedure

(p < 0.05). Means with the same letters are statistically

the same.

1 RelyX ARC/Scotchbond Multi-Purpose, 3M ESPE.

2 Clearfil Esthetic Cement/DC Bond, Kuraray Medical Inc.

3 RelyX Unicem, 3M ESPE.

4 Clearfil SA Cement, Kuraray Medical Inc.


e10 dental materials 26S (2010) e1–e84

Material SBS [MPa] Material SBS [MPa] Material SBS [MPa]

AEB E S 17.4(5.8) ab XV E S 11.8(5.4) bc SB1XT E T 23.8(8.6) a

AEB E T 21.4(8.1) a XV D S 14.8(3.8) abc SB1XT D T 15.6(9.6) abc

AEB D S 17.3(6.3) ab CSE E S 16.9(2.9) b OBSP E T 12.6(6.1) bc

AO E S 5.2(3.9) cd CSE D S 15.2(2.7) bc OBSP D T 9.2(9.6) cd

AO D S 10.4(6.3) cd SC E T 14.1(7.1) bc PBNT E T 7.7(6.9) cd

IBSE E S 14.5(4.1) bc SC D T 9.5(7.8) cd PBNT D T 5.8(3.6) cd

IBSE D S 10.2(4.6) bcd

AEB—Adper Easy Bond, 3 M ESPE; AO—AdheSE One, Ivoclar-Vivadent; IBSE—iBond SE, Heraeus Kulzer; XV—Xeno V, Dentsply; CSE—Clearfil SE

Bond, Kuraray; SC—Syntac Classic, Ivoclar-Vivadent; SB1XT—Scotchbond 1XT, 3 M ESPE; OBSP—Optibond Solo Plus, Kerr; PBNT—Prime&Bond NT,

Dentsply.

Conclusions: Multiple statistically significant differences

were found. Overall, the one step self-etch AEB showed consistent

results approaching and partly exceeding those of

total etch adhesives. This is in accord with the literature

(M. Degrange et al., L’information dentaire 2007;89:112–8; B. van

Meerbeek et al., Dent Mater 2010;26:e100–21).

doi:10.1016/j.dental.2010.08.027

20

In vitro mutans Streptococci colonization of an Mdpbcontaining

adhesive system

A. Ionescu, L. Fadini, M. Gagliani, E. Brambilla

University of Milan, Italy

Objectives: The aim of this study was to evaluate

the activity of an MDPB-containing self-etching adhesive

system against mutans streptococci and its ability to

reduce in vitro colonization of experimental standardized

restorations.

Materials and methods: A round cavity (3 mm diameter

and 1.5 mm depth) was obtained in 40 round enamel slabs.

The disks were randomly divided into four groups and treated

using different adhesive systems as follows:

Group 1 (MDPB-containing adhesive system): Clearfil Protect

Bond, Kuraray;

Group 2: Clearfil SE Bond, Kuraray;

Group 3: Scotchbond SE, 3M-ESPE;

Group 4: Scotchbond MP, 3M-ESPE.

A standard composite restoration (Filtek Supreme XT, 3M-

ESPE) was performed on the cavities and finished using a

finishing diamond bur. A 48-h mutans streptococci biofilm was

developed on the surface of each disk. The specimens were

then processed for scanning electron microscopy examination

to evaluate the amount of biomass adherent to the samples

and its topographical distribution along the marginal area of

the restorations. 4 microphotographs (600×) were recorded

for each specimen at the same places of the marginal area.

The bacterial colonization was evaluated by means of a semiquantitative

6-levels visual scale. Kruskall–Wallis test was

used to compare bacterial colonization among the groups on

three different parts of each microphotograph: the enamel,

the composite and the interface between the material and the

tissue.

Results: No significant difference was found among the

groups regarding enamel and composite colonization. On the

contrary, a significant difference was highlighted on the interface

area, with a reduction of about 50% of the colonization

score in Group 1.

Conclusions: The results of the present study indicate

that the self-etching adhesive tested can exert an inhibitory

effect on in vitro colonization of mutans streptococci. This

activity seems to be limited to the marginal area of the

experimental restorations and was demonstrated only for the

MDPB-containing adhesive system; no inhibitory effect was

shown by any of the three other adhesive systems tested.

doi:10.1016/j.dental.2010.08.028

21

Mechanical strength of dental adhesives cured by violet laser

diode

A. Kameyama 1,2 , J. Kato 1 , H. Hatayama 3 , J. De Munck 2 ,A.

Haruyama 1 , M. Yoshinari 1 , M. Tsunoda 1 , B. Van Meerbeek 2

1 Tokyo Dental College, Japan

2 Katholieke Universiteit Leuven, Belgium

3 Sumitomo Electric Industries, Japan

Objectives: GaN-based violet laser diode (VLD) has been

developed and primarily used for data storage in for example

Blu-ray discs. Apart from soft-tissue surgery and photoactivation

of TiO2-containing tooth bleaching agents, VLD can

be used to initiate polymerization of dental adhesives and

composites. The purpose of this study was to assess the lightcuring

potential of VLD. Therefore, the ultimate micro-tensile

strength (�TS) of 3 commercial dental adhesives was determined

after curing with VLD or 2 commercial LED light curing

units.

Materials and methods: One VLD (VLM500, Sumitomo Electric

Industries) and two LED light-curing units (Curenos, Shofu;

G-Light Prima, Normal Mode, GC) were used. Three dental

adhesives were used in this study; Clearfil SE Bond (Kuraray

Medical), Tokuso Mac Bond II (Tokuyama Dental), and FL-Bond

2 (Shofu). An acrylic mould (inner-diameter 9.0 mm, height

0.6 mm) was filled with adhesive resin and cured for 60 s. After

24 h of water storage, specimens were trimmed into an hourglass

shape with a width of 1.2 mm at the narrowest portion,

and the ultimate micro-tensile strength (�TS) was determined

at a cross-head speed of 1.0 mm/min (N = 10). In addition,


spectral characterizations of each adhesive were determined

using a UV–vis–NIR spectrometer (USB-4000, Ocean Optics).

The obtained data were statistically analyzed by ANOVA and

Tukey’s test (p < 0.05).

Results: No significant differences between LED and VLD

were observed for both FL-Bond 2 (VLM500: 43.7 ± 6.7 MPa,

Curenos: 39.1 ± 2.5 MPa, and G-Light Prima: 31.4 ± 2.5 MPa)

and Tokuso Mac Bond II (VLM500: 82.2 ± 28.0 MPa, Curenos:

83.4 ± 20.6 MPa, and G-Light Prima: 66.7 ± 12.8 MPa). For

Clearfil SE Bond, on the other hand, the �TS of VLD-cured

specimens was higher than that of the LED-cured specimens,

but only significantly higher when compared to the

Curenos light-curing unit (VLM500: 90.2 ± 28.9 MPa, Curenos:

65.1 ± 8.2 MPa, G-Light Prima: 70.2 ± 15.6 MPa). The spectrometric

part of this study indicated that this marked difference

might be attributed to the different light transmittances of

Clearfil SE Bond for visible blue light and the lower area of

UV and visible violet light.

Conclusions: A GaN-based violet laser diode can be used

as an alternative to blue light LED’s to initiate polymerization

of dental resins. Especially its ability to polymerize the resin

deeper might be a valuable clinical feature to ensure proper

curing, even of thicker resin layers.

This work was supported by a Grant-in-Aid for Young Scientists

from the Ministry of Education, Culture, Sports, Science

and Technology, Japan ((B) 21791864).

doi:10.1016/j.dental.2010.08.029

22

Effects of immersion time and frequency of water exchange

on bond strength durability

A.D. Loguercio, L. Skovron, D. Kogeo, Laa Gordillo, A. Reis

State University of Ponta Grossa, Brazil

Objectives: Although it is known that water storage

degrades resin dentin bonds, the role of water immersion time

and frequency of water exchange is yet to be addressed. This

study evaluated the durability of a three- and two-step etchand-rinse

adhesive under different water immersion times

and frequency of water exchange.

Materials and methods: The adhesives systems and composite

resin were applied according to the manufacturer’s

instructions on the flat occlusal demineralized dentin of 48

molars. Teeth were assigned to four groups of immersion

time (immediate, 1, 3 and 6 months), sectioned to obtain

resin–dentin beams (0.8 mm2 area) and then subdivided into

three groups of water replacement (daily, weekly and monthly)

before being tested in tension (0.5 mm/min). One resin–dentin

dental materials 26S (2010) e1–e84 e11

SB (MPa) SBMP (MPa)

IM 49.5 ± 13.1 A 49.9 ± 5.8 a

beam from each tooth was immersed in silver nitrate and

analyzed quantitatively by scanning electron microscopy. The

microtensile bond strength (MPa) and silver nitrate uptake

data were subjected to a two-way ANOVA for repeated measures

for each adhesive and Tukey’s test (˛ = 0.05).

Results: Both adhesives showed faster degradation of

the resin–dentin bonds when water was replaced daily (see

table below). Increases of silver nitrate uptake were observed

for both adhesives after 6-month, mainly when water was

changed daily.

1 months 3 months 6 months 1 month 3 months 6 months

Daily 25.6 ± 3.2 C,D 19.3 ± 2.7 D 21.7 ± 5.2 C,D 35.7 ± 2.1 b,c 23.5 ± 3.3 d 22.5 ± 7.5 d

Weekly 30.9 ± 3.3 B 33.3 ± 4.8 B 28.7 ± 2.7 B,C 41.5 ± 7.5 a,b 32.9 ± 7.4 c 29.3 ± 7.3 c,d

Monthly 31.7 ± 6.5 B 30.4 ± 5.3 B,C 27.7 ± 6.4 B,C 39.3 ± 8.4 a,b 31.0 ± 8.0 c 28.2 ± 4.2 c,d

The same letters indicate statistically similar means (p > 0.05). Comparisons

are only valid for values from the same adhesive.

Conclusions: The daily water exchange is a fast and reliable

in vitro aging method for testing the durability of the adhesive

interface produced by etch-and-rinse adhesive systems.

doi:10.1016/j.dental.2010.08.030

23

Influence of ethanol on E-modulus of experimental adhesive

blends

G. Marchesi 1 , M. Cadenaro 1 , R. Di Lenarda 1 , F.R. Tay 2 , D.H.

Pashley 2 , L. Breschi 1

1 University of Trieste, Italy

2 Medical College of Georgia, USA

Objectives: The purpose of this study was to evaluate the

effect of ethanol (EtOH) content on E-modulus of experimental

adhesive blends using a biaxial flexural test. The hypothesis

tested was that E-modulus of resin blends is affected by

EtOH content in relation to adhesive hydrophilicity. It was

hypothesized that resins having higher EtOH dilution result

in decreased E-modulus.

Materials and methods: Light-curing experimental adhesive

blends with increasing hydrophilicity and different

EtOH concentrations were analyzed: R2 (70%BisGMA,

28.75%TEGDMA); R2 + 10%EtOH; R2 + 20%EtOH; R3 (70%Bis-

GMA, 28.75HEMA); R3 + 10%EtOH; R3 + 20%EtOH; R5 (40%Bis-

GMA, 30%BisMP, 28.75%HEMA); R5 + 10%EtOH; R5 + 20%EtOH.

All blends included 1% EDMAB and 0.25% CQ.

The experimental co-monomer mixtures (n = 10 per group)

were placed in wells made in teflon moulds to form disks

6.0 ± 0.1 mm in diameter and 0.5 mm ± 0.02 mm thick. Disk

surface was covered with a Mylar film to exclude oxygen and

the resin was fully cured. The E-modulus of each specimen

was measured using a biaxial flexural test (universal testing

machine SUN 500 Galdabini) at time 0 and after 24 h. Half of

the disks (n = 5) were then immersed in water for 3 days. Data

were analyzed with two-way ANOVA (resin type and EtOH concentration)

and Tukey’s post hoc test.


e12 dental materials 26S (2010) e1–e84

Results: E-modulus means (SD) are expressed in MPa.

T 0-dry T 24 h-dry T 3 days-water

R2 neat 908.8(30.6) g 1874(15.6) m 1853.7(24.7) m

R2-10% EtOH 912.1(1.3) g 1251.2(4.9) j 1104.8(13.7) i

R2-20% EtOH 762.9(15.3) e 1371(15.3) k 1130.7(4.2) i

R3 neat 1383.2(21.3) k 2366.8(24.1) p 2253.3(30.8) o

R2-10%EtOH 1143.7(4.1) I 2092.7(21.7) n 1566.2(13.3) l

R3-20% EtOH 828.9(5.6) f 1135.9(14.5) i 960.4(13.7) h

R5 neat 642.6(8.4) d 1120.5(13.5) I 454.9(4.1) b

R5-10% EtOH 636.8(8.9) d 1355.1(10.8) k 781.9(13.2) e

R5-20% EtOH 331.1(3.2) a 636.2(16.7) d 530.2(11.4) c

Different superscript letters indicate statistical differences (p < 0.05).

Conclusions: E-modulus was affected by EtOH blended

within the adhesive resins. Addition of 10–20% EtOH reduced

the E-modulus of all resin (p < 0.05) especially after three days

of water storage. The lowest E-modulus was found for R5,

the most hydrophilic blend, at all EtOH concentration after

three days. In conclusion, increasing hydrophilicity and concentrations

of EtOH dissolved in resin blends decreased the

E-modulus compared to neat resins.

doi:10.1016/j.dental.2010.08.031

24

Longevity of the bond created by 0.2% CHX-containing scotchbond

1XT

A. Mazzoni 1 , F. Nato 2 , C. Nucci 1 , M. Carrilho 3 ,L.

Tjäderhane 4 , F.R. Tay 5 , D.H. Pashley 5 , L. Breschi 6

1 University of Bologna, Italy

2 University of Urbino, Italy

3 UNIBAN, Brazil

4 University of Oulu, Finland

5 Medical College of Georgia, USA

6 University of Trieste, Italy

Objectives: Degradation of hybrid layers (HL) within

resin-infiltrated dentin has shown to result from multiple

degradation factors, including the collagenolytic activity of

matrix metalloproteinases (MMPs). The use of chlorhexidine

(CHX) as additional primer during dental bonding procedure

for the stabilization of adhesive interface has been extensively

investigated. With the attempt to simplify the bonding procedure,

this study aimed to determine the effectiveness of CHX

when blended within the adhesive formulation in preserving

(or to preserve) the mechanical properties of hybrid layer.

Materials and methods: Etched dentin substrates were

equally assigned to the following groups: (1) Adper Scotchbond

1XT (SB1XT-3M ESPE; control group) and (2) 0.2% CHXcontaining

SB1XT (experimental group). Composite build-ups

were made and beams were prepared for microtensile bond

strength testing. These specimens were either immediately

pulled to failure or stored in artificial saliva for 1 year prior to be

tested. Two-way ANOVA and Tukey’s test were used to analyze

data. In addition, to investigate the effect of the tested adhesives

on MMPs activity, gelatin zymography was performed on

dentin powder pulverized from extracted human molars and

treated as follow: (1) untreated mineralized dentin; (2) demineralized

with 1% H3PO4 for 10 min; demineralized with 1%

H3PO4 for 10 min then treated (3) with SB1XT or (4) with 0.2%

CHX-containing SB1XT.

Results: Microtensile bond strength values and standard

deviations were expressed as MPa and reported in the table.

Different superscript letters indicate statistical difference

(p < 0.05).

Adhesive system Time 0 Time 1 year

SB1XT 45.3 ± 11.3 a 24.3 ± 5.4 b

0.2% CHX-SB1XT 47.9 ± 10.0 a 33.7 ± 6.9 c

Gelatin zymography revealed no enzymatic activity in

proteins extracted from mineralized dentin while in H3PO4

demineralized dentin presence of MMP-2 and -9 active forms

were evident. Zymograms of SB1XT-treated dentin showed

MMP-2 proform and active form, and a faint band of MMP-

9 active form, while zymograms of CHX-containing SB1XT

showed complete inhibition of MMPs activity.

Conclusions: The microtensile bond strength data confirmed

that when included within the adhesive formulation,

0.2% CHX significantly contributes to preserve the mechanical

integrity of the HL over time. In addition, zymography analysis

revealed the inhibition of dentinal MMP-2 and -9 with

0.2% CHX blended within the adhesive formulation. Further

in vivo studies are needed to confirm the potential benefits of

CHX-containing adhesive systems.

doi:10.1016/j.dental.2010.08.032

25

Proprietary solvent enhances dentin wettability

P. Mehtälä 1 ,K. Agee 2 , L. Breschi 3 , D.H. Pashley 2 ,L.

Tjäderhane 1

1 University of Oulu, Oulu, Finland

2 Medical College of Georgia, Augusta, USA

3 University of Trieste, Italy

Objectives: Surface treatment such as acid etching

increases dentin surface energy. The higher the energy indicated

by lower contact angles, the better the association of

resin onto the dentin surface and into the hybrid layer. The

aim of our study was to investigate the possibility that our

proprietary solvent could further increase surface energy and

improve wettability of acid etched dentin.

Materials and methods: Mid-coronal dentin was exposed to

proprietary solvent in increasing concentrations and contact

angle was measured by means of sessile drop equilibrium contact

angle, using contact angle/surface energy analyzer. LVDT

(linear variable differential transformer) measurements were

used to investigate test solvents ability to expand collagen

matrix. Contact angle results were analyzed using one-way

ANOVA and Tukey’s post hoc test.

Results: Contact angle decreased as the concentration of

our test solvent increased. LVDT measurements showed that

increase in experimental solvent concentration resulted in

diminished collagen matrix expansion (Table 1).

Conclusions: Dentin surface energy correlates to its wettability

and therefore plays an important role in adhesion.

Higher surface energy leads to stronger association between


dental materials 26S (2010) e1–e84 e13

Table 1 – Contact angle measured in degrees, collagen matrix expansion expressed as percentage of fully hydrated

expanded matrix.

Solvent (wt%)

0% 1% 2% 3% 4% 5%

Contact angle ( ◦ ) 48± 1.3 a 44 ± 2.1 b 36 ± 2 c 30 ± 1.4 d 29 ± 1.7 d 25 ± 1.9 e

Solvent (wt%)

5% 10% a 20% 30% 40% 50%

Expansion of dried demineralized dentin 98% ± 2% 92.5% a 84% ± 3% 78% ± 4% 70% ± 3% 66% ± 3%

Same superscripts letters indicate no statistically significant difference (p > 0.05).

a 10% expansion extrapolated from 5% and 15% results.

adhesive and the dentin surface. LVDT results showed that

collagen matrix did not expand more fully with the aid of the

solvent. The change in contact angle may therefore be a result

of improved infiltration into acid etched dentin. Such effect

would be beneficial in maximizing monomer permeation into

acid-etched dentin during bonding.

doi:10.1016/j.dental.2010.08.033

26

The anti-MMP activity of benzalkonium chloride

M.M. Mutluay 1 , A. Tezvergil-Mutluay 1 , K.A. Agee 2 , R.M.

Carvalho 3 , A. Manso 4 , F.R. Tay 2 , B.-Y. Suh 4 , D.H. Pashley 2

1 University of Turku, Finland

2 Medical College of Georgia, USA

3 University of Sao Paulo, Brazil

4 Bisco Inc., USA

Objectives: Matrix metalloproteinases (MMPs) bound to

dentin are known to contribute to progressive degradation

of collagen fibrils in hybrid layers. Inhibition of host-derived

MMPs by quaternary ammonium compounds was shown to

slow the degradation. Benzalkonium chloride is a cationic

surface-acting agent belonging to the quaternary ammonium

group of compounds and widely used for antibacterial properties.

This study evaluated the ability of benzalkonium chloride

(BAC) to inhibit soluble versus bound dentine matrix metalloproteinases

(MMPs).

Materials and methods: The inhibitory effects of four

different BAC concentrations (0.5–5 wt%) on soluble rhMMP-

2, 8 and 9 were initially screened using a commercially

available colorimetric assay kit. Matrix-bound endogenous

MMP-activity was evaluated in completely demineralized

beams using two different concentrations of BAC (0.5 and

1 wt%). Each beam was either dipped into BAC for 10 or 30 s

and then dropped into 1 mL of an complete medium (CM) or

alternatively they were placed in either 1 mL of CM containing

BAC or only CM for 30 days (control). After 30 days, changes

in the dry mass of the beams or in the hydroxyproline (HYP)

content of hydrolyzates of the media were quantitated as indirect

measures of matrix collagen hydrolysis. The data were

analyzed using ANOVA, at ˛ = 0.05.

Results: All tested BAC concentrations showed an inhibition

of 93–100% and were highly effective (p < 0.05) in inhibiting

soluble rhMMP-2, 8 or 9. Matrix-bound MMP model showed

similar trend. BAC inhibited matrix-bound MMPs between 55

and 66% when measured as mass loss or 76–81% when measured

as solubilization of collagen peptide fragments. ANOVA

showed significant effect of BAC compared to control (p < 0.05).

Conclusions: BAC is very effective at inhibiting both soluble

and matrix-bound dentine MMPs in the absence of resins.

Supported, in part, by grants R01 DE015306-06 from the

NIH/NIDCR (P.I. DP) and by the Finnish Academy (P.I. ATM).

doi:10.1016/j.dental.2010.08.034

27

CHX-containing adhesive inhibits dentin MMPs: A zymographic

assay

F. Nato 1,2 , A. Mazzoni 2 , P. Gobbi 1 , M. Carrilho 3 , G. Mazzotti 2 ,

F.R. Tay 4 , D.H. Pashley 4 , L. Breschi 5

1 University of Urbino, Italy

2 University of Bologna, Italy

3 UNIBAN, Brazil

4 Medical College of Georgia, USA

5 University of Trieste, Italy

Objectives: Matrix metalloproteases (MMPs) are a family

of Zn- and Ca-dependent enzymes involved in several

developmental and disease-associated processes. Since these

enzymes have been suggested as playing key roles in the

degradation of resin–dentin matrices, the use of chlorhexidine

(CHX, a non-toxic MMP inhibitor) as additional primer during

bonding procedures has been reported to be effective in the

preservation of the hybrid layer over time. The purpose of this

study was to identify the effectiveness of including CHX within

the formulation of a self-etch adhesive system on MMP-2 and

-9 activity by means of gelatin zymography.

Materials and methods: Dentin powder was pulverized

from freshly extracted human molars. Four lots of dentin powder

were obtained and randomly assigned to the following

treatment group: (1) mineralized dentin + Adper Easy Bond

(AEB; 3M ESPE, St Paul, USA); (2) mineralized dentin + 0.2%

CHX-containing AEB (experimental adhesive, 3M ESPE); (3)

demineralized with 1% aqueous solution of H3PO4 for 10 min;

(4) untreated mineralized dentin (control). After rinsing in acetone

to remove the uncured adhesive system, protein extracts

obtained from the treated dentin powder were then electrophoresed

by gelatin zymography, for detection of MMPs

enzyme activity.


e14 dental materials 26S (2010) e1–e84

Results: Zymograms of AEB-treated dentin showed MMP-

2 proform (72-kDa) and active form, and a faint band of

MMP-9 active form, while zymograms of CHX-containing

AEB showed complete inhibition of MMPs activity. Zymograms

of demineralized dentin extracts showed MMP-2 and

-9 active forms (66 and 86-kDa, respectively). No enzymatic

activity was found in proteins extracted from mineralized

dentin.

Conclusions: Human dentin matrices exhibit collagenolytic

and gelatinolytic activity when mixed with

AEB, while the incorporation of 0.2% CHX within AEB formulation

resulted in complete inhibition of MMP-2 and -9

activity. Further in vitro and in vivo studies are needed to

clarify the benefits of incorporation of MMPs inhibitors within

the adhesive formulation.

doi:10.1016/j.dental.2010.08.035

28

Influence of dentin adhesive on bond strength of selfadhesive

cements

F. Ozer, M.B. Blatz, A. Atlas, L. Daneshmehr, K. Kashyap, F.

Mante

University of Pennsylvania, Philadelphia, USA

Objectives: The aim of this study was to assess and

compare the bonding performance of four new self-adhesive

and one resin cement to human dentin with and without

application of chlorhexidine 2% and a self-etch adhesive

bonding agent.

Materials and methods: Occlusal, buccal, lingual, mesial

and distal dentin surfaces of 80 human molar teeth were

abraded with #600 SiC-paper directly below the enamel. Each

test group comprised 5 teeth and 20 dentin sections (4 sections

for each surface). Four self-adhesive cements ICem(IC),

Clearfil SA Cement (CSA), G-Cem (GC), Bis-Cem (BC) and

one resin cement NX3 were applied to the dentinal surfaces

in cylindrical-shaped plastic matrices according to the

manufacturers’ recommendations with or without application

of chlorhexidine 2% and a self-etch adhesive (Protect

Bond). GC-Fuji Plus (FP) group was the control. Shear bond

strengths were determined at a cross-head speed of 1 mm/min

immediately after application of cements to the flat dentinal

surfaces. Bond strengths were then calculated and expressed

in MPa. Data were analyzed with ANOVA & Tukey’s HSD

test.

Results:

Cement Bond strength (MPa) ± standard deviation

groups

Intact dentin Protect bond Chlorhexidine

CSA 1.5 ± 0.6 ab 8.5 ± 2.0 fgh 0.5 ± 0.7 a

IC 4.8 ± 1.7 cde 15.7 ± 5.2 j 3.0 ± 1.9 abcd

BC 5.0 ± 2.5 de 12.9 ± 2.7 i 2.3 ± 2.5 abc

GC 6.1 ± 1.6 ef 11.2 ± 2.0 hi 3.9 ± 1.6 bcde

NX3 0.0 12.2 ± 2.6 i 9.4 ± 2 gh

FP 7.9 ± 3.1 fg n/a 6.3 ± 2.2 ef

The same superscripts in the table indicate no statistical difference. Protect bond

application dramatically increased bond strength values for all resin cements. FP

and GC showed highest bond strengths to intact dentin surfaces. Chlorhexidine

application decreased bond strengths of study cements.

Conclusions: Bond strength values of self-adhesive

cements are not reliable without application of an adhesive

to dentin surfaces. Application of chlorhexidine 2%

to dentin surfaces is not recommended for self-adhesive

cements.

doi:10.1016/j.dental.2010.08.036

29

Shear-bond strength of a new restorative material to primary

dentin

E. Pacifici 1 , A. Giovannetti 2 , C. Goracci 1 , A. Vichi 1 ,A.

Polimeni 2 , M. Ferrari 1

1 University of Siena, Italy

2 “Sapienza” University of Rome, Italy

Objectives: To assess the shear bond strength to deciduous

dentin of a new self-adhesive flowable resin composite in comparison

with a conventional glass-ionomer cement and with a

flowable composite used in combination with the proprietary

etch-and-rinse adhesive.

Materials and methods: A flat dentin substrate was

obtained on the occlusal surface of 40 primary molars by

grinding with wet abrasive paper (320 grit). Teeth were

randomly divided into 4 groups (n = 10): OFL, phosphoric

acid [PA]/optibond flow/premise flow (Kerr); IX, polyacrylic

acid/Fuji IX (GC); V, vertise flow (Kerr); PV, PA/vertise flow.

The latter group was included in order to assess the contribution

to V bonding mechanism of preliminary PA etching.

Using rubber moulds of 3 mm in diameter, cylinders of

restorative material were built-up over the dentin surface.

A shear load (1 mm/min crosshead speed) was applied

with a steel blade in a direction parallel to the bonded

interface until failure occurred. The failure mode of each

specimen was assessed using a stereomicroscope. Bond

strength and failure mode data were statistically analysed.

As shear bond strength data distribution was not normal, the

Kruskall–Wallis analysis of variance was applied followed by

the Dunn’s Multiple range test (p < 0.05). Differences in failure

mode distribution were assessed with the chi-square test

(p < 0.05).

Results: With OFL significantly higher bond strengths than

in the other groups were recorded. Failures were adhesive in

all groups except OFL, in which also cohesive failures in dentin

were observed.

Shear bond strength (MPa) Failure mode (%)

Mean SD Median 25–75% p < 0.05 %Adhesive %Cohesive p < 0.05

OFL 16.02 4.80 17.95 15.48–18.41 A 60% 40% A

IX 6.04 3.75 4.86 4.0–6.82 B 100% 0% B

PV 4.71 1.87 5.30 3.42–6.22 B 100% 0% B

V 4.30 2.66 3.50 3.29–6.27 B 100% 0% B

Conclusions: The new self-adhesive flowable composite

vertise flow produced on deciduous dentin bond strengths

similar to those of a conventional glass ionomer cement

that has been routinely used for primary teeth restorations.

Preliminary phosphoric acid etching did not significantly

change vertise flow bonding potential to primary dentin. The


etch-and-rinse adhesive/flowable resin composite combination

developed the strongest bond, although involving a more

complex handling.

doi:10.1016/j.dental.2010.08.037

30

Increased exposure times of simplified adhesives: Effects on

degradation and quality of the polymer network

A. Reis, S.Q. Ferreira, T.R.F. Costa, A.D. Loguercio

State University of Ponta Grossa, Brazil

Objectives: One of the reasons of resin–dentin degradation

is the poor polymerization of the adhesive layer. This study

evaluated the effect of prolonged polymerization times on the

immediate and 6-month resin–dentin bond strength, silver

nitrate uptake and polymer quality of etch-and-rinse adhesives.

Materials and methods: A flat dentin surface of 30

extracted teeth was exposed. Adhesives (Adper Single Bond

2 and One Step Plus) were applied and light-cured for 10, 20

and 40 s at 600 mW/cm 2 . Bonded sticks (0.6 mm 2 ) were tested

in tension (�TBS) (0.5 mm/min) and analyzed under scanning

electron microscopy (SEM) after 50% silver nitrate immersion.

The polymer quality of adhesive films was evaluated under

thermogravimetric analysis. The data from �TBS (MPa) and

silver nitrate uptake (%) of each adhesive system were subjected

to a two-way repeated measures ANOVA and Tukey’s

test (˛ = 0.05). The data from TG (%) was submitted to a twoway

ANOVA and Tukey’s test (˛ = 0.05).

Results: Statistically higher microtensile resin–dentin bond

strength were observed for both adhesives light-cured for 40 s.

Degradation of dentin bonds occurred in all conditions but it

was less pronounced for 40 s groups. Higher prolonged exposure

times reduced silver nitrate uptake for Adper Single Bond

2. Solvent retention and remaining residual monomer was

statistically lower when both adhesives were light-cured for

40 s.

Conclusions: Although longer exposure times than those

recommended cannot prevent degradation of the resin–dentin

bonds, it can increase immediate and 6-month bond strength

values, probably due to higher solvent removal and lower

amount of remaining residual monomer.

doi:10.1016/j.dental.2010.08.038

31

MTBS of dentin adhesives on primary dentin subjected to

irradiation

K. Bekes, C. Rettig, J. Klinsmann, H.G. Schaller, C.R. Gernhardt

Martin-Luther-University Halle-Wittenberg, Germany

Objectives: The aim of this study was to evaluate the

effect of different irradiation doses on microtensile bond

strength (mTBS) of four different dentin adhesives/compomer

dental materials 26S (2010) e1–e84 e15

combinations 1,2,3,4 on perfused primary dentin in

vitro.

Materials and methods: 144 freshly extracted primary

molars were included. All teeth were specially prepared allowing

the simulation of dentin perfusion and standardized

conditions. According to four different dentin adhesives and

three irradiation doses (0 Gy, 6 Gy and 60 Gy), the specimens

were randomly assigned to 12 experimental groups of 12 each:

Syntac (S0, S6, S60), Prime&Bond (P0, P6, P60), Futurabond (F0,

F6, F60), Optibond (O0, O6, O60). Each specimen was irradiated

fractionally with 2 Gy/day (6 mV, X-Ray) using a linear accelerator,

respectively, depending on the experimental irradiation

dose group. All materials were applied as recommended by

the manufacturer. Microtensile bond strength was measured

15 min after application of the fissure sealant using a universal

testing machine. Statistical analysis was performed using

SPSS 15.0.

Results: For the test series following tensile bond strengths

were evaluated (mean values and standard deviations in MPa):

S0 S6 S60 P0 P6 P60 F0 F6 F60 O0 O6 O60

17.6 16.6 13.5 21.1 18.7 13.9 21.8 17.9 12.5 25.3 20.6 18.2

±4.0 ±5.5 ±4.4 ±3.9 ±4.4 ±3.1 ±7.1 ±7.1 ±5.2 ±7.0 ±3.7 ±4.7

Statistical analysis showed a significant influence of irradiation on

microtensile bond strength (p < 0.001, ANOVA). The highest mTBS were

found in the non-irradiated groups (S0, P0, F0, O0), the lowest mTBS

were observed in specimens irradiated with 60 Gy (S60, P60, F60, O60).

Comparison of the dentin adhesives in non-irradiated groups showed

significant higher values in specimens treated with Optibond compared

to group S0 (p < 0.05, Tukey’s test). Between groups S0, P0 and

F0 no significant difference could be detected (p > 0.05, Tukey’s test).

The influence of irradiation was significant in the 60 Gy groups except

for Syntac (Tukey’s test, p < 0.05). Irradiation doses of 6 Gy did not show

any significant influence compared to non-irradiated groups (0 Gy).

Conclusions: Within the limitations of this in vitro investigation

it can be concluded that irradiation of primary teeth

in doses of 60 Gy might affect microtensile bond strength of

dentin adhesive/compomer combinations.

doi:10.1016/j.dental.2010.08.039

32

Effects of aging on one-step self-etch adhesives

M. Taschner 1 , F. Nato 2,3 , A. Mazzoni 2 , R. Di Lenarda 4 ,A.

Petschelt 1 , L. Breschi 2,4

1 University of Erlangen, Germany

2 University of Bologna, Italy

3 University “Carlo Bo”, Italy

4 University of Trieste, Italy

Objectives: Preliminary etching of the dentin substrate

before the application of self-etch adhesives is controversial.

Aim of this in vitro study was to analyze (1) the effect of

additional phosphoric acid etching on dentin before the application

of two simplified one-step self-etch adhesive systems

and (2) the effect of different aging methods on the stability of

the adhesive interface.

1 Syntac/Compoglass, Vivadent.

2 Prime&Bond/Dyract, Dentsply DeTrey.

3 Futurabond DC/Glasiosite, Voco.

4 Optibond All in One/Glasiosite, Kerr/Voco.


e16 dental materials 26S (2010) e1–e84

Materials and methods: Adper Easy Bond (3 M ESPE,

Seefeld, Germany) and iBond (Heraeus Kulzer, Hanau, Germany)

were selected for the study. Human sound molars

were flattened and adhesives were applied either with an

etch-and-rinse (phosphoric acid etching for 15 s followed by

extensive water rinsing) or with a self-etch approach (i.e.

according to manufactures’ instructions). Treatment groups

were: (1) Adper Easy Bond on etched dentin; (2) Adper

Easy Bond (control); (3) iBond (on etched dentin); (4) iBond

(control). After bonding application, each group of specimens

was divided in 4 subgroups of storage: (a) 24 h, (b) 6

months or (c) 1 year in artificial saliva at 37 ◦ C, or (d) 5 h

in 10% NaOCl at room temperature. Resin–dentin bonded

specimens were sectioned for microtensile bond strength

test in accordance with the non-trimming technique, then

stressed to failure. Additional teeth were prepared for interfacial

nanoleakage expression under light-microscope and

TEM.

Results:

Adper Easy Bond iBond

No etch Etch No etch Etch

24 h 26.9b ± 6.2 MPa 35.8a ± 5.7 MPa 17.6c,d ± 4.3 MPa24.3b ± 7.9 MPa

5 h NaOCl 18.7c ± 3.2 MPa 33.4a ± 7.9 MPa 8.6g ± 3.8 MPa 17.3c,d ± 3.7 MPa

6 months art.sal. 20.7c ± 4.9 MPa 32.7a ± 6.9 MPa 8.1g ± 4.3 MPa 16.1d,e ± 3.5 MPa

1 year art sal. 15.2e,f ± 3.5 MPa 24.6b ± 7.1 MPa 7.6g ± 4.9 MPa 13.1f ± 3.8 MPa

Different superscript letters indicate statistical difference

(Mann–Whitney U-test, p < 0.05).

Nanoleakage expression for Adper Easy Bond etched dentine

under light microscope ranked in the following order:

group 1a > group 1b = group 1d > group 1c. TEM analysis confirmed

the nanoleakage patterns. Aging in 10%NaOCl for 5 h

showed similar microtensile bond strength than 6 months

aging in artificial saliva at 37 ◦ C irrespective of the tested group

(Mann–Whitney U-test, p < 0.05).

Conclusions: Results of this study support the use of Adper

Easy Bond on etched dentin since increased bond strength and

reduced nanoleakage expression was found compared to its

application on smear-layer covered dentin irrespective from

storage conditions. Further in vivo studies are needed to support

this hypothesis.

Supported by 3M ESPE.

doi:10.1016/j.dental.2010.08.040

33

The inhibitory effect of carbodiimide on soluble and matrixbound

dentin MMPs

A. Tezvergil-Mutluay 1 , M.M. Mutluay 1 , L.S. Gu 2 , K.A. Agee 3 ,

T. Hoshika 4 , M. Cadenaro 5 , L. Breschi 5 , F.R. Tay 3 , D.H.

Pashley 3

1 University of Turku, Finland

2 Sun Yat-sen University, China

3 Medical College of Georgia, USA

4 Okayama University, Japan

5 University of Trieste, Italy

Objective: The progressive degradation of resin–dentin

bonds over time is partly due to the enzymatic degradation

of collagen in the hybrid layer. Collagen cross-linking

agents such as 1-ethyl-3-(3-dimethylaminopropyly) carbodiimide

(EDC) have been previously used to increase

the durability of resin–dentin bonds by means of increasing

the mechanical properties of collagen matrix. This

study evaluated the possible use of EDC to inactivate

soluble and bound dentine matrix metalloproteinases

(MMPs).

Methods: The inhibitory effects of five different EDC concentrations

(0.01, 0.02, 0.03, 0.1, and 0.3 M) and five different

incubation times (30, 20, 10, 5, and 1 min) on soluble rhMMP-9

was initially screened using a commercially available colorimetric

assay kit. Matrix-bound endogenous MMP-activity was

evaluated in completely demineralized beams (10% phosphoric

acid, 18 h) by using the same five EDC concentrations (n =10

per group). After baseline measurements of dry mass and

modulus of elasticity (E), each beam was treated with respective

EDC concentration for 1 min and incubated in 1 mL of

a complete medium (CM) in a shaking bath (37 ◦ C, 30 days)

and retested. The group without EDC pretreatment served

as control. Changes in E, the dry mass of the beams or

in the hydroxyproline (HYP) content of hydrolyzates of the

media were quantitated as indirect measures of matrix collagen

hydrolysis. The data were analyzed using ANOVA, at

˛ = 0.05.

Results: All tested EDC concentrations and pretreatment

times showed inactivation of 98–100% and were highly effective

(p < 0.05) in inactivating soluble rhMMP-9. The beams

incubated in different EDC concentrations showed a slight

change in stiffness and a dry mass loss of only 3.6–5% respectively,

whereas control group lost 28%. Significantly more

solubilized collagen was detected from control group (p < 0.05)

compared to EDC groups.

Conclusions: Within a clinically acceptable incubation time

(i.e. 1 min), EDC is very effective at inactivating both soluble

and matrix-bound dentine matrix metalloproteinases.

Supported, in part, by grants R01 DE015306-06 from the

NIH/NIDCR (P.I. DP) and by the Finnish Academy (P.I. ATM).

doi:10.1016/j.dental.2010.08.041

34

Shear bond strength of an experimental adhesive to various

substrates

C. Thalacker, H. Loll, R. Guggenberger

3M ESPE AG, Seefeld, Germany

Objectives: Aim of this study was to compare the shear

bond strength (SBS) of an experimental adhesive formulation

(EXL-759, 3M ESPE) and the Signum Bonding System (SiBoS,

Heraeus Kulzer) to various substrates before and after thermocycling.

