Abstract

A prominent mandibular angle produces a characteristic quadrangle with a coarse appearance. Asians prefer getting the shape of their jaws surgically corrected into a V-line, which is assumed to give a more intelligent, beautiful, and delicate appearance. According to many studies, mandibular contouring surgery may jeopardize mechanical stability. The aim of this study was to analyse the stress on the mandible during function after mandibular contouring surgery using finite element analysis. Based on computed tomography scans, the three-dimensional models of preoperative mandible, mandibular angle ostectomy, and sagittal cortical ostectomy of the mandibular ramus and body with angle ostectomy were obtained. Boundary conditions to restrict movement on both condyles and clenching tasks (incisal clench, right molar clench, and right group clench) were simulated. The sagittal cortical ostectomy model had the highest strain energy (48.51 J) and von Mises stress (77.39 MPa) during the right molar clench task. The maximum von Mises stress on the sagittal cortical ostectomy was increased by up to approximately four times compared with the cases of preoperative mandible. The stress was concentrated at the site of operation, mandibular condyle, and angle. In the case of the sagittal cortical ostectomy model, bone resorption may occur, and there is a possibility of fracture during the right molar clench task. These results suggest that mandibular contouring surgery may be related to the fragility of the mandible, since surgery significantly alters its biomechanics. The degree of surgery may be a determining factor in the stress and fracture risk of the mandible. Therefore, clinicians should establish an accurate and correct treatment plan for the safe prognosis of patients after surgery.

中文翻译：

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下颌轮廓手术对各种紧握任务过程中应力分布的影响

摘要

下颌角突出会产生具有粗糙外观的特征四边形。亚洲人更喜欢通过手术将颌骨的形状矫正为V形线，这被认为具有更聪明，美丽和精致的外观。根据许多研究，下颌轮廓手术可能会损害机械稳定性。本研究的目的是使用有限元分析法分析下颌轮廓手术后下颌骨在功能过程中的应力。基于计算机体层摄影术扫描，获得了术前下颌骨，下颌角骨造口术和下颌骨和体的矢状皮质骨造口术以及角膜成骨术的三维模型。限制con突和咬合任务移动的边界条件（切牙咬合，右磨牙咬合，和右组握紧）进行了模拟。在正确的磨牙咬合任务中，矢状皮质骨切除术模型具有最高的应变能（48.51 J）和von Mises应力（77.39 MPa）。与术前下颌骨的情况相比，矢状皮质切开术的最大冯·米塞斯应力增加了大约四倍。应力集中在手术部位，下颌con和角。在矢状皮质骨切除术模型的情况下，可能发生骨吸收，并且在正确的磨牙咬合任务期间可能发生骨折。这些结果表明，下颌轮廓手术可能与下颌骨的脆弱性有关，因为手术会显着改变其生物力学。手术程度可能是下颌骨应力和骨折风险的决定因素。所以，