Investigation of uprighting partially impacted mandibular second molar tooth with different methods by finite element analysis

Aim: This study aims to evaluate the results of four different skeletal anchorage treatment methods for uprighting partially impacted mandibular second molars in a mesioangular position using finite element analysis. It will analyze stresses in the tooth, bone, periodontal ligament, and screws, as well as tooth displacements in various directions. Material and Method: The mandibular complex, including mandibular teeth, periodontal ligament, alveolar process, and planned mechanics, was modeled for finite element analysis. Twelve scenarios were created using four skeletal anchorage methods (Open Coil, Niemkemper, Cantilever, Ramus Screw) and three degrees of embedment (45°, 60°, 75°). The analysis focused on stresses in the tooth, bone, periodontal ligament, and screws, along with displacements in the x, y, and z axes. Results: The highest displacement in the transversal direction (x) occurred in the fourth group in which the ramus screw was applied, the highest displacement in the sagittal direction (y) occurred in the second group in which the Nienkemper method was applied, and the highest displacement in the vertical direction (z) occurred in the fourth group in which the ramus screw was applied. Conclusion: The ramus screw and cantilever methods were the riskiest for root resorption. The Niemkemper method is recommended for cases requiring distalization with uprighting, while the cantilever method is better when distalization is not needed. For severely impacted teeth (75°), it's advised to first move the tooth coronally with a ramus screw to make it visible, then continue with the cantilever method for effective mesial root movement. Key Words: Finite Element Analysis, Mandibular Molar Uprighting, Mini Screw, Skeletal Anchorage