INTRODUCTION: The aim of this study was to compare the cyclic fatigue resistance of 3 nickel-titanium (NiTi) endodontic instruments from ProTaper, WaveOne (WO), and Twisted Files (TF). METHODS: Cyclic fatigue testing was conducted by operating instruments from ProTaper F2, WO 25 .08, and TF 25 .08. A total of 184 instruments were rotated in 4 curved artificial canals with different angles and radius of curvature. The time and cycles to failure were calculated. The data were compared for differences by using 2-way analysis of variance (P < .05). RESULTS: In general, WO was the most resistant to fatigue failure of the tested instruments, and TF showed a higher number of cycles to failure than ProTaper. CONCLUSIONS: Reciprocating movement of WO showed a longer cyclic fatigue life than conventional rotary movement of TF and ProTaper. The new manufacturing twisting process of TF produced NiTi rotary instruments more resistant to fatigue than ProTaper instruments produced with the traditional NiTi grinding process.
INTRODUCTION: The aim of this study was to compare the cyclic fatigue resistance of 3 nickel-titanium (NiTi) endodontic instruments from ProTaper, WaveOne (WO), and Twisted Files (TF). METHODS: Cyclic fatigue testing was conducted by operating instruments from ProTaper F2, WO 25 .08, and TF 25 .08. A total of 184 instruments were rotated in 4 curved artificial canals with different angles and radius of curvature. The time and cycles to failure were calculated. The data were compared for differences by using 2-way analysis of variance (P < .05). RESULTS: In general, WO was the most resistant to fatigue failure of the tested instruments, and TF showed a higher number of cycles to failure than ProTaper. CONCLUSIONS: Reciprocating movement of WO showed a longer cyclic fatigue life than conventional rotary movement of TF and ProTaper. The new manufacturing twisting process of TF produced NiTi rotary instruments more resistant to fatigue than ProTaper instruments produced with the traditional NiTi grinding process.