Effect of sodium ascorbate on composite resin bond strength to bleached teeth

Abstract

Objective: The objective of this study was to evaluate the effect of sodium ascorbate on resin composite bond strength. Methods: Forty human premolars were used, which were divided into 4 groups: C - (control) unbleached teeth submitted to a restorative procedure; S - teeth bleached with 35% hydrogen peroxide and stored in artificial saliva for 48 hours; AS - teeth bleached with 35% hydrogen peroxide and irrigated with a 10% sodium ascorbate solution for 10 minutes; AG - teeth bleached with 35% hydrogen peroxide and immersed in 10% sodium ascorbate for 3 hours. After restoration, the samples were section and microtensile bond strength tests were performed in a universal test machine (Emic) at a speed of 1mm/min. The data were evaluated and submitted to the ANOVA and Tukey statistical tests (5% significance level). Results: Group C presented the highest bond strength value, differing statistically from Groups S and AG, however, without statistical difference in comparison with Group AS. Conclusion: Keeping teeth that have been bleached with 35% hydrogen peroxide in saliva for 48 hours is insufficient to recover bond strength. However, the use of 10% sodium ascorbate for 10 minutes may promote adequate bond strength, allowing immediate restoration of the teeth.