Canal cleanliness using different irrigation activation systems: a SEM evaluation

Objectives The purpose of this study was to assess the efficacy of different final irrigation activation methods in removing debris and smear layer in the apical, middle, and coronal portion of straight root canals. Material and methods Straight root canals of 58 freshly extracted mandibular premolars were used. Root canals were prepared to size 40.06. Irrigation was performed using 3% sodium hypochlorite. Samples were divided into four equal groups ( n = 12) according to the irrigation activation techniques: (A) manual irrigation (MI), (B) EndoActivator (EA) (Dentsply Maillefer, Ballaigues, Switzerland), (C) sonic activation EDDY (EDDY; VDW, Munich, Germany), and (D) passive ultrasonic irrigation (PUI). Ten teeth served as negative controls. Roots were split longitudinally, and the canal walls were subjected to scanning electron microscopy. The presence of debris and smear layer at coronal, middle, and apical levels were evaluated using a 5-point scoring system and statistically analyzed using Kruskal-Wallis and chi-square tests. Results Canal cleanliness decreased from coronal to apical ( P = 0.035). Significantly more debris was removed with EA, EDDY, and PUI compared to MI ( P 0.05). Smear layer removal with PUI, EA, and EDDY was not significantly different ( P > 0.05), but only EDDY and PUI were superior to MI ( P