Numerical Simulation of Cu-Al-Mn Endodontic Instruments under Bending and Torsional Conditions

This study focuses on the development of endodontic instruments manufactured from Cu-Al-Mn shape memory alloys (SMAs) which are more economical and easier to process as compared to conventional NiTi SMAs. Finite element analysis of three different numerical instruments was performed using material parameters of Cu-Al-Mn and conventional superelastic NiTi. Flexural and torsional stiffness of these instruments with the resulting von Mises stresses were evaluated under bending and twisting based on the ISO 3630-1 specification. All the studied Cu-Al-Mn endodontic files exhibited superior flexibility and lower reaction stresses as compared to NiTi endodontic files during bending, resulting from their low elastic modulus and starting stress value for the martensitic transformation. However, low torsional stiffness and high von Mises stress values related with the high angular displacement were obtained for Cu-Al-Mn endodontic instruments under torsional loading. Geometric differences of different models have been an important factor in adjusting the stiffness of endodontic instruments. Consequently, it was determined that Cu-Al-Mn SMA could be used as an alternative material in the manufacture of endodontic files that have large cross-sectional area and moment of inertia.