Author(s): Vinoo Subramaniam, R Indira, MR Srinivasan, P Shankar
Nickel Titanium endodontic instruments facilitates instrumentation of curved canals. Continuous unidirectional rotation causes development of complex stresses in nickel titanium rotary instruments. The distribution of torsional anti bending stresses depends primarily on the cross sectional design and mass of the instrument to be cut. The finite element analysis is aimed to study and compare stress distribution and behavior of two rotary instruments, protaper and profile. The stress induced phase transformation of nickel titanium alloy is also studied by Finite Element Model, this model when simulated properly shows better understanding of stress analysis than other methods. The analyses are made by applying a concentrated torsional and bending moment to the protaper and profile instrument models. Under equal loads, protaper model showed uniform stress distribution and less elasticity compared to profile model. Profile model is more elastic but, showed stress peaks between flutes.