Effects of microabrasion association to at-home bleaching on hydrogen peroxide penetration and color change

Purpose: This study aimed to quantify the penetration of hydrogen peroxide (HP) inside the pulp cavity and color change with two different concentrations of HP to at-home bleaching associated or not with enamel microabrasion (MA). Methods: Forty healthy premolars were randomly divided in four groups (n = 10): only HP4%, MA + HP4%, only HP10%, MA + HP10%. The concentration (μg/ml) of HP was assessed using UV–Vis spectrophotometry. The color change (ΔE_ab, ΔE₀₀ and WI_D) was evaluated before and one-week after bleaching. Data were evaluated for a two-way ANOVA and the Tukey's test (α = 0.05). Results: The application of MA increased the amounts of HP inside the pulp chamber when compared to without MA, as well as PH10% when compared to PH4% (p < 0.0001). PH10% showed higher WI_D when compared to PH4%. No significant difference was observed when ΔE_ab, and ΔE₀₀ were used. Conclusions: The enamel MA before at-home bleaching promotes greater penetration of HP, although this procedure did not significantly affect the color change. Clinical Significance: Since greater penetration of HP into the pulp chamber was detected when home bleaching was applied immediately after MA, the clinician should not apply home bleaching gels in the same session when MA was performed.