Materials and methods: Samples of a high gold alloy (Degulor

M, Degudent), a non-noble metal alloy (Wironit, Bego),

titanium (Rematitan, Dentaurum), glass ceramic (Paradigm C,

3M ESPE), composite (MZ 100, 3M ESPE), zirconia (LAVA, 3M

ESPE) were embedded in cold-cure acrylic resin. The surface

was ground with sandpaper (320 grit) and sandblasted with

Rocatec Soft (3M ESPE). Then, either EXL-759 or the appropriate


component of SiBoS 1,2,3,4 was applied followed by a cylindrical

specimen (2.36 mm diameter, 2 mm height) of either Z250

(3 M ESPE) or Signum composite (Heraeus Kulzer). A notchededge

shear method (Ultradent) was used to measure the SBS

(n = 5) either after 24 h in water at 37 ◦ C, or after 5000 thermal

cycles (5–55 ◦ C, 30 s dwell time).

Results: The table shows the SBS in MPa. The standard deviations

(SD) are given in parentheses. All data per substrate

were analyzed by ANOVA and multiple comparisons using

Fisher’s LSD procedure (p < 0.05). Means with the same letters

are statistically the same.

Substrate EXL-759

before TC

EXL-759

after TC

dental materials 26S (2010) e1–e84 e17

SiBoS

before TC

SiBoS

after TC

Degulor M 19.5(3.2) a 16.2(3.7) a 16.2(4.2) a 6.0(2.4) b

Wironit 32.3(9.5) a 33.9(5.3) a 21.6(6.6) b 14.2(4.6) b

Titanium 43.3(3.9) a 34.2(3.0) b 18.2(1.2) c 10.0(2.4) d

Glass ceramic 11.5(3.0) a 7.0(0.6) b 4.8(2.3) bc 3.1(1.7) c

Composite 22.6(6.4) b 29.9(4.0) a 12.1(3.9) c 3.5(0.9) d

Zirconia 38.1(6.8) a 36.3(2.0) a n.d. n.d.

Conclusions: The one component formulation EXL-759

yielded statistically same or higher SBS to all substrates compared

to the multi component SiBoS.

doi:10.1016/j.dental.2010.08.042

35

Chlorhexidine release from adhesive resins after chewing

simulation

G. Turco 1 , G. Marchesi 1 , A. Coslovi 1 , M. Cadenaro 1 ,S.

Paoletti 1 , R. Di Lenarda 1 , F.R. Tay 2 , D.H. Pashley 2 , L. Breschi 1

1 University of Trieste, Italy

2 Medical College of Georgia, Augusta, USA

Objective: The aim of this study was to evaluate the

release of chlorhexidine (CHX) from unfilled non-solvated

methacrylate-based experimental adhesives after chewing

simulation. The tested hypothesis was that CHX release is

related to adhesive hydrophilicity.

Materials and methods: Experimental resin blends

ranked on increasing hydrophilicity were prepared: R2

(70% BisGMA + 28.75% TEGDMA); R3: (70% BisGMA + 28.75%

HEMA); R5: (40% BisGMA + 30% BisMP + 28.75% HEMA). All

blends contained 0.25 wt% camphorquinone and 1.0 wt%

2-ethyl-dimethyl-4-aminobenzoate. Abbreviations: Bis-

GMA = 2,2-bis[4-(2-hydroxy-3-methacryl-oylpropoxy)]-phenyl

propane; TEGDMA = triethyleneglycol dimethacrylate;

HEMA = 2-hydroxyethyl methacrylate; BisMP = bis[2-

(methacryloyloxy)ethyl]phosphate. Tested groups were:

1 Signum metal bond I + II for Degulor M, Wironit, titanium.

2 Signum ceramic bond I + II for glass ceramic.

3 Signum liquid for composite.

4 Signum zirconia bond I + II for zirconia (could not be obtained

at the time of the study).

(1) R2 + 2%CHX; (2) R2; (3) R3 + 2%CHX; (4) R3; (5) R5 + 2%CHX;

(6) R5. Discs of 6 mm in diameter and 0.8 mm in thickness

were immersed in saline solution and the elution kinetics of

CHX was assayed by means of high performance liquid chromatography

(HPLC). Additional specimens were submitted to

chewing simulation (load = 50 N; number of cycles = 309,600;

frequency = 1 Hz; test duration = 86 h) before HPLC

analysis.

Results:

Sample CHX release (%)

Not-cycled Cycled

R2 + 2%CHX 0.9 a (0.3) 2.4 b (0.2)

R2 neat 0 0

R3 + 2%CHX 2.3 b (0.2) 2.9 bc (0.3)

R3 neat 0 0

R5 + 2%CHX 3.4 c (0.3) 5.4 d (0.3)

R5 neat 0 0

Conclusions: Specimens submitted to chewing simulation

revealed higher release of CHX than not-cycled experimental

CHX-containing blends. The tested hypothesis was accepted

since the most hydrophilic experimental resin (R5) exhibited

the highest CHX release, while the most hydrophobic resin

(R2) exhibited the lowest rate. CHX release from resins may be

related to water-induced swelling, which in turn is enhanced

by the hydrophilicity of cured polymer matrices.

doi:10.1016/j.dental.2010.08.043

36

QAM-based primers do not affect immediate bond strength of

an etch-and-rinse adhesive

E. Visintini 1 , M. Cadenaro 1 , R. di Lenarda 1 , F.R. Tay 2 , D.H.

Pashley 2 , L. Breschi 1

1 University of Trieste, Italy

2 Medical College of Georgia, Augusta, USA

Objectives: Preliminary studies showed that quaternary

ammonium methacrylates (QAMs) inhibit dentin metalloproteinases,

which have been shown to be responsible for hybrid

layer degradation. For this reason the use of QAMs in dentin

primer has been proposed. The aim of this study was to assess

the bond strength of commercial adhesive system after dentin

pre-treatment with three different QAMs. The tested hypothesis

was that the use of QAMs as dentin primers would not

affect immediate bond strength.

Materials and methods: Twenty non-carious human

molars were selected for the study and sectioned to expose

middle-deep dentin. Dentin was etched with 35% phosphoric

acid for 15 s and divided in four groups depending on the

QAM used as primer: (1) 70% METMAC, 29% ethanol, 1% TPO;

(2) 70% MCMS, 29% ethanol, 1% TPO; (3) 70% ATA, 29% ethanol,

1% TPO; (4) no primer (control). Each QAM-based primer was

applied twice for 30 s and gently air-dried. All specimens were

bonded with Scotchbond 1XT (SB1XT; 3M ESPE, St Paul, MN,


e18 dental materials 26S (2010) e1–e84

USA) polymerized for 20 s, then a composite build-up was created.

Specimens were sectioned in sticks (0.9 mm × 0.9 mm)

in accordance with the non-trimming microtensile technique.

Bonded sticks were aged for 24 h at 37 ◦ C in artificial

saliva before being pulled to failure (1 mm/min). Data

were analyzed with one-way Anova and Tukey’s post hoc

test.

Results: Means and standard deviations (expressed as MPa)

of microtensile bond strength are reported:

Group Bond strength

METMAC + SB1XT 29.7 ± 16.3 a

MCMS + SB1XT 38.1 ± 10.59 b

ATA + SB1XT 29.0 ± 11.0 a

SB1XT 42.5 ± 11.6 b

Same superscript letters indicate no statistical difference (p > 0.05).

Conclusions: The tested hypothesis was partially accepted

because only MCMS gave microtensile bond strength results

comparable to the control. Further studies are needed to evaluate

if one coating of QAMs can be used as a primer for clinical

applications. Supported, in part, by grant R01 DE01530-6 from

the NIDCR to DP (PI).

doi:10.1016/j.dental.2010.08.044

37

Influence of HAp-nanoparticle reinforcement on the adhesion

to dentin

A. Wagner, R. Belli, C. Stoetzel, F.A. Mueller, A. Hilpert, A.

Petschelt, U. Lohbauer

Dental Clinic 1, University of Erlangen, Erlangen, Germany

Objectives: The aim of the study was to evaluate the

influence of biomimetic HAp-nanoparticles, dispersed in a

commercial, unfilled adhesive, on the adhesive strength to

dentin. The compounding of nanoparticles in the adhesive

was observed as well as the distribution of the particles in

the hybrid and adhesive layer.

Materials and methods: Coronal dentin of freshly

extracted, non-carious human third molars was prepared for

bonding with the nanoparticle modified adhesive (Scotchbond

MP = SBMP, 3M ESPE, Germany). Either 1 or 5% (w/v)

of two differently synthesized (biomimetic growth versus

hydrothermal growth of the particles) hydroxyapatite

(HAp) particles (d50 = 20–30 nm for HAp1, 80–90 nm for

HAp2) were dispersed in the adhesive solution of SBMP.

In addition, the HAp-particles used were either silanized

or not. Following storage in distilled water at 37 ◦ C at

24 h, the bonded specimens were sectioned into �TBS

slabs (n = 40; 0.8 mm 2 ), using a low-speed diamond saw

(Isomet, Buehler, Germany). �TBS was measured in a universal

testing machine (1 mm/min; Zwick, Germany) using

Geraldeli’s testing jigs. Cross sections of adhesive layers

were qualitatively examined under TEM. Data were

statistically analyzed using ANOVA and mod. LSD test

(p < 0.05).

Results: Table1:�TBS [MPA] of the tested adhesives.

Adhesiv composition Strength/MPa

Non-silanized

HAp-particles

Strength/MPa

Silanized

HAp-particles

SBMP 52.09 ± 15.63

SBMP + 1% HAp1 59.37 ± 11.93 a 47.01 ± 11.85

SBMP + 5% HAp1 48.97 ± 13.56 49.87 ± 12.74

SBMP + 1% HAp2 48.46 ± 9.40 48.75 ± 13.02

SBMP + 5% HAp2 53.10 ± 14.64 55.88 ± 13.37

Letters in parentheses = statistically different subsets (p < 0.05).

Only SBMP + 1% of HAp1/not silanized showed a significantly

higher bond strength as compared to unfilled SBMP. No

significant differences between the other tested experimental

adhesives was observed. HAp-nanoparticles dispersed in the

adhesive of SBMP were mainly distributed within the adhesive

layer and were only rarely in close contact to the hybrid layer.

Conclusions: Within the range of 1 and 5% (w/v), addition

of differently manufactured HAp-nanoparticles to an unfilled

commercial adhesive had no statistically significant effect on

the adhesive strength except of SBMP + 1% HAp1/not silanized.

There was also no effect between non-silanized or silanized

HAp-nanoparticles, except of SBMP + 1% HAp1/not silanized

versus SBMP + 1% HAp1/silanized. Particles did not enter the

collagen network as revealed by TEM observation.

doi:10.1016/j.dental.2010.08.045

38

Withdrawn

doi:10.1016/j.dental.2010.08.046

39

Degree of conversion of nano- and micro-hybrid resin composites

cured by different light sources

T.S. Jafarzadeh Kashi, H. Bagheri G, M. Behroozibakhsh, S.M.

Fatemi, Y. Rezaei

Tehran University of Medical Sciences, Tehran, Iran

Objectives: Adequate polymerization is an important factor

in obtaining optimal properties and clinical performance of

resin composite restorative materials. The degree of the conversion

(DC) affects the physical and mechanical properties,

and biocompatibility of the resin composite. Nano-scale particles

containing resin-based composites are currently available

on the dental market. However, the effect of nano-particles on

composite properties, particularly effectiveness of polymerization,

is an important issue regarding clinical performance

and durability of restorations. This study sought to evaluate

the effectiveness of polymerization of new modified composites

cured by blue LED (Demi, KERR Corp, USA), compared

with conventional halogen lamp, using Fourier transformation

infrared (FTIR) spectroscopy at two different depths (topsurface,

2 mm).

Materials and methods: Two nano-hybrid (Tetric EvoCeram,

A2 Shade, Ivocolar/Vivadent and Herculite XRV Ultra

A2 Shade, Kerr), one nano-ceramic filled (CeramX, Shade


M2. Dentsply) and two micro-hybrid (Tetric Ceram A2 Shade,

Ivocolar/Vivadent and Herculite Classic A2 Shade, Kerr) lightcured

resin composites were used in this study. Two different

light curing systems DEMI (Led Kerr Corporation, USA) and

Coltolux ® 75 (Coltene, Whalendent, USA) were applied in this

study. For each light curing system, ten cylinders of each composite

(5 mm diameter × 2 mm length) were polymerized for

20 s. Then 70 �m thick discs were prepared from the surface

and bottom (depth of 2 mm) of each cylinder using a microtome

and 400 grit SiC paper. The infrared spectrum of uncured

sample and each wafer specimen were analyzed with a FTIR

spectrometer (BRUKER TENSOR 27, Germany) operating 16

scans at 4 cm −1 resolution. DC was calculated for each composite.

In this study, for each composite a two way ANOVA was

performed at the 95% significance level.

Results: The statistical analysis showed that the depth

factor was significant for all composites (p < 0.05). Lower DC

was obtained at depth of 2 mm in spite of higher degree of

conversion in nano-hybrid composite polymerized by LED curing

unit. However, no significant differences were detected

between LED and QTH curing units except for CeramX

mono (p < 0.001). Also, nano-hybrid composites showed higher

coefficient of variations (CV%) compared with micro-hybrid

composites.

Conclusions: Light-scattering phenomena and a significant

lower light transmittance may cause lower DC in resin composite

with nano-filler particles. It may be concluded that

reliable DC was obtained with micro-hybrid composites using

different curing units.

doi:10.1016/j.dental.2010.08.047

40

Prophylometric analysis of class-II cavities finished with four

different methods

G. Ciampalini, F. Cerutti, N. Balzanelli, N. Barabanti, A. Cerutti

University of Brescia, Italy

Objectives: This research aimed to evaluate four systems

indicated for the finishing of cervical margins in class II cavities,

in order to find out which instrument guarantees the

smoothest surface in terms of Ra and Wa. The null hypothesis

was to find no significant difference among the test groups

(˛ = 0.05).

Materials and methods: 80 class II cavities were performed

on 20 intact molars by a single skilled operator, using

a diamond-coated bur (granulometry 80 �m) mounted on a

parallelometer, under magnifications in order to reduce variability.

In every tooth, 4 different finishing methods were

randomly applied 1,2,3,4 (A: finishing carbide bur end-cutting,

16 blades; B: manual chisel; C: diamond-coated bur; D:

diamond-coated tip for sonic tools). After that, all the cavity

margins were analyzed by an optical prophylometer, in order

to identify the level of surface finishing. We considered the

1 Dentsply midwest n. 957.

2 Deppeler straight chisel.

3 Dentsply midwest n. 10839.

4 Sonicsys mesial SF34.

dental materials 26S (2010) e1–e84 e19

surface roughness (Ra) and the waviness (i.e. the ripple—Wa).

The results were analyzed by the statistic software Minitab:

the applied tests were a parametric test ANOVA General Linear

Model, after that the Main Effects Plot for Ra and Wa towards

the system and the sample was carried out.

Results: Mean DC and SD are shown.

System Mean SD

Ra Wa Ra Wa

(A) Diamond 0.87 6.43 0.23 2.87

(B) Chisel 0.76 5.79 0.23 3.41

(C) Carbide 0.81 6.99 0.30 3.11

(D) Sonic 0.93 8.02 0.25 4.84

Both parameters reached the lowest values when the chisel was used,

but no significant differences were observed.

Conclusions: According to our data, chisel is the finishing

system that performs smoother surfaces. Among the mechanical

instruments group, carbide burs obtained the best results.

Sonic instruments produced roughness values between diamond

and carbide burs.

doi:10.1016/j.dental.2010.08.048

41

The effect of temperature on the efficacy of polymerization of

a dental resin composite

T.S. Jafarzadeh Kashi 1 , M. Behroozibakhsh 1 , S.M. Fatemi 1 ,M.

Erfan 2 , H. Bagheri G 1

1 Tehran University of Medical Sciences, Tehran, Iran

2 Shahid Beheshti University of Medical Sciences, Tehran, Iran

Objectives: Physical, mechanical and biologic properties

of resin composite restorations are related to their adequate

polymerization. The quality and extent of polymerization

can be measured by degree of conversion (DC) and depth of

cure. Polymerization temperature is one of the factors that

may affect monomer conversion and polymer properties.

This study investigates the effect of different temperatures

(5, 25, 37 ◦ C) on the depth of cure and DC of one commercially

available composite cured by two different light sources, QTH

and LED.

Materials and methods: A commercilly availible, photoactivated

resin composite (Tetric-ceram, shade A2, Vivadent-

Ivoclar) and two different light curing systems DEMI (LED Kerr

Corporation, USA) and Coltolux ® 75 (Coltene, Whalendent,

USA) were used in this study. The depth of cure was recorded

as 50% of the remaining measured length, as required by the

ISO. All experiments were performed at three different temperatures

(5, 25 and 37 ◦ C). Five cylindrical samples (6 mm high

and 4 mm diameter) were prepared for each temperature and

curing unit. The samples were polymerized for 20 s for each

light curing systems. For measurements of DC, six cylindrical

samples (5 mm diameter × 2 mm length) at each temperature

were photopolymerized by two different curing units. Then,

70 �m thick discs were prepared from the surface and bottom

(depth of 2 mm) of the cylinder using a microtome and 400 grit

SiC paper. Then the infrared spectrum of an uncured sample


e20 dental materials 26S (2010) e1–e84

and each wafer specimen were analyzed with a FTIR spectrometer

(BRUKER TENSOR 27, Germany) operating 16 scans at

4cm −1 resolution. Two and three way ANOVA were performed

on data of depth of cure and DC, respectively. Also, Tukey HSD

were performed at the 95% significance level.

Results: Statistical analysis revealed that the depth of cure

was affected by temperature and that the specimens cured at

37 ◦ C had statistically significant higher depth of cure compared

to the specimens cured at 5 ◦ C in both QTH and LED

groups (p < 0.01). Also, lower depth of cure was obtained with

QTH light curing system. Temperature increase also gave

higher DC. The results were statistically significant at three

different temperature groups (p < 0.05) regardless of the curing

unit. Also, a significant difference found between top and bottom

surfaces of specimens polymerized at room temperature.

However, no significant differences were found between top

and 2 mm depth on materials cured at 37 ◦ C and 5 ◦ C(p > 0.05).

Conclusions: Increasing the temperature of resin composites

has an important influence on its degree of conversion

and depth of cure. Thus, it may affect the physical properties.

Thus, increasing the shelf life of composites by storing

them in refrigerator may show a negative-influence on

polymerization.

doi:10.1016/j.dental.2010.08.049

42

Time-dependent fracture toughness of conventional glassionomer

cements

R. Belli, A. Petschelt, U. Lohbauer

Dental Clinic 1, University of Erlangen-Nuernberg, Germany

Objectives: To investigate the fracture toughness KIc of

three commercial dental glassionomer (GI) cements at different

storage intervals.

Materials and methods: Bars with dimensions of

25 mm × 2mm× 2 mm were produced out of Fuji IX GP

(GC Europe, Belgium), Ketac Molar (3M ESPE, Germany) and

Chemfil Rock (Dentsply, Germany) and stored for 3 h, 24 h, 7

days, and 21 days in water at 37 ◦C. After the storage periods,

sharp notches were cut on the lower side of the bars using

a diamond wheel saw blade and a razor blade. Fracture

toughness (n = 15) was measured in bending using the SENB

(single edge notched beam) method. The actual notch depth

for each specimen was measured after fracture under a

light microscope (40×). KIc values were analysed by two-way

ANOVA and mod. LSD test at p < 0.05.

Results: The major increase in KIc was measured between

3 h and 24 h for all the GI cements (p < 0.05). Chemfil

Rock presented the fastest initial toughness, reaching

0.44 ± 0.06 MPam0.5 after 3 h, whereas KIc for Fuji IX GP and

Ketac Molar were 0.36 ± 0.04 MPam0.5 and 0.34 ± 0.04 MPam0.5 ,

respectively at the same period. Final KIc at 21 days was

not statistically different from that of 24 h for Chemfil

Rock and Ketac Molar, while Fuji IX GP showed continuous

KIc increase over the test periods. However, final

(21 days) KIc were not statistically different for the three

GI systems (0.57 ± 0.05 MPam0.5 , 0.57 ± 0.08 MPam0.5 and

0.53 ± 0.09 MPam0.5 Molar, respectively).

for Chemfil Rock, Fuji IX GP and Ketac

Conclusions: Although fracture toughness development

has shown to be material-dependent, GI cements are

more prone to fracture before 24 h due to the early stage of

poly-acid/glass reaction kinetics. Since GI restorations are subjected

to normal chewing forces from first hours of placement,

fast fracture toughness development is of clinical relevance to

prevent early fracture. In this sense, Chemfil Rock has shown

to reach a statistically higher KIc at the earliest test period.

This study was supported by Dentsply, Germany.

doi:10.1016/j.dental.2010.08.050

43

Bond strength to enamel and flexural strength of fiberreinforced

composites

M. Beloica 1 , C. Goracci 2 , N. Chieffi 2 , A. Vichi 2 , Z.R.

Vulicevic 1 , M. Ferrari 2

1 University of Belgrade, Serbia

2 University of Siena, Italy

Objectives: To assess shear bond strength to enamel and

flexural strength of reinforcing fibers used in combination

with a flowable resin composite as splinting materials.

Materials and methods: Quartz Splint (RTD, QS), Triaxial

(Ribbond, TX), THM (Ribbond, THM), Construct (Kerr, CNS),

Connect (Kerr, CNN) and everStick PERIO (StickTech, ES) were

tested. QS, CNS, and CNN were impregnated with the proprietary

resin prior to application. Premise Flow (Kerr) was

used in combination. For shear bond strength testing 10 sound

extracted molars per group were selected. On the buccal surface

of each tooth enamel was etched with 37% phosphoric

acid and Optibond FL adhesive (Kerr) was applied. A 1 mmthick

increment of resin composite was layered in a cylindrical

mould and an adequately sized segment of reinforcing fiber

was placed on top. The fiber was then overlaid by another 1mm

thick layer of resin composite. Twenty-four hours after

preparation, the bonded cylinder of fiber-reinforced resin composite

was sheared off using a universal testing machine.

Failure modes were noted. For flexural strength assessment

10 bar-shaped specimens of fiber-reinforced composite per

group were prepared and tested according to ISO Standard

4049/2000. Shear bond strength and flexural strength

of Premise Flow without fiber reinforcement were measured

with the same methods. The ‘No fiber’ group served as control.

Between-group comparisons in shear bond strength,

failure modes distribution and flexural strength were statistically

evaluated (statistical tests: one-way ANOVA, Tukey;

Pearson’s chi-square; Kruskall–Wallis ANOVA, Dunn’s multiple

range, p < 0.05). Scanning electron microscope observations

were taken to visualize the structure of the reinforcing fibers.

Results:

Group Shear bond

strength (MPa)

Flexural strength (MPa)

Mean SD p < 0.05 Mean SD Median 25–75% p < 0.05

QS 15.4 5.2 A 24.9 4.5 13.7 10.6–14.3 A

TX 16.7 6.2 A 19.3 8.6 18.6 12.5–26.7 ABC

THM 18.6 5.6 A 12.4 3 24.7 21.2–25.9 CD

CNS 16 5.5 A 17.5 5.3 13.6 11–18.6 ABC

CNN 14.4 4.1 A 14.3 5.2 19.7 11.6–21.7 BCD

ES 4.6 3.2 B 18.5 2.6 19.3 18.4–19.5 ABC

No fiber 12.8 4.7 A 5.8 1.4 6.3 4.8–6.9 D


Conclusions: ES achieved significantly lower shear bond

strength to enamel than the other splinting materials and

the resin composite. No statistically significant differences

emerged in the distribution of failure modes among the

groups. QS, TX, CNS, and ES significantly increased flexural

strength of the resin composite. QS yielded significantly higher

flexural strength than THM and CNN.

doi:10.1016/j.dental.2010.08.051

44

Effect of resin shade and LED light intensity on microhardness

K. Tolidis, P. Gerasimou, C. Boutsiouki

Aristotle University of Thessaloniki, Greece

Objectives: The clinical performance of light cured dental

composites is greatly influenced by light intensity of the light

curing unit and the shade of the resin composite used, affecting

microhardness values. The purpose of the present study

was to control multiple combinations of LED curing devices

with different light intensities and various composite resin

shades.

Materials and methods: A nanohybrid resin composite in

shades A3, B2 and C2 was used along with higher and lower

light intensity modes from LED curing devices (Radii, Elipar

S10, Valo in standard and plasma mode). Four groups were

formed for each shade and five specimens were made for

each group, which were 4 mm thick. Specimen were evaluated

with Vickers microhardness (100 gr for 15 s) both at the

top and bottom surface to assess microhardness values. Data

were analyzed with ANOVA and Tukey–Kramer test.

Results: No significant differences were found for A3 shade

at top surface and at the bottom surface for most of the curing

modes used. Shade B2 on top, exhibited no significant difference

in comparison between Elipar S10 and Valo standard

mode (p > 0.05) and within Valo modes (p > 0.05). Shade B2 at

bottom surface exhibited extremely significant difference for

Radii and Elipar S10 (p < 0.001), Elipar S10 and Valo standard

mode (p < 0.001). As for shade C2 at the top surface, it exhibited

significant differences (p < 0.05) in comparison between

Radii and Elipar S10 and for every curing unit at the bottom

except for Valo modes (p > 0.05).

Conclusions: Top surfaces exhibited greater microhardness

values compared to bottom as expected. A3 exhibited acceptable

microhardness values with all the LED curing devices.

Higher power LEDs generally result in lower microhardness

values when curing shade C2, but there is no difference

between Valo modes, which represent the lowest and high-

dental materials 26S (2010) e1–e84 e21

est light intensity of this experiment. Elipar S10, with an

average light intensity, seems to polymerize efficiently all

shades.

doi:10.1016/j.dental.2010.08.052

45

Temperature increase during composites polymerisation

using two LED curing lights

E. Armellin 1 , G. Bovesecchi 1 , P. Coppa 1 , G. Pasquantonio 1 ,L.

Breschi 2 , L. Cerroni 1

1 University of Rome Tor Vergata, Italy

2 University of Trieste, Italy

Light intensity Pulp chambre Occlusal surface M = 3 mm below occlusal

surface

VALO Starlight

PRO

VALO Starlight

PRO

Objectives: The aim of curing light technology has been

the development of lights that would result in faster curing

of resin composites and less heat generation (Aravamudhan

et al., Dent Mater 2006). The purpose of this in vitro study was

to evaluate thermal changes on the tooth structures during

the exposure of two different light emitting diode-curing units

(LED).

Materials and methods: Caries-free human first molar were

randomly selected and pulp residues were removed after root

resection. Four thermocouples were positioned according to

a Hannig and Bott modified method (Dent Mater, 1999). The

experimental set-up was composed by Keithley data acquisition

system (model 2700 with 7700 card) and by a set of type

J-thermocouples with cold junction in ice. The thermocouples

were hand made with a thin-coated wire (0.5 mm in diameter)

fitted in the tooth capable of a fast time-response. The

precision of the thermocouples was ±0.1 ◦ C. Two LED lamps

were tested: A: VALO (ultradent), tested at light intensity of

1000 mW/cm 2 (for 20 s) or 4500 mW/cm 2 (for 3 s); B: Starlight

PRO (Mectron) tested at light intensity of 1000 mW/cm 2 (for

20 s). Maximum temperature rises among the two LED light

tested were analyzed using one-way analysis of variance

(ANOVA).

Results: When composite was light cured the temperature

values increased rapidly reacting the plateau in 0.7–1 s.

Thermal flux generated by monomer conversion was added to

light curing heat. Means and standard deviations of maximum

temperature increase (expressed in ◦ C) measured at different

site of tooth during composite polymerization with VALO or

Starlight PRO are reported in the table.

VALO Starlight

PRO

Composite

VALO Starlight

PRO

1000 mW/cm2 1.58 ± 0.12a,d 1.08 ± 0,13a 7.34 ± 4.40 3.92 ± 1.73 1,99 ± 0.22b,e 1.26 ± 0.11b 20.56 ± 0.48c 12.77 ± 3.07c 4500 mW/cm2 0.87 ± 0.16d – 5.07 ± 0.05 – 1.08 ± 0.08 e – 21.76 ± 4.58 –

Different superscript letters indicate different groups: a, b, d, e (p < 0.005); c (p < 0.01).

Conclusions: Differences in temperature raises during

composite polymerization were found between the two LED

light tested, regardless the selected sites. Further studies are

needed to clarify in vivo the clinical relevance of temperature

increase during light-activated polymerization.

doi:10.1016/j.dental.2010.08.053


e22 dental materials 26S (2010) e1–e84

46

Is pre-heated microhybrid composite effective as a inlay luting

agent?

F. Cerutti 1 , M. Gagliani 2 , A. Cerutti 1

1 University of Brescia, Italy

2 University of Milan, Italy

Objectives: The long-term outcomes of composite inlays

are influenced by adhesive luting; dual-curing and light curing

materials are available for this procedure, however light

contribution still plays a key-role when luting thick inlays.

To obtain a high degree of conversion (DC), good handling

and marginal quality, pre-heating of micro-hybrid light-curing

composites was introduced. Aim of this study was to evaluate

the DC of a pre-heated composite compared to a standard

dual-curing luting material, both cured below inlays by means

of a traditional Halogen curing lamp (QTH) and two LED

curing devices. The null hypothesis was to find no difference

among the materials DC, independently from the curing

source employed, the inlay thickness and the power/time

combinations of light-curing units.

Materials and methods: 90 inlays 1 of increasing thickness

(2 mm × 3mm× 4 mm) were prepared in a custom

template, then randomly split into 3 groups (n = 5) and

luted on glass slides with two different composites: a dualcure

luting cement 2 and a 54 ◦ C pre-heated microhybrid

composite. 3 Light-curing was performed with three LCUs 4,5,6

providing a constant energy density (48J). DC was assessed

with a micro-Raman Dilor-HR-Labram spectrometer, then

ANOVA and post hoc Student–Neumann test were performed

(˛ = 0.05).

Results: Mean DC and SD are shown.

QTH

800 mW/cm2 for 60 s

Venus Variolink

II

LED

800 mW/cm 2

for 60 s

Venus Variolink

II

LED

1200 mW/cm2 for 40 s

Venus Variolink

II

2 mm 69.6 (2.12) 73.6(5.7) 69.6 (2.12) 82.3 (3.38) 71.8 (5.55) 85.1 (3.57)

3 mm 66.8 (2.56) 65.9 (11.7) 64.8 (4.99) 78 (2.74) 70.4 (4.05) 80.9 (1.74)

4 mm 59.4 (3.66) 63.9 (6.54) 59 (6.09) 71.2 (5.11) 66.6 (2.9) 76.5 (2.11)

As expected, DC decreases as the inlay thickness increases.

At the same power LED performed better than QTH in dualcuring

cement; increased power got better results both in

composite and in dual-cure luting cement.

Conclusions: Pre-heated micro-hybrid composite could

be reliably converted under composite inlays of increasing

thickness and could be effective for composite inlays luting

procedure.

doi:10.1016/j.dental.2010.08.054

1 Signum, Heraeus (shade A2).

2 Variolink II, Ivoclar-Vivadent.

3 Venus, Heraeus.

4 SwissMaster Light, EMS.

5 Bluephase C8, Ivoclar-Vivadent.

6 Bluephase G2, Ivoclar-Vivadent.

Table 1

Tested

flowable

composites

Low

compliance

(MPa)

High

compliance

(MPa)

Degree of

conversion

(%DC)

Filtek Supreme XT

Flowable

Restorative

3.39 ± 0.39d 1.58 ± 0.26c 64 ± 3AB Venus Diamond flow 1.17 ± 0.35bc 0.58 ± 0.20a 69 ± 2B Revolution Formula 2 1.03 ± 0.23b 0.61 ± 0.08a 64 ± 3AB Means followed by same superscript (small letter for stress values,

capital letter for DC values) indicate no statistical difference at the

95% confidence level (p < 0.05).

47

Evaluation of polymerization stress correlated with the extent

of polymerization of flowable composites

B. Codan, L. Breschi, E. de Stefano Dorigo, M. Cadenaro

University of Trieste, Italy

Objectives: The aim of this study was to measure the contraction

stress and degree of conversion (DC) of three flowable

resin composites using a halogen curing-light. Stress values

were analyzed using two measurement systems of varying

compliance and correlated with the DC of each composite.

Materials and methods: Materials tested were: Venus Diamond

flow (Heraeus Kulzer), Revolution Formula 2 (Kerr

Corporation, Orange, CA, USA); Filtek Supreme XT Flowable

Restorative (3M ESPE, ST Paul, MN, USA). Composites were

polymerized with a halogen curing unit (Elipar 2500, 3M ESPE,

500 mW/cm2 ) for 40 s. Contraction stress was measured using

a universal testing machine with an extensometer as a feedback

system and a stress-analyzer with no feedback. The

contraction force (N) generated during polymerization was

continuously recorded for 300 s after photo-initiation. Contraction

stress (MPa) was calculated at 300 s. Micro-Raman was

used to calculate the DC of the tested materials. Data were statistically

analyzed by two-way ANOVA and Tukey’s post hoc

test (˛ = 0.05).

Results: Stress values scored as follows: Venus Diamond

flow = Revolution Formula 2 < X-flow (Table 1; p < 0.05), with

both measuring systems. The universal testing machine gave

higher contraction stress than the stress-analyzer for each

flowable (p < 0.05). Venus diamond flow showed the highest DC

among the tested materials, however no correlation between

DC and stress values was observed.

Conclusions: Despite a high DC, the flowable composite

Venus diamond flow showed the lowest stress value irrespective

from the measurement system. Further investigations

are needed to clarify if the use of low-shrinkage nano-hybrid

flowable can be clinically effective in the long lasting of the

restoration.

doi:10.1016/j.dental.2010.08.055


48

Experimental methodology to characterize volumetric

changes of composite during photopolymerization

A. Joubert 1,2 , C. Villat 1,2 , P. Colon 1,3 , B. Grosgogeat 1,2 ,N.

Pradelle-Plasse 1,3

1 LMI, UMR-CNRS 5615, France

2 University of Lyon, France

3 University Paris, Diderot, France

Objectives: To characterize the dimensional variations of

composite resins during the curing process using a hydrostatic

weighting machine.

Materials and methods: Three composite resins were

tested: Clearfil AP-X (Kuraray), Kalore (GC), G-aenial (GC), Gradia

Direct (GC) using a weighting machine XS205DU (Mettler

Toledo Ltd., Leicester, UK) connected to a computer using a

software Lab X Light (Mettler Toledo Ltd., Leicester, UK). This

precision machine (hundredth of mg) measures the density

of an object by means of a kit density. This measurement

is called the Archimede’s method. The sample is weighed in

the air (dry) then in the auxiliary liquid. The volume is then

obtained and dimensional variations are expressed in %. The

originality of this method is the ability to measure the volume

change during the photopolymerization every second by

a specific assembly. An opaque bowl is pierced on its base to

pass the optic fiber of the LED light, which is suspended to

permit the stabilization of the machine. To be weighed in the

auxiliary liquid (oil and water), the sample must be hanged

using a metal rod, rounded at the end in order to deposit the

composite. The shape of the sample is a sphere for a better

repartition of stress. Temperature of the sample is registered

simultaneously.

Results: Results are expressed with curves presenting for

each material two steps:

- Severe contraction (t =0att =50s);

- Low contraction until stabilization (t = 50 until t = 600 s);

The contraction values for each sample measured at the

end of the experimentation were:

- Clearfil AP-X: 2.03%;

- Kalore: 1.65%;

- G-aenial: 2.02%;

- Gradia Direct: 1.91%.

Conclusions: This methodology could be an interesting

way to understand the relationship between stress, exothermic

reaction and shrinkage. The average contraction rate of

a methacrylate based composite resin is only the first step to

characterize the behaviour of the material. Stress measurements,

different from one composite to another with similar

shrinkage values could be explained by these continuous measurements

during the curing process.

doi:10.1016/j.dental.2010.08.056

dental materials 26S (2010) e1–e84 e23

49

Mould materials’ influence on degree of conversion of dental

resins

R.B. Cornelio 1 , H.M. Kopperud 2 , J. Haasum 3 , U. Gedde 3 ,U.

Ørtengren 1

1 University of Tromsø, Tromsø, Norway

2 NIOM, Oslo, Norway

3 Royal Institute of Technology, Stockholm, Sweden

Objectives: The aim of the project was to analyze the influence

of different mould materials on the degree of conversion

(DC) of composite resin-based materials.

Materials and methods: Three different moulds materials

were used: polyethylene (PE), polytetrafluorethylene (PTFE)

and stainless steel (SS). Five samples were made for each

mould using an experimental composite. The degree of conversion

was analyzed by FT-Raman spectroscopy at top,

bottom and at four different sites on the surfaces in contact

with the moulds. The top and bottom of the samples were

additionally analyzed with scanning electron microscope

(SEM). Statistical analyzes were performed using one-way

ANOVA and Bonferroni.

Results: PTFE showed significantly higher overall DC

(p < 0.05) for the composite samples made with PTFE compared

to the other mould materials tested. The samples made in the

stainless steel and polyethylene moulds showed no significant

difference in DC. The analyses of the different sites at the surfaces

in contact with the mould material showed the same

pattern. CRM made in PTFE had mostly of their DC values over

60%, while CRM made in the PE moulds were within 40–50%

DC. The samples made in SS mould had the lowest values of

DC, where 55% were bellow 40% DC. The same pattern was

found at the bottom of the samples tested for DC.

Conclusions: PTFE seems to be a suitable mould material

for making CRM samples in vitro. The risk for oxygen inhibition

using PTFE material seems to be overestimated, since

PTFE had the highest values of DC among the mould materials

tested. The differences in DC at the bottom of the samples

could be caused by the difference in the reflection of the light

depending of the type of the material used.

doi:10.1016/j.dental.2010.08.057

50

Effect of photoactivation mode on cross-link density of resin

composites

A.B. Correr, A.R. Costa, R.L.X. Consani, L. Correr-Sobrinho,

M.A.C. Sinhoreti

Piracicaba Dental School/State University of Campinas, Brazil

Objectives: The aim of this study was to investigate the

influence of photoactivation modes on the cross-link density

of a conventional and a low shrink resin composite, obtained

through softening tests.

Materials and methods: Disc specimens (n = 10) of Filtek

Z350 and Filtek P90 (3M ESPE) were photoactivated with

quartz-tungsten-halogen lamp XL2500 (3M), using the following

modes of curing: continuous (C) with 600 mW/cm 2 for 40 s,


e24 dental materials 26S (2010) e1–e84

continuous low irradiance (CL) with 150 mW/cm 2 for 160 s,

soft-start (SS) with 150 mW/cm 2 for 5 s + 600 mW/cm 2 for 39 s,

and pulse-delay (PD) with 150 mW/cm 2 for 5s+3min in dark

room + 600 mW/cm 2 for 39 s modes. Initial Knoop hardness

(KHN) measurements were performed 24 h after dry storage

at 37 ◦ C. The specimens of each resin–composite were

stored in absolute ethanol (100%), for 24 h at room temperature,

and KHN was determined anew. Percentages of hardness

decrease were analyzed by two-way ANOVA followed by pairwise

Tukey’s test (p = 0.05).

Results: No statistically significant differences were

observed between the different photoactivation modes. After

storage in 100% ethanol solution, KHN was decreased in all

cases but no significant differences were detected between

photo-activation modes (Filtek Z350: C = 27.8%; CL = 26.1%;

SS = 31.3%; PD = 30.5%; Filtek P90: C = 25.1%; CL = 32.8%;

SS = 23%; PD = 24.5%) regardless of the resin-composite tested.

Conclusions: The photoactivation mode and resin composite

formulation did not influence the crosslinking density of

the resin composites evaluated.

doi:10.1016/j.dental.2010.08.058

51

Influence of energy dose on the hardness, depth of polymerization

and internal gap formation of methacrylate- and

silorane-based restorations

P.H.P. D’alpino 1 , V.D. Hipolito 1 , J. Bechtold 1 , P.J. Santos 1 ,

R.C.B. Alonso 1 , F.P. Rodrigues 1 , N. Silikas 2

1 Bandeirante University of São Paulo, Brazil

2 University of Manchester, UK

Objectives: To investigate the influence of energy dose on

the Knoop hardness, polymerization depth, and internal gap

formation of silorane-based and methacrylate-based composite

in Class II restorations.

