In vitro evaluation of visible light-activated titanium dioxide photocatalysis for in-office dental bleaching.

The evaluation of the photocatalysis of visible light activated titanium dioxide employed in hydrogen peroxide (H(2)O(2)) was carried using seven H(2)O(2) solutions (3.5 and 35%) and/or methylene blue (MB), with or without light irradiation (LI); the absorbance of MB was the bleaching indicator. Color analysis was performed on bovine teeth (n=12) using two different concentrations of H(2)O(2), 6 and 35% associated with titanium dioxide (TiO(2)). Data were analyzed with one and two-way ANOVA, and significance level of p<0.05. Solutions containing MB, H(2)O(2) at 3.5 or 35%, and TiO(2), followed by LI, showed significant difference when compared with other groups. Greater MB reduction was found in 35% concentration. H(2)O(2) 35%+TiO(2) gel showed no difference in comparison to control group. All groups for the color analysis assay showed DeltaE higher than 3.3. In conclusion, TiO(2) and H(2)O(2) association is a promisor alternative for reducing the clinical time of in-office dental bleaching.