Evaluation of the stress developed after marginal mandibular resection with different residual bone heights by finite element analysis

Mandibular fractures after marginal mandibular resection are still a problem today. There are many studies that examine various risk factors to eliminate fracture formation. The aim of this study is to compare the resistance to masticatory pressure of mandible models with marginal resections with different residual bone heights. In order to perform finite element analysis, 6 different three-dimensional mandible models were created. These; mandibles with and without a reconstruction plate with a residual bone height of 3 mm, 5 mm and 7 mm. Force vectors were placed in the anatomical muscle attachment areas of the models to mimic incisal biting and molar chewing forces. As a result of the analyzes carried out, the stress values of the bone and titanium alloy were obtained. According to the findings, it was found that the stress occurring in the plate applied models was higher. Out of 6 models, 5 models were found to be at high fracture risk. While it was observed that the model with 7 mm residual bone height was resistant to chewing forces, it was observed that a fracture developed when the plate was applied to the model with the same height. As a result, marginal mandibular resection can be planned without using a 7 mm bone height reconstruction plate. If there is a residual bone amount of less than 7 mm during surgery, the inclusion of this basal bone in osteotomy and segmental resection instead of supporting it with a reconstruction plate will prevent the development of fractures.