comparative evaluation of antioxidative effect of selenium alone and in combination with green tea and alpha-tocopherol on the shear bond strength of universal composite resin to enamel after in-office bleaching.

Background: Antioxidant application soon after bleaching process increases the shear bond strength (SBS) of composite resin to enamel.

Aims: The aim of the study was to evaluate the antioxidant effects of selenium alone and in combination with alpha-tocopherol (αT) and green tea (GT) on SBS of composite resin to enamel following in-office bleaching with 38% hydrogen peroxide (HP).

Methods: Sixty extracted human single -rooted premolar teeth were cleaned and embedded in acrylic resin blocks at the level of cementoenamel junction(CEJ) followed by bleaching with 38% hydrogen peroxide (HP) and arbitrarily divided into seven groups (n=10) for antioxidant application: Group I (negative control): intact teeth, Group II (positive control): only bleaching, Group III: 10% selenium (Se), Group IV: 10% alpha tocopherol (αT), Group V: 10% αT +10% Se, Group VI: 10% Green tea (GT), Group VII: 10%GT+10% Se. In all groups, self-etch adhesive was applied and composite restoration was done, and specimens were stored in distilled water for 24h followed by SBS evaluation.

Statistical Analysis: One-way analysis of variance and post hoc Tukey's tests were used ( < 0.05).

Results: The highest SBS was found in negative control Group I (intact teeth) and least in positive control Group II (bleached teeth), whereas in experimental groups, Group VII (GT + Se) showed highest followed by Groups V (αT + Se), III (Se), and VI (GT) and least in Group IV (αT).

Conclusion: Combination of selenium with green tea and alpha tocopherol enhanced the SBS of composite resin following in-office bleaching.