Biomechanical analysis of different rotary files in varying root canal curvatures: a 3D finite element analysis study

BACKGROUND: Proper biomechanical preparation of the root canal system is fundamental to the success of endodontic therapy. Curved root canals represent a major clinical challenge, increasing the risk of procedural errors such as canal transportation, ledge formation, and instrument separation. This study aimed to evaluate the stress distribution in two single-file rotary systems subjected to different canal curvatures using three-dimensional finite element analysis (FEA). METHODS: Three-dimensional CAD models of root canals with curvatures of 2°, 30°, and 45° were created, along with models of WaveOne Gold and One Curve rotary files. Finite element simulations were performed to replicate clinical instrumentation conditions, and the generated stresses were evaluated using the von Mises stress criterion. RESULTS: WaveOne Gold demonstrated maximum von Mises stress values of 375.42 MPa at 2°, 435.13 MPa at 30°, and 515.36 MPa at 45° curvature. Corresponding values for One Curve were 405.71 MPa, 472.87 MPa, and 565.17 MPa, respectively. Across all curvatures, WaveOne Gold exhibited lower stress values than One Curve. CONCLUSION: WaveOne Gold produced lower von Mises stress values than One Curve across all tested canal curvatures. Increasing canal curvature significantly increased stress levels in both file systems.