Effect of disinfecting the cavity with chlorhexidine on the marginal gaps of Cl V composite restorations bonded with universal adhesive using two bonding strategies (self-etch or etch-and-rinse)

Abstract

Background & Aim: Considering the popularity of the use of disinfecting agents in cavities, this in vitro study aimed to evaluate the effect of disinfecting cavities with chlorhexidine (CHX) on marginal gaps of class V composite resin restorations bonded with a universal adhesive using self-etch and etch-and-rinse bonding strategies.

Materials and Methods: Sixty sound human premolar teeth were selected. The tooth samples were randomly assigned to two groups: group 1 (no use of CHX) and group 2 (use of CHX) (n=30). Each group was divided into two subgroups in terms of the bonding strategy of the universal adhesive (self-etch or etch-and-rinse) (n=15). Class V cavities were prepared on the buccal surfaces of the teeth. In the first and second subgroups of both groups, All-Bond Universal adhesive was applied with self-etch and etch-and-rinse bonding strategies, respectively. After restoring and thermocycling, the samples were sectioned, and the marginal gaps at gingival margins were measured in µm under a stereomicroscope. Two-way ANOVA was used to compare marginal gaps between the groups and subgroups.

Results: The results showed that the mean marginal gap values were affected significantly by the cavity disinfection (P=0.001) and the bonding strategy (P=0.002). However, the interaction of these two factors on the mean marginal gaps was not significant (P=0.79).

Conclusion: Use of CHX resulted in larger marginal gasps at gingival margins of class V composite resin restorations. Furthermore, irrespective of disinfecting or not disinfecting the cavities, the self-etch bonding strategy resulted in larger marginal gaps compared to the etch-and-rinse bonding strategy.