EFFECT OF DIFFERENT CAVITY DISINFECTANTS ON SHEAR BOND STRENGTH OF RESIN COMPOSITES TO DENTIN

Abstract

Purpose: The aim of this study was to evaluate the effect of different cavity disinfectants on dentin shear bond strengths of composite resin applied with two different adhesive approaches. Materials and Methods: eighty caries free third molars were sectioned parallel to the occlusal surface to expose mid-coronal dentin. The specimens were randomly divided into four groups of twenty teeth each. GP1 is control group (no treatment), groups 2,3, and 4 dentin surfaces were treated with the following cavity disinfectants, respectively; 0.12% chlorhexidine solution (CHX), 5% sodium hypochlorite (NaOCl) and 0.15% benzalkonium chloride (BAC). Each group from Gp1 to Gp4 was further divided into two subgroups (𝑛 =10 per sup group) according to the adhesive approaches. Ten specimens were bonded with the total-etch approach and the other ten specimens were bonded with self-etching approach. Then resin composite was applied incrementally to the treated dentin surface into cylindrically-shaped Teflon tube (3mm diameter × 3mm height) then polymerized with LED curing unit. After the specimens were stored in an incubator for 24 h, the shear bond strength was measured at a crosshead speed of 0.5 mm/min. The bond strength data were analyzed with one way analysis of variance ANOVA and independent sample t test. Results: Statistical analysis found that treated dentin surface with different cavity disinfectant resulted in higher shear bond strength compared with the control group (the lowest SBS value 7.58± 0. 85) obtained for the untreated dentin surface (control group). Among the cavity disinfectant groups, the highest SBS was recorded for Tantum (13, 39 ±7.59) group. For the three types of cavity disinfectant, total-etch approach showed higher bond strength than self-etch approach. Conclusion: Treated the dentin surface with cavity disinfectant before adhesive bonding improved the shear bond strength between resin composite and dentin surface in particular with the total-etch adhesive approach. Keywords: bond strength, adhesive, composite resin, cavity disinfection.