Effect Of Preheating On Color Stability Of Two Different Nanohybrid Composite Resins

Backround: Preheating of composite resins has become widespread in recent years in order to improve the properties of the material. The aim of the study was to evaluate the effect of preheating on the color stability of two different composite resins. Methods: In this study, 48 composite discs (2*8mm) were used, 24 of which were universal nanohybrid composite (Clearfil Majesty Estetic (CME), Kuraray, Japan) and 24 posterior nanohybrid composite (Clearfil Majesty Posterior (CMP), Kuraray, Japan). Half of the samples in each group were prepared by preheating at room temperature and the other half at 55°C (n = 12). After the curing process, the samples were kept in distilled water at 37°C for 24 hours. Color was initially measured with a spectrophotometer after soaking in a coffee solution for 1 week and 1 month. Data were analyzed via SPSS 22.0 Two Way Anova, Post-Hoc Tukey and Pared Samples T test. Results: After storage in coffee solution, CME became significantly less discolored than CMP. There was a slight increase in coloration in the preheating groups of composite resins, but it was not statistically significant.The difference between 1-week and 1-month color changes in both composite groups was statistically significant. Conclusions: Within the limitations of this study, preheating did not have a positive effect on the color stability of the composite resins. The preheating method, which has become more common in recent years to improve the mechanical properties of composite resins, may not provide any benefit in the color stability of composite resins. Keywords: Color Stability, Composite, Discoloration, Preheating, Spectrophotometer