Effect of Preheating on color stability of silorane -based composite resin

Abstract

Color change in composite restorations during the time and beacause of different colorful materials is a common problem in esthetic dentistary that impose economic costs to the patients. Purpuse of study: The aim of this study is to survey the effect of preheating on color stability of silorane based composites. Methods: In this in vitro study we got 2 groups that each contain 20 disk shape samples of Filtek P90 composite by plastic molds. The method of preparation of samples in groups was the same but in the second group, composite was preheated to 55-60C before making spieces and temperature was controlled by thermostat. Then the surface of spieces were polished with silicon carbide disks and then restored in distilled water for 2 days. The color indexes were measured by spectrophotometer. The spieces were restored in tea solution for 40 days (3 hours a day) and then the second phase of color assessment were done and was assessed for each one. Degree of conversion was assessed by FTIR test. t-test was applied to compare color changes in samples. Results: According to this study, color change in preheated (average 11.85, std.deviation 1.16) and nonpreheated spieces ( average 11.63, std.deviation 1.11) was higher than acceptable clinical ranges. And color changes in two groups was not noticible. Pv=0.87 Conclusion: Storage of preheated and nonpreheated silorane based composites in tea solution makes noticible color changes.