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

Abstract

The evaluation of the photocatalysis of visible light activated titanium dioxide employed in hydrogen peroxide (H₂O₂) was carried using seven H₂O₂ 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 H₂O₂, 6 and 35% associated with titanium dioxide (TiO₂). Data were analyzed with one and two-way ANOVA, and significance level of p<0.05. Solutions containing MB, H₂O₂ at 3.5 or 35%, and TiO₂, followed by LI, showed significant difference when compared with other groups. Greater MB reduction was found in 35% concentration. H₂O₂ 35%+TiO₂ gel showed no difference in comparison to control group. All groups for the color analysis assay showed ΔE higher than 3.3. In conclusion, TiO₂ and H₂O₂ association is a promisor alternative for reducing the clinical time of in-office dental bleaching.

Keywords: Hydrogen peroxide; Titanium dioxide; Tooth bleaching.