Key Laboratory of Biomechanical Engineering of Sichuan Province, Sichuan University, No. 24 South Section 1, Ring Road No.1, Chengdu 610065, China.
Department of Applied Mechanics, Sichuan University, Chengdu 610065, China.
J Biomech Eng. 2020 Dec 1;142(12). doi: 10.1115/1.4047425.
The purpose of this study was to investigate how sagittal split ramus osteotomy (SSRO) and Le Fort 1 osteotomy affected the stress distribution of the temporomandibular joint (TMJ) during an anterior teeth bite using the three-dimensional (3D) finite element (FE) method. Fourteen orthognathic surgery patients were examined with mandibular prognathism, facial asymmetry, and mandibular retraction. They underwent Le Fort 1 osteotomy in conjunction with SSRO. In addition, ten asymptomatic subjects were recruited as the control group. The 3D models of the mandible, disc, and maxilla were reconstructed according to cone-beam computed tomography (CBCT). Contact was used to simulate the interaction of the disc-condyle, disc-temporal bone, and upper-lower dentition. Muscle forces and boundary conditions corresponding to the anterior occlusions were applied on the models. The stresses on the articular disc and condyle in the pre-operative group were significantly higher than normal. The contact stress and minimum principal stress in TMJ for patients with temporomandibular disorder (TMD) were abnormally higher. The peak stresses of the TMJ of the patients under anterior occlusions decreased after bimaxillary osteotomy. No postoperative TMD symptoms were found. Maxillofacial deformity led to excessive stress on the TMJ. Bimaxillary osteotomy can partially improve the stress distributions of the TMJ and relieve the symptoms of TMD.
本研究旨在通过三维（3D）有限元（FE）方法探讨矢状劈开下颌支截骨术（SSRO）和 Le Fort 1 截骨术对口颌畸形患者髁突和关节盘的影响。14 例下颌前突、面部不对称和下颌后缩的正颌手术患者接受了 Le Fort 1 截骨术联合 SSRO。此外，还招募了 10 名无症状的健康人作为对照组。根据锥形束 CT（CBCT）重建下颌骨、关节盘和上颌骨的 3D 模型。使用接触模拟关节盘-髁突、关节盘-颞骨和上下牙列的相互作用。将对应于前牙咬合的肌肉力和边界条件施加到模型上。术前组的关节盘和髁突的接触应力和最小主应力明显高于正常。颞下颌关节紊乱（TMD）患者的 TMJ 接触应力和最小主应力异常升高。双颌骨截骨术后前牙咬合时 TMJ 的峰值应力降低。术后未发现 TMD 症状。颌面部畸形导致 TMJ 承受过大的压力。双颌骨截骨术可部分改善 TMJ 的应力分布，缓解 TMD 症状。
