Bleaching efficacy and tooth sensitivity using violet LED - single-blind randomized controlled trial

This study aims to conduct a single-blind randomized controlled trial to evaluate the bleaching efficacy and tooth sensitivity (TS) following the use of violet LED associated or not with 35% hydrogen peroxide. Eighty-four participants were randomly allocated into three groups according to bleaching treatments (n = 28): 35% hydrogen peroxide (HP) only, Violet LED only (VLED), and an association of 35% HP with violet LED (HP + VLED). Three sessions were performed, with an interval of seven days between each one. Changes in the objective (ΔE_ab and ΔE₀₀) and subjective (ΔSGU) color and the Whiteness Index for Dentistry (ΔWI_D) were calculated based on before, and seven and thirty days after treatment using colorimetric measurements. Participants self-reported the risk and intensity of TS on a visual analogue scale (VAS). The color assessments seven and 30 days after bleaching were analyzed by two-way ANOVA and Tukey's test. The absolute TS risk was analyzed by Fisher's exact test. The significance level adopted was α = 0.05. HP and HP + VLED treatments showed higher and significant bleaching values (ΔE_ab, ΔE₀₀, ΔSGU, and ΔWI_D) compared to VLED. The HP + VLED and HP groups presented a higher risk and intensity of TS compared to the VLED group (p < 0.05). The bleaching efficacy of VLED alone was lower compared to the HP and HP + VLED protocols both seven and 30 days after the end of treatments.