Materials and methods: Class II cavities were prepared

on mesial and distal surfaces of extracted third molars,

and randomly distributed in 4 groups (n = 10) according to

the restorative systems (1. Filtek P60: methacrylate-based

composite + Adper Easy One; 2. Filtek P90: silorane-based

composite + P90 System Adhesive) and the energy dose (20J:

1000 mW/cm 2 × 20 s; and 40 J: 1000 mW/cm 2 × 40 s). Composites

were applied in two increments and then photoactivated

using an LED curing-light device (Bluephase, Ivoclar Vivadent,

Liechtenstein). After 24 h, restorations were mesio-distally

sectioned. Knoop-hardness was evaluated across the transversal

section of the fillings (1–4 mm below the restoration

surface) using a load of 50 g for 5 s. Samples were then

air-dried and a drop of 1% acid red propylene glycol

solution was applied to the internal margins for 20 s. Samples

were then water-rinsed, air-dried and digitally-imaged

recorded. The internal gap (%) was calculated as the ratio

between the stained margins and the total length of the

internal margin. Two-way (for internal gap) and three-way

(for depth) ANOVA and Tukey’s test were then performed

(˛ = 0.05).

Results: Regarding the internal gap formation, no significance

was seen among experimental groups when

considering both the restorative systems and energy doses.

Most specimens showed perfect sealing of internal margins.

Silorane-based composite presented significantly lower hardness

values than methacrylate-based composite (p < 0.05) for

all depths and doses. Higher energy dose (40 J) produced higher

KHN only for Filtek P90, while Filtek P60 was not affected by the

energy dose applied. KHN was not also affected by the depth,

presenting similar mean values. Results are presented in the

table as follows:

Hardness 20 J 40 J Internal gap (%) 20 J 40 J

Filtek P60 97.1 aA 95.6 aA Filtek P60 4.4 aA 8.8 aA

Filtek P90 59.3 bB 61.7 bA Filtek P90 5.2 aA 8.5 aA

Different small letters in column and capital letters in row: significant

(p < 0.05).

Conclusions: Internal gap formation is neither affected by

the restorative system nor by the energy dose applied. Hardness

values are determined by the type of composite and

energy dose. The methacrylate-based composite is harder

than the silorane-based composite. Higher energy dose produces

increased hardness values only for the silorane-based

composite.

doi:10.1016/j.dental.2010.08.059

52

Effect of hydrogen peroxide topical applications on enamel

and composite resin surfaces

M. D’Amario 1,∗ , G. Turco 2 , M. Castronovo 1 , M. Ciribe 1 ,R.Di

Lenarda 2 , M. Giannoni 1 , M. Baldi 1

1 University of L’Aquila, Italy

2 University of Trieste, Italy

Objectives: The objectives of the present study were to analyze

the morphology and the superficial roughness of enamel

and composite resin restorations after three different bleaching

regimens.

Materials and methods: Enamel specimens were obtained

from buccal surfaces of 21 human incisors. Two specimens

were obtained for each tooth. Half part of each tooth was maintained

in distilled water and served as control; the other part

was treated with one of three professional bleaching agents:

38% hydrogen peroxide (Opalescence Boost; Ultradent Products,

Inc.), 35% hydrogen peroxide (Whiteness HP Maxx; FGM

Produtos Odontológicos Ltda), light-activated 25% hydrogen

peroxide (Zoom 2; Discus Dental Inc.). The same bleaching

protocols were applied on standardized composite resin (CeramX

mono; Dentsply De Trey) surfaces. Composite specimens

were divided in four subgroups (n = 7), according to surface

treatment (distilled water was used for control group). Two

enamel and composite specimens for each group were submitted

to a qualitative scanning electron microscopy (SEM)

analysis. Remaining specimens were measured for roughness

using a 3D optical profilometer (Talysurf CLI 1000; Taylor Hobson).

Data were statistically analyzed.


Results: A preliminary profilometric analysis of the enamel

and composite surfaces after bleaching protocols showed

no significant differences in surface roughness parameters

(p > 0.05) compared with those at baseline. Results of the

correlated SEM analysis showed no relevant alteration on

the enamel surfaces. However, some significant changes of

composite surface morphology were SEM observed at high

resolution (×1000 and ×3000) after conditioning treatments,

suggesting a predominance of depressions after each of the

three bleaching procedures.

Conclusions: Although SEM analysis seems to suggest that

professional bleaching procedures may adversely affect the

microscopic surface texture of composites, the profilometric

results showed that the tested bleaching regimens do not alter

enamel and composite surface roughness.

doi:10.1016/j.dental.2010.08.060

53

Microhardness of a new flowable composite liner for posterior

restorations

M. de Biasi, R.M. Calvi, D. Sossi, M. Maglione, D. Angerame

University of Trieste, Trieste, Italy

Objectives: A recently introduced flowable composite liner

for I and II class restorations is supposed to be efficiently

polymerized up to 4 mm thick increments according to manufacturer’s

indications. This preliminary study investigated

the microhardness of SDR liner in relation to thickness and

storage.

Materials and methods: Four moulds (thickness: 2, 3,

4, and 5 mm, diameter: 4 mm) were prepared. Ten SDR

(Dentsply Caulk) discs for each thickness subgroup (total sample

size = 160) were polymerized following 4 different protocols

by using halogen (Elipar 2500, 3M ESPE) or LED (BluePhase

G2, Ivoclar Vivadent) lamp, for 20 or 40 s. Six indentations per

specimen (3 on top and 3 on bottom surface) were performed

with a Vickers indenter (VHMT 30, Leica). Three measurement

times were considered: t0, immediately after polymerization;

t1, after 24 h in dry environment; t2, after further 24 h in

artificial saliva. Statistical analysis was performed by nonparametric

tests.

Results:

Data

expressed

in HV

Halogen LED

2mm3mm4mm5mm2mm3mm4mm5mm

20 s t0 Top 11.5 11.4 11.6 11.5 13.0 12.6 12.2 12.9

Bottom 9.8 8.6 7.4 5.9 11.7 10.9 9.0 8.7

t1 Top 20.5 20.6 20.5 20.7 20.9 20.9 21.0 21.0

Bottom 20.2 19.8 18.6 17.2 20.8 18.8 16.8 14.9

t2 Top 12.6 12.7 12.7 12.7 13.3 13.3 13.3 13.2

Bottom 12.4 12.0 11.2 8.4 13.2 12.3 12.0 11.0

40 s t0 Top 12.7 11.9 11.9 12.2 14.9 13.6 13.5 13.1

Bottom 11.2 10.2 9.0 7.8 14.0 12.9 10.0 8.9

t1 Top 20.9 20.9 20.8 20.9 21.7 21.7 21.5 21.7

Bottom 20.8 18.9 17.8 16.9 21.5 21.1 19.1 17.6

t2 Top 14.5 14.6 14.6 14.6 14.7 14.7 14.4 14.6

Bottom 14.4 14.1 13.9 11.2 14.7 14.1 11.7 11.1

Differences among groups were found as follows: top vs. bottom surface

(most comparisons p < 0.005); LED vs. halogen lamp (most comp.

dental materials 26S (2010) e1–e84 e25

p < 0.001); 40 s vs. 20 s (most comp. p < 0.05); increased thickness led to

decreased hardness only on bottom surfaces (most comp. p < 0.005);

hardness increased at t1 (all comp. t0 vs. t1, p < 0.05), then decreased at

t2 (all comp. t1 vs. t2, p < 0.05); however, the t2 values remained greater

than those at t0 (most comp. t0 vs. t2, p < 0.05).

Conclusions: SDR showed low hardness values, which

decreased after 24 h storage in artificial saliva; further investigations

are required before its clinical use.

doi:10.1016/j.dental.2010.08.061

54

Evaluation of surface roughness and filler characteristics of

restorative composites

M. Di Francescantonio 1,∗ , R. Pacheco 1 , R.R. Braga 2 ,M.

Giannini 1

1 Piracicaba Dental School, State University of Campinas, Brazil

2 School of Dentistry, University of São Paulo, São Paulo, Brazil

Objectives: The purpose of the present study was to investigate

the surface roughness after finishing and polishing and

the filler characteristics of four resin-based composites.

Materials and methods: Two low shrink composites (Filtek

LS, 3M ESPE e Aelite LS, Bisco Inc.), two composites with conventional

composition (Heliomolar e Tetric N-Ceram, Ivoclar

Vivadent) and finishing and polishing systems of their respective

manufacturers (Sof-Lex Disks, 3M ESPE; Finishing Discs

Kit, Bisco Inc. e Astropol F, P, AH, Ivoclar-Vivadent) were evaluated.

Discs of composites (2 mm high × 15 mm diameter) were

prepared (n = 5). Afterwards, they were finished and polished

according to the manufacturers’ instructions. The polished

surfaces were evaluated using a profilometer (Surfcorder SE

1700, Kosaka Corp.) and the data (Ra/�m) were statistically

analyzed by ANOVA and Tukey test (p < 0.05). The composite

filler particles were observed using scanning electron

microscopy (SEM) (JSM 5600LV, Jeol), after removal of the resin

matrix by organic solvents (ethanol and acetone). The size,

shape, type and other characteristics of fillers were analyzed.

Results: Significant differences were found for the surface

roughness. Aelite LS (0.28 �m) and Tetric N-Ceram (0.25 �m)

presented the roughest surfaces, following by heliomolar

(0.20 �m) and Filtek LS (0.15 �m), respectively. For the filler

characteristics, the materials presented differences in filler

contents (e.g. particle size and shape).

Conclusions: The results showed that the surface roughness

was influenced by the filler characteristics, also by the

finishing and polishing manufacturers’ systems.

doi:10.1016/j.dental.2010.08.062


e26 dental materials 26S (2010) e1–e84

55

Influence of curing time, overlay shade and thickness on

Vicker’s hardness of light cured composites

L. Di Loreto ∗ , F. De Angelis, M. Vadini, M. D’amario, L. Merla

Vitalone, C. D’arcangelo

University G. D’Annunzio, Chieti, Italy

Objectives: The aim of the present study was to assess the

micro-hardness of a 0.5 mm resin composite layer that was

light cured for 40, 80 or 120 s through composite overlays of

different thickness and shade, in order to determine the influence

that the time of cure and the overlay shade and thickness

have on degree of conversion.

Materials and methods: Three different shades (UD2, UD3,

UD4) from a commercially available resin composite (Enamel

Plus HRI) were used. Heat-cured cylinders of 5 different

thicknesses were produced: 2 mm, 3 mm, 3.5 mm, 4 mm and

5 mm. These cylinders served as overlays. To achieve a fixed

thickness of the composite layer to be cured, a 0.5 mm thick

metal ring was placed underneath the overlay and its inner

hole was filled with a standardized amount of composite

paste. Light curing was performed through the overlay for 40,

80 or 120 s: in this way the varying thicknesses overlays were

used to control the amount of light reaching the composite

to be cured. For each specimen the composite to be cured

and the heat-cured overlay were made out of the same shade

of resin composite. 225 samples were manufactured and

assigned to three experimental groups on the basis of the

shade, and to subgroups on the basis of the overlay thickness

and the curing time, resulting in 45 subgroups composed by

5 samples each. 45 additional samples, 15 for each of the

three shades, were produced and subjected to 40, 80 or 120 s

light curing using a microscope glass as overlay; they were

assigned to 9 control subgroups. Three Vicker’s hardness

(VH) readings were carried out on each sample, at about

2 mm from one another. Means and standard deviations

were calculated in each subgroup. Data were analyzed using

a three-way-ANOVA and Holm-Sidak test. VH values lower

than 55% of control were not considered clinically acceptable.

Results: In UD2 groups, acceptable hardness values were

achieved with 3.5 mm or thinner overlays, after 120 or 80 s of

curing time, and with 2 mm overlays after 40 s. With shades

with higher chromaticity, VH values were significantly lower.

Conclusions: Curing time, restoration thickness and its

shade may significantly influence the degree of conversion of

the tested light curing composites employed as luting agents;

the clinician should carefully keep these factors under control.

doi:10.1016/j.dental.2010.08.063

56

Roughness and microhardness of restorative materials submitted

to erosive challenges

P.H. Dos Santos, A.P. Guedes, T.Y. Suzuki, S. Pavan, A.L. Briso,

W.G. Assunção

Araçatuba School of Dentistry – UNESP, Araçatuba, Brazil

Objectives: The aim of this study was to evaluate the effect

of different acidic solutions on the microhardness and surface

roughness of restorative materials.

Materials and methods: 168 specimens were randomly

divided into 3 groups with 8 volunteers. The volunteers

wore palatal device with 7 specimens (Ketac Nano, Ketac

Nano + Biscover LV, Esthet-X, Esthet-X + Biscover LV, Supreme

XT, Supreme XT + Biscover LV and bovine enamel). The group I

was immersed in HCl; the group II was immersed in soft drink

(Sprite) and the group III was subjected to saliva only. The

microhardness and surface roughness data were analyzed by

ANOVA and Fisher’s test (5%).

Results: The Supreme XT showed the highest values of

microhardness before and after aging with a significant difference

for the other materials (p < 0.0001). The lowest values

were found for the materials sealed with Biscover LV in all

periods analyzed (p < 0.0001). The Ketac Nano glass-ionomer

cement showed the highest values of surface roughness after

exposure in acidic solutions. The application of the sealant did

not reduce the roughness values for the composites studied

except for Esthet-X after the challenge in hydrochloric acid.

Conclusions: The acidic solutions promoted changes in

microhardness and surface roughness of restorative materials,

except for the sealed materials.

doi:10.1016/j.dental.2010.08.064

57

Effect of cavity configuration factor on nanoleakage of lowshrinkage

composites

N.A. El-Sahn 1 , H.M. El-Damanhoury 2 , D. El-Kassas 1 , O.M.

Fahmy 1 , H. Gomaa 1 , J.A. Platt 3

1 Cairo University, Egypt

2 University of Sharjah, United Aran Emirates

3 Indiana University, IN, USA

Objective: This study evaluated the nanoleakage of two

low-shrinkage composites in cavities with different cavity

configuration factors (C-Factor).

Materials and methods: Standardized class I cavities

(4.5 mm width × 4.5 mm length × 1.8 mm depth) were prepared

in ninety extracted human molars after removing

occlusal enamel, with six different C-factors by applying nail

polish to four walls (C1), three walls (C2), two walls adjacent to

each other (C3a), two walls opposite to each other (C3b), one

wall (C4), or no walls (C5). Cavities were equally divided and

randomly assigned to one of the resin composites and their

matching adhesive systems; Filtek Silorane/Silorane adhesive

(SIL, 3M ESPE), Aelite LS/One-Step Plus (AL, BISCO) or Filtek

Z250/Adper Single bond Plus (Z, 3M ESPE) that were used as

a control. After 24 h storage in water, the specimens were


sectioned, placed into 50% (w/v) ammoniacal silver nitrate

solution for 24 h, exposed to photodeveloping solution and

observed using SEM. Percentage distribution of metallic silver

particles in the resin/dentin interface was calculated using

digital image analysis software. Shrinkage stresses and stress

rates of resin composites were measured continuously from

start of light curing and up to 30 min using a Tensometer testing

machine (NIST, Gaithersburg, MD). Data were analyzed by

one-way ANOVA followed by a Tukey multiple comparisons

test. (p < 0.05).

Results: Increasing C-factor did not affect the nanoleakage

of low shrinkage composites, meanwhile silver nitrate depositions

were significantly increased in high C-factor cavities in

the control group. Mean maximum shrinkage stresses results

were 0.94 ± 0.1, 1.79 ± 0.18 and 2.14 ± 0.23 MPa for SIL, AL and

Z, respectively.

Conclusion: Using low shrinkage composites in cavities

with high C-factor may be an alternative to avoid the deteriorating

effect of increasing the C-factor on the bond of resin

composite to dentin.

doi:10.1016/j.dental.2010.08.065

58

Can filler-size affect the colour and gloss of resin-composites?

H. Elbishari, J. Satterthwaite, Nick Silikas

School of Dentistry, University of Manchester, United Kingdom

Objectives: To study the effect of filler size on the colour

change and gloss over time in three different storage media.

Materials and methods: Disc shaped specimens

(2 mm × 10 mm) prepared and polished using OptiDisc

(Kerr Dental). Samples allocated to 4 groups (n = 12) according

to their filler size. Gloss and colour measured with a

Novocurve glossmeter and Minolta colourmeter, respectively,

and then stored in three media (water, cola and red wine).

Measurements for gloss and colour were then recorded 24 h,

2 weeks and 3 months, respectively. Data was analysed with

one-way ANOVA (SPSS, 16.0).

Results: Filler distribution resulted in significant changes in

colour (�E). �E values ranged from 1.6 to 15.6 and gloss from

89.6 to 51.3. In all cases the trimodal filler distribution, that

incorporated small size nanofillers (100 nm), resulted in the

least colour change. All materials had high initial gloss values.

Storage media affected gloss and there was a gloss reduction

with all storage media. Red wine had the highest reduction in

gloss values.

Conclusions: Filler size and distribution had a significant

effect on the aesthetic properties (colour and gloss) of resincomposites.

Storage media and storage time also significantly

affected these properties. Prolonged storage time resulted in

the highest changes.

doi:10.1016/j.dental.2010.08.066

dental materials 26S (2010) e1–e84 e27

59

Choosing the allocation method for clinical trials in restorative

dentistry

H. Fron 1 , P. Durieux 2 , G. Chatellier 2 , F. Gillaizeau 2 , J.P. Attal 1

1 URB2I, Université Paris Descartes, France

2 APHP HEGP; INSERM, UMR S 872/20, France

Objectives: Treatment allocation in restorative trials is

generally defined by pre-set random tables. However, this

method does not account for prognostic factors of the restorations

and does not respect allocation concealment, so that

treatment groups are not comparable and conclusions are

biased, especially because the groups are small-sized. Comparable

groups are obtained by optimizing balance between

groups and limiting allocation predictability. Two methods

could be used in restorative dentistry to achieve comparability:

blocked randomization and minimization. Blocked randomization

consists in using a separate randomization list for each

prognostic group. Minimization is an adaptive method that

minimizes the imbalance between the number of patients in

each treatment group over a number of prognostic factors. The

purpose of this study was to choose between these two methods

for a randomized controlled trial comparing ceramic and

composite CAD-CAM inlays.

Materials and methods: A Visual Basic for applications

program was computed. 1000 sets of 350 patients were simulated

according to the proportions expected for each of

the four main predictive factors (inlay/onlay, premolar/molar,

vital/non vital tooth, operator). These patients were allocated

by minimization with a varying random element and stratification

with blocks of 2 and 4. Allocation methods were

compared in terms of predictability and balance.

Results: The balance obtained with blocked randomization

was better than expected, although minimization proved to

better account for balance and predictability at the same time.

Minimization with a random element of 30% achieved the lowest

imbalance (0.51% of the sample size) and predictability

(52.68% when operator remembered his three last allocations).

Conclusions: Minimization with a 30% random element

allowed accounting for four prognostic factors in the planned

clinical trial and achieving excellent group comparability. Simulations

help decide which allocation method is best for a

clinical trial in restorative dentistry.

doi:10.1016/j.dental.2010.08.067

60

Polishability of nanofilled resin-based composites

K. Hirata, J. Yamagawa # , S. Geraldeli ∗ , F. Qian, S.R. Armstrong

The University of Iowa, USA

Objectives: To evaluate baseline laboratory-grade polishability

of six resin-based composites (RBC) in preparation for

polish retention and surface roughness evaluation.

# at time of participation in the research at The University of

Iowa, J. Yamagawa was an employee of Tokuyama Dental

Corporation. Study sponsored by Tokuyama.


e28 dental materials 26S (2010) e1–e84

Materials and methods: 96 disk-shaped specimens

(D = 10.0 mm, 2-mm thick, all A2 shade, n = 16 per RBC) were

formed in a PTFE mold against mylar tape and light polymerized

for 10–30 s, based on the manufacturer’s recommended

curing times, using an Optilux 500 (Kerr). Following 1 day of

37 ◦ C dark storage, specimens were ground under continuously

water cooling at 150 rpm with a 120 g load for 2 min

with P800 grit (21.8 �m), P2400 (8 �m), and P4000 (5 �m) SiC

paper on a grinding/polishing machine (Rotopol V). Followed

by diamond polishing of 1 �m, 0.25 �m, and 0.1 �m suspension

(MetaDi Supreme Polycrystalline Diamond Suspension,

Buehler) on polishing cloths (Micro Cloth, Buehler) with a

60 g load. The 1 �m diamond polishing was not performed for

Durafil VS as pilot studies showed a pitted surface that only

occurred with this step. Gloss was measured (average of 3

measurements for each specimen was used for data analysis)

after each polishing step using a small-area glossmeter

(Novo-Curve, Rhopoint Instrumentation, East Sussex, UK)

with a square measurement area of 2 mm × 2 mm and 60 ◦

geometry. A one-way ANOVA with post hoc Tukey’s HSD test

was conducted to assess the effect of RBCs on the polishability

within each polishing time. When assumption of normality

was violated, one-way ANOVA based on rank-transformed

data with post hoc Bonferroni t-tests was performed.

Results: Mean gloss units after each polishing step

RBC Mylara P800a P2400 P4000a 1 �ma 0.25 �m 0.1 �ma Estelite �

Estelite

87.4 (a) 12.9 (ab) 68.2 (a) 76.4 (ab) 92.5 (ab) 93.9 (a) 94.6 (a)

� Quick 86.9 (a) 13.5 (a) 67.5 (a) 78.6 (a) 92.0 (ab) 93.9 (a) 94.6 (a)

Herculite Ultra 86.1 (a) 10.4 (ab) 40.4 (c) 71.9 (cd) 91.3 (ab) 92.9 (a) 94.6 (a)

Esthet-X HD 85.8 (a) 7.1 (c) 29.4 (d) 61.6 (e) 90.1 (b) 93.8 (a) 95.1 (a)

Supreme Plus 85.8 (a) 8.2 (bc) 51.2 (b) 74.3 (bc) 92.1 (a) 93.7 (a) 94.3 (a)

Durafill VS 76.5 (b) 7.9 (c) 44.3 (c) 69.5 (d) na 76.1 (b) 75.9 (b)

Within columns groups with same letter are not significantly different

(p > .05).

a One-way ANOVA on rank-transformed data.

Conclusions: Polishability is RBC material dependent. This

may be due to differences in filler size, type and coupling to

resin matrix.

Future studies: Polish retention and surface roughness will

be measured after 3k, 10k, 20k, 30k and 50k thermocycles

between 5 and 55 ◦ C and compare to commercial polishing

methods.

doi:10.1016/j.dental.2010.08.068

61

A novel test chip for measuring in situ degradation of dental

composites using electrochemical impedance spectroscopy

S. Grego 1 , J.R. Piascik 1 ,B.Brown 2 , S.D. Wolter 2 , B.R. Stoner 1,2

1 RTI International, Durham, NC, USA

2 Duke University, Durham, NC, USA

Objectives: To demonstrate a novel array-chip technology

used to monitor physical properties of dental composites in

situ and to present a model for correlating electronic properties

to mechanistic changes in material structure and properties.

Materials and methods: The DECAY chip (Degradation via

Electrochemical Array) leverages microfabrication techniques

to construct a uniform array of recessed wells that may be

filled with dental restorative materials and analyzed electrochemically

in solution. The array enables uniform preparation

of multiple specimens and reference controls on a common

substrate, all of which may be evaluated simultaneously. The

DECAY-chip presented here consists of a 3 × 3 array of 100 �m

deep wells, and is used to monitor the degradation of a common

dental composite as a function of time. The data correlate

changes in measured dielectric properties to surface and bulk

changes as the composite is exposed to various chemical and

biological environments. In this preliminary evaluation, Aelite

All-Purpose dental composite (Bisco, Inc., Schaumburg, IL) was

packed into 5 of the 9 test-wells and light-cured for 40 s at

500 mW/cm 2 . A model for the system is presented, as are

future plans to standardize methodology for rapid materials

screening and in vitro analyses.

Results: Electrochemical impedance spectroscopy (EIS)

data show degradation in dielectric properties of the composite

when exposed to ethanol:DI (75:25) mixtures. These

data are then correlated to physical modes of degradation

confirmed ex situ via optical, atomic force, and electron microscopies.

Table: Change in composite as a function of timed exposure

to ethanol:DI (75%EtOH).

Composite property vs. time 1 h 24 h 210 h 360 h

Dielectric capacitance

(nF)

Dielectric leakage

resistance (M-ohms)

Total impedance at

1 Hz (M-ohms)

AFM surface roughness

(nm)

16.6 17.2 19.3 21.0

66.7 64.4 43.4 27.8

10.1 9.6 8.7 7.9

11.2 N/A 26.9 N/A

Conclusions: EIS-DECAY chip was used to detect changes

in composite capacitance and bulk resistance in addition to

total system impedance, all as a function of frequency, and

compared to physical changes in the dental composite. Models

were developed for more complex systems and correlated to

clinical models.

doi:10.1016/j.dental.2010.08.069


62

Simulated clinical polishability of nanofilled resin-based composites

K. Hirata, J. Yamagawa, F. Qian, S.R. Armstrong

The University of Iowa, USA

Objectives: To evaluate baseline simulated clinical polishability

of five resin-based composites (RBC) in preparation for

polish retention and color stability evaluation.

Materials and methods: 80 Disk-shaped specimens

(D = 10.0 mm, 2-mm thick, all A2 shade, n = 16 per RBC) were

formed in a PTFE mold against mylar tape and light polymerized

for 10–20 s using an Optilux 500 (Kerr) based on the

manufacturer’s recommended curing times. Following 1 day

of 37 ◦ C dark storage, light irradiated side of each specimen

was ground with P800 grit size (21.8 �m) SiC paper on a

grinding/polishing machine (Rotopol V) under continuously

water cooling at 150 rpm with a 120 g load for 2 min to

remove resin rich layer and roughen the surface. Then, each

specimen was polished dry at 30,000 rpm with a Sof-Lex disc

Fine and Super-fine grit each for 20 s. Gloss was measured

(average of 3 measurements for each specimen was used for

data analysis) after each polishing step using a small-area

glossmeter (Novo-Curve, Rhopoint Instrumentation, East

Sussex, UK) with a square measurement area of 2 mm × 2mm

and 60 ◦ geometry. A one-way ANOVA with post hoc Tukey’s

HSD test was conducted to assess the effect of RBCs on the

polishability within each polishing time.

Results: Mean gloss units after each polishing step.

RBC Mylar P800 Sof-Lex

fine

dental materials 26S (2010) e1–e84 e29

Sof-Lex

super fine

Premise 89.85 (a) 8.35 (a) 55.99 (a) 67.08 (b)

Durafill VS 85.19 (c) 6.96 (ab) 55.20 (a) 73.53 (a)

Supreme Plus 87.79 (b) 5.81 (b) 50.97 (a) 61.89 (c)

Venus Diamond 84.91 (c) 5.77 (b) 41.29 (b) 63.89 (bc)

Esthet-X HD 89.50 (ab) 5.26 (b) 34.09 (c) 61.34 (c)

Within columns groups with same letter are not significantly different

(p > 0.05).

Conclusions: Polishability is RBC material dependent. This

may be due to differences in filler size, type and coupling to

resin matrix.

Future studies: Polish retention and color stability will

be measured after 3k, 10k, 20k, 30k and 50k thermocycles

between 5 and 55 ◦ C and compare to laboratory-grade polishing

methods.

# at time of participation in the research at The University

of Iowa, was an employee of Tokuyama Dental Corporation.

Study sponsored by Tokuyama.

doi:10.1016/j.dental.2010.08.070

63

Nanometer deformations of wet and dry composites determined

by Speckle interferometry

N. Kachrimanis 1 , P. Zaslansky 2 , W.-D. Müller 1

1 “Charité” Universitaetsmedizin Berlin, Germany

2 Max-Planck Institute for Colloids and Interfaces, Potsdam, Germany

Objectives: Dental composites placed intraorally undergo

dimensional changes due to thermal fluctuations, postpolymerisation

processes and hygroscopic water-uptake

effects. Concerning bonded restorations, these changes result

in the formation of strain and therefore, the purpose of this

study was to develop and adapt a non-destructive standardised

method for the assessment of composite dimensional

changes under dry and wet conditions at 37 ◦ C.

Materials and methods: Standardized Grandio (VOCO, Cuxhaven)

disks, (1 mm thick, 15 mm diameter) light cured (80 s)

were stored in water or in air for 1 h and 3 days at room temperature

(n = 12). Each sample was mounted on a precision heating

stage warmed to 37 ◦ C, where surface deformations over time

were monitored by electronic Speckle pattern interferometry.

Surface displacement maps were used to determine strains

every 4 s for 30 min or more, during which expansion or

contraction was monitored. The cumulative effects of loss

of water and/or post curing polymerisation shrinkage were

quantified (ImageJ).

Results: Fig. 1 depicts typical integrated dimensional

changes over time for samples in each group, placed at

37 ◦ C: Fresh samples (stored for 1 h) revealed strains of up

to 6 × 10 −5 , while dry samples undergo half the shrinkage

of wet samples. Samples stored for 3 days revealed the

curious finding that wet samples undergo half the shrinkage,

compared to dry-stored samples.

Conclusions: Non-contact deformation measurements of

mm sized samples revealed deformations produced by very

different mechanisms: water sorption or post-polymerisation

shrinkage. The Speckle interferometry method allows us to

determine nanometer deformations and small strains, relevant

to the clinical conditions where such composites are

used. Further investigation is needed to compare variations

in composition between different materials.

doi:10.1016/j.dental.2010.08.071


e30 dental materials 26S (2010) e1–e84

64

A new method to measure the linear polymerization shrinkage

of composites with computer vision

I.-B. Lee, S.-H. Min

Seoul National University, Seoul, Republic of Korea

Objectives: To develop a new method to measure the linear

polymerization shrinkage of composites without direct

contact to a specimen using a particle tracking method with

computer vision.

Materials and methods: The linear contraction strain of

composites during light curing was measured by a computer

vision system, which consisted of a CCD camera with 768 × 494

pixels, a lens, a frame grabber, and software for image processing

and analysis. The movement of a marker attached to

a composite specimen was captured by the CCD camera and

stored in a memory device. The marker image was binarized

and filtered to remove noise. The X and Y coordinates of the

marker were obtained using the area center method. The locus

of the marker during photo-polymerization was continuously

tracked as a function of time. The shrinkage kinetics of a

commercial silorane-based composite (P90, 3M ESPE) and two

conventional methacrylate-based composites (Z250 and Z350

(flowable), 3 M ESPE) were investigated and compared. The linear

shrinkage strain of the composites was recorded for 10 min

by light polymerization (Elipar FreeLight 2: 700 mW/cm2 ,

3M ESPE) and volume shrinkage was calculated. The measurements

were repeated five times per each material.

Statistical analysis was conducted by ANOVA and Tukey’s test

(˛ < 0.05).

Results: Linear polymerization shrinkage and volume

shrinkage of composites at 10 min are reported in the table.

Composites Linear

shrinkage (%)

Z250 0.70 (0.03) b 2.11

Z350 1.41 (0.08) a 4.22

P90 0.33 (0.02) c 0.98

Calculated

volume

shrinkage (%)

Number in parentheses is the standard deviation.

Calculated volume shrinkage = 3 × measured linear shrinkage.

Conclusions: The linear shrinkage of composites was

0.33–1.41%. Shrinkage was lowest for the silorane-based (P90)

composite and highest for the flowable Z350 composite. The

new method was able to measure the true linear shrinkage

of composites in real time without sensitivity to specimen

preparation and geometry.

doi:10.1016/j.dental.2010.08.072

65

Exposure reciprocity law: Influence of viscosity on different

materials properties

J. Leprince 1 , G. Springuel 1 , W.M. Palin 2 , J. Devaux 1 ,G.

Leloup 1

1 Université Catholique de Louvain, Belgium

2 University of Birmingham, UK

Objectives: Exposure reciprocity law (ERL) supposes that

equivalent material properties will be acquired, no matter how

similar radiant exposures (RE) are obtained when using different

combinations of irradiance – (I; mW/cm 2 ) and irradiation

time (t; s). As resin viscosity has been shown to influence photopolymerization

efficiency, this work aims to investigate the

applicability of ERL for elastic modulus (M), degree of conversion

(DC) and trapped radical concentration (R) of resins with

different viscosities and to interpret the relationship between

these variables.

Materials and methods: Different proportions of Bis-

GMA and TEGDMA (70/30, 60/40, 50/50, 40/60 and 30/70 wt%,

respectively) were prepared with addition of CQ/DMAEMA

(0.20/0.80 wt%). Samples were photopolymerized with a halogen

light (Optilux 501, Demetron/Kerr) using 3 different I: 200,

400 and 600 mW/cm 2 and t was adjusted to reach either 6

or 12 J/cm 2 radiant exposure. M was measured by a dynamic

mechanical analyzer, DC by FT-NIRS and R by electron paramagnetic

resonance (n = 3).

Results: For a given RE, no significant differences (p > 0.05)

were observed for R at high viscosity, but large differences

at low viscosity (p < 0.001). An increase in R was observed

between 6 and 12 J/cm 2 , and this difference increased with

decreasing viscosity. Interestingly, a good correlation was

found between R and M (R 2 = 0.71) while the correlation was

poor between M and DC (R 2 = 0.26) and between R and DC

(R 2 = 0.38). For DC, at a given viscosity, few differences were

observed, neither between 6 and 12 J/cm 2 , nor between the

modes at a given RE, except above 60 wt% TEGDMA. In the

latter case, a significant decrease in DC was observed for

600 mW/cm 2 –10s(p < 0.05).

Conclusions: The applicability of ERL is dependent on the

property considered. Here, R is the most discriminating property

and shows the largest deviation from ERL, while there

seems to be a saturation effect when considering DC. In this

regard, the comparison between R, DC and M highlights structural

differences. While increased RE has little effect on DC, it

results in increased M and R. The correlation between the latter

two properties is most likely a result of higher crosslinking

in the polymer network.

doi:10.1016/j.dental.2010.08.073


66

Polymerization of dental sealants: Influence of exposure

times and curing-units

G. Liani, B. Codan, R. Di Lenarda, L. Breschi, M. Cadenaro

University of Trieste, Italy

Objectives: The aim of this study was to analyze the extent

of polymerization (Ep) of two dental sealants in relation to

different curing units and curing times. The tested hypotheses

were that (1) sealant type, (2) curing unit type and (3) exposure

time do not affect Ep.

Materials and methods: Tested materials were: Concise

White Sealant (3M ESPE), a white sealant with a relatively

low filler content, and UltraSeal XT Plus (Ultradent

Products, Inc.), with a higher filler content. Ep was measured

with a differential scanning calorimetry (DSC, Q10 TA

Instruments). Specimens were light-cured with Elipar 2500

Halogen Curing Light (3M ESPE), Ultra-Lume LED 5 (Ultradent

Products, Inc.) and Bluephase G2 LED Curing Light

(Ivoclar Vivadent) for 120 s. Polymerization kinetic curves

were obtained. Ep at 20, 40 or 60 s was calculated and statistically

analyzed (three-way ANOVA and Tukey’s post hoc

test).

Results: At 20 s (curing time recommended by manufacturers

of Concise White Sealant and UltraSeal XT Plus) UltraSeal

XT Plus in association with Elipar 2500 halogen curing-light

showed the highest Ep (88.2 ± 2.6%), while the lowest values

were obtained with Concise White Sealant cured with

Ultra-Lume LED 5 curing-light unit (15.2 ± 4.0%) (p < 0.05). No

statistically significative differences where found when using

Bluephase G2 LED Curing Light, for both tested materials.

Ep increased when curing time was prolonged (40 and 60 s)

for both tested sealants with all curing units (p < 0.05). The

low Ep values obtained with Concise White Sealant cured

with Ultra-Lume LED 5 depend on the lack of correspondence

between the output peak of this curing unit and

the camphoroquinone photo-initiator activation wavelength

( = 465 nm). The increase in Concise White Sealant Ep values

observed at 40 and 60 s can be justified by the exothermic

peak reached by the Ultra-Lume curing-light unit only

32 s after the polymerization initiation. Curing times recommended

by manufacturers do not guarantee the optimal

polymerization of Concise White Sealant and UltraSeal XT

Plus.

Conclusions: The tested hypothesis was rejected, because

statistical differences between materials and curing units

were found. Longer curing times than those recommended by

manufacturers significantly increase the extent of polymerization

of the tested sealants, with all curing units.

doi:10.1016/j.dental.2010.08.074

dental materials 26S (2010) e1–e84 e31

67

Changes of microleakage using different composites and

stratification techniques

A. Lizio, F. Lipari, S. Bertolami, C. Panarello, G. Lo Giudice

University of Messina, Italy

Objectives: The aim of this in vitro research is the investigation

and the evaluation of the marginal microleakage

eventually present in class V restorations performed with two

different direct restorations materials (nano-filled and silorane

composites) and different stratification techniques: the

gengivo-occlusal layering (horizontal) and the wedge-shape

layering (oblique).

Methods and materials: Conventional class V cavities

were created on the buccal surface of 96 human teeth

overlapping the cemento-enamel junction. Cavities measured

4 mm × 3mm× 2 mm. The samples were subdivided in

two groups (A and B). Group A was restored with a silorane

composite, 1 group B was restored with a nano-filled

composite. 2 Within each group were identified two subgroups

(A1/A2–B1/B2) for the layering technique used. A1 and B1

groups were restored by apposition of horizontal layers, A2

and B2 were restored with oblique layering. All restorations

were photo-polymerizated using a LED lamp. 3 After restoration

the samples were submitted to thermocycling (500 cycles

for 30 in.), then immersed in 1% methylene blue for 4 h

and finally sectioned. For the microleakage evaluation on

enamel and dentin we used a stereomicroscope (12.2×) 4 . The

microleakage analysis was made using a score proposed by

Fabianelli, Goracci, Thorbourn, Davidson and Ferrari: (0 = no

penetration; 1 = leakage not exceeding the middle of the cervical

wall; 2 = penetration past the middle of the cervical wall;

3 = penetration to the axial wall; 4 = penetration to and along

the axial wall and into the dentinal tubules). The comparison

between groups (B1 vs. A1, B2 vs. A2; A1 vs. A2, B1 vs. B2) was

evaluated using the Student’s t-test with P > 0.001.

Results: The analysis showed that the recorded average

score in every single subgroup was as follows: Group A1

0.67 ± 0.81; Group A2 1.67 ± 1.03. Group B1 3.50 ± 1.22; Group

B2 3.17 ± 0.75.

Conclusions: The evaluation of microleakage among the

groups restored using silorane compared with nano-filled

composite (A vs. B) shows that the silorane offers remarkably

better performance comparing the groups with similar

stratification technique. Comparing the microleakage values

achieved in samples restored with the same material and different

stratification techniques, in silorane restorations the

horizontal layering determined better results; in nano-filled

composite restorations better results were obtained using

the oblique stratification techniques. The influence of the

incremental technique appears of lesser importance in our

research. These data are probably due to the efficiency of the

bonding used, the minimum depth of the cavity (2 ± 1 mm)

1 Filtek Silorane 3M ESPE.

2 Filtek Supreme 3M ESPE.

3 T-Led ANTHOS.

4 OPMI Pro Ergo 7s ZEISS.


e32 dental materials 26S (2010) e1–e84

and the thickness (1 mm) of the composite layers used in the

experimentation.

doi:10.1016/j.dental.2010.08.075

68

Fracture toughness of GIC—A mechanistic approach on the

nanoscale

B. Brandt 1 , K. Durst 1 , R. Belli 2 , M. Goeken 1 , U. Lohbauer 2

1 Department of Materials Science and Engineering, University of

Erlangen-Nuernberg, Germany

2 Dental Clinic, University of Erlangen-Nuernberg, Germany

Objectives: To investigate the fracture toughness KIc of a

dental glassionomer (GI) cement in terms of terms of different

storage intervals and to correlate the development of macroscopic

data with findings on the nanoscale.

