The Effect of a Current Home Bleaching Agent on the Color of Nine Tooth-Colored Restorative Materials Stained with Common Beverages: An In Vitro Study

Bleaching to whiten discolored teeth may affect the color of existing stained restorations. The purpose of this study was to determine the color changes that occurred in nine already stained restorative materials by common beverages after being subjected to a simulated home bleaching. Three glass ionomers (ceramic-reinforced, resin-modified, and conventional) and six composite resins (nanofilled, organically modified ceramic (ormocer), flowable ormocer, polyacid-modified, microhybrid, and flowable microhybrid) were used for this study. Disc-shaped specimens that were stained by coffee, tea or cola beverages were immersed in Opalescence home bleaching agent for 8 hours for 30 consecutive days. A spectrophotometer was used to determine the baseline CIE values (L0, a0, b0) of the stained specimens before bleaching and CIE values (L1, a1, b1) of the stained specimens after bleaching. Statistical analysis was conducted using paired samples T-test for comparing each two test groups at a P value of <.05. Results: The color changed significantly for all stained restorative materials tested after the application of home bleaching with some specimens showing spots of precipitated stain mainly glass ionomer specimens stained with coffee. Glass ionomers showed the highest color change followed by compomer, nanofilled and micro hybrid composites. Ormocers showed the least color change among all the materials tested. Tea stain was the most susceptible to the effect of bleaching in most restorative materials tested. Conclusion: Although home bleaching results in a lighter color change of stained restorations, remaining unesthetic stain precipitation spots may necessitate replacement of these restorations.