An Investigation of the Metal Fatigue of Different Nickel-Titanium Rotary Instruments After Prolonged Use

Abstract

Objective:This study aimed to compare the cyclic fatigue (CF) resistance of nickel-titanium (Ni-Ti) endodontic instruments from ProTaper (PTU), ProTaper Next (PTN), Wave One (WO), and Reciproc (RPC). Materials and Methods:In our study, PTU, PTN, WO, and RPC rotary files were divided into the experimental and control groups containing an equal number of samples. The experimental group files were used in the shaping of 80 extracted human lower premolar and lower molar teeth. The experimental and control group kits were then placed in the test apparatus and observed until they fractured. Fracture times were recorded and statistically evaluated. Results:In the one-to-one comparisons of the experimental and control group files, while the differences between the fracture times of the experimental and control group files were found to be statistically insignificant in RPC, WO, PTU, and PTN X1 files (p>0.05), fracture time differences were statistically significant in all PTN X2 files (p0.05). Conclusion:The files used with reciprocal movement were found to be safer in terms of metal fatigue when compared to the other files used with rotational movement after the preparation.