Materials and methods: Bars with dimensions of

25 mm × 2mm× 2 mm were produced out of a model GI

cement (Schott/Evonik, Germany) and stored for 24 h, 7 d,

and 21 d in water of 37 ◦ C. Sharp notches were cut into the

bars using a diamond wheel saw blade and a razor blade.

Fracture toughness (n = 15) was measured using the SENB

(single-edge-notched-bending) method. The actual notch

depth for each specimen was measured after fracture under a

light microscope. A Nano Indenter (G200, Agilent Tech., USA)

was used to observe the elastic modulus and local hardness

on the nanoscale. Therefore, flat specimens were produced,

surface polished using the lapping technique, and stored as

described above. Local mechanical properties were measured

on glass particles and matrix of the set cement. Load-control

(LCM) and Continuous Stiffness (CSM) measurements were

performed.

Results: An increasing fracture toughness was measured

with extended storage times. The KIc increased from

0.22 MPa m 0.5 after 24 h up to 0.24 MPa m 0.5 (7 d) and finally to

0.27 MPa m 0.5 after 21 d. The elastic modulus of the GI composite

increased from 12.2 GPa (7 d) up to 16.1 GPa after 21 d.

Hardness increased from 0.27 GPa (7 d) up to 0.43 GPa after 21 d.

The glass particles showed an elastic modulus of 65.5 GPa and

a hardness of 0.69 GPa.

Conclusions: Mechanical properties on the nanoscale

reflect the macroscopic data without any disturbing influence

from material inhomogeneities, porosity, etc. Over

time, the elastic modulus showed a higher increase compared

to the macroscopic fracture toughness measurements.

The material performance was found to be determined

by the matrix behaviour. On the nanoscale, a viscoplastic

response of the matrix component could be proved.

Nanoindentation is a very useful technique for improving

the macroscopic behaviour of a GI cement and suitable

for localizing the weakest link in the composite structure.

doi:10.1016/j.dental.2010.08.076

69

Comparison of two self-adhesive composite flowables

R. Guggenberger, T. Luchterhandt, A. Stippschild

3M ESPE, Seefeld, Germany

Objectives: Aim of this study was to compare the bond

strength of a self-adhesive composite flowable (Vertise Flow,

Kerr Corp., USA) with an experimental self-adhesive composite

flowable on dentin and enamel in two different adhesion

test methods.

Materials and methods: The adhesion test methods

used were a macro-shear bond strength test (SBS) (method

described in IADR-CED 2009, abstract # 84, C. Thalacker et al.)

with a bonding area of 21.8 mm 2 and the Ultradent microshear

bond strength test UBS with a bonding area of 4.4 mm 2 .

The substrates were bovine teeth (n = 6) ground to dentin or

enamel, using a 600 grit SiC paper. Bonded specimens were

tested after 24 h storage in tab water at 36 ◦ C, in a universal

testing machine with a crosshead speed of 2 mm/min. Following

manufacture’s instructions, for Vertise (Vts) a first layer

was rubbed on the tooth surface for 20 s and then light cured

for 20 s using an Elipar Freelight (3M EPSE). For the experimental

self-adhesive flowable (Exp-SA) the material was brought

directly on the tooth surface (without a first layer) and light

cured for 20 s.

Results: The following table shows the bond strength in

MPa. The standard deviations are given in parentheses. All

data were analyzed by ANOVA (p < 0.05). Means with the same

letters are statistically the same.

Material Test

method

Adhesion to

dentin [MPa]

Adhesion to

enamel [MPa]

Vts SBS 7.7 (2.1) a 13.3 (2.4) c

Exp-SA SBS 10.6 (1.7) b 11.9 (3.9) c

Vts UBS 7.0 (1.3) I 8.6 (3.6) III

Exp-SA UBS 11.9 (2.2) II 9.1 (4.1) III

Conclusions: In both adhesion tests Exp-SA, used without

a first layer, was found to have a higher adhesion to dentin

than Vts and an equal adhesion to enamel.

doi:10.1016/j.dental.2010.08.077

70

Temperature stress distributions in posterior composite

restorations: A 3D-FEA study

N.A. Manchorova

Medical University, Faculty of Dental Medicine, Department of Operative

Dentistry and Endodontics, Plovdiv, Bulgaria

Objectives: The purpose of this study was to investigate the

thermal stress distributions of dentin-adhesive interfaces in

a three-dimensional finite element (3D FE) model of a human

upper premolar with various Class I and Class II cavity types

and sizes after nanocomposite restorations.

Materials and methods: The human upper premolar was

digitized with a micro-CT scanner with a resolution of


0.625 mm. A 3D solid model was prepared and exported into a

3D-FE program (Solid Works Office Premium, 2009). Additionally

eight models of Class I and Class II cavity preparations

(classical and minimal-invasive types) and restorations were

simulated by a proper choice of mesh volumes. A validation

procedure of the FE model was executed based on comparison

of theoretical calculations and experimental data according to

literature. The polymerization shrinkage was modelled using

temperature dependent expansion. The adhesive layer was

produced in the FE program with a thickness of 30 �m. FE simulations

of thermal loading (5 ◦ C and 55 ◦ C) were carried out

for each combination of cavity geometry, boundary conditions

and material properties.

Results: Thermal stress distributions of tooth-adhesivecomposite

interfaces of restored premolars have been

observed in a series of experiments and depended on the

configuration and size of the restoration. In all cavity types,

enamel-adhesive interfaces and cavity angles were more

stressed than composite-adhesive ones. The low temperatures

caused higher stress in the tooth-adhesive interface than

high temperatures in the mouth.

Conclusions: The low temperatures have a major impact

on marginal integrity of composite restorations in posterior

teeth and increase the unfavourable effects of polymerization

shrinkage.

doi:10.1016/j.dental.2010.08.078

71

SS-OCT as alternative to micro-CT for composites internal

adaptation evaluation

J.R. Mayoral 1 , A. Sadr 2 , Y. Shimada 2 , E. Cho 2 , Y. Sumi 3 ,I.

Krejci 3 , L. Giner 1 , M. Roig 1 , J. Tagami 2

1 Universitat Internacional de Catalunya, Spain

2 Tokyo Medical & Dental University, Japan, National Center for Geriatrics

and Gerontology, Japan

3 University of Geneva, Switzerland

Objectives: The aim of this study was to evaluate the internal

adaptation at dentin cavity floor of resin composites using

swept source optical coherence tomography (SS-OCT) and Xray

micro-tomography.

Materials and methods: Eight extracted human molars

were horizontally sectioned at a buccal-lingual direction

occlusally bellow dentine–enamel junction using a low speed

saw (Isomet, Buehler LTD, USA). From these specimens dentin

discs (Ø: 6 mm; n =4× 2) with cavities (Ø: 3 mm; h: 1 mm) where

prepared, randomly divided in two experimental groups and

single-layer bulk filled with micro-hybrid composite Clearfil

AP-X/APX, and nano-filled Clearfil Majesty Posterior/MP without

any conditioning, priming or bonding treatment. The

dental materials 26S (2010) e1–e84 e33

composites were photopolymerized for 40 s at 750 mW/cm 2

using an LED curing unit (Dentaport, Morita, Japan). All

specimens were cross-sectional imaged using an SS-OCT

unit (Santec, Japan) with 1319 nm laser center wavelength.

Forty-eight B-scan image slices per-group were obtained and

processed with Image J analysis software (NIH, USA) to quantify

interfacial gap area fraction resulting from polymerization

shrinkage, dimensional contraction and structural voids at

dentin cavity floor. Thereafter all samples were imaged by high

resolution micro-XCT (Shimadzu, Japan) and were recorded

using the 2D and 3D software. Identification of the limits

between composites and dentinal micro-voids were made.

Confocal laser scanning microscope (CLSM) analysis at 500×

and 2500× magnification was made to confirm SS-OCT findings.

Data were statistically analyzed by two-way ANOVA to

determine interfacial gap differences between groups.

Results: Image analysis obtained from SS-OCT revealed

significant differences of interfacial gaps between groups

(P < 0.05). The optical contrast between the material and air

helped in detection of interfacial gaps. CLSM analysis confirmed

that SS-OCT was capable of detecting interfacial gaps

and structural voids on submicron-scale. MicroCT images

were not able to assess direct detection of interfacial gap at

composite-dentin cavity floor.

Conclusions: SS-OCT can be used to provide nondestructive

assessment between restoratives materials and

internal tooth interfaces for gap detection at the bottom of

resin composites restorations. Micro-CT was not capable to

detect direct gap interface at dentin cavity floor.

doi:10.1016/j.dental.2010.08.079

72

Curing depth of restorative composites achieved with QTH

and LED units

W.G. Miranda Jr, S.W. Kim, B. Pick, A.O. Lopes, F.A. Maeda

University of São Paulo, Brazil

Objectives: The aim of this study was to evaluate the curing

ability of different light units in polymerizing popular restorative

composites.

Materials and methods: Five blocks (2 mm × 2mm× 5 mm)

were built using four commercial composites (A2, Vita Shade).

Composites were light-activated for 40 s with four curing units

and kept dry for 24 h at 37 ◦ C in the dark. The Knoop microhardness

(50 g/15 s) was assessed at four depths (HMV-2T,

Shimadzu, Kyoto, Japan). Results were analyzed by three-way

ANOVA/Tukey test (˛ = 0.05).

Results: The light unit × composite interaction was statistically

significant (p < 0.001).


e34 dental materials 26S (2010) e1–e84

Composites Depth LED QTH

Translux Power Blue a FLASHlite 1401 b Ultra-Lume Led 5 c XL 2500 d

Z-250 e 0.2 mm 81(0.8)Aa 62(9.7)ABb 67.8(3.6)Aab 68.2(5.9)Aab

1 mm 78.4(2.5)Aa 68.8(6.2)Aa 66(1.9)Aa 68.2(7.1)Aa

2 mm 69.6(4)Aa 63.6(5.8)ABa 63.8(2.9)Aa 62.4(7.5)Aa

4 mm 52(0.6)Ba 54.2(5.8)Ba 48.6(9.7)Ba 42.8(12.3)Ba

TPH f 0.2 mm 49.2(3)Ab 55.2(5)Aa 51.4(10.8)ABb 51(6.9)Ab

1 mm 47(3.3)Aa 52(5.1)Aa 53.4(1.8)Aa 46.8(7.6)Aa

2 mm 41.8(1.6)ABa 52(2.4)Aa 48(4)ABa 43(4.4)ABa

4 mm 28.1(1.2)Bb 36(3.9)Bab 39.2(4.1)Ba 29.8(3.9)Bb

Tetric g 0.2 mm 42.4(5.7)Aa 41.2(3.8)Aa 49.4(3.1)Aa 40(2,3)Aa

1 mm 41.2(5.8)Aa 38.2(6.1)Aa 49.8(8.3)Aa 38.8(4.5)Aa

2 mm 35.2(4.4)Aa 39.2(6.1)Aa 43.4(6.7)ABa 33.2(5.1)Aa

4 mm 18.9(3)Bc 22.6(5.1)Bb 30.6(5.6)Ba 17.6(2.7)Ba

Charisma h 0.2 mm 29.4(4.8)Ab 35.8(5.4)Aab 46.6(11.3)Aa 34.2(4.4)Aab

1 mm 27.8(3.5)Aa 36.8(3.9)Aa 41.6(3.6)ABa 31.6(6.2)Aa

2 mm 22.4(4.4)ABa 30.6(4.9)ABa 35.6(2.1)ABa 27.6(4.5)ABa

4 mm 9.5(1.1)Bb 22.8(2.9)Bab 31.4(0.9)Ba 13.8(6.1)Bb

For each composite and light unit, capital letters compare KHN among depths.

Within the same line, values followed by the same letters are statistically similar (p > 0.05).

a Translux Power Blue, Heraeus.

b FLASHlite 1401, Discus.

c Ultra-Lume Led 5, Ultradent.

d XL 2500, 3M.

e Z-250, 3M.

f TPH, Dentsply.

g Tetric, Ivoclair/Vivadent.

h Charisma, Heraeus.

Conclusions: For all composites, Ultra-Lume 5 resulted in

higher KHN at 4 mm. Also, no differences in KHN were found

up to 2 mm depth for each composite/light unit association.

doi:10.1016/j.dental.2010.08.080

73

Influence of fiber post on degree of conversion of a luting

cement

C.O. Navarra 1 , C. Goracci 2 , G. Corciolani 2 , A. Vichi 2 ,L.

Breschi 1 , M. Cadenaro 1 , M. Ferrari 2

1 University of Trieste, Italy

2 University of Siena, Italy

Objectives: to assess the degree of conversion achieved

at different levels of a simulated dowel space by a dualcure

resin cement in combination with different fiber

posts.

Materials and methods: Similarly sized posts of different

shape and composition were selected: GC Fiber Post

(GC, GC); FibreKleer Serrated Post (Jeneric/Pentron, FK); DT

Light SL (VDW, SL); RelyX Fiber Post (3 M ESPE, RX); Reforpost

(Angelus, RE); DT Light Post Illusion (RTD, LPI); FRC Postec Plus

(Ivoclar-Vivadent, FP); Radix (Dentsply, RA); Snowpost (Abrasive

Technology, S); Dentin Post X (Komet, DP); Macrolock

Illusion (RTD, MI); Composipost (RTD, C). A metal guide was

used to position the post centered within a cylindrical metal

mould simulating the dowel space and filled with Variolink

II (Ivoclar-Vivadent). The cement was light-cured (Trilight, 3M

ESPE), placing the light tip on the post coronal end for 20 s

with the metal guide in position and for additional 40 s after

removing the metal guide. After 24 h, degree of conversion of

the cement was assessed through Raman analysis at the coronal

(C), middle (M), and apical (A) third of the simulated dowel

space. Degree of conversion data were statistically analyzed

(Two-Way ANOVA, Tukey test, p < 0.05).


Results:

Level Post

dental materials 26S (2010) e1–e84 e35

GC A FK A SL AB RX AB RE AB LPI AB FP AB RA AB SP ABC DP ABC MI BC C C

C ˛ 76 a (3) 77 a (2) 81 a (2) 76 a (6) 78 a (6) 77 a (2) 71 ab ,2 (1) 73 b (4) 75 a (2) 73 a (2) 76 a (0) 75 a (2)

M ˇ 72 ab (6) 70 b (0) 73 b (4) 76 b (4) 74 a (2) 69 b (0) 73 ab (3) 69 b (5) 65 b (4) 71 ab (2) 72 a (0) 72 a (2)

A 74 a (4) 76 a (3) 67 b (6) 67 b (1) 65 b (2) 71 ab (0) 70 b (6) 69 b (2) 70 b (1) 64 b (1) 58 bc (0) 47 c (2)

Comparison for posts within levels

Coronal DT Light Safety Lock > FRC Postec Plus*

Middle RelyX Fiber Post > Snowpost*

Apical Reforpost, Dentin Post X, Macrolock Illusion > Composipost*

Both factors significantly influenced degree of conversion

(p < 0.001). Decreasing degrees of conversion were measured

from coronal to apical third. In the table different small letters

label significant differences among dowel space levels regardless

of the post and different capital letters label statistically

significant differences among the posts, irrespective of dowel

space level. Also the interaction between post and dowel space

third was statistically significant (p < 0.001).

Conclusions: Significantly less effective polymerization is

obtained at the apical level of the dowel space, especially when

non-translucent posts are used.

doi:10.1016/j.dental.2010.08.081

74

Thermal evaluation of light-curing composites

M. Petrini, P. Trentini, G. Spoto, M. Ferrante

University G. D’Annunzio of Chieti, Italy

Objectives: The aim of this study is to evaluate light-curing

composites polymerization quality (monomer/polymer) carried

out at various times and distances of irradiation (0–8 mm;

20–60 s) through the thermal analysis (TG–DTA).

Materials and methods: The materials used were X Duo

Ceram (Dentsply, UK), Gradia Direct (GC, USA). Samples have

been prepared with 2-mm thickness and a 4-mm diameter

with a stainless steel matrix to obtain an equivalent mass of

about 50 mg. The light intensity was 1200 mW/cm 2 (Mini Led

Satelec, Acteon Group, Merignac, France). Simultaneous thermal

analysis was used to measure the mass change and heat

effects (TG–DTA) of dental composites performed by TG/DTA

6300 (Model TG/DTA 6300, Seiko Instruments Inc., Torrance,

CA, USA). The samples were heated at a constant rate of

10 ◦ Cmin −1 , from 25 to 600 ◦ C under nitrogen atmosphere

(100 mL/min).

Results:X DUO Ceram Dentsply[0,2-6]Temperature of

5% mass loss/±2 ◦ CMass loss at 600 ◦ C/%[0,2-6]Distance

of irradiationTime0 mm2 mm4 mm6 mm8 mm[3,0]19.45

± 0.23%20 s38938738238037640 s39839239039038460

s399392391391389Gradia Direct[0,2-6]Temperature of 5%

mass loss/±2 ◦ CMass loss at 600 ◦ C/%[0,2-6]Distance of

irradiationTime0 mm2 mm4 mm6 mm8 mm[3,0]49.62

± 0.57%20 s32831731431431240 s33032932732232160

s331330329328328Thermogravimetric (TG) results (%).

Conclusions: TG/DTA analysis shows different thermal

behaviours between samples. Time and distance of irradiation

affect the quality of polymerization; it is necessary to increase

the curing time when the irradiation distance is longer than

2 mm.

doi:10.1016/j.dental.2010.08.082

75

Delayed gelation through chain-transfer reactions: Stress

reduction in methacrylate networks

C.S. Pfeifer, N.D. Wilson, S. Lewis, Z.R. Shelton, J.W. Stansbury

University of Colorado, Aurora, USA

Objectives: Thiol additives with varying number of functionalities

and reactivities were used as chain-transfer agents

in combination with a methacrylate commonly used in dental

materials. The formation of a glassy polymer network in

the presence of thiols is expected to render delayed gelation

and possibly stress reduction with improved conversion and

mechanical properties.

Materials and methods: Ethoxylated bisphenoladimethacrylate

(BisEMA/control) was combined with

methyl-mercaptopropionate (MMP), benzene thiol (BT) – both

monothiols, or pentaerythritol tetra-(3-mercaptopropionate)

(PETMP) – tetrathiol, at 5, 10 or 20 mol% thiol in relation

to methacrylate functional groups. Methacrylate

and thiol reaction kinetics were followed in real-time by

mid/near-infrared (RT-NIR) spectroscopy during photopolymerization

(30 mW/cm 2 , 10 min). Flexural modulus was

used to determine polymeric mechanical strength properties.

Polymerization stress and modulus development were

monitored by a tensometer and a rheometer, respectively,

both coupled with RT-NIR through a newly developed optical

apparatus.

Results: For all thiol-modified materials, conversion values

increased by 5–25% compared to the control (BisEMA = 60 ± 2%

conversion), and that reflected in an increase in flexural modulus

of the same magnitude. Maximum reaction rate was

reduced by 40–60%, and deceleration was observed at much

later stages in conversion (MMP at 50%, PETMP at 35% and BT

at 60%, compared to 20% for the control). Even with higher conversion/modulus,

stress values were either equal or reduced

compared to the control (1.8 ± 0.1 MPa), with more pronounced


e36 dental materials 26S (2010) e1–e84

reductions for the higher thiol concentrations (for MMP at

5, 10 or 20%, stress was 1.9 ± 0.2, 1.8 ± 0.1 and 1.4 ± 0.1 MPa,

respectively). Comparing only groups with 10% thiol added, BT

was the most efficient in reducing stress, followed by PETMP

and MMP (0.8 ± 0.1, 1.3 ± 0.2 and 1.8 ± 0.1 MPa, respectively).

This reduction in stress is explained by the delayed gelation

due to chain-transfer reactions, well demonstrated in the

NIR-coupled rheometer experiments. Gelation (defined as the

point on the modulus development curve where tan delta = 1)

was observed at conversions of 15–28% for PETMP and MMP

and at 38–58% for BT, much higher than the control (4%). This

allowed for extended opportunity for viscous flow before the

reaction became diffuse-controlled, with consequent stress

relaxation. The results show a dependency on thiol reactivity

and concentration.

Conclusions: Delayed network formation was demonstrated

with the use of simple thiol additives, both by the

delayed deceleration profiles and directly by the rheometer

experiments. Significant stress reductions were achieved,

accompanied by improvement in mechanical properties.

This approach does not require any modifications in the

bonding/photoactivation procedure, and seems promising for

stress management in the clinic

Support: NIH/NIDCR 2R01DE14227.

doi:10.1016/j.dental.2010.08.083

76

In vivo quantification of Streptococcus mutans in composite

restored teeth

I. Piccinelli, F. Cerutti, L. Madini, N. Barabanti, A. Cerutti

University of Brescia, Italy

Objectives: The purpose of this in vivo study was to investigate

the effect of a low-shrinkage composite surface on tooth

plaque, in particular on the presence of S. mutans in class II

restorations 60 months after the placement.

Materials and methods: 12 Class II restorations were performed

in 8 patients1 in 2004. A plaque sample was taken

from the margin of each restoration at the baseline and at

each recall (3–6–12–24–36–48–60 months) by means of a paper

cone. In each patient, a plaque sample taken from a sound

tooth in the opposite arch was considered as a control. Plaque

assays were assessed with Taq-Man real-time PCR. A quantitative

estimate of the presence of S. mutans was obtained.

Both qualitative and quantitative real-time PCR techniques

were used for the test. First, the presence of bacterial DNA was

investigated, in order to check the correctness of the genomic

extraction procedure; then the gtf� was amplified in order to

quantify the presence of S. mutans.

Results: Qualitative PCR analysis revealed in 6 samples collected

on restored teeth the presence of S. mutans NTCT 10449

at the 60-month recall. Only 2 samples showed a S. mutans

ratio higher than 105 , while the remaining samples elicited

values lower than 103 . As a comparison, a qualitative analysis

at baseline on the same 8 patients showed presence of S.

1 Tetric Evo Ceram, Ivoclar-Vivadent.

mutans in 6 individuals; at the 3 months recall, only one of

them was positive.

Conclusions: The cariogenic potential of dental plaque

does not seem to be affected by the placement of composite

resin restorations after 60 months.

doi:10.1016/j.dental.2010.08.084

77

Energy delivered to a simulated restoration at the 2010 AADR

meeting

R.B. Price, C.M. Felix

Dalhousie University, Halifax, Canada

Objectives: This study measured the curing energy delivered

to a simulated restoration in the maxillary second molar

by attendees at the 2010 AADR meeting.

Materials and methods: A light curing measurement and

teaching device, MARC (Measurement of Accurate Resin Curing,

BlueLight Analytics) has been developed. MARC uses a

laboratory grade spectrometer (USB 4000, Ocean Optics) to

accurately record the irradiance and energy delivered to simulated

restorations in a mannequin head attached to a dental

chair. Attendees at the 2010 AADR meeting were asked choose

from nine popular curing lights to cure a simulated restoration

in the maxillary second molar, just as they would for

a patient using manufacturers’ recommended curing times.

A total of 136 recordings were made during the meeting,

where the top selling curing lights were popular choices.

The effect of different energy doses that were recorded at

the meeting on the degree of conversion and microhardness

recordings were then determined. Two-millimeter thick

specimens of Tetric EvoCeram A2 (Ivoclar-Vivadent) were

cured at 30 ◦ C using a polywave LED violet/blue or a single

peak LED blue light delivering 1.8, 3.0, 6.0, 8.0, 10.0, 12.0 and

35.4 J/cm 2 . The same irradiance was used at each energy

level. The degree of conversion was measured using Attenuated

Total Reflectance FT-IR on a Tensor 27 (Bruker) over

the first 90 s at a rate of 8 measurements/s. The specimens

were then removed from the ATR plate and nine

Knoop microhardness recordings were made at the bottom

of each specimen at five minutes, and again after 24 h

storage in the dark at 37 ◦ C. Three specimens were made


at each energy level. The degree of conversion results at

90 s and Knoop microhardness results made after 5 min

and 18 h were analyzed with ANOVA and Fisher’s PLSD at

˛ = 0.01.

Results: The energy delivered by the attendees to the

same tooth ranged from 2.0 to 20.9 J/cm 2 . There was no

significant improvement in the DC or Knoop hardness of

Tetric EvoCeram A2 between 12 and 35.4 J/cm 2 confirming

the manufacturer’s curing instructions. 43% of light curings

obtained at the AADR meeting would result in Tetric EvoCeram

not receiving the manufacture’s recommended minimum

amount of energy. This will adversely affect the degree of

conversion and the Knoop microhardness. 82% of the simulated

light curings would deliver less than the 16 J/cm 2

recommended in the Phillip’s Science of Dental Materials

textbook.

Conclusions: This and other studies using MARC strongly

suggest that the curing energies delivered to resins in many

dental offices are inadequate and will result in undercured

resins, despite the fact that the dentists may think they are

following the manufacturer’s guidelines. BlueLight Analytics

supported this study.

doi:10.1016/j.dental.2010.08.085

78

Effect of modulated photoactivation methods on mechanical

properties of composites with different loading systems

E.J. Souza-Junior 1 , R.C.B. Alonso 2 , Lams Paulillo 1 ,C.

Anauate-Neto 2 , R.M. Puppin-Rontani 1

1 State University of Campinas, Brazil

2 Bandeirante University of São Paulo, Brazil

Objectives: To investigate the influence of modulated

photoactivation methods on degree of conversion, Knoop

hardness, crosslink density, elastic modulus, and flexural

strength of composites with different loading systems (microfilled,

nanofilled and hybrid).

Material and methods: Different composites were selected

based on the loading system (Microfilled: Durafill; Nanofilled:

Z350; Hybrid: Z250). Bar specimens (5 mm length × 2mm

width × 1 mm height) were confectioned in a polyvinylsiloxane

mold and photocured using 3 methods: Continuous

light (CL); Soft-Start (SS); and Pulse-delay (PD). For all

methods the energy dose was 16 J. All properties were

evaluated on the same specimens (n = 10). Degree of conversion

(DC) was determined by means of FTIR. Knoop

hardness (KHN) was conducted using microhardness tester

(50 g for 5 s). Crosslink density (CLD) evaluation was performed

by hardness measures before and after storage in

absolute-ethanol for 24 h. The % of hardness reduction was

considered. To determine flexural strength (FS) and elastic

modulus (E), a three-point flexural test was conducted

in a Universal testing machine (3 mm between the supports)

with a cross-head speed of 0.5 mm/min. Data of each

test were submitted to two way ANOVA and Tukey’s test

(p > 0.05).

dental materials 26S (2010) e1–e84 e37

Results: Results are showed in the tables as follows:

DC (%) CL SS PD KHN CL SS PD

Micro 69.4 aB 70.9 aB 80.4 aA Micro 13.3 cA 14.9 cA 14.9 cA

Nano 54.6 bA 53.9 bA 47.6 cB Nano 57.1 bA 59.4 bA 57.7 bA

Hybrid 54.1 bA 52.1 bA 52.6 bA Hybrid 71.8 aA 66.6 aB 64.2 aB

CLD (%) CL SS PD E (GPa) CL SS PD

Micro 09.7 bB 29.5 aA 26.7 cA Micro 1.16 bA 1.31 bA 1.04 bA

Nano 29.2 aB 28.8 aB 38.4 bA Nano 3.63 aA 4.05 aA 3.35 aA

Hybrid 35.1 aB 36.2 aB 44.9 aA Hybrid 3.26 aA 3.37 aA 3.47 aA

FS (MPa) CL SS PD

Micro 48.3 cA 32.0 cA 42.0 bA

Nano 93.8 bAB 76.5 bB 99.3 aA

Hybrid 141.7 aA 104.7 aB 104.3 aB

For all tables, mean values followed by different small

letters in the column and capital letters in the row differ statistically

among themselves for the Tukey test at the level of

5%.

Conclusions: Filler loading affected all the tested properties.

In general, microfilled composite showed inferior

mechanical properties, while hybrid and nanocomposites

shows better properties. Modulated photoactivation methods

affected in different ways the DC, reduced KHN, CLD and FS,

but not affected E.

doi:10.1016/j.dental.2010.08.086

79

Withdrawn

doi:10.1016/j.dental.2010.08.087

80

Evaluation of depth of cure in nanohybrid composite: Scraping

vs. Micro F-TIR analysis

R. Rota 1 , N. Scotti 1 , A. Venturello 2 , D. Pasqualini 1 , E. Berutti 1

1 University of Turin, Italy

2 Polytechnical School of Turin, Italy

Objectives: The aim of this in vitro study was to compare

two different methods for evaluating depth of cure of resin

composites.

Materials and methods: A commercially available nanohybrid

resin composite (Venus Diamond, Heraeus Kultzer,

Hanau, Germany) was selected for this study. The resin composite

was bulk placed inside a metal mold, which allowed

the depth of cure examination. Semicircular samples (10 mm

depth) were obtained, with a later flat surface parallel to the

curing light direction. A total of 48 samples were prepared with

different curing parameters: energy density (400 mW/cm 2 ;

2000 mW/cm 2 ) and curing time (10 s; 40 s). The curing device

employed in this study was a halogen light (Swiss Master

Light, EMS, Switzerland). The degree of conversion (DC) was

accomplished by Micro Attenuated Total Reflection Fourier

Transform Infrared (ATR F-TIR) analysis 24 h after the polymerization.

DC was recorded every 0.25 mm along the lateral

surface of the sample. Sufficient depth of cure was considered

at the level where DC was 80% of the maximum DC of

each sample. After Micro F-TIR examinations, the composite

was carefully removed from the mold and uncured material

gently removed using a plastic spatula. The height of the

cylinder of cured material was measured with a microme-


e38 dental materials 26S (2010) e1–e84

ter and this value was the depth of cure. Differences among

DC progression and ISO4049 methods were analyzed with the

non-parametric Mann–Whitney U-test (p < 0.05).

Results: The descriptive analysis showed that ISO 4049

revealed a mean depth of cure of 3480 �m, while DC evaluation

evidenced that 80% value of maximum DC obtained was

placed at 1965 �m from the surface exposed to curing light.

Conclusions: Within the limits of this in vitro study we

could conclude that the measurement of DC progression along

the resin composite is a reliable and more sensitive method in

evaluating depth of cure of resin composite.

doi:10.1016/j.dental.2010.08.088

81

UK-GDPs’ knowledge of light curing of resin based composites

materials

A. Santini, S. Turner

University of Edinburgh, Edinburgh Postgraduate Dental Institute,

Edinburgh, UK

Objectives: To determine GDPs’ knowledge of visible LCUs

and the curing of light activated resin based composite materials.

Materials and methods: An email list of FGDP(UK) members

in England and Scotland (UK) was obtained. Only GDP

members were eligible for the study. These were sent emails

linking to a web-based questionnaire (Surveymonkey.com).

Responses were analysed using SPSSv17.

Results: 60% (173) responded (provisional). Principal findings

were: 57% described their unit type as LED, 25% as

halogen, and 17% did not know. From the model details they

gave it is possible to confirm that 46% were accurate in their

description of their unit type. 57% said they did not know

the unit’s intensity, and another 6% described the intensity

incorrectly, based on their description of their unit. 21% gave

insufficient information to confirm the accuracy of their report

of the unit’s intensity. 30% reported having a radiometer in

their practice, 53% reported that they did not, and 15% did

not know. Of those with a radiometer, 45% reported using it

at least twice a year, 18% once a year, and 37% less often or

never. Asked to compare the efficiency of halogen v LED units

at polymerizing composites, 26% incorrectly said halogen was

less efficient, and 46% did not know or did not respond. 31%

correctly reported the degree of conversion of a composite (following

manufacturer’s instructions) as about 75%; 39% did not

know or did not respond. 23% correctly reported the degree

of conversion of adhesives (following manufacturer’s instructions)

as about 75%; 41% did not know or did not respond.

62% were unsure or disagreed that elutable substances may

be present in cured RBCs.

Conclusions: Few surveyed dentists had or made use of

a radiometer. Knowledge of the relative efficiency of halogen

versus LED lights and of the degree of conversion of

resin based composites and adhesives were poor. Together

with the fact that 62% are unsure or disagreed that elutable

substances may be present in cured RBCs, findings suggest

that few responding dentists possessed the relevant current

knowledge to appropriately inform patients on the suitability

of these materials. Further research is required to corroborate

these findings within a wider population sample, and identify

the level of understanding of material science within the

dental profession.

doi:10.1016/j.dental.2010.08.089

82

Factors influencing depth of cure of nanohybrid composite:

Micro F-TIR analysis

M. Scansetti 1 , N. Scotti 1 , A. Venturello 2 , D. Pasqualini 1 ,E.

Berutti 1

1 University of Turin, Italy

2 Polytechnical School of Turin, Italy

Objectives: The aim of this in vitro study was to evaluate the

depth of cure of a nanohybrid resin composite irradiated with

an halogen lamp with different irradiation time and energy

densities and composite’s temperature.

Materials and methods: A commercially available nanohybrid

resin composite (Venus Diamond, Heraeus Kultzer,

Hanau, Germany) was selected for this study. The resin composite

was bulk placed inside a metal device, which allowed

the depth of cure examination. Semicircular samples (10 mm

depth) were obtained, with a later flat surface parallel to the

curing light direction. A total of 48 samples were prepared

and divided in different groups, which differed for: preheated

composite (20 ◦ or 50 ◦ ), energy density (400 mW/cm 2 ;

2000 mW/cm 2 ) and curing time (10 s; 40 s). The curing device

employed in this study was a halogen light (Swiss Master

Light, EMS, Switzerland). The degree of conversion (DC) was

accomplished by Micro Attenuated Total Reflection Fourier

Transform Infrared (ATR F-TIR) analysis 24 h after the polymerization.

DC was recorded every 0.25 mm along the lateral

surface of the sample. Sufficient depth of cure was considered

at the level where DC was 80% of the maximum DC of

each sample. Differences among groups were analyzed with

the non-parametric Mann–Whitney U-test (p < 0.05).

Results:

Group Energy

density

Curing

time

Mean

depth of

cure (�m)

Group Temp Mean

1 400 10 750 5 20 2134

2 400 40 2200 6 50 2098

3 2000 10 1758

4 2000 40 3525

Conclusions: Within the limits of this in vitro study the

depth of cure was not influenced by the temperature of the

composite (p = 0.725). Energy density and curing time are both

important in obtaining sufficient curing depth. The increase

of light energy density and curing time could give high values

of depth of cure, which could clinically allow to increase the

thickness of composite layers during restorations.

doi:10.1016/j.dental.2010.08.090


83

12-h Post-polymerization of a nanohybrid resin composite:

Conversion degree’s evaluation

N. Scotti 1 , A. Venturello 2 , F. Pera 1 , D. Pasqualini 1 , E. Berutti 1

1 University of Turin, Italy

2 Polytechnical School of Turin, Italy

Objectives: The aim of this in vitro study was to

evaluate the conversion degree progression, during the

post-photopolymerization, of a nanohybrid resin composite

irradiated with a LED lamp (Trouffier-Boutry et al., J Dent Res;

2006).

Materials and methods: A commercially available nanohybrid

resin composite (Venus Diamond, Heraeus Kultzer,

Hanau, Germany) was selected for this study. The resin

composite was bulk placed inside aluminum rings, 10 mm

diameter, with different thickness (1 mm, 2 mm). A total of 32

samples were prepared and divided in 2 groups of sixteen samples

each. The curing device employed in this study was a LED

light (Translux Power Blue, Haereus Kultzer, Hanau, Germany).

Each group was divided in 2 subgroups on the basis of the irradiation

time (10 s, 40 s). The degree of conversion at the bottom

surface of each sample was accomplished by Attenuated Total

Reflection Fourier Transform Infrared (ATR F-TIR) analysis

(Eqinox 55, Bruker Optics S.p.A.) immediately after photopolymerization

and every 10 min for 12 h. In this study the

conversion degree obtained immediately (T = 0), after 30 min

(T = 1) and after 12 h (T = 2) from the photo-polymerization was

considered. Differences among groups were analyzed with the

non-parametric Mann–Whitney U-test (p < 0.05).

Results:

dental materials 26S (2010) e1–e84 e39

T =0 T =1 T =2

10 s 1 mm 31.8% 44.6% 52.4%

40 s 1 mm 24.1% 35.9% 43.1%

10 s 2 mm 40.5% 47.8% 54.2%

40 s 2 mm 38.6% 45.3% 52.3%

Conclusions: Within 1 mm specimens, 10 s curing time produced

in T = 0 and T = 1 a conversion degree significantly lower

than the conversion degree obtained with a curing time of

40 s (p < 0.05); however, during the post-polymerization process,

the mean conversion degree values got closer being

not statistically different after 12 h (p = 0.09). On the contrary,

2 mm samples did not achieve a satisfactory conversion

degree after 10 s curing, which is significantly lower than 40 s

curing time (p < 0.05). Even during post-polymerization the

conversion degree did not significantly increase, concluding

that 2 mm composite stratification needs 40 s curing time to

achieve a sufficient conversion degree.

doi:10.1016/j.dental.2010.08.091

84

Rugosimetric analysis of a microhybrid composite polished

with four protocols

D. Angerame, D. Sossi, M. Cattaruzza, F. Spizzo, M. De Biasi

University of Trieste, Trieste, Italy

Objectives: Composite restorations with complex anatomy

are difficult to polish; rigidity of rubber points can alter surface

texture. The purpose of this study was to investigate the

surface roughness of a microhybrid composite polished with

abrasive pastes or rubber points, with or without superficial

light-cured resin.

Materials and methods: Forty discs (diameter

7mm× 1.5 mm) of composite (Filtek Z250, 3M ESPE) were

light cured and randomly divided into four groups (n = 10):

group 1 (G1), rubber points (70, 40, and 5 �m, Identoflex AG);

group 2 (G2), abrasive pastes (80, 35, and 4 �m, FGM); group 3

(G3), rubber points (=G1) and Seal Coat Fast resin (DEI Italia);

group 4 (G4), abrasive pastes (=G2) and Seal Coat Fast resin.

The specimens were analyzed using a rugosimeter (Talysurf

CLI 1000, Taylor Hobson) considering a linear parameter (Ra);

nine standardized 0.5 mm long measurements were made for

each specimen. A 0.2 �m roughness value was assumed as

clinically acceptable threshold. Collected data were statistically

analyzed with Kruskal–Wallis and Mann–Whitney tests

(p < 0.05). Samples were then observed with SEM, running in

low vacuum mode, without any sample preparation and by

means of backscattered electron detector.

Results: Roughness values were lower than 0.2 �m in

all groups. Mean Ra values ± SD (�m) were: G1 = 0.07 ± 0.02,

G2 = 0.06 ± 0.01; G3 = 0.06 ± 0.04; G4 = 0.03 ± 0.01. Significant

differences among groups were found: G1 vs. G2 (p < 0.05); G1,

G2 and G3 vs. G4 (p < 0.01). Grooves and loss of superficial filler

were found in G1 and G2; grooves in G1 were parallel. Specimens

treated with surface resin coat presented smoother

aspect than untreated specimens.

Conclusions: All tested techniques offered roughness values

under clinically acceptable threshold on flat surfaces.

Abrasive pastes seem to be a valid alternative to rubber points

when used on restoration with complex anatomy. Best results

were obtained in G4; resin coating improves surface smoothness

obtained with pastes.

doi:10.1016/j.dental.2010.08.092

85

Nanogel-modified composite materials: Route to low shrinkage

and stress

J.W. Stansbury, R.R. Moraes, J.W. Garcia, M.D. Barros, S.H.

Lewis, C.S. Pfeifer

University of Colorado, Aurora, USA

Objectives: The use of reactive pre-polymerized, nanosized

particles to reduce reactive group concentration (and, as a consequence,

shrinkage and stress) is proposed here. As opposed

to ground, micro-sized, cured composite particles previously

used as additives, nanogels allow for a higher amount of prepolymer

to be added, without interfering with inorganic filler


e40 dental materials 26S (2010) e1–e84

loading. In addition, because they bear methacrylate reactive

groups in their backbones, these particles are covalently

bound to the resulting network, with potential mechanical

reinforcement.

