Evaluation of the effect of repeated preheating of methacrylate and silorane-based composite resins on their color stability

Abstract

The aim of the present study was to evaluate the effect of preheating methacrylate- and silorane-based composite resins to 5560C up to 40 times on their color stability. Materials and methods: Methacrylate- and silorane-based composite resin samples, measuring 10 mm in diameter and 2 mm in height were assigned to 4 groups; group 1: methacrylate-based composite resin samples at room temperature; group 2: methacrylate-based composite resin samples preheated 40 times to 5560C; group 3: silorane-based composite resin samples preheated 40 times to 5560C. After the samples were prepared, their color parameters were determined using a reflective spectrophotometer. The composite resin samples were separately stored in a solution of tea for 40 consecutive days. Then the samples underwent a color determination procedure again using a spectrophotometer and color changes were recorded. Finally, to evaluate the effect of composite resin temperature on its staining, two-factor ANOVA was used at P<0.05. Independent-samples t-test was used to evaluate changes in conversion rates of preheated composite resin samples compared to non-preheated samples at P=0.02 for silorane-based composite resin samples and at P=0.11 for Z250 composite resin samples. Results: Both composite resin type (P=0.014) and preheating (P<0.001) had significant effects on E. Repeated preheating of methacrylate- and silorane-based composite resin samples to 5560C for 40 rounds resulted in color changes in composite resin samples. Color changes in silorane-based composite resin samples were more severe than those in Z250 composite resin samples after storage in a solution of tea.