The impact of root dentine conditioning on sealing ability and push-out bond strength of an epoxy resin root canal sealer

P>Aim To investigate the impact of dentine conditioning on sealing ability and dentine bond strength of an epoxy resin sealer. Methodology Root canals in 90 single-rooted teeth were instrumented using a rotary Ni-Ti system. Fifty canals were irrigated with water during instrumentation, 40 with 3% NaOCl. A final flush was performed in the water-irrigated specimens with water (negative control), 3% NaOCl, 17% EDTA, 7% maleic acid (MA) or 2% chlorhexidine. The hypochlorite irrigated specimens received a final flush with a decalcifying agent (EDTA or MA) and then 3% NaOCl or 3% NaOCl and then the decalcifying agent (n = 10, each). Canals were all filled with AH Plus. Fluid transport was measured on day 3 and 30. Roots were then sectioned, and push-out tests were performed in coronal, middle and apical root thirds. Results were analysed using analysis of variance (anova) with Bonferroni's adjustment. Spearman's rank correlation was computed between fluid transport and push-out bond strength. Results Leakage decreased over time (P < 0.05). Push-out bond strength was highest in coronal and lowest in apical root thirds (P < 0.05). Irrigating protocols with final application of a decalcifying agent greatly decreased the leakage and increased push-out bond strength values, in contrast to groups where NaOCl was applied last (P < 0.05), wherein the effect of the decalcifying agent was abolished. Chlorhexidine had no impact on the outcomes. Fluid transport and push-out bond strength correlated strongly (rho = -0.83). Conclusions AH Plus appears to bond to the organic phase of dentine. This bond influences its sealing ability.