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

More documents

Recommendations

Info

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
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 19 and 20: e10 dental materials 26S (2010) e1-
Page 49: e40 dental materials 26S (2010) e1-

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

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?