Analysis of cyclic fatigue resistance of different endodontic nickel–titanium rotary instruments: An in vitro study

Abstract

Abstract Aims: The aim of this in vitro study was to compare the cyclic fatigue resistance of three different endodontic nickel–titanium rotary instruments using a dynamic testing device. Materials and Methods: Ten files each of ProTaper Gold (PG), Hyflex Electro-discharge Machining (HEDM), and TruNatomy (TN) were tested in a custom-fabricated dynamic cyclic fatigue testing device at 60° curvature having a radius of curvature of 5 mm. The number of cycles to the fracture (NCF) of each instrument was calculated and three continuous groups were compared by the Kruskal–Wallis test and Dunn post hoc test was used for pairwise comparison. Results: Cyclic fatigue resistance of HEDM was the highest, followed by TN. PG had the lowest among the three. Conclusion: Within the limitations of the present in vitro results, it can be concluded that HEDM files appeared to be suitable for shaping complex canals with the greater number of cycles before it fractures.