Comparison of different fixation techniques used in sagittal split ramus osteotomy with three-dimensional finite element analysis

Sagittal Split Ramus Osteotomy (SSRO) is one of the methods frequently applied to the mandible in orthognathic surgery. Most used technique for fixation after SSRO is miniplate systems. Various miniplates have been designed and used to increase the success of SSRO operations. The aim of this study is to determine a safe fixation technique by evaluating the biomechanical agents related to the stabilization of SSRO fixation. After SSRO was applied to three-dimensional mandible models that created by Finite Element Analysis method, the distal segment was advanced 10 mm. Segments were fixed with 4-hole straight miniplate, 4-hole curved miniplate, 6-hole straight miniplate, 6-hole curved miniplate, the new design martin straight miniplate and the martin curved miniplate. Forces were applied to the models from the mastication muscles to simulate bite. The stresses in the mandible and fixation systems and the amount of displacement between the segments were evaluated. Higher maximum stress values were found in the martin miniplates compared to other miniplates. Stress in screws; it was observed that the least stress occurred in the screws used in the fixation of the martin miniplates. In stresses occurring in the cortical and spongious bones, less stress was observed in the models using the martin miniplates. In addition, when the displacement amounts occurring between segments are evaluated; it was found that the least displacement was in models fixed with martin miniplates. Based on the results of this study, using the new design martin miniplates are the most successful fixation technique among the evaluated techniques and compared to the 4-hole and 6-hole miniplates that routinely used in SSRO operations, the less stress deliver to the bone, the more stable it gets.