Finite Element Analysis of the Mechanical Behaviors of Endodontic Nickel–Titanium Rotary Files: A Review

Abstract

An endodontic rotary file is a special instrument used in the treatment of dental pulp and surrounding tissues. They are available in a wide range of sizes and configurations, specifically tailored to accommodate the narrow and curved root canals of the teeth. Consequently, dental rotary files are slender, flexible, and generally made of a nickel-titanium alloy. The investigation of mechanical behaviors of dental files can be effectively conducted using computational approaches, such as the finite element method. This numerical tool is widely used in many engineering applications, especially for solid mechanics and structural problems. With the finite element method, the reliability and safety of dental files can be preliminarily assessed in a short period of time. This report reviews applications of the finite element analysis method to investigate the mechanical responses of endodontic rotary files. Both the finite element modeling of the files and applications of the method to rotary file problems are included in the study. This review includes the stress distribution, flexibility and stiffness, and fatigue life of the files. There have been a variety of approaches to model files under flexural and torsional loads. Static analysis with simple loading conditions was adopted in most of the studies. The analytical approach can be improved so that files under working conditions are accurately modelled. Moreover, there is a need for verification of the finite element solutions with experimental or clinical studies.