Materials and methods: Nanogels were synthesized

by photoactivating a 30:70 mol% mixture of urethane

dimethacrylate and isobornyl methacrylate, respectively, in

solution with toluene (1:4 vol%). Mercaptoethanol was added

to control molecular weight and provide reaction sites for

isocyanoethyl methacrylate, rendering the material polymerizable.

After purification, the resulting powder was added to

triethyleneglycol dimethacrylate at 0 (control), 5, 10, 20, 30

and 40 wt%. Materials were tested as neat resins or composites

(70 wt% silanated barium glass; 0.4 �m average diameter).

Real-time monitoring of polymerization kinetics was carried

out using near-infrared (NIR) spectroscopy. Volumetric shrinkage

was evaluated in a linometer. Polymerization stress was

obtained with a NIR-coupled tensometer. Flexural modulus

was obtained by three-point bending. In all cases, samples

were irradiated for 5 min at 50 mW/cm 2 (Acticure 4000, EFOS).

Results: The onset of autodecceleration in the nanogelmodified

materials (resins and composites) occurred at lower

conversion compared with the control, but no differences in

final conversion were observed (approximately 70% for all

materials). The maximum rate of polymerization decreased,

as expected, since the presence of nanogel limits the potential

exotherm. Because of the polymerizable methacrylate groups

at readily accessible chain ends, the prepolymer behaves as a

macromolecular monomer (macromer) and even at the highest

nanogel loading mechanical strength properties remain

unaffected, which was true both for resins and composites,

indicating that effective covalent attachment is maintained

between the filler and the nanogel-modified polymeric matrix.

As expected, volumetric shrinkage and polymerization stress

decreased monotonically with nanogel content. Stress reductions

reached 50% with 40 wt% nanogel loading.

Conclusions: Nano-scaled, highly crosslinked, reactive

polymeric particles have efficiently reduced shrinkage and

stress with no compromise to final degree of conversion or

mechanical properties of neat resins or composites. The relatively

simple synthesis procedure and the swellability in

common dimethacrylates allows for commercial dental materials

to be envisioned in the near future, especially because

the incorporation of nanogels would not require any modifications

in the photopolymerization procedure used currently

in the clinic.

Support: NIH/NIDCR 1R21-DE18354 and RC1-DE020480.

doi:10.1016/j.dental.2010.08.093

86

Coefficient of thermal expansion of different types of composite

resins

K. Tolidis 1 , T. Vaimakis 2 , P. Gerasimou 1 , C. Boutsiouki 1

1 Aristotle University of Thessaloniki, Greece

2 University of Ioannina, Greece

Objectives: Temperature changes induced mainly by hot

and cold drinks are frequent in the oral cavity. Thermally

induced stress in teeth restored with resin composites, due to

the differences between the coefficients of thermal expansion

(CTE) of tooth tissues and the restorative materials, seem to be

related to induction of microleakage and mechanical degradation.

The purpose of this study was to measure the CTE values

of 4 types of composite resins and the effect of light intensity

of the LED curing device on the values of CTE.

Materials and methods: A nanohybrid resin composite, a

giomer, an experimental ormocer and silorane (color A2) were

tested. Eight 4 mm thick specimen were made from each material

and divided into two groups and polymerized with a high

and a low energy LED curing device. Dilatometer Netzsch DIL

402c was used to determine the values of CTE of composite

resin materials at a 20–85 ◦ C temperature range, with a heating

rate of 2 ◦ C/min.

Results:

Group Results

(10 −6 / ◦ )at

36.6 ◦ C

Mean Standard

deviation

Results

(10 −6 / ◦ )at

55.0 ◦ C

Mean Standard

deviation

Ormocer low 14.89 3.58 35.82 3.217

Ormocer high 8.760 5.075 23.77 5.564

Giomer low 15.49 9.453 47.06 6.159

Giomer high 38.67 23.44 48.87 14.13

Nanohybrid low 5.434 3.962 22.20 9.937

Nanohybrid high 12.04 15.49 30.69 13.12

Silorane low 16.47 12.44 47.54 9.128

Silorane high 5.753 2.640 41.74 28.76

Despite the differences in CTE diagrams, statistical analysis showed no

significant differences.

Conclusions: All the tested materials demonstrated a

reduction in CTE values at the beginning of the temperature

rise. During the entire measurement period, CTE values of the

resin composites were still higher than those of enamel (11.4)

and dentine, as expected. CTE values of the samples cured

with high energy LEDs exhibited fluctuation for all materials,

especially for silorane. Ormocer seemed to have the less fluctuations

of CTE, even less when polymerized with low power

LED. Silorane and ormocer polymerized with high power LED

demonstrated the lower values of CTE.

doi:10.1016/j.dental.2010.08.094

87

Manipulation of a dental composite resin using bovine

enamel as reinforcing filler

J.T. Tribioli, D.P. Jacomassi, V.S. Bagnato, C. Kurachi

Physics Institute of São Carlos-University of São Paulo, Brazil

Objectives: We propose a new dental composite resin based

on the replacement of the conventional fillers by bovine

enamel particles.

Materials and methods: Charged particles were obtained

from grinded bovine enamel, sinalized and incorporated in a

resin matrix of Bis-GMA, TEGDMA, UDMA. Camphorquinone


and amine were used as activators. The composite resin was

manipulated with several percentages of filler weight in the

range of 60–85%. Sample disks (5 mm × 1 mm) of manipulated

resin (MR) and two conventional resins 1 , 2 were photoactivated

using a LED-based device at 1000 mW/cm 2 and 60 s. Twentyfour

hours after polymerization, the degree of conversion and

microhardness were measured. Laser-induced fluorescence of

the manipulated and conventional resins and of human teeth

was measured. Data were analyzed using one-way analysis of

variance followed by the Tukey test.

Results: The bovine enamel particles were successfully

silanized and incorporated in the resin matrix. Degree of

conversion values were about 69 ± 3% for all tested compositions.

Vickers hardness increased for higher filler contents,

showing satisfactory values (p < 0.05). Fluorescence emitted

by the manipulated resin was more similar to the one from

the human teeth, when compared to the conventional resins

(p < 0.05).

Conclusions: The manipulated resin presented similar

results of the investigated properties when compared to conventional

resins, showing its potential use. Other tests as

tensile strength and tensile distribution within a restoration

are being performed.

doi:10.1016/j.dental.2010.08.095

88

Self-curing dental composition with improved cure temperature

M. Trujillo-Lemon, K. Esquibel, K. Ida, I. Ahmed, B. Gallagher,

A. Sotiros, C. Bonner, C. Bracho-Troconis

Septodont Colorado Research Center, Louisville, CO, USA

Objectives: The aim of this study was to compare the temperature

increase during polymerization of four experimental

temporary crown and bridge materials (C&BM) containing

different initiator compositions. The hypothesis tested

1 Filtek Z-250 3M ESPE.

2 Filtek Supreme XT 3M ESPE.

dental materials 26S (2010) e1–e84 e41

was that the temperature increase during the chemical

curing of C&BM can be reduced by using initiator combinations.

Materials and methods: Benzoyl peroxide (BPO), ditert

amyl peroxide (DTAPO), dicumyl peroxide (DCPO)

and/or bis(tert-butyl peroxide)-dimethyl hexane (TBHPO) were

employed in a conventional self-curing initiator/amine system.

The experimental catalysts used contained BPO:DTAPO

(CAT1); BPO:DCPO (CAT2) or BPO:TBHPO (CAT3) in a 2:3 molar

ratio. The control sample contained BPO (CATcontrol). The

experimental materials consisted of a paste/paste system of

Bis-GMA/UDMA/HDDMA resin matrix and barium glass filler

(50:50 wt%). For our experimental C&BMs, one universal base

containing the amine and 4 catalysts containing the different

initiator combinations were tested. The temperature of a 1:1

weight ratio of catalyst and base was monitored immediately

after mixing using a digital thermometer with type k-probe

embedded in the material. The results were compared with

commercial temporary crown and bridge materials: Structure

2 (Voco), Premium (Voco), Protemp II (3M ESPE), Luxatemp

(DMG America) and Cool Temp (Coltène). Statistical analysis

was performed by ANOVA and Student–Newman–Keuls

(p < 0.001).

Results: The results of this study demonstrated that

temperature increase differed between the experimental compositions,

in relation to initiator combination used. Thus the

tested hypothesis was accepted. Data are shown in the following

table.

Maximum

temperature

reached ( ◦ C)

�T ( ◦ C)

CATcontrol 44.0 21 ± 1 (a)

CAT1 30.0 7 ± 1 (b)

CAT2 35.0 12 ± 1 (c)

CAT3 41.0 18 ± 1 (d)

Structure 2 29.0 6 ± 1 (b)


e42 dental materials 26S (2010) e1–e84

Maximum

temperature

reached ( ◦ C)

�T ( ◦ C)

Premium 35.0 12 ± 2 (c)

Protemp II 32.0 9 ± 1 (b)

Cool Tempearture 34.0 11 ± 1 (c)

�T ( ◦ C) = (maximum temperature − initial temperature). Initial temperature

23 ◦ C.

Materials with similar letters do not differ statistically.

Conclusions: Final results indicate that BPO/DTAPO(CAT1)

temperature increases are well within the lowest temperature

range of the commercial materials presented by Structure 2

and Protemp II.

doi:10.1016/j.dental.2010.08.096

89

Colorimetric difference between two composites with the

same shade

M.A. Verlicchi, F. Fazzi, G. Dondi Dall’orologio

University of Bologna, Italy

Objectives: The purpose of this study was to use a

spectrophotometric analysis to evaluate colorimetric differences

between two composite resins, a microhybrid and a

nanohybrid, from the same manufacturer, with the same

shade.

Materials and methods: Three shades (A2, A3, and

A3.5) of two composite resins (Dentalica Micro and Dentalica

Nano) were tested. Samples of material were prepared

in small resin cavities, 5 mm in diameter, 3 mm

deep. Colorimetric analysis was performed with a reflection

spectrophotometer (SpectroShade Micro, M.H.T.) with

a 2× 45 ◦ /0-type illuminating and viewing geometry, with

18 mm × 14 mm lecture area: the measure was automatically

reported after three identical recordings. Each sample

was measured on black and white backings. The white

background had L* 83.69, a* −0.22, b* −0.60, the black background

had L* 1.45, a* 0.51, b* −0.84. Each sample was

light cured from the top for 20 s with a LED light unit,

with a power > 1.000 mW/cm 2 with 7 mm diameter tip. All

the data were directly reported in CIELAB coordinates (CIE

1986) with respect to standard light source A. The manufacturer

states that the precision of the machine is within

1%. Color differences (�E) was calculated from the equation:

�E =[(�L*) 2 +(�a*) 2 +(�b*) 2 ] 1/2 .

Results: �E values for each couple of shades, ranged

between 1.5 and 8.76. �T% data for each couple of shades,

ranged between 0.9 and 12.2.The analysis indicated that

the parameters L* and b* had a significant effect on �E,

while a* showed effect only between Micro K 000 and Nano

K 003 A2.

Conclusions: If two shades are within two �E units, the

match is clinically acceptable, a mismatch ranges from 2.1 to

3.7, a �E value greater than 3.7 indicates a poor match based

upon clinical observations (O’Brien). Different materials, even

if with the same shade and from the same manufacturer, generally

show different colors that are the result of a difference

in each dimension of the color. All the samples tested showed

great colorimetric differences. Overall, poor color compatibility

of pairs of identical shade was recorded: only three

couples of samples showed �E < 3.7 (Nano003 vs. Micro000 A2;

Micro000 vs. Micro 001 A2; Nano002 vs. Micro000 A3), anyway

the difference in translucency was significant. The best

color match was recorded for Nano002 vs. Micro000 A3. The

shade designation is arbitrary and subjective and it may also

change substantially between the materials of the same manufacturer,

also if the reference guide is the same: structure of

the composite, amount of resin, quality and dimension of the

filler play a key role. Both products worked very well, but the

clinician should know that colorimetric data are often very

different.

doi:10.1016/j.dental.2010.08.097

90

Restoration interface gap evaluation proposal by 3Dmicrotomography

F. Zuppante 1 , L. Manzon 2 , R. Pecci 1 , R. Bedini 1

1 Technology and Health Department, ISS, Rome

2 Aging Science Department, “Sapienza” University of Rome, Rome

Objectives: In restored dental cavities it is possible to predict

the presence of gaps due to polymerization shrinkage.

This work aimed to reveal by 3D images and by microCT

analysis the gaps generated after polymerization during dental

restoration procedures/practice. Five adhesive systems for

dental restoration were studied by in vitro analysis and their

performance evaluation done by means of 3D microtomography

technique (3D microCT).

Materials and methods: In this experimental study five

sound human crown teeth were selected, from patients 30 to

50-year old, all restored with the same composite material,

using five different adhesive systems (TECO (DMG, Germany),

Adper Scotchbond SE (3M ESPE, USA), CONTAX (DMG, Germany),

Adper Scotchbond 1 XT (3M ESPE, USA), Bond - 1

SF PENTRON CLINICAL All-in-one (Pentron Clinical Technologies

LLC, USA). After about 48 h each tooth was analyzed by

means of Skyscan mod.1072 microCT instrument and successively

processed by 3D reconstruction and microCT analyser

software to display and evaluate gaps obtained after polymerization

shrinkage.

Results: Table 1 shows values of tooth plus material volumes

(Vtot), the material volumes only (Vm) and the gap

volumes (Vg).

3D microCT analysis showed that the two adhesive systems

did not show as much gaps as expected, especially samples 5

and 2.

Conclusions: This proposal of microtomography evaluation

of the restoration-interface gaps seem to be an innovative

and very useful technique that can substitute the traditional

SEM investigations used until now, even if tooth sample

cutting and treatment for SEM observations surely causes

alterations like gaps or creeps on the same sample. Further

in vitro 3D microCT analysis on several samples is needed


Table1–MicroCTanalysis results.

dental materials 26S (2010) e1–e84 e43

Samples Materials Vtot (mm 3 ) Vm (mm 3 ) Vg (mm 3 )

1 TECO 406.94 ± 0.01 42.43 ± 0.01 0.80 ± 0.01

2 AdperScotchbondSE 641.44 ± 0.01 88.24 ± 0.01 0.27 ± 0.01

3 CONTAX 414.34 ± 0.01 55.32 ± 0.01 2.67 ± 0.01

4 AdperScotchbond1XT 499.55 ± 0.01 96.59 ± 0.01 1.00 ± 0.01

5 Bond-1SF 490.06 ± 0.01 67.91 ± 0.01 0.02 ± 0.01

to validate the proposed gap evaluation method by statistical

evaluation.

doi:10.1016/j.dental.2010.08.098

91

Potential of cure of resin cements mixed with bonding agents

T.R. Aguiar 1 , M. Oliveira 2 , L. Correr-Sobrinho 1 , C. Arrais 2 ,M.

Giannini 1

1 State University of Campinas, Piracicaba, SP, Brazil

2 University of Guarulhos, Guarulhos, Brazil

Objectives: The purpose of this study was to evaluate the

effects of bonding agents on the potential of cure (PC) of 2 dualpolymerizable

resin cements using infrared spectroscopy (IR).

Materials and methods: Two dual-cured cementing

systems (resin cements/bonding agents) were tested:

RelyX ARC/Scotchbond Multipurpose 1 and Clearfil Esthetic

Cement/DC Bond. 2 The resin cements were applied to the

surface of a horizontal attenuated-total-reflectance unit

solely or following the application of the bonding agents,

which were left in the uncured state prior to the resin cement

application. The resin cements and the mixture of bonding

agents and resin cements were light-cured (XL3000, 3M ESPE)

either through a glass slide or through pre-cured resin disc

(shade B2, 2 mm thick, Sinfony, 3M ESPE) for 40 s, or were

allowed to self-cure (autopolymerized mode). Infrared spectra

were obtained after placing components and 20 min later.

The degree of conversion was calculated using standard

techniques of observing changes in aliphatic-to-aromatic

peak ratios pre- and post-curing. The PC of each product

was calculated as a ratio of conversions in autopolymerized

mode or through pre-cured resin disc relative to direct

light-cure. Data (n = 5) were analyzed by two-way ANOVA

and Tukey’s post hoc test (pre-set alpha of 5%) within each

brand.

Results: The presence of uncured bonding agent increased

the PC of both resin cements when they were allowed to

self-cure (p < 0.001). Both products exhibited higher PC after

light-activation through pre-cured resin disc than when they

were allowed to self-cure (p < 0.0001), regardless the presence

of bonding agent.

Conclusions: The presence of an uncured bonding

agent increased the potential of cure of resin cements

when they depended solely on the self-curing mode.

However, the self-curing mechanism was always less

1 RelyX ARC/Scotchbond Multi-Purpose, 3M ESPE.

2 Clearfil Esthetic Cement/DC Bond, Kuraray Medical Inc.

effective than light-activation through pre-cured resin

disc.

doi:10.1016/j.dental.2010.08.099

92

Effect of the incorporation of potassium titanate fibers on the

strength of a dental porcelain

M.D. Araujo 1 , R.B.P. Miranda 1 , P.F. Cesar 1 , H.N. Yoshimura 2

1 University of São Paulo, Brazil

2 Federal University of ABC, Brazil

Objectives: To evaluate the effects of the incorporation of

potassium titanate fibers (K2O·6TiO2) and of the variation in

sintering temperature on the flexural strength of a dental

porcelain.

Materials and methods: One dental porcelain

(Shofu/Vintage Halo) was used to fabricate 170 discs (13 mm

in diameter and 1-mm thick). Ten discs were used for the

control group (no fibers, sintering temperature of 915 ◦ C), 60

discs were fabricated with the addition of 5 wt% of fibers and

60 discs were produced with the addition of 10 wt% of fibers.

The porcelain powder was mixed with potassium titanate

fibers and immersed in isopropyl alcohol for one hour. After

alcohol evaporation, the resulting slurry was used for disc

fabrication (vibration/condensation method). The discs containing

different fiber contents were sintered at 6 different

temperatures: 915, 925, 935, 945, 955 and 965 ◦ C. After sintering,

all specimens were finely polished up to 1 �m. Specimens

were tested in a piston on three balls apparatus using a

universal testing machine (37 ◦ C/water/1.0 MPa/s). Data were

analyzed with ANOVA and Tukey’s test (alpha = 0.05).

Results: The control group obtained mean strength of

52.7 ± 7.9. The mean strength (MPa ± standard deviation) of

the porcelain studied as a function of the temperature and

fiber content is shown in Table 1. For the specimens with

Table1–.

Sintering

temperature ( ◦C) Fiber content

(in wt%)

5% * 10% *

915 53.0 ± 8.9 (c,d) 65.2 ± 4.5 (a)

925 56.1 ± 3.4 (b,c,d) 64.3 ± 5.3 (a)

935 59.1 ± 1.2 (a,b,c,d) 63.3 ± 9.2 (a,b)

945 58.3 ± 2.4 (a,b,c,d) 64.8 ± 0.5 (a)

955 55.7 ± 5.1 (b,c,d) 62.8 ± 2.1 (a,b)

965 61.4 ± 7.8 (a,b,c) 64.3 ± 6.1 (a)

* Values followed by the same letter are statistically similar (p > 0.05).


e44 dental materials 26S (2010) e1–e84

addition of 5% of fibers, only the group sintered at 965 ◦ C

obtained statistically higher flexural strength compared to

the control. Specimens with fiber content of 10% showed

statistically higher strength values compared to the control

regardless of the sintering temperature. The flexural strength

of the groups containing 10% of fibers was only statistically

higher than that of the group with 5% of fibers at

the temperatures of 915 and 925 ◦ C. At the other sintering

temperatures both fiber contents resulted in similar flexural

strength.

Conclusions: The effect of the incorporation of K2O·6TiO2

fibers on the flexural strength of the dental porcelain studied

depended on the fiber content and on the sintering temperature.

The addition of 10 wt% of these fibers is promising to

improve the mechanical properties of dental porcelains.

doi:10.1016/j.dental.2010.08.100

93

CD117 expression in peri-implantitis soft tissues: An

immunohistochemical study

S.D. Aspriello, A. Zizzi, F. Bambini, M. Lorenzi, C. Rubini, M.

Piemontese

Polytechnic University of Marche, Torrette, Ancona, Italy

Objectives: Mast cells play important roles in mucosal

inflammation, host defense and tissue repair. Fibrinogen

adsorption to the implant surface and histamine release by

local mast cells are involved in biomaterial-mediated acute

inflammatory responses. Administration of histamine receptor

antagonists prior to, and shortly after, medical device

implantation should improve the functionality and longevity

of medical implants. CD117 (c-kit) is expressed by pluripotential

or committed progenitors, immature and mature mast

cells. Our aim was to investigate the immunohistochemical

CD117 expression of healthy or diseased peri-implant soft tissue.

Materials and methods: Immunohistochemical detection

of CD117, revealed by streptoavidin-biotin peroxidase technique,

was performed in 12 paraffin-embedded tissue sections

of 6 healthy gingiva (controls) and 6 gingiva with periimplantitis.

All data were statistically analyzed by Student’s

t-test.

Results: CD117 expression was significantly increased in

patients with peri-implantitis compared to healthy subjects

(p < 0.05). In particular, normal gingival showed occasional

CD117+ cells at superficial mucosal stroma level. In periimplantitis

gingiva, with a low inflammatory infiltrate, CD117+

cells were increased compared to control, and confined in

papilla or in superficial mucosal stroma, beneath the basal

membrane. Where inflammatory infiltrate was higher, we

found a significant increase of CD117+ cells compared to control

(p < 0.05), above all in lymphoplasmacytic inflammatory

cells and at profound mucosal stroma level also.

Conclusions: The involvement and higher expression of

CD117 are important factors in peri-implant diseases. Mast

cells function, together with inflammatory infiltrate cells, constitute

a network that can orchestrate protective immunity

and peri-implant host defence or can lead to consider-

able harmful inflammation and tissue damage, such as

osseointegration loss process. The close association between

peri-implantitis and mast cells needs further investigation to

disclose a possible pathological interaction in this disease.

doi:10.1016/j.dental.2010.08.101

94

Self-adhesive cement adhesion to zirconia ceramic: Effect of

surface treatments

D. Augusti 1 ,D.Re 1 , M. Ferrari 2 , G. Augusti 1 , F. Caimi 1

1 University of Milan, Milan, Italy

2 University of Siena, Siena, Italy

Objectives: The aim of this investigation was to assess

the influence of several surface treatments on the immediate

shear bond strength of a self-adhesive resin cement to densely

sintered zirconia ceramic.

Materials and methods: 40 Densely sintered zirconia cylinders

(d: 20 mm; h: 8 mm, approximately) (Lava ® , 3M ESPE, St.

Paul, MN) were divided into four groups (n = 10). Each of them

received a different surface treatment:

Group [Sand H] – ceramic blocks were air-abraded using

50 �m Al2O3 particles at a pressure of 2.8 bar/0.28 MPa;

Group [Sand S] – ceramic blocks were air-abraded using

50 �m Al2O3 particles at a pressure of 1 bar/0.1 MPa;

Group [HE] – an experimental etching solution (methanol,

37% HCl and ferric chloride) was heated up to 100 ◦ C and

applied for 10 min.

Group [No T] – no treatment.

Composite cylinders were bonded with a self-adhesive

resin cement (Clearfil TM SA Cement, Kuraray Medical Ltd.) to

ceramic surfaces. After fabrication, specimens were stored in

deionized water (37 ◦ C) for 7 days before testing. Finally, all

bonded specimens were placed in a jig for shear bond strength

testing and loaded to failure. The data were analyzed by oneway

ANOVA model with ˛ = 0.05; surfaces were examined with

a light microscope (25×) to assess the mode of failure. Further,

4 surface-treated only specimens were addressed to scanning

electron microscope (SEM) analysis to evaluate topographic

modifications.

Results: Mean shear bond strengths (MPa) obtained from

the tested samples were: [Sand H] 16.24 ± 2.95; [Sand S]

16.01 ± 2.68; [HE] 10.22 ± 1.94; [No T] 13.29 ± 1.58. No statistically

significant difference (p = 0.8580) was found between

[Sand H] and [Sand S] groups. Experimentally etched surfaces

were characterized by islands of granular appearance and a

high degree of topographic complexity; however, mean SBS

value of [HE] was statistically lower (p < 0.05) than that of

[No T].

Conclusions: Within our study limitations, low-pressure air

abrasion positively affected the self-adhesive cement adhesion

to zirconia but did not prevent scratches and microcracks

formation on the ceramic surfaces.

doi:10.1016/j.dental.2010.08.102


95

Evaluation of the mechanical behavior of ceramic systems

using fractographic analysis

M. Borba 1 , K.A. Fukushima 1 , H.N. Yoshimura 2 , P.F. Cesar 1 ,

J.A. Griggs 3 , A. Della Bona 4

1 University of São Paulo, Brazil

2 University of São Carlos, Brazil

3 University of Mississippi, USA

4 University of Passo Fundo, Brazil

Objectives: To evaluate the fracture strength ( f) and fracture

toughness (KIC) of ceramic systems used for fixed partial

dentures (FPDs).

Materials and methods: Five ceramic materials were used:

a yttria partially stabilized tetragonal zirconia polycrystal

(YZ – In-Ceram YZ, Vita), a glass-infiltrated alumina/zirconia

composite (IZ – In-Ceram Zirconia, Vita), a polycrystalline

alumina (AL – In-Ceram AL, Vita), and two feldspathic

ceramics (VM7 and VM9, Vita). Bar-shaped (BS) specimens

(2 mm × 4mm× 16 mm) were produced according to the manufacturer

instructions and polished to 1 �m (n = 30). Fixed

partial denture (FPD) frameworks were fabricated using CEREC

InLab and veneered with the recommended porcelain (n = 10).

BS specimens were tested in three-point flexure using a universal

testing machine at 1 MPa/s in 37 ◦ C artificial saliva.

FPDs were cemented in metal dies with zinc phosphate

cement and tested with the load being applied by a stainless

steel sphere in the center of the pontic with 1 MPa/s

stress rate until failure in a 37 ◦ C distilled water bath. Fracture

surfaces were analyzed under a stereomicroscope and

SEM. Fractography principles were used to determine the fracture

mode, to measure the critical flaw (c) and to calculate

KIC of the BS specimens, based on the following relation:

KIc = f·Y·c 1/2 , where f is the stress at fracture and Y is

the geometrical constant dependent on the flaw shape. For

FPDs, c values were also determined fractographically, and f

was estimated using the KIc values calculated for BS specimens,

using the same relation described above. Data were

statistically analyzed using Kruskal–Wallis and Tukey test

(˛ = 0.05).

Results: Considering the framework materials, the same

ranking of f observed for BS specimens was found for

FPDs. YZ had the highest f value (861 MPa) followed by

AL (474 MPa) and IZ (412 MPa). The porcelains showed the

lowest f results, approximately 65 MPa. The c values measured

for the framework materials were also similar in

both configurations (BS and FPD), varying from 35 to 45 �m.

Porcelain BS specimens showed c values from 75 to 86 �m.

KIC values were significantly different among the materials.

YZ showed the highest KIC value (6.5 MPa m 1/2 ). AL

and IZ presented intermediate KIC values (3.5 MPa m 1/2 ) followed

by the two porcelains (0.7 MPa m 1/2 ). The fracture

mode of FPDs was influenced by the framework material.

Conclusions: As the flaw population and mean f values

were similar for both specimen configurations (BS and FPDs),

the three-point flexural test is a reliable tool to predict the

mechanical behavior of FPDs. In addition, the material with

dental materials 26S (2010) e1–e84 e45

the best mechanical performance in both BS and FPD configuration

was YZ.

doi:10.1016/j.dental.2010.08.103

96

Clinical performance of posterior three-unit zirconia-based

fixed partial dentures: 63-Month prospective clinical study

B. Borelli, R. Sorrentino, G. De Simone, S. Tete’, F. Zarone

University of Naples “Federico II”, Italy

Objectives: This prospective clinical trial aimed at evaluating

the clinical performance of tooth-supported three-unit

posterior zirconia FPDs after 63 months of clinical function.

Materials and methods: Thirty-seven patients received

48 3-unit zirconia-based (Procera, NobelBiocare) FPDs. The

restorations replaced either a premolar or a molar. Specific

inclusion criteria were needed. Tooth preparation was standardized:

2 mm occlusal reduction, 1.5 mm axial reduction

and circumferential chamfer shoulder placed 0.5 mm subgingivally,

buccally and supragingivally lingually on sound tooth

structure; all internal angles were rounded. Impressions were

made with polyether (3M ESPE). CAD-CAM frameworks (Procera,

NobelBiocare) with 9 mm 2 connector and 0.6 mm retainer

were made. The restorations were luted with resin cement

(RelyXUnicem, 3M ESPE). The patients were recalled after 1, 6,

12, 24, 36, 48, 60 and 63 months. Survival and success of ceramics

and zirconia were evaluated. The technical and esthetic

outcomes were examined using USPHS criteria. The biologic

outcomes were analyzed at abutment and contralateral teeth.

Modified Ryge criteria were used to assess marginal adaptation

and discoloration. Descriptive statistics were performed

(Kaplan–Meier, Wilcoxon).

Results: All FPDs completed the study, resulting in 100%

cumulative survival rate and 93.75% cumulative success rate.

No losses of retention were recorded. 42 Restorations were

rated Alpha in all measured parameters. Minor chipping of

ceramics was detected in 3 restorations. 3 restorations were

rated Bravo for marginal integrity at 63 months. No significant

differences between the periodontal parameters of the test

and control teeth were observed. As to esthetics, 44 restorations

were rated Alpha and 4 were rated Bravo by both the

clinicians and the patients either at baseline and 63-month

follow-up.

Conclusions: 63-month clinical results proved that 3-unit

posterior zirconia-based FPDs were successful in the mediumterm.

This type of restoration may be considered reliable to

replace a missing tooth.

doi:10.1016/j.dental.2010.08.104


e46 dental materials 26S (2010) e1–e84

97

Mechanical properties of particulate glass fiber-reinforced

acrylic resins

R.G. Soares, A.L. Botelho, D. Cecchin, A.P. Farina, A.C. Reis,

M.O. Mazzetto

University of São Paulo, Brazil

Objectives: The objective of this study was to evaluate some

mechanical properties such as surface roughness, hardness,

elastic modulus and flexural strength in acrylic resins after

the incorporation of pre silanized glass fiber particulate.

Materials and methods: Twenty-four specimens

(65 mm × 10 mm × 3 mm) of each brand of acrylic resin,

used for fabrication of occlusal splints, were made: Vipi

Flash 1 (self-curing), Vipi Wave 1 (by thermo microwave heat),

Vipi CRILL 1 , Lucitone 2 and QC-20 2 (thermo heat water bath),

with 12 control specimens and twelve experimental ones

with the addition of 10 wt% glass fiber particulate 3 . After the

polymerization processes, specimens were removed from the

molds and the excesses were removed by polishing, using

carbide paper with progressively increasing grit of 200, 500,

600, 800 and 1200 in a polishing device. The specimens were

polished with a felt wheel and alumina. Surface roughness

was evaluated with a roughness tester 4 with three readings

for each specimen, the microhardness was examined with a

hardness tester 5 with five measurements for each specimen,

while flexural strength and modulus of elasticity of the specimens

were evaluated using a universal testing machine 6 ,

with an speed of 5 mm/min. Data were statistically analyzed

using parametric and nonparametric tests, according to the

sample distribution.

Results: A statistically significant difference was observed

between groups with different polymerization methods. Based

on the results of this study, the conventional heat-polymerized

acrylic resin and the microwave polymerized resin presented

the highest roughness values when compared with autopolymerized

resin. The addition of glass fiber particulate

increased the roughness values of some acrylic resins Vipi

CRILL, Vipi Flash and Vipi Wave and remained constant in the

resins Lucitone and QC-20. The addition of glass fiber did not

increase significantly the microhardness in the groups. With

respect to flexural strength glass fiber particulate significantly

increased all values, as well as the modulus of the acrylic resin

reinforced by the addition of glass fibers.

Conclusions: The conclusion is that the incorporation of

fibers resulted in significant changes in almost all properties

examined, and can thus be effectively used as an additional

reinforcement for acrylic resins.

doi:10.1016/j.dental.2010.08.105

1 Vipi, Pirassununga, SP, Brazil.

2 Dentsply Intl, York, USA.

3 Reforplás S/A, São Paulo, Brazil.

4 Mitutoyo, Japan.

5 Micro Hardness Tester, Shimadzu, Japan.

6 Emic DL 2000, Emic, São José dos Pinhais, PR, Brazil.

98

Effect of ceramic surface conditioning on resin-MTBS durability

to leucite ceramic

M.A. Bottino 1 ,A.Amaral 1 , L.F. Valandro 2

1 São Paulo State University, São Jose dos Campos, São Paulo, Brazil

2 Federal University of Santa Maria, Rio Grande do Sul, Brazil

Objectives: To evaluate microtensile bond strength of

a resin-based cement to a leucite-based ceramic (Vita

PM9), after different conditioning methods of the ceramic

surface.

Materials and methods: Forty-five blocks were fabricated

and divided into 5 groups (n = 8) according to each surface

conditioning (SC): SC1: without surface conditioning; SC2:

hydrofluoridric acid (HF) 9% gel during 1 minute + wash/dry;

SC3: HF 4% gel during 1 minute + wash/dry; SC4: HF 5% gel

during 1 min + wash/dry; SC5: CS4 + neutralizer + wash/dry

+ ultrasonic cleaning. All blocks were treated with silane

before cementation with resin cement. The specimens were

stored in distilled water at 37 ◦ C for 24 h and cut into 2 axes

(x and y), to produce bar specimens, which were submitted to

the following conditions: Dry- immediate microtensile bond

strength test after cutting; TC- storage (150 days) + thermocycling

(6000×, 5–55 ◦ C). Therefore 10 groups were composed,

considering the 2 study factors (surface conditioning in 6

levels, storage condition in 2 levels). Two-way ANOVA and

Tukey test were used for statistic analyses (˛ = 0.05).

Results: 2-way ANOVA showed that storage (dry > TC)

and surface conditioning (SC3 = SC4 = SC2 > SC5 > SC1) factors

influenced the bond strength results (p < 0.0001). All surface

conditioning groups decreased the bond strength significantly

after aging (2.3–9 MPa), when compared to the respective

groups in dry conditions (3.4–16.8 MPa).

Conclusions: The resin bond strengths to leucite ceramic

etched by different hydrofluoric acids and silanized were not

stable. The acid neutralization procedure did not contribute to

adhesion.

doi:10.1016/j.dental.2010.08.106

99

Influence of cement color on final shade of all-ceramic

restorations

M. Carrabba, A. Vichi, C. Goracci, M. Ferrari

University of Siena, Siena, Italy

Objectives: Different cement colors can influence the

final shade of all ceramic restorations (Chang J et al. J

Dent 2009;37:937). The aim of this study was to investigate

the influence of cement in different colors on the

final shade of CAD/CAM chairside restorations of various

thickness.

Materials and Methods: Specimen of three different thickness,

0.5, 1.0 and 1.5 mm, of feldspatic ceramic 1 were prepared

by cutting a CAD/CAM block (sample size 18 mm × 14 mm).

1 VITA Mark II #2M2, Vita Zahnfabrik.


Disks of composite resin2 were used as substrate. Cementations

were performed with a self-etch/self-adhesive resin

cement3 in 5 different colors with a standardized seating

force. In the control group, glycerin was used instead of

cement. The specimen were measured in CIELab* system with

a spectrophotometer equipped with an integrating sphere.

The formula �E = 2� �L∗2 + �a∗2 + �b∗2 was used to calculate

the differences in color between samples and the control

group.

Results:

dental materials 26S (2010) e1–e84 e47

Thickness 0.5 mm 1 mm 1.5 mm Sign. total shade

Shade Mean SD Sign. Mean SD Sign. Mean SD Sign.

Clear 1.154 0.489 a 0.879 0.506 a 0.971 0.494 a A

White 1.426 0.140 b 1.955 0.577 b 1.048 0.216 a B

Yellow 2.567 0.670 c 3.049 0.670 c 1.269 0.509 a C

Brown 3.503 0.405 d 2.659 0.600 c 1.953 0.801 b D

White Op 2.207 0.557 bc 3.911 0.656 d 3.376 0.229 c E

Tot. mean 2.171 0.200 B 2.490 0.066 C 1.723 0.241 A

The Two Way ANOVA was applied, followed by the Tukey

test for post hoc comparisons (p < 0.05).

Conclusions: For the ceramic tested, and in relation with

its thickness the color of the cement is able to influence the

final color of the restoration.

doi:10.1016/j.dental.2010.08.107

100

Effect of surface conditioning on bonding to zirconium-oxide

ceramic

A. Casucci 1 , C. Goracci 1 , F. Monticelli 2 , N. Chieffi 1 ,M.

Sedda 1 , M. Ferrari 1

1 University of Siena, Italy

2 University of Huesca, Spain

Objectives: To evaluate the influence of different surface

treatments and metal primer application on the microtensile

bond strength of zirconia ceramic to cured resin cement.

Materials and methods: Twenty-four cylinder-shaped (Ø

12 mm × 5.25 mm high) of zirconia sintered CAD/CAM blocks

(Aadva Zirconia, GC, Tokyo, Japan) were randomly divided

into 4 groups (n = 6), based on the surface treatment to be

performed: (1) airborne particle abrasion with 125 �m Al2O3

particles (S); (2) experimental hot etching solution applied

for 30 min (ST); (3) selective infiltration etching (SIE); (4) no

treatment (C). Paradigm MZ100 blocks (3M ESPE) were cut

into 24 cylinders of 4 mm in thickness. Half of the zirconia

specimens of each group received the application of

Metal Primer II. Conditioned Zirconia and composite cylinders

were luted using a resin cement (G-Cem), in combination

with the proprietary adhesive system. After 24 h bonded

2 Herculite XRV Ultra Dentine #A2, Kerr.

3 Maxcem Elite #Clear, White, White Opaque, Yellow and

Brown, Kerr.

Table1–.

Surface

treatment

No metal primer II Metal primer II

[MPa] PF (%) [MPa] PF (%)

Sandblasting (S) 14.98 (7.97) A 0 24.49 (7.89) B 0

Hot etching

30 min (ST)

17.97 (8.57) B 11.11 18.70 (8.13) A 11.11

SIE (SIE) 12.25 (10.96) A 30.00 19.37 (9.59) A 5.16

No treatment (C) 10.66 (9.89) A 31.25 16.0 (10.34) A 26.66

Different capital letters indicate groups that are statistically different (p < 0.05).

specimens were cut into microtensile sticks and loaded in tension

until failure. Data were analyzed with two-way ANOVA

and Tukey test for multiple comparisons (p < 0.05). Failure

mode distribution was recorded and the interfacial morphology

of debonded specimens was analyzed using a scanning

electron microscope (SEM).

Results: Means of bond strength are reported in Table 1.

Both surface treatment and the application of Metal Primer II

improved significantly bond strength values (p < 0.05). When

Metal Primer II was not applied on to the zirconia surface

ST treatment achieved highest bond strength values (p < 0.05).

Sandblasting in combination with metal primer obtained the

highest bond strength values. Premature failures were mostly

recorded in the C group.

Conclusions: Conditioning the high-strength ceramic surfaces

with metal primer II significantly improved the zirconia

bond strength with all surface treatment tested.

doi:10.1016/j.dental.2010.08.108

101

Effect of multiple sintering cycles on the translucency parameter

of dental ceramics

P.F. Cesar 1 , C.C. Gonzaga 2 , C.F.S. Pereira 1 , M.M. Pinto 3 , H.N.

Yoshimura 4

1 University of São Paulo, Brazil

2 Positivo University, Brazil

3 UNINOVE, Brazil

4 Federal University of ABC, Brazil

Objectives: The objective of this study was to determine the

translucency parameter (TP) of dental enamel and eight commercial

veneering ceramics. The effect of multiple sintering

cycles on the TP of the ceramics was also investigated.

