Smear-layer Removal Using Two Instrumentation and Irrigation Techniques in a Closed System

Aim: The aim of this study was to evaluate the effectiveness of two instrumentation and irrigant techniques in smear-layer removal from root canals. Methodology: Thirty single-rooted teeth were randomly divided into two groups. Group 1 (continuous irrigation) was prepared using Selfadjusting file, and group 2 (manual irrigation; conventional needle irrigation) was prepared using with ProTaper file system. Groups were irrigated using sodium hypochlorite (5%) as an initial irrigant following MTAD in a closed system. Canals were bisected and examined by scanning electron microscopy. Smear layers were evaluated using a five-point scoring system with 2500x magnification. Results: Smear layers were eliminated in the coronal, middle, and apical thirds of the root canal, respectively, in 93%, 80%, and 60% of samples in the group 1, and 67%, 60%, and 27% in the group 2, of the coronal, middle, and apical thirds of the root canals, respectively. Evaluation by SEM showed continuous irrigation differed not-significantly from the manual irrigation group in all areas (P >0.05). Conclusions: Smear layer can be removed properly with suitable irrigation methods.