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Made available in DSpace on 2019-09-12T16:53:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2013 Objectives: This study measured the degree of conversion (DC), sorption, solubility and microhardness of methacrylate (Filtek Z250 and Filtek Z350XT) and silorane-based composites (Filtek P90). Methods: DC was measured using near infrared spectroscopy immediately and 24 h after the photoactivation. Sorption and solubility measurements were performed after 24 h, 4 weeks and 12 weeks of storage in water. Knoop microhardness was measured after 24 h and after thermal cycling. The data were statistically analyzed using ANOVA followed by Tukey's, Tamhane or paired t-tests (alpha = 0.05). Results: The DC for P90 (37.22 +/- 1.46) was significantly lower than the Z250 (71.44 +/- 1.66) and Z350 (71.76 +/- 2.84). Water sorption was highest in the Z250 and lowest in the P90. All the tested composites exhibited similar values after 24 h of immersion, and no significant differences were observed. No significant differences were observed between the solubilities of the P90 composite (12 weeks) and the Z250 or Z350 composites (4 weeks). KHN values were less elevated for the P90 composite and similar for the Z250 and Z350 composites. An effect of thermal cycling on KHN values was observed for all the composites (p < 0.001). Conclusions: Silorane produced the lowest DC and KHN values and exhibited lower water sorption and solubility compared to methacrylate- based composites. These differences suggest that silorane composites exhibit better hydrolytic stability after 3 months of water immersion compared to conventional methacrylate-based composites. Clinical significance: Silorane had higher hydrolytic stability after 3 months of water immersion than the methacrylate-based resins, despite the lower values of DC and KHN recorded. (c) 2013 Elsevier Ltd. All rights reserved. [Celerino de Moraes Porto, Isabel Cristina] Univ Fed Alagoas, Dept Restorat Dent, BR-57072970 Maceio, Alagoas, Brazil [Baggio de Aguiar, Flavio Henrique] Univ Estadual Campinas, Dept Restorat Dent, BR-13414903 Sao Paulo, Brazil [Brandt, William Cunha] Univ Santo Amaro, Dept Dent, BR-04829300 Sao Paulo, Brazil [Susy Liporoni, Priscila Christiane] Universidade de Taubaté (Unitau), Dept Restorat Dent, BR-12020340 Sao Paulo, Brazil

Objectives Verify if media and time of storage affect the translucency of a silorane-based composite (Filtek P90) compared to two methacrylate-based composites (Z350 and ROK), and compare two methods of translucency evaluation. Methods Specimens were divided into two groups ( n = 7) according to the storage media (deionized water or red wine). With a spectrophotometer (SP60) in reflectance mode, the CIE L * a * b * parameters and opacity percentage readings were conducted at baseline, 24 h, 30 days, and 180 days. Data were analyzed using two-way repeated measures ANOVA and Tukey ( p Results When stored in water, P90 showed an increase, whereas Z350 decreased in translucency. ROK did not exhibit any tendency over time. When stored in wine, the translucency of all materials decreased. A negative relationship was found between translucency parameter and opacity percentage. When stored in water, the a * values for P90 decreased, whereas Z350 and ROK showed values increasing over time. When stored in wine, the L * parameter tended to decrease over time, an effect that was less intense for P90. Moreover, the b * parameter for P90 decreased, whereas methacrylate-based composites increased over time. Conclusions P90 was more stable in red wine than the other materials and became more translucent in water whether metacrilate-based materials became more opaque. Both media as well as storage time affected the translucency of the materials tested. Translucency could be measured with both methods tested. Clinical significance Silorane-based composites seemed to be more stable than methacrylate-based composites in red wine and became more translucent over time in water, which was different than methacrylate-based composites. More studies are needed to clarify silorane-based composites performance.