Abstracts of the Academy of Dental Materials Annual ... - IsiRed

More documents

Recommendations

Info

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 covering mantle in G3 around the enamel prisms and lower spaces among the hydroxyapatite crystals. The use of NaOCl associated to the bleaching with hydrogen peroxide modifies the enamel morphology. Conclusion: The application of the ACP-CPP post-bleaching agent recovers the enamel surface when applied during a week after in-office bleaching sessions. doi:10.1016/j.dental.2010.08.160 dental materials 26S (2010) e1–e84 e71 153 Biomimetic dentine remineralization by a novel bioactive light-curing calcium-silicate composite M.G. Gandolfi 1 , F. Siboni 1 , P. Taddei 2 , E. Modena 2 , C. Prati 1 1 Department of Odontostomatological Sciences, University of Bologna, Bologna, Italy 2 Department of Chemistry, University of Bologna, Bologna, Italy Objectives: A light-curing resin-modified calcium-silicate cement was designed to obtain a bioactive calciumreleasing remineralizing material (Ic-MTA) for rehabilitation of deciduous teeth and remineralization of dentine lesions. Materials and methods: Ic-MTA was prepared by mixing a tailored calcium-silicate bioactive filler with an anphiphilic HEMA/TEGDMA-based resin. Calcium release and alkalinizing activity (i.e. pH of soaking water) of the cement were tested. The dentine remineralization capability and the bioactivity (i.e. apatite-forming ability) were investigated by ATR-FTIR and ESEM/EDX analyses after immersion in DPBS at 37 ◦ C for 7 days. Dentine disks 0.8 ± 0.2 mm thick were obtained from coronal side of healthy third molars and demineralized in 15 mL of sterile 17% EDTA for 2 h. EDX element distribution maps confirmed the complete absence of apatite on dentine disks from the surface to a 10 �m depth. Results: The experimental material releases calcium (200 ppm at 3 h), increases the environmental pH to 10–11 and showed marked bioactivity. After 7 days a thick layer of carbonated apatite (Ap) was noticed on dentine surface. Apatite precipitates obturated the dentinal tubules. Conclusions: Calcium-silicate materials are bioactive. Silanol groups from the mineral particles induce heterogeneous nucleation of apatite by sorption of calcium and phosphate ions. The improved bioactivity of Ic-MTA is related to the oxygen-containing groups from HEMA/TEGDMA, which provide additional apatite nucleating sites through the formation of calcium chelates. An improved biomimetic remineralization of dentine and a faster bioactive behaviour was proved by the novel light-curing calcium-silicate material. The coupling of a hydraulic calcium-silicate powder with a HEMA-TEGDMA hydrophilic resin creates conditions (enhanced calcium release and functional groups able to chelate Ca ions, with a consequent rapid apatite deposition)
e72 dental materials 26S (2010) e1–e84 promising for the remineralization and regeneration of mineral hard tissues. doi:10.1016/j.dental.2010.08.161 154 Post retention using a new resin-based-composite with low curing stress A. Giovannetti 1 , C. Goracci 2 , A. Polimeni 1 , E. Pacifici 2 ,M. Ferrari 2 1 “Sapienza” University of Roma, Italy 2 University of Siena, Italy Objective: To assess by means of push-out test the post retentive potential of a new light-cure flowable resin composite with low polymerization stress. Materials and Methods: SDR (Dentsply, S) was compared with the dual-cure resin cement Calibra (Dentsply, C) tested as control. S and C were used in combination with the adhesive XP Bond (Dentsply, XPB). In C groups the Self-cure Activator was mixed with XPB. The following types of fiber posts were luted into 24 extracted premolars: Radix (Dentsply, R), Light Post (RTD, LP), ER Dentin Post (Komet, ER), DT Light SL (VDW, SL). Three posted roots per group were tested. Each root provided 3–5 1 mm-thick slices. Measured pushout strengths were differentiated by post space level (coronal, middle, apical) and statistically analyzed. The Three-Way Analysis of Variance was applied (push-out strength dependent variable; luting agent, post, post space level factors). The Tukey test was applied for pairwise