The aim of this study was to compare the effects of solution and different sodium ascorbate hydrogels on dentin-resin composite shear bond strength subsequent to a bleaching procedure with 10% carbamide peroxide.

Sixty buccal dentin surfaces obtained from intact human third molars were randomly divided into five groups (n=12). Dentin surfaces received different treatments: (1) no treatment; (2) bleaching (10% carbamide peroxide gel); (3) bleaching + 10% sodium ascorbate solution; (4) bleaching + 10% sodium ascorbate hydrogel, and (5) bleaching + 20% sodium ascorbate hydrogel. Dentin surfaces were bonded with Single Bond™ and restored with a composite (Z100). The samples were tested for shear bond strengths. Data was analyzed using analysis of variance (ANOVA) and Tukey tests.

Significantly higher bond strengths were observed subsequent to treatment with hydrogel and solution forms of sodium ascorbate (p<0.05). No significant differences were demonstrated between different forms of sodium ascorbate preparations. In addition, no significant differences were observed among groups with antioxidant treatment (Groups 3, 4, and 5) and Group 1 (no treatment).

Reduced bond strength to bleached dentin can be amended by the use of sodium ascorbate as an antioxidant.

Both hydrogel and solution forms of sodium ascorbate can significantly improve the reduced bond strength of resin composite to dentin subsequent to a bleaching procedure with 10% carbamide peroxide.

Kimyai S, Valizadeh H. Comparison of the Effect of Hydrogel and a Solution of Sodium Ascorbate on Dentin-composite Bond Strength After Bleaching. J Contemp Dent Pract 2008 February;(9)2:105-112.