Cyclic Fatigue Resistance of OneShape, HyFlex EDM, WaveOne Gold, and Reciproc Blue Nickel-titanium Instruments

Abstract

Introduction: The purpose of this study was to compare the cyclic fatigue resistances of Reciproc Blue (VDW, Munich, Germany), HyFlex EDM (Coltene/Whaledent, Altstitten, Switzerland), WaveOne Gold (Dentsply Maillefer, Ballaigues, Switzerland), and OneShape (Micro Mega, Besancon, France) single-file NiTi systems. Methods: Thirty Reciproc Blue R25 (25/.08), 30 HyFlex EDM (25/.), 30 WaveOne Gold Primary (25/.07), and 30 OneShape (25/.06) instruments were included in this study. All the instruments were rotated in artificial canals, which were made of stainless steel with an inner diameter of 1.5 mm, a 60 degrees angle of curvature, and radii of curvatures of 5 mm until fracture occurred, and the time to fracture was recorded in seconds using a digital chronometer. The data were analyzed statistically using Kruskal-Wallis and post hoc Dunn tests via SPSS 21.0 software (SPSS Inc, Chicago, IL). The statistical significance level was set at 5%. Results: The HyFlex EDM file (3456.33 +/- 633.37) file had the statistically highest fatigue resistance, and the OneShape file (1221.63 +/- 812.4) had the least fatigue resistance (P < .05). The mean number of cycles to fracture of the Reciproc Blue file (2875.89 +/- 105.35) file was statistically higher than the WaveOne Gold file (1737.00 +/- 376.32) (P < .05). There was no statistically significant difference (P > .05) in the mean length of the fractured fragments of the files (P > .05). Conclusion: Within the limitations of the present in vitro study, it was found that cyclic fatigue resistance of HyFlex EDM files was higher than the cyclic fatigue resistances of OneShape, Reciproc Blue, and WaveOne Gold files.