Effect of sage extract as a natural antioxidant on shear bond strength of metal orthodontic brackets bonded to bleached teeth: An in vitro study.

Abstract

Background The purpose of this study was to evaluate the effect of sage extract, a natural antioxidant, on the shear bond strength (SBS) of metal orthodontic brackets bonded to bleached enamel with 40% hydrogen peroxide (HP). Methods and Materials The sample consisted of 100 maxillary premolars, which were divided into five groups: group I (control, no bleaching), group II (bleaching using HP40% + immediate bonding after bleaching), group III (bleaching using HP40% + SA10% + bracket bonding), group IV (bleaching using HP40% + sage extract 10% + bracket bonding) and group V (bleaching using HP40% + sage extract 20% + bracket bonding). All teeth were bonded using composite resin cement and immersed in distilled water for 24 hours. The shear bond strength (SBS) was assessed by a universal testing machine (Instron) after 24 hours of bracket bonding. After debonding the brackets, the residual adhesive remnant index (ARI) was checked using a stereoscope at 20x magnification. The statistical analysis was carried out using one-way ANOVA to determine differences among the five groups and the least significant difference (LSD) test for bilateral comparisons of the average shear bond strength of the brackets. For the ARI, the Kruskal‒Wallis test was performed. Results ANOVA revealed statistically significant differences among the five groups (р<0.001). Compared with those in the bleached group without antioxidant treatment, the shear bond strengths of the groups treated with 10% and 20% sage extracts significantly improved. According to the LSD test, there was no significant difference between the groups treated with 10% and 20% sage extracts (р>0.05). The Kruskal‒Wallis test revealed no statistically significant differences between the frequencies of the residual adhesive remnant index (ARI) among the five study groups, with the most frequent score being (2). Conclusion The shear bond strength of brackets bonded to bleached teeth can be improved by applying 10% and 20% sage extracts immediately after bleaching and before bracket bonding.