Materials and Methods: Disk specimens (n = 10, Ø

12 mm × 1 mm) were produced with the ceramics shown

in Table 1. Specimens were sintered and both sides were

mirror-polished. Enamel samples (1 mm-thick) were obtained

from seven sound human molars. A spectrophotometer was

used to measure the L*, a* and b* coordinates using two


e48 dental materials 26S (2010) e1–e84

Table1–.

Ceramic Brand/ Number of firing cycles

manufacturer

1 4 7

CO-ZR Cerabien

ZR/Noritake

25.4 ± 3.0a 22.8 ± 1.8a 21.8 ± 2.2a DK Duceram

Kiss/Degudent

29.5 ± 1.8a 28.1 ± 3.0a,b 25.0 ± 2.2b EMAX E.max

ceram/Ivoclar

17.3 ± 1.4a 20.4 ± 2.1a 19.1 ± 0.8a VAL Vintage

AL/Shofu

27.0 ± 1.0a 27.0 ± 1.0a 26.5 ± 0.5a VH Vintage

Halo/Shofu

18.8 ± 4.1a 19.1 ± 2.9a 18.5 ± 1.9a VM7 VM7/Vita 17.0 ± 2.6a 19.4 ± 1.9a 17.6 ± 1.1a VM9 VM9/Vita 25.3 ± 1.0a 27.1 ± 2.2a 24.3 ± 2.1a VZR Vintage

ZR/Shofu

16.8 ± 1.1b 27.2 ± 0.6a 25.1 ± 0.8a * Within the same line, values followed by the same superscript are

statistically similar (p > 0.05).

standard cards as background: black (CIE L* = 24.58, a* = 0.27,

b* = 2.58) and white (CIE L* = 92.95, a*=−0.78, b* = 3.57). All measurements

were performed after 1, 4 and 7 firing cycles in the

diffuse reflectance mode (range of between 400 and 700 nm

and intervals of 10 nm). Fixed parameters were: illumination

of CIE D65 (day light, 6500 K) and observer at 2◦ . TP was determined

by: TP = [(L∗ b − L∗w )2 + (a∗ b − a∗w )2 + (b∗ b − b∗w )2 ] 1/2

, where

the subscripts b and w indicate the color of the background

(black and white, respectively). Results were analyzed by

ANOVA and Tukey’s test (˛ = 0.05).

Results: The mean TP value obtained for dental enamel

was 18.4 (±2.7). The values of TP as a function of the ceramic

material and number of firing cycles are shown in Table 1. The

results indicated that these materials can be divided in 3 distinct

groups: (a) those for which the TP was not significantly

affected by the multiple firing cycles and all values were similar

to that of the enamel (EMAX, VH and VM7), (b) those for

which TP was not significantly affected by the multiple firing

cycles but the values were statistically different from that of

the enamel (CO-ZR, VAL, and VM9); and (c) those for which

the TP values were significantly affected by the multiple firing

cycles (DK and VZR).

Conclusions: Only two materials showed the same translucency

level compared to dental enamel, regardless of the

number of firing cycles. The effect of multiple sintering cycles

on the TP values depended on the ceramic material studied.

doi:10.1016/j.dental.2010.08.109

102

Risks of ceramic veneer fracture under different occlusal loading

conditions

Y. Chaiyabutr 1 , J.C. Kois 1 , V. Isvilanonda 2

1 Kois Center, USA

2 University of Washington, USA

Objectives: This study used 2D finite element analysis to

investigate the risks of ceramic fracture and cement failures

on maxillary central incisors when different ceramic veneer

preparation designs and occlusal conditions were applied.

Materials and methods: The software ANSYS version 10.0

was used to develop a FEA mesh consisting of 23,974–42,291

elements and 73,037–128,941 nodes. Two different preparation

designs were tested: incisal shoulder finish line (FI) and

incisal shoulder finish line with a palatal chamfer margin (FIP).

The materials used in this study were pressable ceramics (IPS

Empress) and resin-based luting agents (RelyX Veneer). The

maximum principal stress ( max) in all models was calculated

from four interincisal load angulations: 90 ◦ , 120 ◦ , 135 ◦ and 160 ◦

to the long axis of the tooth. A 120-N, which is the maximum

human bite force for maxillary anterior teeth (Kumagai et al. J

Oral Rehabil 1999;26:932), was applied on the palatal surfaces

of ceramic veneers at 2 mm from the incisal edges. The risks of

ceramic fracture (RCF) were calculated by dividing the tensile

( max) stress (registered in material) by its tensile strength (TS)

as described in the literatures. The tensile and shear stresses

in the ceramic and resin cement interfaces were analyzed to

determine the risks of cement failures (RCEF).

Results:

Models Ceramic Cement Maximum crown

displacement

(mm)

max TS RCF max TS RCEF

FI-90 138.2 135.0 1.02 109.5 77.6 1.41 1.65

FIP-90 152.2 135.0 1.13 93.1 77.6 1.20 1.45

FI-120 125.5 135.0 0.93 74.5 77.6 0.96 1.36

FIP-120 113.1 135.0 0.84 45.2 77.6 0.58 1.14

FI-135 100.4 135.0 0.74 43.5 77.6 0.56 1.08

FIP-135 91.3 135.0 0.68 26.9 77.6 0.35 0.87

FI-160 94.6 135.0 0.70 13.9 77.6 0.18 0.44

FIP-160 85.1 135.0 0.63 12.0 77.6 0.15 0.35

Conclusions: Interincisal load angulation has effects on the

biomechanical behavior of ceramic veneers in terms of stress

distribution, risks of ceramic fracture and cement failures. In

most loading conditions, the shoulder finish line is susceptible

to tensile stress in ceramic 10–15% higher than the other

samples, suggesting higher risks of ceramic fracture. This

trend, however, excludes interincisal load angulation at 90 ◦ .

Increasing interincisal load angulation contributes to lower

tensile stress in cements, suggesting lower risks of cement

failures for both preparation designs. As the interincisal load

angle increases, the maximum displacement of the crown

decreases.

doi:10.1016/j.dental.2010.08.110

103

Shade match of two ceramic systems with 3D-Master

Toothguide

G. Corciolani, A. Vichi, M. Sedda, C. Goracci, M. Ferrari

University of Siena, Italy

Objectives: The purpose of this study was to test the ability

of two different dental porcelains to correctly reproduce

the selected color with reference to 3D-Master Toothguide by

using a clinical spectrophotometer.

Materials and methods: Two ceramic systems were

selected for this study, Vita Omega 900 and Vita VM13. Three

shades in Vita 3D-Master Toothguide were selected for each

system, 2M3, 3M2 and 4M2. 30 ceramic discs, 15 mm in diameter,

were fabricated with 2 different layering schemes (LS)


for each ceramic system, maintaining the overall total thickness

at 1.3 mm. The thicknesses of the layers were: metal

base disc 0.3 mm, opaque 0.15 mm, dentin opaque 0.35 mm

and 0.45 mm, dentin 0.5 mm and 0.7 mm, enamel 0.1 mm and

0.2 mm. The thickness of each layer was verified after each firing.

A clinical spectrophotometer (Vita Easyshade) was used

for color comparison in “Restoration” mode, which allows

comparing the instrument set color data with the measured

ones. The obtained �E values (differences between intended

and obtained shade) were statistically analyzed with a 3-way

ANOVA and the Tukey HSD test (˛ = 0.05).

Results:

Shade LS Ceramic �E Significance

2M3 1 VM13 0.98 (0.08) a

Omega 900 0.88 (0.08) a

2 VM13 1.40 (0.12) b

Omega 900 1.94 (0.09) c

3M2 1 VM13 1.06 (0.08) a

Omega 900 1.76 (0.05) c

2 VM13 1.48 (0.08) b

Omega 900 1.48 (0.04) b

4M2 1 VM13 0.96 (0.09) a

Omega 900 1.90 (0.07) c

2 VM13 1.42 (0.08) b

Omega 900 0.96 (0.11) a

Significance column = homogeneous subsets (Tukey HSD test

level = 0.05).

Interaction shade × LS × ceramic (F = 189.62, p < 0.001).

Conclusions: Both Vita VM13 and Vita Omega 900 ceramics

exhibited a close shade match with reference to the selected

shades of the Vita 3D Master Toothguide. The layering scheme

has influenced the final color of the restorations.

doi:10.1016/j.dental.2010.08.111

104

Precision of different transfer impression techniques in multiple

implants

F.L.G. Cruz 1 , J.C.B. de Faria 2 , F.P.P. Leite 1 , A.P.P. Leite 1 ,Mgam

Chaves 1 , L.R.S. Concílio 2 , A.C.C. Neves 2

1 Universidade Federal De Juiz De Fora, Brazil

2 Universidade de Taubaté, Brazil

Objectives: The aim of this study is to compare different

materials and techniques used in multiple implant transfer

impressions, measuring the gap between superstructure and

implants.

Materials and methods: Four external hexagonal implants

(Neodent, Curitiba, Brazil) were fixed in a master cast and

over a superstructure. Afterwards, the impressions were made

using polyether (Impregum, 3M Espe, Seefeld, Germany) and

condensation silicone (Speedex, Coltène AG, Altstatten SG,

Swiss), using open and closed tray techniques with splinted

and non-splinted implant transfers. Auto (Duralay) or photopolymerized

(Duolay) acrylic resin was used for the splints

dental materials 26S (2010) e1–e84 e49

and the implant transfers were splinted, or not, resulting in

sixteen groups with five casts in each. The space between

master superstructure and the implants was measured using

a microscope, with a precision of 0.0005 mm and data were

statistically analyzed by T test (=0.05) and Mann–Whitney.

Results: With regard to the impression material tested, no

significant differences were observed, with the exception of

the groups that used photopolymerized Duolay resin to splint

transfers (groups 7 and 15) (p = 0.012). Regarding splint material,

no significant differences were observed, except for the

groups that employed autopolymerized Duralay (group 4) and

photopolymerized Duolay (group 8) for the splint, and that

were subsequently re-splinted (p = 0.004) with autopolymerized

Duolay (group 5) and photopolymerized Duolay (group

7) (p = 0.012). When comparing the techniques with divided

and re-splinted techniques with non-divided techniques, no

significant differences were observed (group 3 × group 4 –

p = 0.158; group 5 × group 6 – p = 0.094; group 7 × group 8 –

p = 0.144; group 11 × group 12 – p = 0.331; group 13 × group 14

– p = 0.203; and group 15 × group 16 – p = 0.092).

Conclusions: The impression materials provided similar

results, favoring the use of condensed silicone due to its lower

cost. The autopolymerized acrylic resin was better than photopolymerized

resin for use in the splint implant transfers.

The techniques with splinted transfers or non-splinted transfers

provided similar results.

doi:10.1016/j.dental.2010.08.112

105

Effect of hydrothermal aging on zirconia crystal phases and

strength

R. Dittmann ∗ , E. Mecher, A. Schmalzl, T. Kuretzky

3M ESPE, AG, Seefeld, Germany

Objectives: Yttria-stabilized zirconia is a state of the art

material for all ceramic dental restorations. In humid atmosphere

tetragonal to monoclinic phase transformation can

slowly occur at the outer surface of the zirconia ceramic

(Chevalier et al. J Am Ceram Soc 1999;82(8):2150). The purpose

of this study was to investigate the phase transformation of

two dental zirconia materials due to hydrothermal accelerated

aging and the effect on biaxial fracture strength.

Materials and methods: Disks (d =14mm, t = 1.5 mm) were

prepared from Lava Frame zirconia (3M ESPE) and a commercial

available generic dental zirconia. The samples were

sintered according to the recommendations of the manufacturers,

grinded plane-parallel and final polished on one side

with a 1 �m diamond suspension. Afterwards all samples were

thermally etched at 1350 ◦ C for 30 min to avoid effects of phase

transformation induced by grinding and polishing.

Samples of both zirconia materials were split into two

groups (n = 15 each group). One group of each material was

characterized initially and the other group was hydrothermal

aged in a steam autoclave at 135 ◦ C, 2 bar for 5 h.

X-ray measurements were performed on n = 5 samples each

group in Bragg-Brentano geometry (Bruker D8 Discover) and

quantitative phase analysis were done by the Rietveld method

(Bruker TOPAS software). Biaxial fracture strength measure-


e50 dental materials 26S (2010) e1–e84

ments were carried out with a punch (d = 3.6 mm) on 3-balls

(circular diameter 12 mm) test (Instron 5566).

Results:

Group XRD Rietveld analysis Biaxial fracture strength

Weibull statistics

Monoclinic

[wt.%]

Tetragonal

[wt.%]

Cubic

[wt.%]

Distorted

cubic [wt.%]

0 [MPa] m

Lava frame 0 78 22 0 1170 14.9

Lava frame aged 21 52 14 13 1120 24.8

Generic zirconia 0 80 20 0 937 5.5

Generic zirconia aged 23 50 8 19 946 7.9

Conclusions: The initial biaxial fracture strength and

Weibull modulus were higher for Lava Frame zirconia compared

to the generic dental zirconia material. Hydrothermal

accelerated aging caused an increased monoclinic crystal

phase, 21 wt.% for Lava Frame and 23 wt.% for the generic

zirconia on the outer surface of the samples. However, the

increased monoclinic phase on the surface of the ceramic did

not affect the biaxial fracture strength of both zirconia materials,

but an increase in Weibull moduli was observed.

doi:10.1016/j.dental.2010.08.113

106

Fatigue lifetime prediction of dental implant using finite element

analysis

Y. Duan 1 , P.A. Kulkarni 1 , J.A. Gonzalez 2 , W.W. Nagy 2 , J.A.

Griggs 1

1 University of Mississippi Medical Center, USA

2 Texas A&M University System Health Science Center, USA

Objectives: To predict using non-linear finite element analysis

the fatigue behaviour that one dental implant system will

exhibit when tested according to ISO 14801.

Materials and methods: A titanium dental implant system

(Standard Plus Implant NN, Straumann, Switzerland)

was scanned using an X-ray Micro-CT scanner (Skyscan1172,

Skyscan, Belgium) with the pixel size set at 4.25 �m. Transverse

sections (n = 5882) were generated and processed using

medical image modelling software (Mimics X64 13.1, Materialise,

Belgium). 3D models of implant body, abutment,

abutment screw, cylindrical base and hemispherical loading

cap were created and assembled in the finite element analysis

software (ABAQUS V6.8-4, Simulia, US). Non-linear contact

analysis was performed under 30 ◦ off-axis loading to simulate

the laboratory test based on ISO 14801. After obtaining static

stress results, finite life fatigue assessment was performed

using Brown-Miller strain criteria with Morrow mean stress

correction in fatigue analysis program (Fe-safe 5.4-04, Safe

Technology, UK). Test loading was set as a cyclic pulsating load

with R = 0.1.Three different levels of Young’s modulus values

for specimen holder material were applied in the analysis.

Results: The fatigue life contour showed that the highest

probability of failure was located at the root of the second

screw thread of implant body (adjacent to the bone level),

which showed good agreement to the SEM observations in the

laboratory test for the same implant in a previous study. The

lifetime prediction (1007356 cycles under 110N) was located

within the 95% confidence boundary of Weibull data from the

laboratory results (98 to 224N for 1 M cycle mean lifetime). The

lifetime predictions corresponding to different Young’s modulus

values for the specimen holder and the same loading

amplitude are given in the following table.

Young’s

modulus

(GPa)

Maximum

VM stress

(MPa)

Mean

lifetime

1 4 35.30 2443747

2 16 35.22 1007356

3 30 36.88 403315

Conclusions: Three-dimensional finite element analyses

could be used to perform strain-based fatigue lifetime prediction

for a titanium dental implant. An influence of specimen

holder elastic modulus on fatigue lifetime was observed,

although there was no significant difference in static stress

results, which should be taken into consideration for dental

implant fatigue study in order to obtain more clinically relevant

results.

Support: The study was supported by NIH-NIDCR grants

DE017991 and DE013358.

doi:10.1016/j.dental.2010.08.114

107

Traditional and CAD/CAM generated metal-free restorations.

12-Month follow-up

A. Fabianelli, A. Vichi, M. Sedda, M. Ferrari

Department of Fixed Prosthodontics and Dental Materials, University

of Siena, Siena, Italy

Objectives: The recent increased demand for aesthetics

and the development of strong ceramics, as well as the progresses

in adhesive luting strategies led to the increased use

of all-ceramic crowns. Among these materials, Lithium disilicate

is one of the most promising. The objective of this

prospective controlled clinical study is to evaluate the clinical

performances of lithium disilicate posterior crowns fabricated


with 2 different techniques, heat pressed IPS e.max Press 1

ingots and CAD/CAM milled IPS e.max CAD 1 blocks.

Materials and methods: Two crown systems were selected

for this study, a lost wax and heat pressure technique, IPS

e.max Press, and a milled out of prefabricated blanks system

using CAD/CAM technology, IPS e.max CAD.The study participants

were 38. Preparations were performed by two operators.

Abutments were prepared with smooth angles, and a chamfer

finishing line was preferred. In Group 1 the crowns were

fabricated using the heat pressed technique, while in Group

2 crowns were fabricated with CAD/CAM technology using

prefabricated blocks milled with a CEREC 3 2 unit. The same

luting strategy was employed for both groups. Modified USPHS

Cements Curing time Contraction stress measured at

criteria for evaluation of indirect restorations were used. A

one-year survival rate analysis of the restorations was conducted

according to the Kaplan–Meier method.

Results: For the period of 12 months all the patients could

be observed and all the parameters evaluated scored Alfa. No

recurrent caries was reported at crown margins and all crowns

showed marginal integrity, all the crowns were in place and in

service, change of proximal contacts was not detected after

the use of dental floss to test the resistance of the contact

points.

Conclusions: Within the limitation of this short time recall,

clinically satisfactory performances were achieved in a 12month

period of observation with both IPS e.max Press and

IPS e.max CAD fabricated crowns.

doi:10.1016/j.dental.2010.08.115

108

Contraction stress of two self-adhesive cements

A. Frassetto, G. Marchesi, B. Codan, R. Di Lenarda, L. Breschi,

M. Cadenaro

University of Trieste, Trieste, Italy

Objectives: Polymerization stress is an important side

effect potentially leading to failure of the bonded interface.

The aim of the study was to evaluate the contraction stress

of two self-adhesive cements at different intervals after polymerization

initiation.

Materials and methods: Materials tested were: MaxCem

Elite (Kerr, Orange, CA, USA) and Clearfil SA Cement (Kuraray,

1 Ivoclar Vivadent.

2 Sirona Dental Systems.

dental materials 26S (2010) e1–e84 e51

Tokyo, Japan). Cements were dispensed between two stainless

steel cylinders (h = 2 mm) fixed to a universal testing

machine (Sun 500, Galdabini) then exposed to a LED-curing

unit (Bluephase, Ivoclar Vivadent, 1200 mW/cm 2 ) for 20 or 40 s.

The contraction force (N) generated during polymerization

was continuously recorded for 6 h. Contraction stress (MPa)

was calculated at 10 and 30 min, 1, 2, 5 and 6 h. Data were statistically

analyzed by two-way ANOVA and Tukey’s post-hoc

test (˛ = 0.05).

Results: Means and standard deviations of contraction

stress (expressed in MPa) at different time intervals for each

of the two tested material.

10min 30min 1h 2h 5h 6h

MaxCem Elite 20 s 1.8 ± 0.3 e 2.6 ± 0.1 f 3.1 ± 0.2 f,g,h 3.7 ± 0.3 i,j,k 4.0 ± 0.4 j,k 4.1 ± 0.4 j,k

MaxCem Elite 40 s 2.7 ± 0.4 f,g 3.2 ± 0.4 g,h,i 3.6 ± 0.4 h,i,j 4.3 ± 0.3 k,l 4.8 ± 0.3 l 4.8 ± 0.3 l

Clearfil SA Cement 20 s 0.5 ± 0.1 a 0.7 ± 0.1 a,b 0.8 ± 0.1 a,b,c 1.0 ± 0.1 a,b,c,d 1.2 ± 0.1 c,d 1.2 ± 0.1 b,c,d

Clearfil SA Cement 40 s 1.0 ± 0.1 a,b,c,d 1.1 ± 0.0 b,c,d 1.2 ± 0.0 b,c,d 1.3 ± 0.1 c,d,e 1.3 ± 0.1 d,e 1.4 ± 0.1 d,e

Means followed by the same superscript letters indicate no statistical difference at the 95% level of significance (p < 0.05).

Conclusions: Clearfil SA Cement showed lower stress values

than MaxCem Elite at each time interval. Irrespective from

exposure time. Additional in vivo studies are needed to clarify

the role of polymerization stress in the clinical performance

of the self-adhesives cements.

doi:10.1016/j.dental.2010.08.116

109

Influence of surface finishing on flexural strength of veneered

zirconia

J. Geis-Gerstorfer, C. Goldammer, C. Schille ∗

University Hospital Tuebingen, Germany

Objectives: For all ceramic Y-TZP restorations, different

veneering ceramics adjusted to the zirconia framework are

available. The aim of this study was to compare the flexural

strength of zirconia with three different veneering ceramics

depending on the surface finishing conditions.

Materials and methods: Y-TZP specimens (Zenotec Zr,

25 mm × 4mm× 1 mm, sandblasted with 110 �m Al2O3, 1 bar)

were veneered with the veneering ceramics Zirox, Cercon

Ceram Kiss and Vintage Zr according to manufacturer’s information

(total sample thickness 2.5 mm). A liner firing, dentin

firing (2×) and glaze firing were made. For each veneering

ceramic four surface finishings were tested: (1) as fired, (2)

grinding with a 46 �m diamond instrument, (3) polishing the

grinded part, and (4) glazing again after grinding and polishing.

From each surface and veneering ceramic 8 samples were

tested. 3-point-bending tests according to ISO 6872 were performed

using a universal testing machine (Z010, Zwick, Ulm)

with a crosshead speed of 0.5 mm/min. During each measurement

the acoustic signal of a microphone was recorded to get

additional information about crack initiation. The statistical

significance of the results was evaluated using t-test (p < 0.05).


e52 dental materials 26S (2010) e1–e84

Results: The results of the flexural strength values [MPa]

for each veneering ceramic and surface condition (sandwich

sample) can be seen in the table:

Kind of surface

finishing

Zirox Cercon

Ceram Kiss

Vintage

Zr

As fired 141 ± 19 128 ± 28 92 ± 18

Grinded 91 ± 13 91 ± 8 83 ± 7

Grinded + polished 86 ± 10 98 ± 13 93 ± 8

Glazed after

grinding

+ polishing

152 ± 18 158 ± 28 88 ± 8

With the exception of Vintage Zr the specimen with the

glazed surface showed the highest flexural strength, even after

grinding and glazing. The lowest strength was obtained by

the grinded and polished surface, due to early fracture of the

veneering.

Conclusions: Polishing of grinded surfaces is not effective

enough to eliminate surface defects and to regain sufficient

strength. After grinding initial strength can only be achieved

by an additional glazing process.

Support: This study was supported by “Wieland Dental

+ Technik”, Pforzheim, Germany.

doi:10.1016/j.dental.2010.08.117

110

Comparison of Elastomeric Impression Materials’ Thixotropic

Behavior

P. Gerasimou ∗ , K. Tolidis, C. Boutsiouki, D. Tortopidis

Aristotle University of Thessaloniki, GR

Objectives: The most common impression materials currently

used in restorative dentistry are the vinylpolysiloxanes

and polyethers. The purpose of this study was to compare the

thixotropic behavior of seven elastomeric impression materials

using a shark fin test, under applied low pressure.

Materials and Methods: Five commercially available lowviscosity,

automixed vinylipolysiloxanes (VPS), one polyether

and a hybrid VPS-polyether were subjected to shark fin test

under a load of 150gr, 30 s after mixing. The shark fin device

was used to determine the fin height and the thixotropic

behavior of each impression material. Five samples were made

for each material. The data were analyzed using the ANOVA

method. Means were compared with Tukey-Cramer test.

Results: Comparison between shark fin height of Virtual and

Affinis exhibited no significant difference (p > 0.05), as well

as comparison between Honigum and Panasil (p > 0.05). Identium

exhibited no significant differences when compared with

Panasil or Honigum (p > 0.05) and Permadyne also exhibited no

significant differences when compared to Virtual and Affinis

(p > 0.05). Extremely significant differences were noted when

Panasil was compared with Affinis or Permadyne, and when

Affinis was compared with Identium (p < 0.001). Chromaclone

showed significant differences in comparison with every other

material (p < 0.001) exhibiting lower values, except for Panasil

(p < 0.05). The material with the highest shark fin value was

Affinis, followed by Permadyne, Virtual, Honigum, Identium,

Panasil and Chromaclone.

Panasil Virtual Chromaclone Affinis Honigum Identium Permadyne

Mean

(mm)

19.57 22.16 17.53 22.91 20.32 20.05 22.47

SD 0.86 1.55 0.35 0.98 0.62 0.59 0.93

Conclusions: The hybrid material’s thixotropic properties

seem to be between VPS and PE thixotropicity values.

Polyether shows high shark fin values as expected. The

thixotropic behavior of the majority of VPS materials tested

is acceptable.

doi:10.1016/j.dental.2010.08.118

111

Resin bond strength to alumina coated dental oxide ceramics

M. Golobič 1 , A. Kocjan 2 , T. Kosmač 2 , P. Jevnikar 1

1 University of Ljubljana, Ljubljana, Slovenia

2 Jozef Stefan Institute, Ljubljana, Slovenia

Objectives: Surface functionalization of Y-TZP ceramics

with a nano-structured alumina coating improves resin bond

strength (Jevnikar et al. Dental Mater 2010;26:688). The aim

of this study was to evaluate the shear-bond strength of the

self-adhesive resin cement containing 4-META to as-prepared,

sandblasted and alumina coated surfaces of yttria partially

stabilized tetragonal zirconia (Y-TZP), alumina (Al2O3) and

In-Ceram Zirconia (InZ) ceramics.

Materials and methods: A total of 3 × 80 specimens

were prepared. Densely sintered disc-shaped specimens

(diameter 15 mm × height 2.5 mm) were produced from

TZ-3YSB-E zirconia powder (Tosoh, Japan) and Reactive

Alumina CT 3000 SDP powder (Almatis, Germany). InZ specimens

(14 mm × 15 mm × 2 mm) were prepared from VITA

In-Ceram ZIRCONIA for inLab ® (Vita, Germany) and infiltrated

with Zirconia glass powder Z21N as recommended by the

manufacturer. Specimens of each of the materials were

randomly divided into two groups of 40 with different surface

treatments: AS – as-prepared and APA – airborne-particle

abraded (110 �m Al2O3, 4 bar, 15 s). Half of the specimens

in each group received an alumina coating that was fabricated

by exploiting the hydrolysis of aluminium nitride

powder (groups AS-C, APA-C). The composite cylinders

(diameter 4 mm × height 4 mm) were bonded to the ceramic

specimens with G-Cem (GC, Japan). Shear-bond strength

was then tested (Instron Corp., USA) for the coated and

uncoated surfaces of the as-sintered and airborne-particle

abraded specimens before and after thermocycling (5–55 ◦ C,

12,000×, 15 s). The adhesive surfaces were characterized

using scanning electron microscopy (SEM). The data were

analyzed by two-way ANOVA and the Tuckey post hoc test

(SPSS).

Results: The SEM analysis showed that the nano-structured

alumina coating was successfully applied to as-prepared and

sandblasted surfaces of Y-TZP, Al2O3 and InZ ceramics and a

highly retentive surface for resin penetration was created. The

shear-bond strength to the coated groups AS-C and APA-C of


all three oxide ceramics (28.4 ± 3.3 MPa to 32.7 ± 3.4 MPa) was

significantly higher (p ≤ 0.05) than to the non-coated groups

AS and APA (9.0 ± 1.8 MPa to 19.6 ± 2.2 MPa). In contrast to

some of the AS and APA groups thermocycling had no significant

effect (p ≤ 0.05) on resin-bond strength to the coated

groups.

Conclusions: The bond strength of self-adhesive resin

cement containing 4-META to Y-TZP, Al2O3 and In-Ceram

Zirconia ceramics can be improved by the surface functionalization

of oxide ceramics with a nano-structured alumina

coating. Furthermore, bond strength to coated oxide ceramic

surfaces is resistant to degradation by thermocycling.

doi:10.1016/j.dental.2010.08.119

112

Effect of tooth preparation on the fit of Y-TZP copings

R.I. Hmaidouch, P.E. Neumann, W.-D. Mueller

“Charité” Universitaetsmedizin Berlin, CC3 Dental School, Berlin,

Germany

Objectives: This study evaluated marginal and internal

adaptation of Cerec3 copings using two occlusal preparation

forms.

Materials and methods: Two metal master models (tooth

36: A, normal occlusal reduction; B, flat occlusal reduction)

were used. 80 gypsum dies were produced from

each master model. 16 groups were established by combining

the two preparation forms with two luting space

settings/ LSS (100 and 50 �m) and four cements (zinc phosphate/ZPC,

Panavia21/p21, experimental cement.1/Exp.1 and

Exp.2). 80 copings were milled using Y-TZP 1 ceramic, 5

pieces for each group. Copings were cemented, embedded

and then sectioned bucco-lingually and mesio-distally.

Marginal gaps (MG) and internal gaps (IG) were measured

using a light microscope at 40×, 82 measurements for each

coping.

Results: One-way ANOVA (P < 0.05) showed significant difference

between copings with normal occlusal form and

copings with flat occlusal form, between copings with LSS

of 100 �m and those with LSS of 50 �m. Also between copings

cemented with P21 and the other cements. Results are

summarized in Table 1:

Preparation

form

CementLSS 100 �m LSS 50 �m

MG IG MG IG

A ZPC 81.69 ± 2.55 120.46 ± 8.60 110.31 ± 7.22 131.68 ± 18.16

P21 73.63 ± 6.81 112.39 ± 4.23 85.69 ± 4.88 96.09 ± 4.27

Exp.1 76.19 ± 9.12 121.43 ± 10.17 94.78 ± 14.63 122.43 ± 13.11

Exp.2 74.73 ± 7.06 130.30 ± 6.04 103.91 ± 8.12 132.12 ± 9.28

B ZPC 44.59 ± 7.09 113.12 ± 2.48 71.26 ± 3.34 87.67 ± 10.20

P21 31.57 ± 9.16 102.87 ± 1.96 61.54 ± 5.97 71.42 ± 4.29

Exp.1 50.73 ± 19.94 109.16 ± 6.88 81.04 ± 9.42 106.06 ± 2.59

Exp.2 49.87 ± 8.85 117.22 ± 7.98 68.64 ± 15.14 104.84 ± 11.03

1 Vita YZ-20.

dental materials 26S (2010) e1–e84 e53

Conclusions: Fit of copings with flat occlusal form was better

than those with normal occlusal form, copings milled with

100 �m LSS fitted better than those milled with 50 �m LSS. Fit

of copings cemented with P21 was better than those cemented

with the other cements.

doi:10.1016/j.dental.2010.08.120

113

Evaluation of newly developed experimental zirconia primer

S. Hotta, A. Arita, T. Kumagai, T. Sakuma

GC, Corp., Tokyo, Japan

Objectives: Zirconia ceramics are of current interest

because of metallic, allergy-free, recent improvement of the

CAD/CAM system, and aesthetic requirement. The aim of this

study was to evaluate the bond strength of newly developed

experimental zirconia primer and various commercially available

zirconia primers.

Materials and methods: Zirconia block (GC Aadva Zr) was

polished with SiC paper (#1500) or sandblasted by alumina

(50 �m). Tested primers were MSZ007 (GC), Clearfil ceramic

primer (Kuraray), AZ primer (Shofu), Metal/Zirconia primer

(Ivoclar Vivadent), Monobond plus (Ivoclar Vivadent), and Z-

PRIME PLUS (BISCO). The zirconia surface was treated with

each primer according to the manufactures instructions, then

delimited by masking tape with a hole of 3.0 mm in diameter,

and bonded to a stainless rod using LINKMAX (GC).

In addition, we evaluated some company’s primers using

the same company’s resin cement and self-adhesive resin

cements, SA cement (Kuraray), Maxcem Elite (Kerr), and

Unicem capsule (3M ESPE). These bonded specimens were

immersed in water at 37 ◦ C for 24 h and then subjected to

tensile bond strength (TBS) testing with a crosshead speed of

1 mm/min.

Results: TBSs including standard deviations were shown as

follows (n = 5):

Primer/LINKMAX TBS/MPa

(SD)/#1500

TBS/MPa(SD)/

Sandblasted

MSZ007 45.4(9.3) 40.6(8.4)

Clearfil

ceramic

primer

43.8(8.3) 45.6(9.0)

AZ primer 45.5(5.7) 44.5(13.9)

Metal/Zirconia

primer

39.2(6.4) 35.3(12.9)

Monobond

plus

46.2(4.5) 36.5(9.8)

Z-PRIME

PLUS

37.0(10.3) 47.9(8.0)


e54 dental materials 26S (2010) e1–e84

Primer Cement TBS/MPa

Clearfil ceramic

primer

Clearfil

esthetic

cement

(SD)/#1500

TBS/MPa(SD)/

Sandblasted

36.0(10.9) 28.6(13.1)

AZ primer Resicem 37.5(3.7) 36.7(3.9)

Metal/Zirconia Multilink 26.4(5.4) 30.7(10.1)

primer

automix

No primer SA cement 28.4(13.5) 38.1(3.7)

No primer Maxcem

elite

38.7(10.7) 43.0(11.3)

No primer Unicem

capsule

34.9(4.7) 27.8(8.8)

Conclusions: Tensile bond strength of newly developed

MSZ007 performed as well as other zirconia primers currently

available in the market at 1 day. Tensile bond strength depends

on the resin cement used. This study suggests that it is important

to use the same resin cement to evaluate the bonding

performance of the primer.

doi:10.1016/j.dental.2010.08.121

114

Effect of light on the micro-mechanical properties of dualcured

self-adhesive resin cements

N. Ilie, A. Simon

Ludwig-Maximilians-University, Munich, Germany

Objectives: To analyze the effect of light on the

micro-mechanical properties of 8 popular dual-cured

self-adhesive resin cements (G-Cem, RelyX Unicem, G-

Cem Automix, Max-cem Elite, Breeze, SmartCem2, i-CEM,

Clearfil SA) by comparing them with two conventional

dual-cured resin cements (Dentin Build and Multilink

Automix).

Materials and methods: For each material, four different

curing procedures were applied. The cements were cured for

20 s with an LED curing unit (Freelight 2) by applying the unit

directly on the samples’ surface, at a distance of 5 mm and

10 mm. Additionally, no light was allowed to reach the samples

in order to determine the effect of the chemical curing

only. Twenty minutes after curing, the samples were stored

for one week at 37 ◦ C in a water saturated atmosphere. The

micro-mechanical properties – Vickers hardness, modulus of

elasticity, creep and elastic/plastic deformation – were analysed.

Results: A very strong influence of the material as well

as filler’s volume and weight on the micro-mechanical

properties was measured, whereas the influence of the

amount of light and type of cement – conventional

or self-adhesive – was generally low. The influence of

light on the polymerization process was material dependent,

with four different behaviour patterns to be distinguished.

1. Less sensitivity to the way of cure, be it dual-cured with

different light intensities or only chemical cured (Dentin

Build, Breeze).

2. Significant differences only between dual-curing and

chemical-curing, whether the amount of light was not

a significant factor of influence (max-cem Elite, i-CEM,

Clearfil SA).

3. Significant differences not only between dual-curing and

chemical-curing, but also between the different amount of

light (RelyX Unicem, Multilink Automix, G-Cem).

4. Decrease of properties with decreased light amount but no

differences between chemical curing and dual-curing with

lower intensity (G-Cem automix, SmartCem2).

Significant higher micro-mechanical properties were measured

for the conventional resin cements compared to the

self-adhesive cements, although this difference was low.

Within the self-adhesive resin cements group, the variation

in micro-mechanical properties was high (Tukey’s HSD test,

˛ = 0.05).

Conclusions: The selection of the suitable resin cements

should be done besides its adhesive properties also by

considering its micro-mechanical properties and curing

behaviour.

doi:10.1016/j.dental.2010.08.122

115

Effect of silane heat treatment on resin-cement and glassceramic

adhesion

F.P.P. Leite 1 , R.F. Carvalho 1 , F.L.G. Cruz 1 , Memn Martins 1 ,

J.R.C. Queiroz 2 , A.D. Vanderlei 2 , M. Ozcan 3

1 Universidade Federal De Juiz De Fora, Brazil

2 Universidade Estadual Paulista, Brazil

3 Zurich University, China

Objectives: The following hypothesis was tested: silane

heat treatment improves the bond strength of resin cement

to glass ceramic.

Materials and methods: 24 Ceramic blocks (Vita VM7, VITA)

(6 mm × 6mm× 8 mm) were obtained. The cementation surface

of each block was duplicated in resin-composite (W3D

Master, Wilcos). Ceramic blocks were randomly assigned into 3

groups (n = 6/per group): G1: etching with 10% HF (Dentsply) for

20 s + rinsing with water for 60s+drying (control); G2: 10% HF

for 20 s + rinsing with water for 60s+drying + silane then dried

in a furnace at 100 ◦ C for 2 min (F-1800-EDG, São Paulo, Brazil);

G3: silane then dried in a furnace at 100 ◦ C for 2 min (F-1800-

EDG, São Paulo, Brazil). The ceramic blocks were cemented to

the composite blocks using a resin cement (Panavia F, Kuraray).

The cemented blocks were sectioned with a diamond disk

under coolant irrigation to obtain microbars with 0.8 mm 2 of

bonding area. Each bar was attached to an adapted device and

the microtensile test was performed.

Results: Silane heat treatment media resulted in significant

differences among the groups (P < 0.05) (One-way

ANOVA and Tukey test, ˛ = 0.05). The mean bond strengths

(MPa) were as follows: G1: 17.63 ± 2.30a; G2: 19.01 ± 3.19a; G3:

9.13 ± 2.76b.


Conclusions: The silane heat treatment media decreased

the bond strength between ceramic and resin cement when

the etching with 10% HF was not done. Hypothesis was

rejected.

doi:10.1016/j.dental.2010.08.123

116

Influence of veneer thickness on residual stresses in zirconia

prostheses

A.K. Mainjot 1 , G.S. Schajer 2 , A.J. Vanheusden 1 , M.J. Sadoun 3

1 University Hospital of Liège, Belgium

2 University of British Columbia, Canada

3 University Paris Descartes, France

Objectives: Mismatch in physical, especially thermal properties

between veneering ceramics and high-strength ceramic

cores can induce residual stresses and lead to crack initiation

when combined with functional stresses. Stresses distribution

within the veneering ceramic in function of depth, is a key

factor influencing failure by chipping, which is a well-known

problem with Y-TZP (Yttria Tetragonal Zirconia Polycrystal)

based fixed partial dentures. The objective of this study was

to investigate thickness dependence of the stress profile in

veneering ceramic layered on zirconia frameworks.

Materials and methods: The hole-drilling method, often

used for engineering measurements, was adapted for use

with veneering ceramic. The stress profile was measured in

10 bilayered disc samples of 20 mm diameter, with a 1 mm

thick Y-TZP framework. Different veneering ceramic (Vita

VM9) thicknesses were performed: 1 mm, 1.5 mm, 2 mm and

2.5 mm.

Results: All samples exhibited the same type of stress vs.

depth profile, starting with compressive at the ceramic surface,

decreasing with depth, getting close to the tensile area.

The magnitude of the stress and its decreasing rate vs. depth

profile were found to increase with veneering ceramic thickness.

Calculated residual stresses were lower than 20 MPa.

Conclusions: Veneering ceramic thickness increases magnitude

of residual stresses and then influences mechanical

behaviour of zirconia-based bilayered systems.

doi:10.1016/j.dental.2010.08.124

dental materials 26S (2010) e1–e84 e55

117

Identifying subsurface fatigue cracks in resin bonded ceramics

subjected to cyclic compression

L.H. Mair 1 , P. Padipatvuthikul 2

1 University of Central Lancashire, Preston, UK

2 Srinakharinwirot University, Bangkok, Thailand

Objectives: To identify fatigue cracks in ceramics using silver

nitrate staining.

