Evaluation of cyclic fatigue resistance of modern Nickel–Titanium rotary instruments with continuous rotation

Aim The aim of present study was to compare cyclic fatigue resistance of three modern Ni–Ti instruments used with continuous rotation. Materials and methods For this study 3 groups of rotating instruments with continuous rotation (HyFlex EDM, Twisted File Adaptive, Revo S SU) have been used, each group consisted of 20 files. The various groups were subjected to cyclic fatigue testing through an artificial metal device. A statistical analysis with Kruskal–Wallis test and Mann–Whitney test was performed. Results There were statistically significant differences between the three groups. The HyFlex EDM instruments have a fracture resistance slightly higher than the Twisted file and far higher than Revo S SU. Conclusions Modern Ni–Ti alloys increase resistance of the rotating instruments to cyclic fatigue.