Effect of altering the reciprocation range and instrument speed on the shaping ability and working time of WOG NiTi instruments

Abstract

Introduction: The purpose of this study was to investigate the effect of altering the reciprocation range and speed of the WaveOne Gold instrument on its shaping ability regarding canal centering ratio and preparation time. Methods: Sixty simulated resin canal blocks with a S-shaped canal were divided into 6 equal groups according to the reciprocation range and speed of the primary WaveOne Gold instrument (n=10): G1: 170 counterclockwise (CCW)–50 clockwise (CW)/ 150 rpm; G2: 170 CCW–50 CW/ 300 rpm; G3: 90 CCW–30 CW/ 150 rpm; G4: 90 CCW–30 CW/300 rpm, G5: 150 CCW–30 CW/150 rpm, and G6: 150 CCW–30 CW/300 rpm. Pre- and post-instrumentation images were superimposed, and centering ratios were calculated at 2, 5, and 9 mm from the apex. The time taken to complete canal preparation was compared and the incidence of instrument fracture was recorded. The mean/standard deviation values were analyzed using analysis of variance and the Tukey post hoc test. The significance level was set at P < .05. Results: Regarding preparation time, G2, G4 and G6 had the lowest mean for the preparation time, which was statistically significant in comparison with the other experimental groups (P < .05). Results for canal centering ratio showed that at 2, 5, and 9 mm from the apex there were no significant differences between all groups tested. Conclusions: Altering the reciprocation range did not significantly affect the shaping ability of WaveOne Gold primary instruments. Increasing the speed of WaveOne instruments resulted in faster preparation times.