Özet:

Purpose: The purpose of our study is to be able to find an ideal resection design to prevent breaks that may occur in the residual bone after marginal mandibulectoms using the final element analysis method. There are two different types of designs that are often used for this purpose. Tools and methods: on the mathematical mandibula models obtained in three-dimensional forms from the tomographic images, two different types of marginal mandibulectomy have been applied in the posterior corpus area, cornered and curved. In these two models, the stress under the bite forces was evaluated by the final element analysis method. Results: Models have been evaluated and compared in terms of minimum and maximum original voltage (minimum and maximum principal stress), equivalent original voltage (Von Mises stress) and location changes. In both models, the stress is formed in the postero-inferior corners of the defect. Similarly, the location change values were found higher in both models in the back corners. In the corner model, it has been shown that higher stress and location changes occur in all areas compared to the curved model. The conclusion is that both models are more likely to break from the postero-inferior corners of the defect and the cornered model also has a higher postoperative break risk than the curved model. Keywords: Final element analysis, marginal mandibulectomy, postoperative broken THE EVALUATION OF DIFFERENT FORMS OF MARGINAL MANDIBULECTOMIES IN TERMS OF POSTOPERATIVE FRACTURE RISK ABSTRACT Aim: The purpose of this study is to reveal an optimal marginal mandibulectomy design to prevent postoperative fractures. So then, two different common designs were compared with finite element analysis. Material and methods: Two types of marginal mandibulectomies (angular and curviliniear) were performed on the posterior corpus of a 3 dimensional mathematical mandible model which was created from the tomography images. Stresses that took place on those two models under bite forces, were evaluated with finite element analysis. Results: The models were evaluated and compared in terms of; minimum and maximum main stresses, Von Mises stress and displacement magnitude. The highest stresses occured in the postero-inferior corners of the defects on both of the models. Similarly, the highest displacement magnitudes were measured in the posterior corners of both models. Higher stresses and displacement magnitudes were measured in all sites of the angular model compared to curvilinear one. Conclusion: We conclude that, both of the models' postero-inferior corners were more prone to be fractured and the angular model had more postoperative fracture risk in comparison with the curvilinear one. Key words: Finite element analysis, marginal mandibulectomy, postoperative fracture