Comparison of Cyclic Fatigue Resistance of 5 Heat-treated Nickel-titanium Reciprocating Systems in Canals with Single and Double Curvatures.

Introduction: The goal of this study was to compare the cyclic fatigue resistance of 5 heat-treated nickel-titanium files in reciprocating movement with the same tip size and different cross sections.

Methods: Five groups (WaveOne [Dentsply, Ballaigues, Switzerland], WaveOne GOLD [Dentsply], RECIPROC [VDW, Munich, Germany], RECIPROC BLUE [VDW GmbH, Munich, Germany], and TF [Sybron Endo, Glendora, CA] Adaptive) of 24 files each of the rotary files were examined. Cyclic fatigue resistance was compared between groups by determining the time needed to fracture and the number of cycles to failure in a cyclic fatigue testing device with 2 different curvatures, the first with a 5-mm radius of curvature and a 60° angle and the second with a double curvature, coronal curvature of 60° angle and a radius of 5 mm, and an apical curvature of 70° angle and a 2-mm radius.