Effect of sodium ascorbate on the bond strength of silorane and methacrylate composites after vital bleaching

Eda Guler,Nihan Gonulol,Ozgun Yusuf Ozyilmaz,Ali Cagin Yucel

doi:10.1590/s1806-83242013000400002

Abstract

We investigated the effect of sodium ascorbate (SA) on the microtensile bond strengths (MTBSs) of different composites to bovine enamel after vital bleaching with hydrogen peroxide (HP) or carbamide peroxide (CP). Thirty bovine incisors were randomly divided into five groups and treated with no bleaching application (control), 35% HP alone, 35% HP+10% SA for 10 minutes (HP+SA), 16% CP alone, or 16% CP+10% SA for 10 minutes (CP+SA). Specimens were restored with Silorane adhesive and Filtek Silorane composite (designated as S/group) or with Clearfil SE bond and Filtek Supreme XT (designated as F/group). Composite build-up was created on the enamel. Sectioned specimens (n=10 per group; 1 mm2; cross-sectional area) were created and stressed in a universal testing machine at 1 mm/min crosshead speed. The application of 10% SA immediately after bleaching with 16% CP or 35% HP increased the enamel MTBS, regardless of the adhesive/composite resin used. The resulting MTBS values were similar to those of the control groups. Use of 16% CP and 35% HP alone decreased the enamel MTBS, regardless of the adhesive/composite resin used, with F/CP+SA=F/HP+SA=F/CP=S/CP+SA=S/HP+SA=S/C>S/CP=S/HP=F/CP=F/HP (p<0.05). We concluded that the application of SA for 10 minutes immediately after vital bleaching increases the enamel BS for dimethacrylate- and silorane-based composites.

Highlights

Whereas extrinsic tooth discoloration can be removed by prophylactic cleaning procedures, intrinsic tooth staining requires chemical bleaching.[1]
The slabs were randomly divided into five groups and treated with no bleaching, 35% hydrogen peroxide (HP), 35% HP followed by 10% sodium ascorbate (SA) for 10 minutes, 16% carbamide peroxide (CP; group CP), or 16% CP followed by 10% SA for 10 minutes
The microtensile bond strengths (MTBSs) values were significantly different by two-way analyses of variance (ANOVA) (p < 0.01)

Summary

Introduction

Whereas extrinsic tooth discoloration can be removed by prophylactic cleaning procedures, intrinsic tooth staining requires chemical bleaching.[1]. Bleaching treatments adversely affect the bond strength (BS) of composite to enamel when bonding is immediately performed after bleaching.[4] This decreased BS has been related to the presence of residual hydrogen peroxide (HP) in the interprismatic spaces,[5,6] which can prevent adequate infiltration. The use of antioxidant agents after bleaching has been suggested to avoid compromising BS.[8,9,10] Biocompatible reducing agents, such as ascorbic acid and its salts, neutralize residual free radicals and decrease various oxidative compounds.[11] If antioxidant treatment of bleached enamel before bonding can reverse the reduced BS of composite resin, this approach could be used as an alternative to delaying the restorative procedure after bleaching.[12]

Methods

Results

Conclusion