DOI: 10.36347/sjds.2019.v06i10.001

Pages: 454-457

Introduction: The aim of the present study was to observe the incidence of cracks in root canal dentin using the ProTaper Gold system (Dentsply Maillefer) at low- and high-torque settings. Methods: Sixty mandibular premolar teeth that had been extracted for different reasons were selected. The teeth were divided into 3 groups: an unprepared control group, a low-torque settings group (SX = 3, S1 = 3, S2 = 1, F1 = 1, F2 = 2, F3 = 2, F4 = 2 Ncm), and a high-torque settings group (SX = 5, S1 = 5, S2 = 1.5, F1 = 1.5, F2 = 3.10, F3 = 3.10, F4 = 3.10 Ncm). After a root canal procedure, all the teeth were horizontally sectioned at 3, 6, and 9 mm from the apex. Then, under a stereomicroscope, all the slices were examined to determine the presence of cracks. A chi-square test was used for data analysis. The significance level was set at P = .05. Results: Vertical root fractures were not observed in any of the groups. There were no cracks in the unprepared control group. There were significantly fewer cracks (15.6% of the sections) in the low-torque group than in the high-torque group (27.3% of the sections) (P < .05). Conclusions: In this in vitro study, the instrumentation of root canals with the ProTaper Gold instrument caused more crack formation in root canal dentin at high-torque than at low-torque settings.