Effect of antioxidant treatment on the shear bond strength of composite resin to bleached enamel

Abstract

Introduction. This study examined the antioxidant treatment on the shear bond strength of composite resin to enamel after bleaching with two different bleaching systems. Materials and methods. Seventy flat enamel surfaces were prepared from freshly extracted human molars using a low speed diamond saw. Then the specimens were divided into seven random groups (n = 10) to apply different procedures; namely, bleaching with White Smile and bonding with composite resin (G1), bleaching with White Smile, treatment with ascorbic acid and bonding with composite resin (G2), bleaching with White Smile, immersing in artificial saliva for 2 weeks and bonding with composite resin (G3), bleaching with Opalesence and bonding with composite resin (G4), bleaching with Opalesence, treatment with ascorbic acid and bonding with composite resin (G5) and bleaching with Opalesence, immersing in artificial saliva for 2 weeks and bonding with composite resin (G6). Another group was used as a control group. Shear bond test was performed on all specimens and data were analyzed using one way ANOVA and Bonferroni's test (p < 0.05). Results. Bond strengths of bleached specimens were significantly lower than those of non-bleached specimens. No statistical difference was found in bond strength between the bleached and non-bleached groups when the antioxidant treatment was carried out. Conclusion. Ten per cent ascorbic acid treatment was found to be an effective method to reverse the compromised bond strength.