SUMMARYThis study investigated the effects of an at-home bleaching gel containing 15% carbamide peroxide on the susceptibility of tooth-colored restorative materials to different staining solutions. The tooth-colored restoratives used in this study were a nano resin composite (Filtek Z350), a packable resin composite (Filtek P60), a polyacid-modified composite (Dyract AP) and a glassionomer cement (Ketac Molar Easymix). Each material was equally divided into two groups (n=34): the bleaching group and the control group. This study included two treatment segments. In the first part (days 1-14), the specimens of the bleaching group were bleached with 15% carbamide peroxide gels for eight hours daily, while the specimens in the control group were stored in deionized water. Subsequently, four specimens from each group were randomly selected for observation under an environmental scanning electron microscope. In the second part (days 15-42), the samples were not bleached. Instead, they were stored in five different kinds of solutions. Color measurements for each sample were taken at six different time periods using a spectrophotometer. The data was then analyzed using SPSS statistical software. After two- The staining susceptibility of esthetic restorative materials is significantly affected by the use of 15% carbamide peroxide. The effects of bleaching on the surface morphology and color of restorative materials are material dependent.
INTRODUCTIONColor stability is considered an important factor in the success of an esthetic restoration.1-2 In the literature, color stability has been defined as the ability of a material to retain its color over a period of time and in a specified environment.2 To maintain excellent esthetic properties, tooth-colored restorative materials should have good color stability. It has been shown that both extrinsic and intrinsic factors contribute to color changes of restorative materials. Intrinsic factors influencing color changes involve chemical changes of the materials. The causes for such chemical discoloration have been identified as the oxidation of monomer or catalysts, exposure to various energy sources and immersion in water for a long period.3-6 Extrinsic factors influencing color changes include staining by adsorption or absorption of colorants, a result of contamination from exogenous sources, such as coffee, tea, other stain-producing beverages and colored solutions. [7][8][9] In recent years, many tooth-colored restorative materials have been introduced into the market. The staining susceptibility of these materials has been widely investigated.