Effect of Herbal Antioxidant on Push-out Bond Strength of Resin-based Composite to Dentin after Intracoronal Bleaching: An in vitro Study

Background: Bleaching can enhance the appearance of stained teeth while maintaining their structural integrity. The antioxidant properties of green tea and pine bark extracts related to the effect on dental hard tissues have not been updated. Objectives: This in vitro study aims to evaluate the influence of herbal antioxidants on the push-out bond strength of resinbased composite materials to dentin following intracoronal bleaching. Materials and Methods: In this in vitro study, 60 human mandibular premolar teeth were randomly divided into six groups as follows (n = 10): GI (control), no bleaching; GII, bleaching with 35% hydrogen peroxide (HP) and sodium perborate; GI, bleaching with 35% HP and sodium perborate bleached and restored after 14 days; GIV, bleaching with 35% HP and sodium perborate followed by 10% sodium ascorbate; GV, bleaching with 35% HP and sodium perborate followed by green tea. GVI, bleaching with 35% HP and sodium perborate, followed by pine bark. The specimens were bonded to composite in all groups. The push-out bond strength of specimens was measured in megapascals (MPa). Data were entered into an Excel sheet and analyzed using one-way analysis of variance (ANOVA) (p = 0.05). Results: The unbleached teeth (GI) demonstrated the highest shear bond strength, followed by the bleached teeth treated with a 10% pine bark extract (GVI) antioxidant. The peak stress values were significantly higher in GI (control) and GVI, followed by other groups such as GIV, GIII, GV, and GII. Conclusion: All the antioxidants used in this study were equally effective in neutralizing the adverse effects of HP on the bonding ability of immediately restored teeth. Group VI displayed the peak load, followed by Group IV and Group V, and successfully restored the weak bond strength of bleached dentin; this can be inferred from the current in vitro study.