Pulp oxygen saturation levels and tooth sensitivity after bleaching with led light-activated hydrogen peroxide: randomized clinical trial

Objective: The main purpose of this study is to evaluate the effect of dental bleaching with 460 nm LED light on pulp tissue by assessing pulp oxygen saturation (SaO 2 ) and dental sensitivity in different dental groups and follow-up times. Materials: and Methods This study is a randomized clinical trial using a split-mouth design. SaO 2 levels were measured using a pulse oximeter adapted for dentistry, and dental sensitivity was assessed using the visual analog scale on 600 intact anterior teeth. Fifty volunteers were selected, and their upper dental arches were randomly divided into two halves (right and left) to create two groups. G1 - half arch that received LED activation to activate the bleaching agent for 1 minute at each gel change, totaling 3 minutes of activation; and G2 - half arch where LED was not used to activate 35% hydrogen peroxide. SaO 2 levels were analyzed before bleaching (T0), immediately after the first session (T1), on the seventh day of treatment (T2), 30 days (T3), 6 months (T4), and 1 year (T5) after dental bleaching. Sensitivity testing was conducted until T3. The data were analyzed using the Shapiro-Wilk test for normality, independent samples t-test to evaluate differences between groups, and repeated measures ANOVA with Tukey's multiple comparisons test to assess variability over time. The significance level was set at 5%. Results: An increase in SaO 2 was observed in the upper central incisors immediately after light application, followed by a reduction after 24 hours (P 0.05). For both dental arches, the quadrants that received light during bleaching exhibited higher sensitivity to stimuli immediately after treatment (P < 0.05). Conclusions: Dental bleaching with 460 nm LED light increases SaO 2 and dental sensitivity immediately after the procedure in the upper central incisors. However, these changes are reversible after 24 hours. Clinical relevance: The clinical significance of the study lies in the potential for increased oxygen saturation levels and dental sensitivity following dental bleaching with 35% hydrogen peroxide in conjunction with the use of an LED light.