Peroxide-Free Titanium Dioxide Nanoparticle-Based Photocatalytic Bleaching: In Vitro Study on Bovine Teeth.

Objective: This study is aimed at assessing the bleaching efficacy of titanium dioxide (TiO2) nanoparticle suspensions at different concentrations and exposure times for photocatalysis and evaluating their potential as a peroxide-free alternative to carbamide peroxide in dental bleaching. Materials and Methods: Sixty bovine incisors were stained with black tea and treated with different bleaching protocols: (1) control (16% carbamide peroxide), (2) TiO₂-50 wt% for 10 min (TiO₂ 50/10), (3) TiO₂-50 wt% for 50 min (TiO₂ 50/50), (4) TiO₂-10 wt% for 50 min (TiO2 10/50), and (5) TiO₂-10 wt% for 10 min (TiO₂ 10/10). The agents were exposed to UV light (395 nm) for photocatalysis before application. All treatments were applied daily for 2 h over 21 days. Color change (ΔE00) was measured using a digital spectrophotometer (VITA Easyshade V), and pH was assessed using pH strips. Results: The data were analyzed using one-way ANOVA and Tukey's test. TiO₂ 50/50 showed significantly superior bleaching effects compared to all other groups (p < 0.001). TiO₂ 10/50 and TiO₂ 10/10 demonstrated intermediate bleaching results, with no significant difference between them (p = 0.0875). The control and TiO₂ 50/10 groups exhibited the lowest color variation (p = 0.102). All groups maintained a pH of 6 before and after 2 h of the at-home bleaching protocol. Conclusion: TiO₂ nanoparticle suspensions may be a viable peroxide-free alternative for dental bleaching, particularly at higher concentrations and longer photocatalysis exposure times.