comparisons as needed. In all the analyses the level of significance was set at p < 0.05. Post Luting agent N Mean Std. Deviation Light Post A Calibra ab 11 9.5 3.4 SDR a 12 14.2 3.6 Radix AB Calibra ab 13 11.3 4.2 SDR b 10 9.1 5 ER Dentin Post AB Calibra ab 10 10.6 2.8 SDR ab 11 9.4 5.2 DT Light SL B Calibra b 9 6.2 2.2 SDR b 9 8.1 1.6 Results: The type of luting agent did not have a significant effect on post retention (p = 0.9). Conversely post type was a significant factor for push-out strength (p = 0.004). Particularly, LP exhibited significantly higher retentive strength than SL. In the table different capital letters label statistically significant differences among the posts regardless of the other factors. Also post space level was a significant factor for push-out strength (p < 0.001). Specifically, significantly higher push-out strengths were recorded at the coronal third than at the middle and apical levels that offered similar conditions for bonding. The post–cement interaction was significant (p = 0.002). In the table different small letters label statistically significant differences in the post × cement interaction. The other between-factor interactions were not statistically significant. Conclusions: When the new flowable low-curing stress resin composite was used to lute fiber posts, similar retentive strengths to those of a marketed resin cement from the same manufacturer were achieved. SDR should however be tested also in combination with posts exhibiting lower translucency than those selected in the present study. Also SDR’s potential as core material should be investigated. doi:10.1016/j.dental.2010.08.162 155 Varying PLA functionality and texture to influence osteoprogenitors R. Lakhman 1 , K. O’Brien 1 , R. Kasi 1 , R.A. Weiss 2 , L.T. Kuhn 1 , M. Mina 1 , A.J. Goldberg 1,∗ 1 University of Connecticut, USA 2 University of Akron, USA Objectives: Polylactic acid (PLA) has many benefits as a scaffold for tissue engineering and has been used to regenerate a dentin-pulp-like structure. The purpose of this study was to evaluate PLA homopolymer and a functionalized PLA, with and without nano-scale surface roughness, as 2D surfaces for the culture of osteoprogenitors, preliminary to study of mineral producing pulp cells. Materials and methods: PLA and PLA-ionomer were spin coated onto glass discs. Discs were annealing for 24 h at 80 ◦ C (PLA) or 75 ◦ C (PLA-i), a procedure shown in preliminary experiments to cause regional dewetting of the polymer from the glass and formation of nm-scale texturing. The coated-discs were characterized with atomic force microscopy (AFM). Cell attachment (4 h) and proliferation (48 h) were evaluated with MC3T3-E1 cells. Differentiation was evaluated with primary transgenic calvaria osteoblast progenitor cells harbouring a green fluorescent protein (GFP) and Xylenol Orange (XO) staining at 14 and 21 d. Tissue culture polystyrene (TCPS) was used as a control. Results: Non-annealed, as-coated PLA and PLAi samples were topographically featureless. The RMS roughness values of the annealed PLA and PLA-i were 8.08 and 15.88 nm, respectively. All groups comparably supported cell attachment and proliferation, except the smooth, non-annealed PLA, which exhibited lower cell adhesion and proliferation (Table). All surfaces supported differentiation to osteoblasts and mineralization at 14d and 21d as evidenced by GFP expression and co-localization with XO stain. Both functionality and surface roughness influenced cell behavior.
Page 1 and 2:
materials dental dental materials d
Page 3 and 4:
Volume 26 Supplement 1 2010 ISSN 01
Page 5 and 6:
e26 57. Effect of cavity configurat
Page 7 and 8:
e58 125. Adhesion between zirconia
Page 9 and 10:
© 2010 by the Academy of Dental Ma
Page 11 and 12:
e2 dental materials 26S (2010) e1-e
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
e10 dental materials 26S (2010) e1-
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30: e20 dental materials 26S (2010) e1-
Page 79: e70 dental materials 26S (2010) e1-
show all

Abstracts of the Academy of Dental Materials Annual ... - IsiRed

Create successful ePaper yourself

Delete template?

Save as template?