effect of accelerated artificial aging on translucency of methacrylate and silorane-based composite resins

objectives: composite restorations must have tooth-like optical properties namely color and translucency and maintain them for a long time. this study aimed to compare the effect of accelerated artificial aging (aaa) on the translucency of three methacrylate-based composites (filtek z250, filtek z250xt and filtek z350xt) and one silorane-based composite resin (filtek p90). materials and methods: for this in vitro study, 56 composite discs were fabricated (n=14 for each group). using scanning spectrophotometer, cie l*a*b* parameters and translucency of each specimen were measured at 24 hours and after aaa for 384 hours. data were analyzed using one-way anova, tukey’s test and paired t-test at p=0.05 level of significance. results: the mean (±standard deviation) translucency parameter for filtek z250, filtek z250xt, filtek z350xt and filtek p90 was 5.67±0.64, 4.59±0.77, 7.87±0.82 and 4.21±0.71 before aaa and 4.25±0.615, 3.53±0.73, 5.94±0.57 and 4.12±0.54 after aaa, respectively. after aging, the translucency of methacrylate-based composites decreased significantly (p<0.05). however, the translucency of filtek p90 did not change significantly (p>0.05). conclusions: the aaa significantly decreased the translucency of methacrylate-based composites (filtek z250, filtek z250xt and filtek z350xt) but no change occurred in the translucency of filtek p90 silorane-based composite. keywords: composite resins; silorane resins; methacrylates