Mechanical evaluation of EGUH burs in dentin during guided endodontics: Finite element analysis

Introduction: This study investigated the mechanical and thermal behavior of EGUH burs used in guided endodontics through simulations performed using Finite Element Analysis. Materials and Methods: Geometric models of four EGUH burs (0.50 mm and 0.70 mm tips; 18 mm and 21 mm lengths) were developed using three-dimensional CAD software based on scans of a mandibular incisor. Finite Element Method simulations incorporated dentin and bur material properties from the literature, with boundary conditions replicating clinical parameters (loads of 0.49–1.47 N, 200,000–350,000 RPM, 37°C, 100% humidity). High-resolution tetrahedral meshing (up to 0.02 mm) and nonlinear contact modeling were applied to assess stress distribution, deformation, and thermal behavior. Mesh convergence and refinement ensured accuracy and stability in the simulations. Results: Larger burs (0.70 mm) withstood 115 MPa and deformed only 0.01 mm, while smaller ones (0.50 mm) reached 80 MPa and deformed 0.03 mm. With guides, the stress in smaller burs dropped to 45 MPa. Thermal peaks were 45°C for small burs and 39.5°C for larger ones. Conclusions: These results emphasize the relevance of selecting burs with geometries tailored to clinical demands. Larger diameter burs are recommended for extended or high-load procedures due to their mechanical and thermal advantages, whereas thinner burs require guiding systems to ensure safe and effective performance.