Reaction kinetics of hydrogen peroxide in teeth for teeth whitening applications

Clinical parameters for dental whitening such as peroxide concentration and treatment time have been empirically derived. However, limited quantitative analyses examine reactivity of hydrogen peroxide on in vivo tooth stains under various catalytic settings. The wide range of possible activators and stains are challenging in creating a standardized tooth model to isolate various effects for clinical applications. This study uses three model systems to determine the effects of heat, light, metal catalysts, and pH on peroxide bleaching. By first using a model chemical stain, alkaline pH levels (7.4), 35°C heat treatment, and 490nm light activation were optimal for increasing overall bleaching efficacy. When the same conditions were applied to bleaching stained bovine teeth using liquid peroxide, only 35°C heat treatment showed catalytic effect, increasing overall luminosity and decreasing yellowness. A final evaluation of the activation parameters on teeth treated with commercially used gel peroxides revealed positive catalytic activity for heat alone. These results, in conjunction with future clinical studies, can provide the basis for optimizing clinical whitening parameters and ultimately control peroxide reactivity to enhance bleaching efficacy while minimizing undesired side-effects