Can Sodium Ascorbate Increase the In Vitro Bond Strength of the Interface between a Composite and Bleached Enamel?

Abstract

Recently, the use of antioxidants before the bonding of bleached enamel was considered effective for reversing the reduction in the bond strength. This article aimed to assess the influence of different sodium ascorbate (SA) presentations (liquid, gel, and semi-gel) on the composite resin–enamel bond strength after a bleaching protocol. Sound human anterior teeth were collected, cleaned, prepared for a bond strength test, and randomly allocated into groups according to the bonding procedure. Group 1 acted as a control, without bleaching treatment, and without applying an antioxidant agent. In groups 2–6, specimens were bleached using 10% carbamide peroxide. In groups 3, 4 and 5, 10% wt% SA was applied for 10 min as an antioxidant in the form of a liquid, gel, and semi-gel, respectively. In group 6, samples were bleached and immersed in fresh human saliva for 14 days. After the bleaching process, the materials were restored by means of an adhesive system and a resin composite material. The analysis revealed that the differences between the shear bond strength (SBS) between the different groups were statistically significant (p = 0.0469). The highest SBS was achieved for the group where the 10 wt% SA liquid was applied before the bonding procedures. The application of liquid 10 wt% SA might reverse the negative impact that bleaching has on the bond strength of a resin composite and enamel.