BackgroundThe aim of this study was to evaluate the mechanical behavior of M-wire, controlled memory (CM), and R-phase files under bending and torsion conditions and compare it to the mechanical response of NiTi file with the same geometry using finite element analysis.MethodsA geometric model of HyFlex file size 25 and taper 0.06 was generated by micro-computed tomographic and stereomicroscope scanning. The file FE model was built using MATLAB and SolidWorks software. Four FE files models were constructed with different material properties, the data for the M-wire, CM, R-phase, and NiTi alloys were obtained from the literature. The mechanical behavior of the different models under bending and torsion was analyzed mathematically in SolidWorks software package.ResultsUnder bending conditions, the maximum Von Misses stress value was related to NiTi file model (330 MPa), followed by M-wire (311 MPa), then CM file model (191 MPa), while the least amount of stress value was related to R-phase file model (169 MPa). When torsion test was performed the maximum stress value was also related to NiTi file model (270 MPa), followed by M-wire (261 MPa), then CM file model (191 MPa), while the least amount of stress value was related to R-phase file model (188 MPa).ConclusionsMetallurgical improvement of rotary files resulted in increasing the flexibility and the torsional resistance of these files.