Mastication is a vital human function and uses an intricate coordination of muscle activation to break down food. Collection of detailed muscle activation patterns is complex and commonly only masseter and anterior temporalis muscle activation are recorded. Chewing is the orofacial task with the highest muscle forces, potentially leading to high temporomandibular joint (TMJ) loading. Increased TMJ loading is often associated with the onset and progression of temporomandibular disorders (TMD). Hence, studying TMJ mechanical stress during mastication is a central task. Current TMD self-management guidelines suggest eating small and soft pieces of food, but patient safety concerns inhibit in vivo investigations of TMJ biomechanics and currently no in silico model of muscle recruitment and TMJ biomechanics during chewing exists. For this purpose, we have developed a state-of-the-art in silico model, combining rigid body bones, finite element TMJ discs and line actuator muscles. To solve the problems regarding muscle activation measurement, we used a forward dynamics tracking approach, optimizing muscle activations driven by mandibular motion. We include a total of 256 different combinations of food bolus size, stiffness and position in our study and report kinematics, muscle activation patterns and TMJ disc von Mises stress. Computed mandibular kinematics agree well with previous measurements. The computed muscle activation pattern stayed stable over all simulations, with changes to the magnitude relative to stiffness and size of the bolus. Our biomedical simulation results agree with the clinical guidelines regarding bolus modifications as smaller and softer food boluses lead to less TMJ loading. The computed mechanical stress results help to strengthen the confidence in TMD self-management recommendations of eating soft and small pieces of food to reduce TMJ pain.

咀嚼是人类的一项重要功能，它利用肌肉激活的复杂协调来分解食物。详细肌肉激活模式的收集很复杂，通常仅记录咬肌和颞前肌激活。咀嚼是肌肉力量最高的口面部任务，可能导致颞下颌关节 (TMJ) 负荷较高。颞下颌关节负荷增加通常与颞下颌关节紊乱病 (TMD) 的发生和进展有关。因此，研究咀嚼过程中颞下颌关节的机械应力是一项中心任务。目前的 TMD 自我管理指南建议吃小而软的食物，但患者安全问题阻碍了 TMJ 生物力学的体内研究，并且目前不存在咀嚼过程中肌肉募集和 TMJ 生物力学的计算机模型。为此，我们开发了最先进的计算机模型，结合了刚体骨骼、有限元 TMJ 盘和线执行器肌肉。为了解决有关肌肉激活测量的问题，我们使用了前向动力学跟踪方法，优化了下颌运动驱动的肌肉激活。我们的研究中总共包括 256 种不同的食物团大小、硬度和位置组合，并报告运动学、肌肉激活模式和 TMJ 盘 von Mises 应力。计算的下颌运动学与之前的测量结果非常吻合。计算出的肌肉激活模式在所有模拟中都保持稳定，但相对于推注的硬度和大小的幅度发生变化。我们的生物医学模拟结果与有关推注修改的临床指南一致，因为较小且较软的食物推注会导致较少的颞下颌关节负荷。 计算出的机械应力结果有助于增强人们对 TMD 自我管理建议的信心，即吃软的小块食物以减轻 TMJ 疼痛。