Materials and methods: 45 Disks of ceramic 1 (˚

5mm× 4 mm) were fabricated by sintering and randomly

divided into 3 groups. They were etched with 9.5% HF for

15 min and sandblasted with 50 �m alumina; then bonded

onto enamel using three bonding systems 2,3,4 following the

manufacturer’s instructions. The bonded specimens were

subjected to a Staircase Fatigue Limit test using 5000 cycles

with a load/unload increment of 4 kg. The “survivors” were

sectioned using a diamond disk saw, ground flat with wet

SiC papers (240, 400, 600, 1200 Grit) and polished with 1 �m

Al2O3. They were immersed in AgNO3 (3 mole/l) for 48 h. The

specimens were examined by incident light microscopy using

crossed polars to filter directly reflected light and reveal the

colour of silver. The specimens were subsequently sputter

coated with gold and examined by SEM.

Results: In a number of “survivors” there was a network of

cracks extending from the point of load application into the

subsurface. These cracks were not visible on the SEM because

they were obscured by filler particles. This corresponded with

the “failures” where the crack started in the specimen rather

than at the bonding interface.

Conclusions: Silver nitrate staining is a useful technique to

indentify forming fatigue cracks in ceramics.

The cracks started under the point of load application

rather than at the interface with the bonding resin.

doi:10.1016/j.dental.2010.08.125

1 Vitadur Alpha; VITA Zahnfabrik, Germany.

2 Prime and bond + Calibra, Dentsply, USA.

3 Clearfil SE Bond + Panavia, Kuraray, Japan.

4 Optibond Solo Plus + Nexus, Kerr, USA.


e56 dental materials 26S (2010) e1–e84

118

Withdrawn

doi:10.1016/j.dental.2010.08.126

119

Adhesion mechanisms at the interface between Y-TZP and

veneering ceramics

C. Monaco 1 , P. Cardelli 1 , A. Tucci 2 , L. Esposito 2 , R. Scotti 1

1 University of Bologna, Italy

2 Centro Ceramico Bologna, Italy

Objectives: Zirconium oxide based ceramics, in particular

Y-TZP, present positive characteristics as high flexural

strength and fracture toughness (Studart et al. Dental Materials

2006;23:106). Since poor information is available about the

interfaces of Y-TZP and veneering ceramics, the aim of this

study was to analyse this interface regarding phase composition

and microstructure.

Materials and methods: Sixteen specimens of Y-TZP 1 were

sintered following manufacturer’s instructions and divided

into 4 groups (n = 4). The specimens of group A were veneered

with a pressable ceramic 2 without a ceramic liner; group B

were liner coated 3 and fired before the final veneering; group C

were sandblasted with 30 �m SiO2 4 and then veneered without

application of liner; group D were both sandblasted and liner

layered before veneering. The microstructure of the surface

and the interfaces between the two ceramics were analyzed

by a scanning electron microscope (SEM) equipped with an

energy-dispersive X-ray analyzer (EDS).

Results: The SEM analysis of the samples showed that

sandblasting zirconia surfaces, before applying the veneering

ceramic, drastically changed their surface microstructure.

For samples of groups C and D, several fine silica particles,

from CoJet abrasive, were smeared on the zirconia surface.

Different punctual microanalysis, conducted in the contact

area of zirconia-veneering ceramic of group D, presented a

reaction area at the interface of the different materials. The

EDS spectrum corresponding to the interface area presented

a large amount of zirconia and characteristic elements of the

veneering layer. It is to underline as the sandblasting, after

the sintering step, as in groups C and D, not only caused a

widespread silica particles smearing the surface, but it was

also responsible for a partial zirconia phase transformation

from tetragonal to monoclinic

Conclusions: Sandblast the zirconia before veneering,

could be able to give a higher reactivity to the zirconia surfaces

with the veneering ceramic, increasing, in this way, the

bonding and the mechanical performance of the component.

doi:10.1016/j.dental.2010.08.127

1 e.max ZirCAD, Ivoclar Vivadent.

2 ZirPress, ivoclar Vivadent.

3 ZirLiner, Ivoclar Vivadent.

4 CoJet, 3M ESPE.

120

Fit and fracture behaviour of metal laser sintered posterior

bridges

W.-D. Mueller, U.W. Stecher, R.I. Hmaidouch

“Charité” Universitaetsmedizin Berlin, CC3 Dental School, Berlin,

Germany

Objectives: The purpose of this study was to evaluate the

marginal fit and fracture strength of four-unit fixed partial

dentures (FDPS) constructed using direct laser sintering.

Materials and methods: A steel model with two abutments,

a first premolar and a second molar was scanned and a framework

designed. 25 Frameworks were produced by metal laser

sintering using CoCrMo-alloy. Cross sections of 5 samples

were produced to illustrate the microstructure. 10 frameworks

were cemented using zinc phosphate cement, embedded, and

then sectioned buccolingually and mesiodistally. Widths of

the marginal and internal gap were measured using a light

microscope at magnification 40×, 82 measurements for each

framework. 5 samples were positioned on the steel model

as delivered after machining without cementation and then

loaded in a universal testing machine; the fracture strength

was determined; 5 samples were cemented on the metal

model using zinc phosphate cement, sorted in distilled water

at 37 ◦ C for 24 h before testing to failure (CHS = 1 mm/min). The

maximum force was registered.

Results: Cementation significantly (P < 0.05) affected the

fracture resistance (1677.48 N before and 2210.44 N after).

Mean values of marginal fit (87.87 ± 17.27) and internal fit

(126.84 ± 15.37).

Conclusions: The fit of tested frameworks was clinically

acceptable, the fracture strength increased considerably after

cementation, based on the accepted minimum initial strength

of 1000 N for posterior FDPS. The results of this study show

that the laser sintering core material tested can be used for

the construction of the four-unit posterior FDPS.

doi:10.1016/j.dental.2010.08.128

121

Different protocol for silane application on ceramic: A FTIR

analyses

J.R.C. Queiroz, H.C. Garcia, L.F.C. Oliveira, C.E. Silva, M.P.C.

Neto

Universidade Federal de Juiz de Fora, Brazil

Objectives: To characterize by attenuated total reflection

infrared Fourier transform analysis (ATR-FTIR) the ceramic

surface after silane application with different dry protocols.

Materials and methods: Sixteen ceramic bars

(2 mm × 4mm× 10 mm) of VM7 (VITA-Zahnfabrik, Germany)

were prepared and finished to 1 �m alumina paste.

Before silane application, the specimens were cleaned in

a distilled water sonic bath for 10 min. Four groups (n =4)

were treated with different silane dry protocols. The silane

3M ESPE SIL (3M/ESPE) was applied to all specimens using

a microbrush and left to dry at 20 ◦ C for 2 min (G20). After

first drying, the specimens were submitted to heating at


38 ◦ C (G38), 80 ◦ C (G80) or 100 ◦ C (G100) for 60 s. Half of the

specimens of each group were rinsed with water at 80 ◦ C for

15 s (B). ATR-FTIR was performed using a spectrometer and

zinc selenide crystal.

Results ATR-FTIR analyses showed a band at 1637 cm −1 in

G20 referring to �(O–H), which disappeared in other IR spectra,

and changes in Si–O peaks with an enlarged band around

940 cm −1 and a decrease in the band at 1296 cm −1 , assigned

to the ester group, after heat treatment (G38, G79, G100). The

spectra of silane submitted to rising with 80 ◦ C water (G20b,

G38b, G79b and G100b) showed a pattern of bands with intensity

variation only, without wave-number shifts.

Conclusions The results suggested that heat treatments or

rinse with water at 80 ◦ C after silane application could improve

the silane layer network.

doi:10.1016/j.dental.2010.08.129

122

Clinical follow-up of direct adhesive bridges up to 7 years

M. Özcan

University of Zurich, Dental Materials Unit, Clinic for Fixed and

Removable Prosthodontics, Zurich, Switzerland

Objectives: This study evaluated the clinical performance

of direct, one-pontic, inlay-retained, fiber-reinforcedcomposite

restorations (DOI-FRC) up to 7 years.

Materials and methods: Between June 2002 and June 2009,

55 patients (39 females, 16 males, 23–83 years old) received

a total number of 75 posterior DOI-FRCs (n = 43 mandible,

n = 32 maxilla). Box preparations were made on the abutments.

Teeth were conditioned using a three-step adhesive system

(Quadrant Unibond Primer and Sealer, Cavex). All restorations

were made under rubber-dam directly. Restorations were constructed

with unidirectional, preimpregnated E-glass fibers

(everStick C&B, StickTech) using one type of resin composite

(Clearfil Photo Posterior, Kuraray). Colour was improved using

flowable composites (Sinfony, 3M ESPE). After baseline recordings,

patients were followed at 6 months and at annual recalls.

Patients were instructed to call upon experience of a failure or

any kind of intervention. The evaluation criteria involved technical

failures such as chipping or fracture (tooth/restoration)

and caries.

Results: During the observation period, a total of 3 debondings

in the inlay cavities, and 3 chippings were observed

on the buccal surfaces of pontics within 1 and 2 years’

recall. Chippings were repaired using CoJet system (3M ESPE)

and remained functional until the last follow up date. Two

restorations could not be observed after 1 year and 2 years,

respectively due to caries and subsequent bridge construction.

Based on the life-tables calculated from the data, estimated

survival rate up to 7 years was 95.3% [Kaplan–Meier, Log Rank

(Mantel–Cox) 95% CI].

Conclusions: Direct, one-pontic, inlay-retained, FRC

restorations with the adhesive system, veneering composite

and the technique used, offer acceptable clinical survival rate.

doi:10.1016/j.dental.2010.08.130

dental materials 26S (2010) e1–e84 e57

123

Adhesive behaviour of resin-based sealer cements in thin and

thick layers

E.S. Pane 1 , J.E.A. Palamara 2 , H.H. Messer 2

1 University of Melbourne, Australia and University of Sumatera

Utara, Medan, Indonesia

2 University of Melbourne, Australia

Objectives: In root canal treatment, a thin layer of sealer

cement is recommended for obturation. However, with resinbased

sealers, lower bond strength has been shown in thin

layer compared to thick (Jainaen et al., IEJ 2007 40:882). This

contradicted the finding with resin composite restorative

materials which showed that tensile strength decreased gradually

with increasing thickness (Alster et al., J Dent Res 1995

74:1745). The aim of this study was to evaluate tensile and

shear strength of thin and thick layers of three resin-based

sealers (methacrylate-based: EndoREZ, Ultradent; RealSeal,

SybronEndo; and epoxy-based: AH Plus, Dentsply).

Materials and methods: Thin and thick layers of sealer

cements were prepared between metal-to-metal joints of

plano-parallel stainless steel aligned rods with diameter

4.7 mm. Ten samples of thin layers averaged 0.1 mm and

thick layers 1.0 mm were prepared for each group of sealer,

measured from the layer images by Image Tool (UTHSCSA).

Tensile and shear strength were tested after 48 h for the

methacrylate-based and 7 days for the epoxy-based material

using a universal testing machine (Instron model 5544)

with a crosshead speed of 1 mm/s. Force data were used

to calculate the bond strength (MPa). Modes of failure were

examined under magnification and replicas of the fractured

surfaces were examined with SEM (Quanta FEG SEM,

FEI Co.). Data were analyzed using two-way ANOVA (SPSS

Statistics 17.0).

Results: Higher mean tensile and shear strength of thin

layers than the thick were found in the methacrylate-based

sealers (statistically significant, p < 0.05). For the epoxy-based

sealer, similar behaviour was found for the shear strength (not

statistically significant), and the opposite tendency in the tensile

strength (p < 0.05) with higher values in thick layers. There

was no association between thicknesses and mode of failure.

However, numerous voids were noted with thin layer of AH

Plus.

Conclusions: The behaviour of resin-based sealers was

influenced by layer thickness. Further study regarding the

behaviour of resin-based sealer in different thicknesses

applied to root dentin will be undertaken.

doi:10.1016/j.dental.2010.08.131


e58 dental materials 26S (2010) e1–e84

124

Zirconium oxy-fluoride surface activation for improved bonding

to zirconia substrates

J.R. Piascik 1 , S.D. Wolter 2 , B.R. Stoner 1,2

1 RTI International, Durham, NC, USA

2 Duke University, Durham, NC, USA

Objectives: The purpose of this study was to compare an

oxy-fluoride surface activation process to other techniques

used to enhance adhesion of dental materials to zirconia surfaces.

The effect of this novel pre-treatment on the adhesive

strength to both as-received and mechanically roughened surfaces

will be presented along with a discussion of bonding

mechanisms, their advantages and limitations.

Materials and methods: The study leverages a novel gasphase

fluorination process that creates a thin oxy-fluoride

conversion layer on the surface of zirconia, making it more

reactive to conventional adhesive bonding protocols. Zirconia

specimens, polished and roughened, were pre-treated and

both composite and zirconia cylinders were bonded to them

using conventional adhesive techniques. All specimens were

subjected to a shear force at a crosshead speed of 0.5 mm/min

in an electro-mechanical testing device. Single factor analysis

of variance (ANOVA) at a 5% confidence level was performed

for the bonding strength data. Optical and scanning electron

microscopy was used to evaluate and quantify failure surfaces.

Results: Data for composite-to-zirconia shear bond tests,

comparing the oxy-fluoride activation to other surface treatments,

conventional and recently reported. The fluorinated

roughened zirconia surfaces resulted in the highest shear

bond stress to fracture, while demonstrating the highest

(90%) occurrence of mixed mode (adhesive/cohesive) failures

(Table 1).

Conclusions: Simple shear bond mechanical tests demonstrated

that a fluorination pre-treatment is a viable method

to chemically activate zirconia surfaces for improved adhesive

bonding. Data show that even on polished zirconia, the

oxy-fluoride activation is as-good, or better than conventional

pre-treatments.

doi:10.1016/j.dental.2010.08.132

125

Adhesion between zirconia and luting cements: Effect of surface

treatments

M. Querzè 1 , P. Baldissara 1 , N. Scotti 2 , L.F. Valandro 3 ,R.

Scotti 1

1 University of Bologna, Italy

2 University of Turin, Italy

3 University of Santa Maria, Brazil

Objectives: To compare the bond strength values of two

luting cements to Y-TZP ceramics having different surface

treatments: feldsphatic liner application and tribochemical

silica coating.

Materials and methods: Zirconia tablets made of Lava and

IPS e.max ZirCAD were surface treated with two feldsphatic

liners (Framework Modifier and Intensive Zirliner Brown)

or tribochemical silica coating (CoJet) and bonded to resin

composite cylinders using two chemically different cements

(Panavia F 2.0 and RelyX UniCem). Specimens with untreated

surface served as controls. The specimens were thermally

cycled at 5–55 ◦ C, then shear bond strength (SBS) test was used

to evaluate the bonding. Twelve specimens were tested for

each group (n = 12). Data were analyzed with one-way ANOVA

and Tukey’s test (˛ = 0.05). Failure pattern analysis was performed

using a stereomicroscope and SEM.

Results:

Mean (SD)

PANAVIA F 2.0 RelyX UNICEM

Mean and standard deviation SBS (MPa)

Lava

No treatment 7.569 (3.575) a12 4.757 (3.191) a1

Silica-coating 8.025 (2.264) a12 13.46 (1.651) b23

Liner 12.86 (3.247) a3 12 (2.271) a234

ZirCAD

No treatment 5.08 (2.559) a2 2.103 (1.735) a1

Silica-coating 9.515 (2.376) a14 14.08 (1.148) b2

Liner 12.23 (1.482) a34 10.73 (1.536) a34

For each horizontal row: values with identical letters indicate no statistically

significant differences (p > 0.05). For each vertical column: values with identical

numbers indicate no statistically significant differences (p > 0.05).

Conclusions: Within the limits of this study, tribochemical

treatment with CoJet may represent the method of

Table 1 – Shear bond stress (MPa) with standard deviation of the different test groups. Columns with A shows the

percent of samples displaying adhesive failure; A/C a mixed mode of adhesive and cohesive failure.

Sample group (with surface finish) Shear bond stress (MPa) Standard deviation A (%) A/C (%)

Fluorination (rough) a 32.7 6.4 10 90

Fluorination (polished) b 26.3 6.4 30 70

Co-JetTM (rough) b 24.4 4.9 30 70

3nmSixOy (rough) b 22.9 4.7 40 60

3nmSixOy (polished) c 18.6 2.8 80 20

Untreated (rough) c 15.6 2.0 90 10

Untreated (polished) d 10.1 3.8 100 0

a,b,c,dValues followed by the same letter are statistically similar (p > 0.05).


choice to improve the bonding between zirconia and luting

cements, particularly when RelyX UniCem self-etching

cement is employed. Furthermore, CoJet treatment is easy to

perform and does not affect the final ceramic thickness as liner

application do.

doi:10.1016/j.dental.2010.08.133

126

FIB/SEM analysis of metal- and zirconia- ceramic interfaces

R. Salvi 1 , G. Merlati 1 , P. Battaini 2 , M. Sebastiani 3 ,F.

Massimi 3 , P. Menghini 1 , E. Bemporad 3

1 University of Pavia, Italy

2 8853 S.p.A., Italy

3 University of Roma “Roma Tre”, Italy

Objectives: Recently introduced FIB/SEM analysis in

microscopy seems to provide a more detailed characterization

of the samples by 3D (FIB) cross-sectioning and (SEM) high resolution

imaging. Even if some studies are already available in

the literature, further FIB/SEM based studies are still required

for improving the understanding of the actual clinical failure

modes. The aim of this study was to apply the FIB/SEM analysis

to the interfaces of a metal-ceramic vs. two zirconia-ceramic

systems.

Materials and methods: Plate samples (4 mm ×

4mm× 3 mm) of the three different prosthetic systems 1,2,3

were prepared in the dental lab following the manufacturers’

instructions, where metal-ceramic was the result of a ceramic

veneering (porcelain-fused-to-metal) and the two zirconiaceramic

systems were produced by the dedicated CAD-CAM

procedures of the zirconia cores (both with final sintering)

and then veneered by layered or heat pressed ceramics. In

a FEI Helios NanoLab TM 600 (FEI Company TM , Eindhoven,

Netherlands), a thin layer of platinum (1 �m) was deposited

on samples surface crossing the interfaces, in order to protect

them during milling. Then, increasingly deeper trenches were

milled by a focused ion beam, first using a relatively higher

and later using a lower ion current (from 9 nA to 0.9 nA).

Finally, FEG-SEM (5KV) micrographs (1000–50,000×) were

acquired.

Results: Despite the presence of many voids in all the

ceramic layers, it was possible to identify: (1) the grain structures

of the metallic and zirconia substrates, (2) the thin oxide

layer at the metal-ceramic interface and its interactions with

the first ceramic layer (wash technique), (3) the roughness of

the two different zirconia cores and their interactions with

the ceramic interface, where the presence of zirconia grains

in the ceramic layer was reported in one system possibly due

to sandblasting before ceramic firing.

1 ® ® Alloy VE - 8853 S.p.A. (Pero, MI, Italy) and Ceramic Avanté -

Pentron Ceramics Inc. (Somerset, NJ, USA).

2 ® TM Will-Ceram Z Zirconia ‘K’ Blocks - Provident Dental

Products (Somerset, NJ, USA) and Ceramic Avanté ® ZTM - Pentron

Ceramics Inc. (Somerset, NJ, USA).

3 ® ® IPS e.max ZirCAD and Ceramic IPS e.max ZirPress -

Ivoclar-Vivadent AG (Schaan, Liechtenstein).

dental materials 26S (2010) e1–e84 e59

Conclusions: By the limits of this in vitro study, FIB/SEM

analysis of metal- and zirconia-ceramic systems seems to be

useful in the morphological characterization of the interfaces

improving the knowledge about the interpretation of failures.

Acknowledgments: The authors are grateful to 8853 S.p.A.

for providing and manufacturing part of the samples.

doi:10.1016/j.dental.2010.08.134

127

An in vitro fatigue resistance of CAD/CAM occlusal veneers

L.H. Schlichting 1,2 , H.P. Maia 1 , L.N. Baratieri 1 , P. Magne 2

1 Universidade Federal de Santa Catarina, Brazil

2 University of Southern California, USA

Objectives: To assess the influence of CAD/CAM restorative

material (ceramic vs. composite resin) on the fatigue resistance

of ultra-thin occlusal veneers.

Materials and methods: A standardized non-retentive

tooth preparation (simulating advanced occlusal erosion) was

applied to 40 extracted molars including removal of occlusal

enamel, and immediate dentin sealing (Optibond FL). All

teeth were restored with a 0.6 mm-thick occlusal veneer

(Cerec3 chairside CAD/CAM system). The reinforced ceramics

Empress CAD (Ivoclar Vivadent) and e.max CAD (Ivoclar

Vivadent) and the composite resins Paradigm MZ100 (3M-

ESPE) and XR 1 were used to mill the restorations (n = 10). The

intaglio surfaces were HF-etched and silanated (reinforced

ceramics) or airborne-particle abraded and silanated (composite

resins). Preparations were airborne-particle abraded

and etched before restoration insertion. All restorations were

adhesively luted with preheated Filtek Z100. Cyclic isometric

loading was applied at 5 Hz, starting with a load of

200 N (5000×), followed by stages of 400, 600, 800, 1000, 1200

and 1400 N at a maximum of 30,000 cycles each. The number

of cycles at initial failure (first cracks) was recorded.

Specimens were loaded until catastrophic failure (lost restoration

fragment) or to a maximum of 185,000 cycles. Groups

were compared using the life table survival analysis (P = .008,

Bonferroni-corrected).

Results: Empress CAD and e.max CAD initially failed at an

average load of 500 N and 800 N, respectively with no specimen

withstanding all 185,000 load cycles (survival 0%); with MZ100

and XR the survival rate was 60% and 100%, respectively.

Conclusions: Both composite resins MZ100 and XR

increased the fatigue resistance of ultra-thin occlusal veneers

(P < .001) when compared to Empress CAD and e.max CAD.

doi:10.1016/j.dental.2010.08.135

1 XR (experimental blocks), (under patent approval process).


e60 dental materials 26S (2010) e1–e84

128

Flexural strength and Weibull analysis of materials for CEREC

CAD/CAM

M. Sedda, A. Vichi, F. Del Siena, A. Casucci, G. Corciolani, M.

Ferrari

Department of Fixed Prosthodontics and Dental Materials, University

of Siena, Siena, Italy

Objectives: To measure the flexural strength ( ), the

Weibull modulus (m), and the Weibull characteristic strength

( 0) of ceramic materials marketed for CEREC CAD/CAM

system following the recently introduced ISO 6872:2008

standard.

Materials and methods: 19 types of ceramic blocks were

selected. Samples (n = 15) were obtained by cutting the commercial

blocks with a low-speed water-cooled saw, treated

as indicated by the manufacturer, finished (300 grit paper)

to the required dimensions (l =15± 0.2 mm, w =4± 0.2 mm,

h = 1.2 ± 0.2 mm), and polished (600, 1200 grit). A three-point

bending test appliance was prepared (span = 13 mm). Specimens

were loaded until failure at 0.5 mm/min speed.

Results:

Material , S.D. (MPa) m 0 (MPa)

Chairside

Paradigm C a 109.14 ± 10.10 12.69 113.58

Empress CAD LT b 125.10 ± 13.05 11.55 130.64

Empress CAD Multi b 100.86 ± 15.82 7.52 107.38

Cerec Blocs c 112.68 ± 7.97 16.68 116.24

Cerec Blocs PC c 105.40 ± 5.39 22.45 107.93

Mark II d 102.77 ± 3.60 33.80 104.42

Triluxe d 101.95 ± 7.28 16.35 105.25

Triluxe Forte d 105.06 ± 4.93 25.55 107.27

Structural

e.max CAD HT b 336.06 ± 40.09 9.04 355.27

e.max CAD LT b 376.85 ± 39.09 11.27 394.10

e.max CAD MO b 234.40 ± 93.93 2.51 266.30

Zir-CAD b 1074.46 ± 102.09 6.45 1154.06

inCoris AL c 441.78 ± 26.67 18.97 454.23

inCoris ZI c 1084.41 ± 219.60 5.78 1170.96

In-Ceram ALUMINA d 405.50 ± 47.48 10.13 425.75

In-Ceram SPINELL d 376.95 ± 39.00 11.51 393.70

In-Ceram ZIRCONIA d 400.65 ± 60.28 7.47 427.04

In-Ceram AL d 541.64 ± 53.70 11.89 565.17

In-Ceram YZ d 940.33 ± 150.08 7.43 1002.45

a 3M-Espe.

b Ivoclar.

c Sirona.

d Vita.

Conclusions: All chairside materials satisfy the limit of

100 MPa (Class 2 – Single unit, adhesively cemented). All structural

materials satisfy the limit of 300 MPa (Class 4 – Three unit

not involving molars); only a few materials satisfy the limit of

500 MPa (Class 5 – Three unit involving molars) and 800 MPa

(Class 6–Fourandmoreunits involving molars).

doi:10.1016/j.dental.2010.08.136

129

Flexural strength of dental alumina ceramic systems reinforced

by Al2O3/GdAlO3 fibers

R. Sgura 1 , I.S. Medeiros 1 , A.C. Hernandes 2

1 University of São Paulo, São Paulo, Brazil

2 University of São Paulo, São Carlos, Brazil

Objectives: This study evaluated the addition of

Al2O3/GdAlO3 fibers (0.5 mm in diameter) obtained by LHPG

(Laser Heated Pedestal Growth) to one veneering porcelain

(VM7) combined with two different core ceramics: In-Ceram

Alumina and In-Ceram 2000 AL Cubes (VITA Zahnfabrik).

Materials and methods: Bar-shaped specimens

(2 mm × 4mm× 16 mm) were composed by both the veneer

and the core ceramic (bilayers). Longitudinal fibers were

added to the specimens in two different contents: (10 or

17 vol%). Specimens without fibers were used as controls.

A metallic device was developed for the standardization of

the fibers’ position within the specimens. After grinding and

polishing the specimens were submitted to a three point

bending test (crosshead speed = 0.5 mm/min). The mean

values of density and flexural strength of the specimens were

analyzed by means of one-way ANOVA and a Tukey’s test

(˛ = 5%).

Results: Mean values of density and flexural strength for

bilayers as a function of the core material and fiber content

(n = 10). Values followed by the same letters are statistically

similar (p > 0.05).

Material Fiber

volume

(%)

In-Ceram Alumina

(framework + VM7)

In-Ceram AL Cubes

(framework + VM7)

(g/cm 3 ) t (MPa)

– 2.7 (0.2) ab 114 (18) B

10 2.9 (0.3) a 130 (37) AB

17 2.8 (0.3) ab 169 (46) A

– 2.3 (0.2) c 157 (8) A

10 2.5 (0.1) bc 165 (11) A

17 2.6 (0.1) bc 167 (36) A

Conclusions: The addition of 17 vol%. of Al2O3/GdAlO3

fibers to In-Ceram Alumina bilayers significantly improved its

flexural strength. In-Ceram Alumina bilayers in absence of

fibers presented lower flexural strength compared to the other

groups.

doi:10.1016/j.dental.2010.08.137


130

Effect of sintering and SiO2 deposition on core–veneer ceramic

bonding

J.R.C. Queiroz 1 , P. Benetti 1 , S.F. Fissmer 2 , M. Massi 2 , A.M.

Silva 1 , L. Nogueira Junior 1 , A. Della Bona 3

1 UNESP, Brazil

2 ITA, Brazil

3 Universidade de Passo Fundo, Brazil

Objectives: To test the hypotheses that the bond strength

between zirconia core and veneer is influenced by multiple

sintering of the veneering ceramic and by SiO2 film deposition.

Materials and methods: Zirconia-based ceramic blocks (YZ)

were polished and randomly divided into 4 groups according

to the veneer ceramic sintering protocol and to the presence of

SiO2 film on the YZ surface: G1 – two sintering procedures; G2

– three sintering; G3 – two sintering procedures + film deposition;

and G4 – three sintering + film deposition. SiO2 films were

deposited on the YZ surface using plasma method (physical

vapor deposition-PVD) with reactive magnetron sputtering

technique, prior to the veneer application and EDS analysis

was performed to determine the elements present on the

zirconia surface after silica deposition. The blocks were sectioned

in order to obtain bars with 1 mm 2 of cross-sectioning

area. The bars were fixed to a universal test machine device

and microtensile bond strength test (�TBS) was performed.

Specimens’ fracture surfaces were analyzed under optical

microscopy (Stemi 2000-C, Carl Zeiss) in order to characterize

the failure mode. The thickness of the silica film was estimated

on zirconia fractured samples using the EDS scan line technique.

Data were analyzed using ANOVA (2-way), Tukey’s post

hoc test (˛ = 0.05). The Weibull modulus was calculated.

Results: The mean values of �TBS (MPa) for the groups

were:G1(15± 6.6); G2 (18 ± 6.7); G3 (13.8 ± 2.2); G4 (17.7 ± 4.8).

The number of veneer ceramic sintering procedures affected

significantly the core–veneer bond strength (p < 0.05). The

bond strength values were not affected by the SiO2 film

(p > 0.05). G3 showed the highest Weibull modulus (7), followed

by G4 (4), G2 (3), and G1 (2). The analyses of fracture surface

revealed the failure was originated on the core–veneer interface

and run through the veneer porcelain for the most part of

the specimens in group G1 and G2, and for all the G3 and G4

specimens. The film thickness was estimated in 0.5 �m and

EDS surface analysis showed a homogeneous Si deposition in

the Y-TZP surfaces.

Conclusions: The number of the veneer ceramic sintering

procedures affects the core–veneer bond strength of the

bilayer ceramic system tested in this study. SiO2 film deposition,

using PVD method, decreases the probability of failure of

the system.

doi:10.1016/j.dental.2010.08.138

dental materials 26S (2010) e1–e84 e61

131

Effect of sintering temperature on three-point flexural

strength of different zirconia materials

B. Stawarczyk, M. Özcan, M. Roos, A. Trottmann, C.H.F. Hämmerle

University of Zurich, Switzerland

Objectives: This study tested the 3-point flexural strength

of zirconia materials with different sintering temperatures.

Materials and methods: Three-point flexural strength of

one hipped zirconia 1 (control group) and 9 different zirconia

materials in white state 2,3,4,5,6,7,8,9,10 (N = 150, n =15

per group) was measured according to ISO 6872: 1995

(1.2 mm × 4mm× 25 mm). Before sintering, the specimens of

the white state zirconia materials were ground and finished

to the final dimensions using silicone carbide discs of 220,

500 and 1200 in sequence. Thereafter, all specimens of white

state zirconia materials were sintered in the sintering oven

(LHT 02/16, Nabertherm) according to each manufacturer’s

instructions. The dimensions of the specimens were measured

at an accuracy of 0.01 mm. The specimens were placed

in their respective jigs and loaded in the Universal Testing

Machine (Z010, Zwick, 1 mm/min) until failure. Data were analyzed

using descriptive statistics (95% CI), one-way ANOVA,

followed by post hoc Scheffé test (alpha = 0.05). In addition,

Weibull moduli were calculated.

Results:

Groups Final sintering

temperature

3-point flexural

strength (SD) (N)

Weibullmodulus

(95% CI)

DC Zircon (control) – 1643 (64) a 10.1 (6.6, 15.6)

ZENO ZR 1450 913 (52) b,c,d 5.7 (3.7, 8.7)

DD BioZWiso 1550 821 (29) d 9.6 (6.3, 14.6)

GC ZR Disc CIP 1550 818 (45) d 8.3 (5.5, 12.6)

Ceramill Zi 1450 1195 (58) b 5.6 (3.8, 8.2)

Copran 1450 1124 (62) b,c 5.9 (3.8, 8.9)

InCoris ZI 1530 963 (37) b,c,d 8.8 (5.8, 13.3)

InCeram YZ 1530 1106 (40) b,c 7.4 (5.1,10.8)

Cercon ZR 1350 868 (43) c,d 6.6 (4.3, 10.0)

LAVA Zirkon 1500 939 (32) b,c,d 7.7 (5.3, 11.2)

a,b,c,dValues followed by the same letter are statistically similar (p > 0.05).

Conclusions: Sintering temperature exceeding 1540 ◦ C

resulted in significantly lower 3-point flexural strength compared

to those of the zirconia materials sintered at lower

temperatures. Hipped zirconia exhibited the highest 3-point

flexural strength and the Weibull-modulus.

doi:10.1016/j.dental.2010.08.139

1 DC Zircon, DCS.

2 ZENO ZR, Wieland Dental.

3 DD BioZWiso, Dental Direkt.

4 GC ZR Disc CIP, GC Europe.

5 Ceramill Zi, Armann Girrbach.

6 Copran, White Peak.

7 InCoris ZI, Sirona.

8 InCeram YZ, Vita Zahnfabrik.

9 Cercon ZR, DeguDent.

10 LAVA Zirkon, 3M ESPE.


e62 dental materials 26S (2010) e1–e84

132

Cementation strategy and mechanical-cycling effects on

human-dentin and composite-inlays MTBS

L.F. Valandro 1 , E.P. Prochnow 1 , C. Bergoli 1 ,M. Amaral 1 ,G.

Saavedra 2

1 Federal University of Santa Maria, Rio Grande do Sul, Brazil

2 São Paulo State University, São Jose dos Campos, São Paulo, Brazil

Objectives: To evaluate the effect of fatigue load cycling

and cementation strategy on microtensile bond strength

(MTBS) between human dentin and composite resin

inlays.

Materials and methods: The roots of 36 human premolars

were embedded into plastic cylinders (20 mm × 25 mm)

with acrylic resin. MOD inlay preparations were performed,

impressions were created (polyether) to obtain special gypsum

dies. Thirty-six indirect restoration of composite resin

(Sinfony, 3M) were made. Restorations were cemented according

to 2 strategies (N = 18): E1 – total-etch two steps adhesive

system (Adper Single Bond) + resin cement (RelyX ARC); E2 –

self-adhesive cement (RelyX U100). On E1, restorations were

treated with silica deposition through sandblasting combined

with silanization (Cojet System), while no treatment was carried

out for E2. Nine specimens from each strategy were

submitted to mechanical cycling (2 × 10 6 x, 88 N, 4 Hz, 45 ◦ ,

37 ◦ C). Non-cycled specimens (control group) were stored into

37 ◦ C water during the same period of cycling. Thus, four

groups were formed (n = 9), according to the two tested factors

(strategy in 2 levels, mechanical cycling in 2 factor). Afterwards,

each specimen was sectioned to obtain non-trimmed

bar specimens (1 mm × 1 mm) composed by vestibular dentin

– restoration – lingual dentin, which were submitted to

MTBS.

Results: Bond strength was significantly affected by cementation

strategy only (p < 0.0001). Higher values of bond of MTBS

were obtained by E1 (2-way ANOVA and Tukey; p ≤ 0.05).

Conclusions: Surface treatment of the hard dental structure

and restoration are essential to promote higher bond

strength.

doi:10.1016/j.dental.2010.08.140

133

Microstructural changes on sandblasting Y-TZP before and

after sintering

A. Verna 1 , A. Tucci 2 , L. Esposito 2 , C. Monaco 3 , P. Cardelli 3 ,R.

Scotti 3 , L.F. Valandro 4 , P.F. Cesar 1 , M. Oda 1

1 University of São Paulo, Brazil

2 Centro Ceramico Bologna, Italy

3 University of Bologna, Italy

4 University of Santa Maria, Brazil

Objectives: The aim of this study was to evaluate the

induced effects of sandblasting on the surface of Y-TZP

ceramic before and after sintering by means of X-ray diffraction

and Scanning Electron Microscope (SEM).

Materials and methods: 56 zirconia ceramic 1 specimens

were ground flat and divided in 7 groups (n = 8): Group A

untreated; Groups B, C and D were sandblasted 2 before

sintering with 30 �m, 50 �m and 110 �m Al2O3 grain size,

respectively; Groups E, F and G were sandblasted after sintering

with 30 �m, 50 �m, 110 �m grain size, respectively.

The roughness values for each group and the phase fraction

amounts (tetragonal and monoclinic) were calculated

with X-ray diffraction (XRD) before and after sintering.

SEM observations were performed to detect the morphology

alterations.

Results:

Group Surface

roughness

(Ra/�m)

A – untreated 0.35 ± 0.16 0

Before sintering

B – sandblasted 30 �m 1.22 ± 0.22 0

C – sandblasted 50 �m 2.33 ± 0.46 0

D – sandblasted 110 �m 3.44 ± 0.44 0

After sintering

E – sandblasted 30 �m 0.41 ± 0.03 10

F – sandblasted 50 �m 0.48 ± 0.04 8

G – sandblasted 110 �m 0.60 ± 0.04 14

Monoclinic

phase

contents (%)

The SEM analysis demonstrated that the bigger the alumina

particles dimension the higher damage on zirconia

sandblasted after sintering.

Conclusions: Zirconia sandblasting before sintering can

increase the surface roughness without phase transformation

induction from tetragonal to monoclinic.

doi:10.1016/j.dental.2010.08.141

134

Performance profile of different new self-adhesive resin

cements

C.A. Wiedig, G. Raia, M. Ludsteck, R. Hecht

3M ESPE, Seefeld, Germany

Objectives: The purpose of this in vitro investigation was

to compare different new self-adhesive resin cements regarding

their bond strength to enamel, dentin and zirconia, their

degree of neutralization, ACTA abrasion and discoloration in

water to create a comprehensive performance overview.

Materials and methods: Materials tested were Maxcem TM

Elite (Kerr), SmartCem TM 2(Dentsply), GCEM TM (Automix),

Speedcem TM (Ivoclar Vivadent) and new self-adhesive resin

cement RelyX TM Unicem 2 Automix (3M ESPE). For shear

bond strength testing (SBS) bovine teeth were ground, polished

(600 grit sandpaper), water-rinsed and air-dried. In

case of zirconia (Lava TM , 3M ESPE), discs (15 mm × 3.5 mm)

1 e.max ZirCAD, Ivoclar Vivadent.

2 CoJet Prep, 3M ESPE.


were pre-treated as recommended by cement manufacturers.

Steel rods were cemented under pressure (20 g/mm 2 )

onto teeth and zirconia discs. After light-curing (lc) following

the manufacturers’ instructions, specimens were

stored for 24 h at 37 ◦ C and 100% rel. humidity. SBS was

measured using a universal testing machine (Zwick Z010,

crosshead speed: 0.75 mm/min). Intrinsic discoloration was

tested using lc cement discs (15 mm × 1.5 mm). After storing

in water for 1 month at 36 ◦ C, color of the discs was

determined with a d/8 ◦ spectro-photometer (Color i7, xrite)

and �E values were calculated. Degree of neutralization

was determined by measuring the increase of pH of the

mixed cement within 24 h (�pH) using pH indicator sticks

(Fisherbrand). ACTA abrasion was measured according to

ISO/TS 14569-2 (200,000 cycles, load 15 N, slip 15%). Data

obtained were analyzed using Multiple Range Test (95%

LSD).

Results:

– Values in one column with the same characters are

statistically not different.

Material SBS Enamel

(MPa)

dental materials 26S (2010) e1–e84 e63

SBS Dentin

(MPa)

SBS Zirconia

(MPa)

Discoloration (H2O)

(�E)

�pH within

24 h

ACTA

abrasion

(�m)

Maxcem Elite 24.3 a,b 4.6 c 24.3 b 5.2 2.5 71.4 ± 2.0 d

SmartCem 2 20.5 b 5.0 c 24.7 b 1.4 4.5 51.4 ± 6.1 b

G-CEM 21.6 a,b 9.8 b 28.5 a,b 2.6 5 56.6 ± 3.8 c

RelyX Unicem 2 Automix 25.9 a 19.2 a 37.6 a 1.1 6.5 45.9 ± 2.5 a

Conclusions: RelyX Unicem 2 Automix showed the best performance

profile with excellent results in all tested material

properties compared to all other cements in this study. Neutralization

as indicated by a high �pH-value contributes to the

longevity of the cementation.

doi:10.1016/j.dental.2010.08.142

135

Measurement of the phase transformation of 3Y-TZP in depth

using Raman spectroscopy

C. Wulfman 1,2 , N. Dupont 2 , M. Sadoun 1 , M. Lamy De La

Chapelle 2

1 URB2I-EA4462, University Paris Descartes, France

2 CSPBAT, University of Paris 13, France

Objectives: Kinetics of phase transformation of partially

stabilized zirconia (TZP) is usually studied through X-ray

diffraction (XRD) or atomic force microscopy (AFM). Those

techniques enable the observation of the surface of the sample,

in a grain-size or nm depth, respectively. Furthermore,

XRD permits a quantitative measurement of the transformed

volume. The aim of this study is to measure the monoclinic

phase amount in 3Y-TZP in relation with depth using Raman

spectroscopy (RS).

