Effect of Final Irrigation Protocols on Radicular Dentin Permeability and Push-Out bond Strength in Endodontically Treated Teeth

This study aimed to analyze the effect of several final irrigation protocols on tubular permeability and push-out bond strength of an epoxy resin-based cement to radicular dentin. The crowns of 110 human teeth were removed to standardize at 17mm in length. The root canals were instrumented and irrigated with 5ml of 5% NaOCl and 17% EDTA. The samples were then randomly divided into 5 groups (n=22) according to the final irrigation protocol. Subsequently, the samples were subdivided into two different groups to assess dentin permeability or the evaluation of the push-out bond strength. In Group 1, all samples displayed the formation of brown-like precipitates. Group 2 and Group 5 demonstrated cleaner dentin walls. The push-out bond test after 72 hours denoted a significant difference when comparing Group 1 vs Group 2 and Group 1 vs Group 3. After thermocycling, a significant difference is observed between Group 1 and all remaining groups. The irrigation protocol using distilled water prior to irrigation with chlorhexidine significantly reduces the formation of intracanal precipitates by avoiding interactions between irrigants. The push-out bond strength of epoxy resin-based cement is directly influenced by the precipitates formed in the root canal after irrigation and the time of thermocycling.