Effect of Sodium Ascorbate and Delayed Bonding on the Bond Strength of Silorane and Two-step Self-etch Adhesive Systems in Bleached Enamel

Abstract

Aim: The aim of the present study was to evaluate the effect of sodium ascorbate and delayed bonding on the bond strength of two adhesive systems in bleached enamel. Materials and methods: A total of 152 sound bovine incisor teeth were selected. The labial surfaces were abraded with 240-and 600-grit abrasive paper. Then the teeth were randomly divided into 8 groups. Group A = control, group B= bleached with 35% hydrogen peroxide, group C= bleached with 35% hydrogen peroxide+ sodium ascorbate gel group D = bleached with 35% hydrogen peroxide+delayed bondin. In groups A to D Silorane adhesive system and Filtek silorane composite resin were used. In groups E to H the same preparation methods of groups A to D were used then two-step self-etch Clearfil SE Bond adhesive systems and AP-X composite resin was administered. Shear bond strength of each group was measured. Two samples were prepared for each surface preparation for ultra-structural evaluation. Two-way ANOVA and Tukey test was used for data analyzing at P<0.05. Results: There were significant differences in shear bond strengths in terms of the adhesive system (P<0.01, F1,144=139.86). In addition, there were significant differences in the means of shear bond strength in terms of the surface preparation technique irrespective of the adhesive system used (P<0.01, F3,144=14.773), i.e. there were significant differences in the mean bond strength values between the control and bleached groups (P<0.001), and the bleached and bleached + sodium ascorbate groups (P<0.001). However, there were no significant differences in bond strength between the other groups (P>0.05). In addition, the interaction between the type of the adhesive system and surface preparation protocol was significant (P=0.014, F3,144=3.67). Conclusion: Results showed that bleaching with 35% hydrogen peroxide decrease the shear bond strength values in both adhesive systems and a one-week delay in bonding and 10% sodium ascorbate in 10 minutes can restore the bond strength in both adhesive systems.