Effect of Pomegranate Peel and Green Tea Extract as Antioxidants on Shear Bond Strength of a Microhybrid Composite to Bleached Enamel

Background and Aim: This study evaluated the effect of pomegranate peel and green tea extracts on shear bond strength (SBS) of a microhybrid composite to bleached enamel. Materials and Methods: In this in vitro, experimental study, 44 maxillary premolars were divided into 4 groups of control A (composite cylinders bonded to teeth without bleaching), group B (composite bonding immediately after bleaching), group C (5 g of green tea extract was dissolved in 100 mL of distilled water, applied for 10 minutes, and rinsed for 30 seconds, followed by bleaching and composite bonding) and group D (5 g of pomegranate peel extract was dissolved in 100 mL of distilled water; the rest was similar to group C). In groups B, C and D, 35% hydrogen peroxide was applied on the teeth for 20 minutes and rinsed. This process was repeated two more times. The teeth were etched with 35% phosphoric acid for 15 seconds and rinsed for 15 seconds. A microhybrid composite was applied in Tygon tubes, bonded to the teeth with single Bond, and light-cured. Mode of failure was also determined. SBS was measured by a universal testing machine and data were analyzed by one-way ANOVA and Tukey’s test. Results: A statistically significant difference was found in the mean SBS of the groups (P<0.001). The mean SBS of group B (not treated with antioxidant after bleaching) was significantly lower than that in other groups (P<0.05). Conclusion: Application of 5% pomegranate peel and green tea extracts increase the SBS of composite to bleached enamel.