Bleaching efficacy of in-office bleaching with violet light using low-concentration hydrogen peroxide nanoparticulate photocatalyst gel: a randomized controlled trial.

Objective: This randomized controlled trial aimed to evaluate the bleaching efficacy and tooth sensitivity (TS) of participants submitted to different application protocols of in-office bleaching with violet light using 6% hydrogen peroxide (HP) nanoparticulate photocatalyst gel.

Materials and methods: Sixty-six participants were randomized and bleached using either a 6% HP (Nano White, DMC), and/or violet light (Bright Max Whitening, MMOptics), according to the following protocols: 1) only violet light (VIOL); 2) only bleaching gel application (BG) and; 3) combined bleaching gel application + violet light (BG+VIOL). The bleaching efficacy was evaluated with the Vita Easyshade spectrophotometer, Vita Classical and Vita Bleachedguide scales. The risk and intensity of TS were recorded using a 0-10 visual analogue scale (VAS) and a 0-4 numerical scale (NRS). Color change and intensity of TS values were compared using one-way ANOVA and Tukey's test were used. The absolute risk of TS was compared using the Chi-square test (α = 0.05).

Results: A significant and higher degree of bleaching was observed in the BG and BG+VIOL groups compared to the VIOL group (p < 0.003). Despite no significant differences in the risk (p > 0.07) and intensity (p > 0.28) of TS among groups, a higher risk of TS was observed in the BG and BG+VIOL groups.

Conclusions: Using VIOL reduced the risk of TS but did not improve bleaching. However, BG+VIOL with low-concentration HP nanoparticulate photocatalyst gel achieved equal efficacy and was less likely to cause TS compared to BG.