Journal - Operative dentistry (United States )

Abstract :

This in vitro study evaluated whether the treatment of human enamel with whitening agents containing different concentrations of carbamide or hydrogen peroxide changes the susceptibility of enamel to caries. Twenty-four sound human incisors were selected for this study. For each tooth, the crown was sectioned into two halves in the cervical-incisal direction. One half of the sectioned tooth was treated and the other half was used as a control specimen. Each half was randomly divided into three treatment groups (eight two-halves/group). The whitening agents were 10% carbamide peroxide, 20% carbamide peroxide with fluoride and 35% hydrogen peroxide. Following pretreatment, the specimens were demineralized for four days in an in vitro microbial caries model and then analyzed using a confocal laser scanning microscope (CLSM). Results showed that there were no significant differences between the treated and controlled specimens for teeth treated with 10% carbamide peroxide or 35% hydrogen peroxide. However, specimens treated with 20% carbamide peroxide with FP (0.11% fluoride and potassium nitrate) were less susceptible to caries than their controls at p < or = 0.05. In conclusion, application of bleaching agents does not increase the caries susceptibility of human enamel.