Effects of bleaching gel containing TiO 2 and chitosan on tooth surface roughness, microhardness and colour

This study aimed to evaluate the effects of an experimental bleaching gel made with TiO and chitosan, along with the Opalescence Boost PF and Philips Zoom bleaching agents, on tooth surface roughness, microhardness and colour. The experimental gel, containing 6% hydrogen peroxide (HP), was evaluated against the two existing treatments, which incorporate 40% and 25% HP. For colour evaluation, 36 human premolar teeth were divided into three groups (n = 12). For surface roughness and microhardness evaluation, 72 bovine incisor samples were divided into six groups (n = 12). Data on colour alteration were analysed with the CIEDE2000 formula. Surface roughness was measured using a profilometer, and microhardness was measured with a Vickers hardness tester. ANOVA was used for statistical analysis. There were no statistically significant differences among the groups for surface roughness, microhardness values or colour change after bleaching (P > 0.05). The lowest bleaching efficacy was observed for the 40% HP agent, and the highest efficacy was observed for the 25% HP agent (P