Effect of Different Forms of Natural Antioxidants on Free Radical Eradication in Bonding: An In vitro Study

A BSTRACT Aim: Residual peroxides from the bleaching procedure result in a compromised bonding to the enamel. Antioxidant application remains one of the promising strategies to regain the lost bond strength. We aim to compare and evaluate the outcome of aqueous and oil-based natural antioxidants on the shear bond strength (SBS) of bleached enamel. Materials and Methods: Fifty-six sound human anterior teeth crowns were mounted in an acrylic resin block the labial surface was flattened by exposing the enamel and bleaching was done. Specimens were randomly categorized into four groups ( n = 14), and the following antioxidant application was done for 10 min, respectively. Group I: vitamin E, Group II: 10% Guava seed extract, Group III: 10% oil-based Sea buckthorn (SBT) extract, and Group IV: 10% aqueous SBT extract. Standard bonding protocols were followed and composite restoration was placed. Specimens were mounted in a universal testing machine and load to fracture values were recorded as SBS values and statistical analysis was performed. Results: Group IV performed better statistically compared to other groups ( P < 0.04). Aqueous-based groups performed better than oil-based groups. The increasing order of mean SBS values was Group I < Group III < Group II < Group IV. Conclusions: Ten percent SBT extract in an aqueous base outperformed other experimental antioxidants. Exclusively, the aqueous and oil-based formulation of the newer herbal agent, SBT, provides better SBS in postbleaching scenarios.