The Effect of Different Sealer Removal Protocols on Micro-Tensile Bond Strength of Single Bond Plus to Dentin Exposed with Different Chemical Root Canal Irrigants: An Ex Vivo Study

Abstract

Background: Chemical substances used to prepare root canals and their residuals can alter dentin surface composition, affecting restorative systems bonding to dentin. Objectives: This ex vivo study evaluated the effects of different sealer removal methods on the micro-tensile bond strength of dentin surfaces exposed using endodontic irrigants. Methods: A total of 45 extracted healthy mandibular molars were sliced from the occlusal surface to expose their dentin surface and were randomly divided into three main groups (n = 15) based on the irrigants as G1: Distilled water (control), G2: Sodium hypochlorite (NaOCL) 5.25%, and G3: Chlorhexidine (CHX) 2%. AH Plus endodontic sealer, was applied to all exposed dentin surfaces. Each group was divided into four subgroups (SG) according to the sealer removal methods: SG1: No root canal sealer (control), SG2: Moist cotton pellet, SG3: Ethanol 95% saturated cotton pellet, SG4: Round diamond bur. The teeth were restored using single bond plus and Z250 composite and sectioned to prepare sticks for micro-tensile bond testing. Additionally, failure patterns were investigated. Comparison between experimental groups was performed using Kruskal-Wallis H and Dunn's post-hoc tests. The accepted significance level for all tests was P < 0.05. Results: A significant decrease was observed in the micro-tensile bond strength of the control group cleaned with 95% Ethanol saturated cotton pellets. In addition, the highest micro-tensile bond strength was observed in dentin cleaned through a diamond round bur and in the group irrigated with CHX. The failure modes were mainly adhesive. Conclusions: Within this study's limitations, the dentin bond strength is affected by the irrigation protocol and sealer removal method.