Effect of antioxidant and resin infiltration on the bond strength of composite resin to bleached enamel- an invitro study

Background: Tooth discoloration is one of the most common esthetic complaints encountered by dentists worldwide. Bleaching combined with direct composite restorations is used for esthetic correction of moderate to severe intrinsic discolorations. Bleaching can lead to decreased bond strength of composite resin to bleached enamel. Antioxidants have been suggested for reversal of compromised bond strength in various researches. Therefore in this study, we have used antioxidant sodium ascorbate before resin infiltrant application to bleached enamel to test for reversal of bond strength of composite resin.
Aim: The aim of the study is to investigate the bond strength of composite resin to enamel bleached with 35% carbamide peroxide when the surface is pre-treated with 10% sodium ascorbate antioxidant and resin infiltration technique.
Methodology: Sixty extracted incisors were bleached with Opalescence (35% carbamide peroxide gel). Then the bleached samples were treated accordingly:
Group A(immediate bonding of composite).
Group B (10 % sodium ascorbate application followed by bonding of composite)
Group C (resin infiltration and bonding of composite)
Group D (10 % sodium ascorbate application followed by resin infiltration and bonding of composite)
Then the samples were subjected to shear bond strength testing in universal testing machine.
Values were recorded, tabulated, statistically analysed and results drawn.
Results: Group D(bleached enamel treated by 10 % sodium ascorbate followed by resin infiltration and bonding of composite ) > Group C (bleached enamel treated by resin infiltration and bonding of composite) > Group B (bleached enamel treated by 10 % sodium ascorbate followed by bonding of composite) > Group A(bleached enamel with immediate bonding of composite).
Conclusion: Based on the results of this study, it was concluded that surface pretreatment with 10% sodium ascorbate antioxidant followed by resin infiltration can significantly improve the bond strength of composite to bleached enamel. Therefore, this study recommends and confirms the use of antioxidant as pretreatment on bleached enamel before the immediate placement of composite resin.