Structural assessment of endodontic instruments

This thesis presents a comprehensive computational methodology based on Finite Element Analysis (FEA) for the structural assessment of rotary endodontic files made from conventional austenitic NiTi alloys. The primary objective is to understand and accurately capture the mechanical behavior and failure modes of these instruments under various operational conditions. The study focuses on the torsional and bending stiffness characteristics of endodontic files and their fatigue behavior during root canal procedures. Methodology development involved simulating bending and torsional tests as per ISO 3630-1 standards, as well as cyclic fatigue tests using a selected simulated canal configuration. The root canal treatment procedure was also simulated for a molar tooth with significant root canal curvature to understand the influence of a realistic canal geometry on the fatigue behavior of endodontic files. Utilization of the dissipated energy method for fatigue life estimation of NiTi endodontic files is one of the contributions of this work. The ProTaper Universal file set was chosen for methodology development due to the availability of extensive data. The endodontic files and molar tooth geometries were acquired through three dimensional scanning, and geometry data for physical tests were retrieved from the literature. The study showed reasonable correlation between simulation results and physical test data for ISO 3630-1 and cyclic fatigue simulations. Pecking and reciprocating motions were found to increase the fatigue life of endodontic files.