LAUSR

Introduction: The aim of this study was to compare the cyclic fatigue resistance of the ProTaper Gold (PTG; Dentsply Maillefer, Ballaigues, Switzerland), K3XF (SybronEndo, Orange, CA), and XP‐endo Shaper (FKG Dentaire, La Chaux‐de‐Fond, Switzerland) nickel‐titanium rotary instruments at intracanal temperatures. Methods: Eighteen XP‐endo Shaper (30.01), 18 K3XF (30.04), and 18 PTG F3 (30.09v) instruments were used to test the cyclic fatigue resistance at an intracanal temperature of 35° ± 2°C. The instruments were tested in a metal block that simulated a canal curvature angle of 60° and a curvature or radius of 5 mm. All instruments were operated until fracture occurred, and then the number of cycles to failure was calculated. The lengths of fractured fragments were measured with a digital caliper. The data were analyzed statistically using 1‐way analysis of variance and the Tukey post hoc test with significance set at P < .05. Results: The XP‐endo Shaper instruments showed a significantly higher number of cycles to fracture than the K3XF and PTG instruments (P < .05). There was no difference between the PTG and K3XF instruments (P > .05). Conclusions: The XP‐endo Shaper instruments exhibited greater cyclic fatigue resistance compared with the other instruments at the intracanal temperature. Highlights:The cyclic fatigue (CF) resistance of the novel XP‐endo Shaper instrument was compared with the ProTaper Gold F3 and K3XF instruments.The XP‐endo Shaper (30.01) exhibited the highest CF resistance.There was no significant difference between ProTaper Gold (30.09v) and K3XF (30.04) regarding CF resistance.