The Effect of Taper and Apical Diameter on the Cyclic Fatigue Resistance of Rotary Endodontic Files Using an Experimental Electronic Device

The aim of this study was to analyze the effect taper and apical diameter nickel–titanium (NiTi) endodontic rotary files on dynamic cyclic fatigue resistance. A total 50 unused conventional NiTi wire alloy instruments were used in study. All submitted a custom-made device until fracture occurred. time failure, number cycles pecking movements, length fractured file tip analyzed using analysis variance (ANOVA) test. In addition, Weibull characteristic strength modulus also calculated. paired t-test revealed statistically significant differences between in-and-out movement both (p ˂ 0.001) files; however, results did not show mean regarding = 0.344) groups 0.344). Increased decreased their resistance fatigue.