Evaluation of different plate systems used in fixation of mandibular subcondyle fractures by finite element analysis

The mandible is one of the most traumatized and fractured bones of the maxillofacial bones. Condyle, angulus and symphysis parts of the mandible are the most sensitive anatomical regions for fractures. Correction of mandibular fractures in patients with craniofacial trauma is very important in terms of providing a satisfactory cosmetic appearance, providing occlusion, maintaining a healthy level of functions such as chewing and phonation, and preventing possible sequelae. Fractures developing in the mandible are treated with open reduction internal fixation or non-surgical (conservative) methods, depending on the type, grade, localization of the fracture, and the relationship between the fragments. In some cases, internal fixation with open reduction is inevitable. While performing internal fixation with open reduction, different fixation methods and systems are used in clinical practice. In our study, 5 different plate systems made of titanium alloy were applied to the mandible model with a unilateral subcondyle fracture, and the models were examined by finite element analysis technique under 250 N vertical loading condition applied to the first molar tooth. As a result of the applied force, the stresses occurring in the cortical bone around the screw, plates and screws and the amount of displacement between the fragments were evaluated and comparisons were made between the groups. The tensile and compressive stress values in the cortical bone around the screws were found within physiological limits in all groups. While the minimum amount of displacement between fragments in the fracture region was observed in the double plate in group 2, it was within acceptable limits in the other groups. Von Mises stress values occurred mostly in a single plate in group 1, and the stress values on the plate were found to be less than the value that would cause permanent deformation or breakage of the plate in all groups. It has been observed that the fixation system using a double plate provides the best biomechanical stability. With this study, we believe that the effect of stress on the material used by selecting the appropriate plate and screw system will be examined, and complications such as loss of plate or screw, infection, failure to achieve full stabilization of the fracture line due to this stress accumulation will contribute to healing, and will also pave the way for newer studies in the future.