Cyclic and Torsional Fatigue Resistance of XP-endo Shaper and TRUShape Instruments

Introduction: The purpose of this study was to evaluate the cyclic and torsional fatigue resistance of the XP-endo Shaper (FKG Dentaire, La Chaux-de-Fonds, Switzerland) and TRUShape (Dentsply Tulsa Dental Specialties, Tulsa, OK) instruments. Methods: Twenty XP-endo Shaper (30/0.01) instruments and 20 TRUShape (30/0.06v) instruments were used. Cyclic fatigue resistance was tested by measuring the number of cycles and time to fracture in an artificial stainless steel canal with a 60 angle and a 5-mm radius of curvature (n = 10). The torque and angle of rotation at failure of new instruments (n = 10) were measured according to ISO 3630-1. The fracture surface of all fragments was examined with a scanning electron microscope. Results were statistically analyzed using the Student t test at a significance level of P<.05. Results: The XP-endo Shaper instruments showed a significantly longer number of cycles to fracture and time to failure in seconds than the TRUShape instruments (P<.05). The XP-endo Shaper also presented a lower maximum torque load (P<.05) but a significantly higher angular rotation to fracture than TRUShape (P<.05). Conclusions: The XP-endo Shaper instruments showed a higher cyclic fatigue resistance and angle of rotation to fracture but lower torque to failure than TRUShape instruments.