Total temporomandibular joint replacement (TMJR) surgery is the established treatment for severe temporomandibular joint disorders. While TMJR surgery is known to increase mouth-opening capacity, reduce pain and improve quality of life, little is known about post-surgical jaw function during activities of daily living such as biting and chewing. The aim of this study was to use subject-specific 3D bite force measurements to evaluate the magnitude and direction of joint loading in unilateral total TMJR patients and compare these data to those in healthy control subjects. An optoelectronic tracking system was used to measure jaw kinematics while biting a rubber sample for 5 unilateral total TMJR patients and 8 controls. Finite element simulations driven by the measured kinematics were employed to calculate the resultant bite force generated when compressing the rubber between teeth during biting tasks. Subject-specific musculoskeletal models were subsequently used to calculate muscle and TMJ loading. Unilateral total TMJR patients generated a bite force of 249.6 ± 24.4 N and 164.2 ± 62.3 N when biting on the contralateral and ipsilateral molars, respectively. In contrast, controls generated a bite force of 317.1 ± 206.6 N. Unilateral total TMJR patients biting on the contralateral molars had a significantly higher lateral TMJ force direction (median difference: 63.6°, p = 0.028) and a significantly lower ratio of working TMJ force to bite force (median difference: 0.17, p = 0.049) than controls. Results of this study may guide TMJ prosthesis design and evaluation of dental implants.

全颞下颌关节置换术（TMJR）手术是治疗严重颞下颌关节疾病的既定治疗方法。虽然众所周知，TMJR 手术可以增加张口能力、减轻疼痛并改善生活质量，但人们对术后咬和咀嚼等日常生活活动中颌骨的功能知之甚少。本研究的目的是使用受试者特定的 3D 咬合力测量来评估单侧总 TMJR 患者关节负荷的大小和方向，并将这些数据与健康对照受试者的数据进行比较。使用光电跟踪系统测量 5 名单侧 TMJR 患者和 8 名对照者咬橡胶样本时的下颌运动学。采用由测量的运动学驱动的有限元模拟来计算在咬合任务期间压缩牙齿之间的橡胶时产生的咬合力。随后使用受试者特定的肌肉骨骼模型来计算肌肉和颞下颌关节负荷。单侧 TMJR 患者在咬合对侧和同侧磨牙时产生的咬合力分别为 249.6 ± 24.4 N 和 164.2 ± 62.3 N。相比之下，对照组产生的咬合力为 317.1 ± 206.6 N。咬合对侧磨牙的单侧总 TMJR 患者的外侧 TMJ 力方向显着较高（中位差：63.6°，p  = 0.028），而工作 TMJ 比率显着较低力与咬合力的比值（中位差：0.17，p  = 0.049）高于对照组。这项研究的结果可以指导颞下颌关节假体的设计和牙种植体的评估。