Factors Affecting the Cyclic Fatigue of Heat-Treated NiTi Rotary File: A Review

Abstract

NiTi) rotary endodontic instruments fracture occurs inside the canal during treatment. It is time consuming for removal of these separated instruments, in addition to its technical difficulty. So for these reasons it is important to reduce the risk of file fracture. As a sequel, several attempts have been made to improve the mechanical features of NiTi rotary files, like changes in speed of operation, changing the geometric and dimensional characteristics, and several different metal treatments. The revolution of new heat-treated NiTi instruments opens a new era for basic, clinical and scientific research. This article concerns mostly with environmental and heat-treated factors, irrigation and type of rotation and their effects on heat-treated NiTi instruments found in most studies.