Materials and methods: Two XRD controlled pure tetragonal

samples of 3Y-TZP (VITA ® ) were exposed to in vitro aging at

130 ◦ C in Ringer solution under a pressure of 6 bar for 0, 25 and

90 h. The monoclinic volume (Vm) was measured using XRD,

following the Garvie and Nicholson relations. Deeper measurements

were also performed with Raman spectroscopy,

using an excitation wavelength at 632 nm with a power of

1 mW (HeNe Laser), coupled with confocal microscope. Objectives

10× and 100× are used to reach spatial resolutions at the

micrometer scale (around 3 �m and 1 �m, respectively). Confocal

pinhole aperture is gradually enlarged to deepen laser

penetration. According to Clarke and Adar, monoclinic volume

is given by:

Vm =

0.97(I 145

t

I178 m + I189 m

+ I256

t ) + I178 m + I189 m

where It and Im indicate the intensities of the peaks of the

tetragonal and monoclinic phases with peaks wavenumber in

superscript.

Results:

Method Depth (�m) Vm (%)

0h 25h 90h

XRD 0.1 0 70 70

RS 100× 1 0 42 64

RS 10× 2 0 12 37

RS 10× 14 0 7 24

RS 10× 70 0 2 15

In-depth measurements show a higher and deeper transformation

rate after 90 h, due to water penetration, that was

not detected with XRD.


e64 dental materials 26S (2010) e1–e84

Table1–EM(GPa(SD)) and FS (MPa (SD)) data from the

tested materials.

Material EM FS

G-CEM Automix (GC) 7.75 a (1.15) 114.03 e (13.55)

G-CEM Capsules (GC) 7.85 a (0.71) 60.04 f (11.12)

RelyX Unicem Clicker (3M ESPE) 3.58 b (0.6) 49.0 g (5.24)

RelyX Unicem Maxicap (3M ESPE) 5.36 c (0.59) 41.6 g (7.9)

Maxcem Elite Automix (Kerr) 4.32 d (0.19) 69.74 f (7.83)

SpeedCEM Automix (Ivoclar Vivadent) 5.02 c (0.42) 79.81 h (19.83)

Superscript letters indicate statistically homogenous subsets.

Conclusions: Raman spectroscopy enables quantitative

measurement of zirconia monoclinic phase from subsurface

(1 �m) to a depth of 70 �m. This method is thus appropriate to

explore diffusion of water in the thickness of the material and

its clinical consequences.

doi:10.1016/j.dental.2010.08.143

136

Mechanical performance of self-adhesive resin cements

J.I. Zorzin, A. Petschelt, U. Lohbauer

Dental Clinic 1, University of Erlangen-Nuernberg, Germany

Objective: Elastic modulus (EM) and Flexural strength (FS)

are main material properties characterizing the mechanical

performance of self-etching resin luting cements. The aim of

this study was to obtain the EM and FS from a representative

spectrum of this material class.

Materials and methods: Six different self-etching resin

luting cements were selected for measuring EM and FS. Barshaped

specimens (2 mm × 2mm× 25 mm) were produced

(n = 15, self-curing mode) and stored in distilled water for 24 h

at 37 ◦ C prior to measurements in a universal testing machine

(Z2.5, Zwick, Germany). Statistical analysis was performed

using ANOVA and Tukey’s test (p < 0.05).

Results: The material G-Cem showed the highest EM and

FS, at least in the automix application. Different application

forms of the same material showed a significant difference in

FS whereas not in EM (Table 1).

Conclusions: Self-etching resin luting cements have heterogenous

mechanical properties. EM and FS have a great

variation depending on the brand and application form. The

automix/clicker application form produced improved results

compared to their capsule counterpart, probably due to less

internal porosity.

doi:10.1016/j.dental.2010.08.144

137

Self-etching cement–dentine interface: A macrostructural

evaluation

P.A. Acquaviva, F. Cerutti, M. Gagliani, A. Cerutti

University of Brescia, Italy

Objectives: The aim of this study was to evaluate the

adhesive interface of a new self-adhesive material used for

fiber post cementation, studying the macrostructural aspect

of adhesive interface and how a further etching step affects

the dye infiltration after thermocycling. The null-hypothesis

was an absence of infiltration and voids after thermocycling.

Materials and methods: 40 single-rooted teeth were

endodontically treated and sectioned at CEJ, randomly split

into two groups (A & B) then the same kind of post 1 was luted

with an experimental cement 2 : in group A the post space was

etched with H3PO4 – for 15 s prior to placement, while no additional

etching was performed in group B. Each root was cut

into 4 slices at increasing distance from CEJ (1-3-5-7 mm), then

analyzed after thermocycling (ISO/TS11405:2003) and immersion

in a 2% methylene-blue solution (24 h). After the image

steromicroscope acquisition (13×), the macrostructural analysis

exploited a digital automated software, 3 in order to assess

the degree of infiltration, presence of guttapercha, micro or

macrovoids. The data were statistically analysed using 2 and

Student’s t-test (p = 0.05).

Results: The etching procedure improves the compositedentin

bond by reducing the rate of infiltration: we observed

a significant infiltration in sections until 5 mm in group

B (p < 0.05). The presence of voids was due only to operator

errors or anatomical variables, since the self-mixing

application system ensures no air bubbles within the

material.

Conclusions: A further etching step could be a reliable

method to improve the cement–dentin adhesion in post luting.

doi:10.1016/j.dental.2010.08.145

138

Effective fluoride recharging protocols for various orthodontic

adhesives

B.S. Lim 1 , S.J. Lee 1 , D.Y. Lee 2 , S.J. Ahn 1

1 Seoul National University, Seoul, South Korea

2 Korea University, Seoul, South Korea

Objectives: The purpose of this study was to evaluate the

fluoride recharging capacity of various orthodontic adhesives

and to find the most effective fluoride recharging protocol for

them.

Materials and methods: Five orthodontic adhesives were

used: a non-fluoride-releasing composite (Transbond XT),

a fluoride-releasing composite (Lightbond), a polyacidmodified

composite (compomer) (Transbond Plus), and two

resin-modified glass-ionomers (RMGI) (Fuji Ortho LC and

Multi-Cure). Each sample was placed into deionized water

(DW) and the initial fluoride release was measured for 2

months. Each sample was then subjected to four different

treatments to simulate a fluoride recharge: 1000 ppm NaF

solution, acidulated phosphate fluoride gel (APF), fluoridecontaining

dentifrice and DW. After topical fluoride treatment,

each sample was submitted to fluoride re-release tests.

Results: Amounts of fluoride re-release (ppm/g/day) of

orthodontic adhesives after various topical fluoride treatments.

1 FRC Postec Plus #3, Ivoclar-Vivadent.

2 Experimental cement, Ivoclar-Vivadent.

3 Jmicrovision.


dental materials 26S (2010) e1–e84 e65

DW 1000 ppm NaF solution 1.23% fluoride gel Fluoride-dentifrice

1st

treatment

2nd

treatment

1st

treatment

2nd

treatment

1st

treatment

2nd

treatment

1st

treatment

2nd

treatment

TB a 0.03 ± 0.00 0.08 ± 0.01 0.41 ± 0.07 0.65 ± 0.13 0.59 ± 0.16 0.74 ± 0.10 0.84 ± 0.27 0.68 ± 0.04

LB b 0.06 ± 0.00 0.08 ± 0.01 0.49 ± 0.04 0.60 ± 0.05 0.82 ± 0.15 0.81 ± 0.18 0.86 ± 0.14 0.81 ± 0.07

TP c 0.22 ± 0.03 0.26 ± 0.04 3.32 ± 0.55 2.59 ± 0.26 3.93 ± 0.30 6.17 ± 0.45 2.29 ± 0.27 1.83 ± 0.20

FO d 2.47 ± 0.21 2.25 ± 1.54 13.74 ± 2.40 7.44 ± 0.99 9.40 ± 1.33 13.71 ± 3.66 8.04 ± 1.02 6.12 ± 1.11

MC e 0.91 ± 0.07 0.64 ± 0.07 14.29 ± 2.37 8.94 ± 1.55 10.84 ± 0.78 18.38 ± 4.02 6.13 ± 0.95 4.62 ± 0.57

a TB, Transbond XT, 3M/Unitek, Monrovia, CA, USA.

b LB, Lightbond, Reliance Orthodontics, Itasca, IL, USA.

c TP, Transbond Plus, 3M/Unitek, Monrovia, CA, USA.

d FO, Fuji Ortho LC, GC Corporation, Tokyo, Japan.

e MC, Multi-Cure, 3M/Unitek, Monrovia, CA, USA.

Conclusions: Using the combination of either RMGIs or

compomer and a fluoride-containing gargle solution is the

most effective protocol for long-term fluoride re-release from

orthodontic adhesives, given the difficulty of routine use of

APF at home.

doi:10.1016/j.dental.2010.08.146

139

Does the disk-specimen height impact the push-out bond

strength results?

M. Amaral, C.D. Bergoli, L.F. Valandro

Federal University of Santa Maria, Santa Maria, Brazil

Objectives: To investigate the effect of different heights of

the push-out slices on the push-out bond strength test.

Materials and methods: Eighteen lower bovine teeth were

sectioned (20 mm) and the root canals were prepared to a

length of 15 mm with the same post system drill (Light Post

#1, Bisco, Schaumburg, IL, USA). The apical third of each

specimen was embedded in a plastic matrix filled with a

chemically cured acrylic resin (Dencrilay, Dencril, Caieiras, SP,

Brazil). The posts were cleaned with 96% alcohol, silanized

(MPS-based silane; ProSil ® , FGM, Joinvile, SC, Brazil) and

cemented using the self-adhesive cement, RelyX U100 (3M

ESPE, St Paul, MN, USA). Each specimen was sectioned along

its long axis into three slices of different heights: 1 mm, 2 mm,

and 4 mm. These disk-samples were allocated into 3 groups

(n = 18) according to slice thickness and subjected to push-out

testing.

Results: One-way ANOVA showed no influence of the specimen

height on the push-out bond strength results (p = 0.842).

No correlation was observed between thickness vs push-out

bond strength (Pearson Correlation, r2 = 0.0688; P = 0.6209).

Conclusions: The push-out bond strength test was not

affected by the height of the disk-specimens (range from 1 mm

to 4 mm).

doi:10.1016/j.dental.2010.08.147

140

MIH hypoplasic enamel treated with a novel bioactive lightcuring

calcium-silicate material: A pilot clinical study

C. Baroni, M.G. Gandolfi, C. Prati

University of Bologna, Bologna, Italy

Objectives: MIH (molar-incisor-hypoplasia) is a frequent

disease affecting the erupting permanent molars and incisors

showing low level of calcium and phosphate. Clinical remineralizing

therapies are required and tried out by clinicians

(Baroni et al., 2010). Calcium-silicate materials have been

recently proposed as dentine remineralizing materials. They

are able to induce apatite deposits formation. A novel bioactive

light-curing calcium-silicate material has been recently

designed (Gandolfi & Prati). This material adheres to the

etched enamel surface and proved the ability to release calcium

and to form apatite. The goal of the study was to evaluate

the effectiveness of the novel material in reducing incisors

defects and improving the mineralization of MIH enamel

lesion in children.

Materials and methods: 8 children aged 6–9 with hypoplasic

incisors (identified as white-yellow-brownish spots) were

selected. The spots on enamel surface were gently polished

and etched with H3PO4 gel for 20 s, washed with water and

air dried. A thin layer of the bioactive light-curing calciumsilicate

material was applied on the spots with a small brush

to completely cover the entire surface of the spot lesion, then

light-cured for 120 s with a photo-curing unit (Anthos, Italy)

and finally covered by orthodontic wax. The patients were

recalled after 15 days. Clinical pictures and polyvinylsiloxane

impressions were taken before and after the treatment and

acrylic resin replicas were taken and observed by SEM.

Results: SEM analysis before treatment shows a very clear

demarcation between normal and hypoplasic enamel. At 35×

magnification affected surfaces are overall characterized by

porosities. At 500× the prismatic structure is present, but crystal

organization in the affected tissue is lacking connections,

resulting looser and less organized. At 35× magnification MIH

affected incisor enamel treated with bioactive agent showed a

smoother surface profile, difficult to distinguish from normal

enamel. At 500× no porosities and irregularities were observed

on enamel surface.

After the treatment the white spots appeared clinically less

evident.


e66 dental materials 26S (2010) e1–e84

Conclusions: The calcium releasing of the novel material

may create the local condition for the apatite formation inside

the enamel porosities that is responsible for the reduction of

the spot lesions with aesthetic and clinical advantage.

doi:10.1016/j.dental.2010.08.148

141

Reliability of fractal dimension analysis based on round-robin

tests

A.A. Barrett 1 , P.F. Cesar 2 , S.S. Scherrer 3 , J.A. Griggs 4 ,U.

Lohbauer 5 , K. Gopalakrishnan 1 , C. Shen 1 , J.J. Mecholsky Jr. 1 ,

K.J. Anusavice 1

1 University of Florida, FL, USA

2 University of São Paulo, Brazil

3 University of Geneva, Switzerland

4 University of Mississippi, MS, USA

5 University Erlangen, Germany

Objectives: The fractal dimensional increment, D* (slitisland

technique), is based on measurements of a fracture

“coastline” of fractured specimens. The objectives of this study

were proposed to verify the reproducibility and repeatability

of measurements (D*) based on round robin tests.

Materials and methods: An epoxy replica of a fracture surface

was produced using a ceramic disc (Ce-TZP/Al2O3, Panasonic,

JP) subjected to biaxial flexure. By polishing, a coastline

of the replicated fracture surface was exposed, imaged

and stored electronically. Printed images (1.4 m × 0.4 m) and

dividers for measurements were mailed individually to participants

(novices: A, B and D; experienced: C).

Aim 1: To determine the reproducibility among four independent

labs, instructions were: (a) delineate the coastline

between pre-marked endpoints; (b) measure the coastline

using step-lengths of: 20, 10, 5, 4, 3 mm; (c) repeat measurements

three times with 24 h minimum between sessions. Aim

2: To determine repeatability of counts within and among

labs, participants were instructed to perform steps b and c

(Aim 1) on a pre-delineated coastline. D* is the slope of total

length counts versus step-length in a log–log graph. Statistical

analysis (ANOVA) was performed to determine significance

for step-length counts (n = 120) and D* values (n = 24).

Results: Aim 1: Mean D* was the same statistically

(p > 0.05) for the first three of the following: [(A) 0.21 ± 0.01;

(B) 0.22 ± 0.01; (C) 0.19 ± 0.01; (D) 0.17 ± 0.01]. The differences

between B and D were statistically significant (p ≤ 0.05). Aim

2: There were no statistically significant differences within

each participant’s replicate measurements (p > 0.05). When

compared with A and C [(A) 0.22 ± 0.01; (C) 0.22 ± 0.01], participants

B and D [(B) 0.26 ± 0.00; (D) 0.25 ± 0.00] had differences in

mean D*. For the 3-mm step-length counts, the coefficient of

variation for Aim 1 ranged from 0.9 to 4.6%, compared with

a range from 0.5 to 3.0% for Aim 2. The maximum difference

between participants was 26% for Aim 1 and 17% for

Aim 2.

Conclusions: This study demonstrated that D* can be

determined accurately and reliably for individuals with no previous

training. Fractal analysis of fractured ceramic surfaces

may provide a reproducible method of describing differences

between fracture surfaces of zirconia-based ceramics.

Acknowledgement: Supported in part by NIH/NIDCR Grant

DE 006672.

doi:10.1016/j.dental.2010.08.149

142

TiO2, poly-l-lysine and hydroxyapatite differently affect

osteoblastic differentiation and IL-6 production

E. Canciani 1,∗ , M. Frattini 1 , S. Mele 1 , B. Palazzo 2 ,L.

Rimondini 1

1 University of Piemonte Orientale, Italy

2 MeLab, Mesagne, Italy

Objectives: TiO2 surface modification and hydroxyapatite

coating of implant titanium surfaces are demonstrated to

affect bone cells response in vitro and healing potential in

vivo. Bacteria contamination is a major cause of lack or loss

of osseointegration and implant failure. The presence of bacteria

affect cell response and their cytofuntionality in various

manner including signalling. The aim of the presence study

was to investigate the single and combined effect of surface

titanium modifications and presence of bacteria lipopolysaccharide

(LPS) on osteoblastic proliferation, differentiation and

expression of pro-inflammatory cytokines.

Materials and methods: Different surface modifications

of titanium disks, including poly-l-lysine (PLL) grafting and

electrosintered hydroxyapaptite coating (HA) were used. Plastic

and machined titanium were used as controls. Coated

and uncoated disks were characterized with XRD, SEM and

profilometry. Murine pre-osteoblasts MC3-T3 were used for

biological characterization. 2 × 10 4 cells/disk were seeded and

cultured in proliferative (DMEM + FBS), and in presence of

LPS; the cultures were assessed for vitality and proliferation

(MTT) morphology (SEM), alkaline phosphatase (ALP) expression

using Lowry’s method, total protein absorption onto

materials (BCA) and LPS production by ELISA tests. Statistical

analysis was preformed by one-way and two-ways ANOVA

and Sheffé’s tests.

Results: Cells proliferated more on machined and HA

coated titanium than on PLL coating. Cells on PLL and HA

specimens showed a greater differentiation ability in respect

with those machined with significantly higher production of

ALP/total proteins after 7 days but not after 14 days.

The presence of HA emphasized the expression of IL-6 in

presence with and without LPS.

T0 7 gg 14 gg FBS 0,

1%-7

days

LPS–7

days

Plastic 0.121 0.726 0.430 0.326 0.252

Ti machined 0.103 0.668 0.616 0.438 0.341

Ti - HA 0.166 1.111 1.362 1.100 1.032

Ti - PLL 0.089 0.401 0.283 0.284 0.195

Adsorbance (wavelength = 450 nm).


Conclusions: In conclusion, HA coating seemed to improve

differentiation potential of osteoblasts but also signaling for

clasts differentiation and bone remodeling.

doi:10.1016/j.dental.2010.08.150

143

Effects of external bleaching agents on dental tissues and

cement–enamel junction

M.G.A.M. Chaves, M. Oliveira, M.N. Pereira, M.R.S.P. Soares,

H.D.M. Chaves Filho, F.P.P. Leite

Universidade Federal De Juiz De Fora, Brazil

Objectives: Evaluate with a scanning electron microscope

(SEM) the alterations occurring in enamel, cementum and

cementum–enamel junction after the use of different external

bleaching agents.

Materials and methods: Fifteen healthy pre-molars were

sectioned in the middle with the aid of a cutting machine

(Labcut 1010), in the longitudinal direction along the axis

of the teeth, obtaining mesial and distal surfaces of each

tooth. The mesial surfaces were divided into three groups

in accord with the material used (AI – carbamide peroxide

10% – Whiteness Standard 10 FGM ® , AII – carbamide

peroxide 16% Whiteness Standard 16 FGM ® , e AIII – hydrogen

peroxide 35% Whiteness HP Maxx FGM ® ), applied

according to the instructions of the manufacturers. The

distal surfaces of each tooth were maintained in artificial

saliva, in a bacteriological sterilizer at 37 ◦ C. After whitening

the specimens were dehydrated in increasing solutions

of acetone and metalized for evaluation using a scanning

electron microscope. The results were submitted to statistical

evaluation using the Kruskal–Wallis and Mann–Whitey

tests.

Results: Statistically significant differences were observed

between the whitened and unwhitened specimens (p < 0.001).

In enamel, insignificant alterations were observed, and no differences

between the groups were found. Loss of structure,

with formation of gaps and dental exposure were observed in

the cemento-enamel junction of the three whitened groups.

Conclusions: Tooth whitening should be done with

caution principally in patients who possess gingival recession.

doi:10.1016/j.dental.2010.08.151

144

Solubility in water or DMEM of F-doped MTA cements with

increasing F-content

A. Colin, C. Prati, G.A. Pelliccioni, M.G. Gandolfi

Laboratory of Biomaterials and Oral Pathology, Department of

Odontostomatological Sciences, University of Bologna, Bologna,

Italy

Objectives: Fluoride increases the expansion and retards

the setting time of F-doped calcium-silicate MTA cements.

These cements may be successfully used as endodontic sealer.

The assessment of the solubility of the endodontic cements

dental materials 26S (2010) e1–e84 e67

allows to predict the loss of material from the surgical site,

where they are in contact with physiological fluids (blood,

tubular fluid). The aim of the study was to evaluate the solubility

in deionized water (ISO 6876) or in simulated body fluid

(DMEM) of designed F-doped calcium-silicate MTA cements

with increasing amount of fluoride.

Materials and methods: A calcium-silicate powder containing

di- and tricalcium-silicate, calcium sulphate and barium

sulphate was prepared. An increasing percentage of fluoride

(F0%, F1%, F5% and F10%) was added to the powder

to obtain 4 cements. The cements were mixed with DPBS

(liquid/powder ratio 0.22), placed into a mould (10 mm diameter;

2.21 mm height) and stored at 37 ◦ C and 98% relative

humidity for the 75% of their own setting time. Each sample

(n = 5 for each cement) was weighed (initial weight, IW)

and immersed in 10 mL of DMEM or deionized water keeping

a vertical position. After 1 or 21 days the samples were

dehydrated at 37 ◦ C and weighed (final weight, FW), then

demoulded and the moulds weighed (mould weight, MW).

The percentage of weight loss (solubility) was calculated as

[(IW − FW)/(IW − MW)] × 100.

Results: The solubility of all cements decrease over time

(from 1 to 21 days) in both soaking solutions. High F concentration

increases the solubility of calcium-silicate MTA cements.

The solubility in DMEM is lower than in water for all the

cements; this difference is more evident at 21 days.

Conclusions: The innovative MTA cement containing 1% of

fluoride represents an interesting material for the endodontic

surgery. The presence simulated body fluid solutions lows

the solubility rate of endodontic MTA cements suggesting a

reduced solubility in in vivo conditions.

doi:10.1016/j.dental.2010.08.152

145

In vivo, morphological and clinical effects of a desensitizing

agent

E. Milia 1 , E. Cotti 2 , G. Sotgiu 1 , G. Castelli 1 , M. Masarin 1 ,A.

Manunta 1 , G. Gallina 3

1 University of Sassari, Italy

2 University of Cagliari, Italy

3 University of Palermo, Italy

Objectives: This study evaluated the in vivo effectiveness

of Universal Dentin Sealant (UDS), a new resin-based mate-


e68 dental materials 26S (2010) e1–e84

rial, as dentinal desensitizing agent on dentin morphology and

clinical symptoms.

Materials and methods: Thirty premolars, exhibiting noncarious

cervical lesions, and scheduled for extraction for

periodontal reasons, were selected for the ultrastructural

study. These samples were randomly divided into three groups

(n = 10): group 1, brushing with UDS; group 2, brushing with

Flor-Opal ® Varnish (FOV); and group 3, untreated control. After

7 days, teeth were extracted and samples processed for SEM

and TEM comparative observations. The in vivo study was carried

out on 90 teeth with non-carious cervical lesions. The

assessment method used to quantify sensitivity was the cold

air syringe, recorded using the visual analogue scale (VAS),

prior to treatment (baseline) and after 7 days. Teeth were randomly

assigned to three groups (n = 30): group 1, UDS; group 2,

FOV; and group 3, untreated control. Analysis was based on the

Student’s t-test for paired data, with a 5% significance level.

Results: The ultrastructure of UDS/dentin interface was

characterized by a superficial porous layer of spherical clusters

immersed in a loose matrix that fully covered the superficial

dentin. A poorly crystalline aspect of peritubular and intertubular

fibrils with sealed tubular orifices was observed. The

FOV/dentin interface showed an irregular layer of precipitates

with partial exposure of the dentin surface. The presence of

intratubular crystals partially occluding the tubular orifices

and densely mineralized peritubular fibrils was also noted.

Untreated control dentin showed a superficial thin layer of

smear with porous plugs within the tubular orifices. Comparing

clinical results, the statistical analysis revealed significant

differences between both the tested materials (p < 0.001) and

the control group (p > 0.05) in term of the periods of examination.

Conclusions: The application of UDS resulted in effective

and stable dentinal tubular occlusion, leading to a statistically

significant decrease in clinical discomfort of particular

relevance to cases of dentinal hypersensitivity.

doi:10.1016/j.dental.2010.08.153

146

Increases of intracanal and root surface temperatures during

the obturation of canal using the E&Q master system and the

system

E. Cumbo 1 , R. Russo 1 , E. Milia 2 , G. Gallina 1

1 University of Palermo, Italy

2 University of Sassari, Italy

Objectives: The purpose of our study is to assess the

increases of intracanal and root surface temperatures during

the obturation of canal system using the E&Q Master System

and the System B.

Materials and methods: A split-tooth model was built. To

measure the temperature, 6 grooves for the placement of thermocouples

were made in the buccal half of the model. On the

mesial side, three grooves were made at 2, 4 and 6 mm from

the anatomical apex and were extended to the root surface,

while on the distal side three grooves were made at 2, 4 and

6 mm up to the intracanal portion. In each of these grooves

was inserted a type T thermocouple (Copper-Costantana) with

a diameter of 0.076 mm. 40 canal obturations were done: 20

using the E&Q Master System and 20 using the System B, set

at 250 ◦ C, both with plugger FM increased to 3.5 mm from WL.

The temperatures were recorded at 1 s intervals for a period of

200 s.

Results: During the continuous wave obturation technique

two peaks in temperature occurred, the first caused by the

plugger in the canal, the second during the separation phase.

In the E&Q Master System the highest increases were recorded

in the thermocouple N.6, which reported average increases of

6.30 ◦ C, while the lowest were recorded in the thermocouple

N.1, which reported a value of 2.11 ◦ C. In the System B group

the highest increases were recorded in the thermocouple N.6,

which reported average increases of 2.80 ◦ C, while the lowest

were recorded in the thermocouple N.1, which reported a value

of 0.4 ◦ C.

Conclusions: Analysis of the obtained results showed that

both systems allow us to get a good thermal mass increase of

gutta-percha. Results show that the use of E&Q Master System

and System B, in vitro, appears to cause a dangerous increase

in temperature along the surface of the root that may create

iatrogenic injury.

doi:10.1016/j.dental.2010.08.154

147

Assessment of gutta-percha adaptation with different root

canal obturation techniques

P. Cusimano 1 , E.M. Cumbo 2 , S. Provenzano 2 , C. Goracci 1 ,G.

Gallina 2 , M. Ferrari 1

1 University of Siena, Italy

2 University of Palermo, Italy

Objectives: To compare in vitro the gutta-percha adaptation

obtained with three different root canal obturation systems,

using an experimental model of a single-root tooth.

Materials and methods: A ‘split-tooth’ model was prepared.

Lateral grooves and dentin depressions were created

at 2, 4, 6 and 8 mm from the established apex length. Sixty

models were randomly divided into 3 groups (n = 20), based

on the obturation technique to be performed: System B,

non-standardized 06-30 gutta-percha cones (VDW, Munchen,

Germany) and System B (SybronEndo, Orange, Usa); GuttaFlow,

calibrated master cone (taper 06-30) and gutta-based fluid

cement carried by an applicator (Coltene, Whaledent Switzer-


land); Thermafil: non-standardized 06-30 cones with plastic

carrier heated in the Thermaprep Plus oven (Dentsply Maillefer,

Baillagues, Switzerland). Following obturation, the two

halves of each model were separated and photographed using

a digital camera (Nikon ® D50 Macro lens with 105 mm f

2.8). The gutta-percha filling ability was evaluated at 2, 4,

6, and 8 mm from the established apex length by assigning

the following scores: lateral grooves: 0 = absence of material,

1 = presence of material; dentin depressions: 0 = absence of

material, 1 = partial filling, 2 = total filling. Scores at lateral

grooves and dentin depressions were statistically compared

among techniques at the same level and among levels within

the same technique (Kruskal–Wallis ANOVA, Dunn’s Multiple

Range test, p < 0.05).

Results:

Level Dentin depression scores: median (25–75%)

Thermafil GuttaFlow System B

2 mm 0.5 (0–1) a 1 (0–1) aA 2 (2) b

4 mm 0.5 (0–1) a 2 (2) bB 2 (2) b

6 mm 0 (0) a 2 (2) bB 2 (2) b

8 mm 0 (0–0.5) a 2 (2) bB 2 (2) b

Level Lateral grooves scores: median (25–75%)

Thermafil Guttaflow System B

2 mm 0 (0) a 0 (0) aA 1 (1) b

4 mm 0 (0) a 1 (1) bB 1 (1) b

6 mm 0 (0) a 1 (1) bB 1 (1) b

8 mm 0 (0) a 1 (1) bB 1 (1) b

In the table different small letters label statistically

significant differences among techniques at the same

level, while different capital letters label statistically significant

differences among levels within the same technique.

Conclusions: The GuttaFlow and System B techniques

exhibited a significantly better gutta-percha filling ability than

Thermafil, particularly at 4, 6, and 8 mm from the established

apex length.

doi:10.1016/j.dental.2010.08.155

148

In vitro loading curve of an orthodontic distalizing spring

D. Dalessandri, L. Laffranchi, F. Zotti, S. Bonetti, L. Visconti

University of Brescia, Italy

Objectives: The objective of this in vitro study was to individually

evaluate the force delivered by a no compliance molar

distalizing appliance, the Frog, before its clinical use. We

tested five different springs made out of 0.032-in. iron wire. In

a second time we compared these springs with other 0.032-in.

alloy wires: TMA and blu-nickel.

Materials and methods: Different types of springs has

been evaluated by the Instron machine 54848, an engineer-

dental materials 26S (2010) e1–e84 e69

ing system that is able to describe their mechanical behaviour

registering the value of force sourcing from the appliance activation

by the original screw driver. In vitro simulation is based

on a custom built support for the Frog screw, where the spring

is plugged in, that allow to apply the controlled load on the

supposed first upper molar palatal tube position, at the end of

the spring.

Results:

Activation SS mean TMA mean BN mean

1 mm 50.99 gr 10.20 gr 20.39 gr

2 mm 81.58 gr 20.39 gr 40.79 gr

3 mm 101.97 gr 40.79 gr 71.38 gr

4 mm 132.56 gr 50.99 gr 101.97 gr

5 mm 163.15 gr 71.38 gr 132.56 gr

6 mm 183.55 gr 81.58 gr 163.15 gr

7 mm 198.34 gr 90.21 gr 186.79 gr

Conclusions: According to most of the literature about

molar distalization, the bilateral first upper molar distalization

requires 300 gr of force. To gain this value with a personalized

Frog spring this study showed that 9 rotations of the screw

were needed. Iron preformed 0.032-in. springs express high

values of strength with few activations, so they have a low risk

of plastic deformation and they are indicated for this kind of

appliance.

doi:10.1016/j.dental.2010.08.156

149

Intraradicular marginal integrity of fiber posts relined and

fixed with composite resin

M.F. De Goes, A.C.R.L. Caiado, M.C. Alves, F. Souza-Filho

Dental School of Piracicaba-University of Campinas, SP, Brazil

Objectives: The dislodging of fiber posts from the root canal

is the main cause of failure of fiber post-retained restorations.

This study evaluated the marginal integrity of Fiber Reinforced

Posts (FRP) confectioned using a conventional technique (CT)

or an anatomic composite relining technique (ACRT) and

cemented with a self-adhesive resin cement or a conventional

dual-cure resin cement in the presence or absence of

light.

Materials and methods: Bovine incisors had crowns

removed. Roots were endodontically prepared using saline

solution. Apexes were sealed externally with composite resin

and post spaces were prepared 15 mm deep. Samples were

randomly assigned to 8 experimental groups (n = 10) according

to FRP technique used (CT or ACRT), adhesive cement

employed (Unicem (U) or Scotch Bond Multipurpose + Rely X

ARC (R)) and activation mode (light-cure or self-cure). After

48 h, roots were longitudinally sectioned, surfaces were polished

and impressions were taken for replication using epoxy

resin. The length of the post inside the root canal was divided

on the replicas into three (cervical-C, middle-M and apical-

A) thirds. After obtaining baseline impressions, roots were

immersed in a solvent solution of methyl ethyl ketone and


e70 dental materials 26S (2010) e1–e84

a new set of impression and replicas was made. Samples

were examined by SEM. Values were expressed as a percentage

of continuous interface (%) and standard deviation (SD).

Data were analyzed by three-way ANOVA and Tukey tests

(˛ = 5%).

Results: Marginal integrity was statistically superior for

ACRT than CT techniques in all thirds, before (C: p = 0.0001; M:

p = 0.0001; A: p = 0.0062) and after (C: p = 0.0057; M: p = 0.0001;

A: p = 0.0074) solvent immersion. UNICEM presented a statistically

superior marginal integrity than Rely X ARC (U = 73.4

(35.9); R = 42.4 (45.5)) when the ACRT was employed. No statistically

significant difference was observed among cements

when the CT was employed (U = 7.7 (15); R = 8.6 (18.1)). Marginal

integrity was greater in the absence of light (43.1 (44.2)) than

in the presence of light (22.9 (35.5)) independent of fiber post

technique or cement employed.

Conclusion: (1) Marginal integrity of posts relined with

composite resin is superior compared to conventionally

cemented posts; (2) absence of light during cementation

procedures increased the marginal integrity of relined and

conventional posts; (3) the ACRT associated with cementation

using self-adhesive cement present the highest values of

marginal integrity.

doi:10.1016/j.dental.2010.08.157

150

Antimicrobial activity of a new endodontic irrigant against

Enterococcus faecalis

C. Dettori, S. Pisu, E. Cotti

Surgical and Oral Sciences Department, University of Cagliari, Italy

Objectives: The aim of this study was to compare the

in vivo antimicrobial activity of 2%TetraAcetylEthyleneDiamine

+ Sodium Perborate (TAED+P) against E. faecalis with 5%

Sodium Hypochlorite (NaOCl).

Materials and methods: Single species biofilms were generated

using cellulose nitrate membrane filters (0.2 �m pore size

and 13 mm diameter). The membranes were inoculated with

a suspension of bacteria in BHI agar. An aliquot of 20 �l of bacterial

strain was seeded onto cellulose membrane filters. Nine

membranes were used for each plate. Plates containing membranes

were then incubated for 48 h at 37 ◦ C. After incubation

membrane filters were transferred into tubes containing 5 ml

of selected antimicrobial solution test agent and saline sterile

solution (Positive Control). Microbial samples were taken

after 2, 5, 20 and 30 min and transferred aseptically into tubes

containing neutralizing broth for 5 min. Different concentrations

from 1:1 to 1:30 and to 1:100 were tested respectively

for TAED+P and NaOCl solutions. Each dilution was plated

onto BHI plates and incubated for 48 h at 37 ◦ C and CFUs per

membrane were calculated. Three replicates were performed

for each antimicrobial agent and control. Statistical analysis

was performed using Anova test at a P level of 0.05. For each

strain a regression model was fitted to the dependent variable

(viable count) for the independent variables of time and

concentration using the software packages Stata and SPSS-PC.

Results: No statistical differences were found between

NaOCl and Perasafe solutions when used in concentrations

respectively ranging from 0.0667 to 2% and from 0.05 to 5% at

various time points. For 5 and 0.5% dilutions NaOCl showed

a complete eradication of biofilm after each time point tested

in this study. Similar results were obtained with 0.1% NaOCl

at 20 and 30 min and with 0.0667 NaOCl at 30 min of time

exposure. E. faecalis biofilms treated with TAED+P were totally

eradicated at 20 and 30 min at any dilution.

Conclusions: The antimicrobial agents investigated in this

experimental biofilm model showed a different efficacy correlated

to the concentration and the duration of exposure.

TAED+ P and NaOCl used for high concentrations are able to

completely eliminate E. faecalis at different exposure times.

Based on these data TAED+P showed promising antibacterial

efficacy against E. faecalis biofilm.

doi:10.1016/j.dental.2010.08.158

151

In vitro resistance to sliding: Self-ligating bracket/archwire

0.014 ′′ using a customized typodont

P. Fontana, L. Laffranchi, D. Dalessandri, I. Tonni, L. Visconti

University of Brescia, Italy

Objectives: The aim of this study was to compare the resistance

to sliding (RS) of active and passive self-ligating brackets

(SLBs) using different archwires during during the alignment

phase of orthodontic treatment.

Materials and methods: We used two active self-ligating

brackets (ASLB), In-Ovation R and SPEED, and two passive

self-ligating brackets (PSLB), Damon 3 and SmartClip with

two archwires, 0.014 ′′ SentalloyTM ® GAG-New York-USA and

0.014 ′′ Copper Ni-Ti ® Ormco. To simulate crowding found at

the initial stages of treatment, the central upper incisors on

the maxillary arch were displaced 2 mm forward from the

ideal position on the arch. A custom made typodont in conjunction

to an Instron Testing Machine 54848, were used to

measure the resistance to sliding (RS). Each bracket/archwire

combination was tested 5 times. Statistical analyses were performed

using Two-Way Analysis of variance (ANOVA) followed

by Bonferroni’s multiple comparisons. The level of statistical

significance was set at p < 0.05.

Results: We found no significant difference in resistance to

sliding between 0.014 ′′ SentalloyTM ® GAG-New York-USA and

0.014 ′′ Copper Ni-Ti ® Ormco for all the brackets investigated.

SmartClip showed significantly the lowest RS for both wires

investigated followed by Damon 3. SPEED and In-Ovation R

showed the highest RS.

Conclusions: In this in vitro study, when the central upper

incisor was displaced 2 mm on a custom typodont to simulate

crowding, commonly found at the initial stage of leveling and

aligning, the PSLBs provided lower RS values than the ASLBs.

There was no difference in RS between 0.014 ′′ SentalloyTM ®

GAG-New York-USA and 0.014 ′′ Copper Ni-Ti ® Ormco for the

brackets investigated.

doi:10.1016/j.dental.2010.08.159


152

Structural analysis of the enamel subjected to pre- and postbleaching

agents

C. Francci 1,2 , M.N. Gomes 1,2 , A.G. Devito-Moraes 1,2 , F.P.

Rodrigues 1,2 , L.C. Yamazaki 1,2 , L.M. Silva 1,2 , N.R.G. Fróes-

Salgado 1,2 , A.C. Nishida 1,2

1 University of São Paulo-USP, Brazil

2 Bandeirante University of São Paulo -UNIBAN, Brazil

Objective: To evaluate the effects of pre and post-bleaching

agents as NaOCl and ACP-CPP on the structure of the enamel

surface.

Material and methods: Six human premolars were buccallingual

and mesio-distal sectioned and then subjected to the

following experimental conditions (n = 24): G1: 35% H2O2 (Pola

Office, Australia, SDI) – 4 sessions of 8 min; G2: 5.25% NaOCl

during 1 min previously to the application of 35% H2O2 and

G3: similar to G1 + ACP-CPP (MI-Paste, Japão, GC America), during

5 min daily repeated during 7 days. The samples were

covered with platinum to be evaluated with Scanning Electron

Microscopy (Stereoscan 440, LEO) and with High Vacuum

Field Emission Microscopy (Quanta 600 FEG, FEI). The images

were obtained using secondary electrons detector (Everhart-

Thornley), with a work distance of 10 mm, and a high voltage

of 10 kV, probe of 500 A with magnifications from 3000 through

100,000.

Results: In group G1, erosions on enamel prisms were

noticed. In G2, the application of the NaOCl previously to

the bleaching generated a smoother surface. There was a