Finite element analysis and comparison of protaper and hero endodontic file segments subjected to bending and torsional load

Abstract

Cleaning and shaping have been performed by numerous file systems. It is particularly difficult to shape complex root canal anatomy with stainless steel instruments. However, NiTi instruments are used routinely as they are more flexible, strong and provide more ease in operation. The present study aims at comparison of two endodontic file systems [ProTaper and HERO] using Finite Element Models analyzed by commercial software ANSYS 11.0 Workbench. The models were subjected to bending and torsion by applying moments at one end while the other end was kept fixed. Non-linear material behavior of Nitinol and complex Von Misses stress was considered during the analysis. Maximum stress of 631 and 390 MPa was observed in ProTaper and HERO file model when subjected to axial rotation of 20° simulating torsional load. Bending conditions were simulated by applying lateral rotation of 20° on free end. Transient analysis was carried out to obtain the moment rigidity curve and was found to be identical for both the file systems. Based on obtained results, it was concluded that the HERO file model is more flexible as compared to ProTaper file model.