The role of passive muscle tensions in a three-dimensional dynamic model of the human jaw
The role of passive muscle tensions in a three-dimensional dynamic model of the human jaw
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DOI：
10.1016/s0003-9969(99)00034-5
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发表时间：
1999-07-01
影响因子：
3
通讯作者：
Hannam, AG
中科院分区：
文献类型：
--
作者：
Langenbach, GEJ;Hannam, AG
被动肌肉张力在人类下颌功能中的作用在很大程度上是未知的。这似乎是合理的假设，被动肌肉紧张性能优化的多种生理任务的下巴在体内执行。然而，下颌肌肉的不可接近性是测量其被动张力和了解其影响的主要障碍。计算机建模提供了一种替代方法来做到这一点。在这里，一个三维的，动态模型被用来预测主动和被动的下颌肌肉紧张，在模拟姿势休息，下巴打开和咀嚼。该模型包括一个刚性下颌骨，两个颞下颌关节，多个牙齿咬合点，以及位于右第一磨牙之间的人工食物团。它由18个代表9对下颌肌肉的Hill型致动器驱动。模型中使用的所有解剖形式、位置和属性均基于先前发表的平均值。两种状态被刺激，一种状态是当切牙相距2 mm时（S2），闭合肌肉中长度-张力曲线的所有最佳长度被定义为它们的纤维成分长度，另一种状态是将最佳长度设置为12.0 mm的切间间隔（S12）。在休息时，SZ和S12的钳口达到3.6 mm的切间分离。在各种组合中，下翼外肌（ILP）和二腹肌（DG）的激活总是引起被动的下颌闭合张力和压缩髁状突载荷。S2和S12的最大中线间隙（来自DG和ILP的最大双侧共同激活）分别为16.2 mm和32.0 mm。当这两个模型的状态被驱动与肌肉模式典型的人类咀嚼，可识别的单边和垂直的“切碎”咀嚼周期。两种状态均显示在咀嚼的打开和关闭阶段的髁突负荷。单侧咀嚼时，工作侧髁突的压力大于平衡侧。相反，在“斩波”周期，平衡侧的负载大于工作侧。在S2中，咀嚼在垂直和横向方向上都受到限制。这些结果表明，S12中使用的假设比S2中的假设更接近人类行为。尽管它的局限性，建模似乎提供了一个有用的概念框架，为发展假设肌肉紧张的作用，在人类颌骨功能。(C)1999爱思唯尔科技有限公司。保留所有权利。
The role of passive muscle tensions in human jaw function are largely unknown. It seems reasonable to assume that passive muscle-tension properties are optimized for the multiple physiological tasks the jaw performs in vivo. However, the inaccessibility of the jaw muscles is a major obstacle to measuring their passive tensions, and understanding their effects. Computer modelling offers an alternative method for doing this. Here, a three-dimensional, dynamic model was used to predict active and passive jaw-muscle tensions during simulated postural rest, jaw opening and chewing. The model included a rigid mandible, two temporomandibular joints, multiple dental bite points, and an artificial food bolus located between the right first molars. It was driven by 18 Hill-type actuators representing nine pairs of jaw muscles. All anatomical forms, positions and properties used in the model were based on previously published, average values. Two states were stimulated, one in which all optimal lengths for the length-tension curves in the closing muscles were defined as their fibre-component lengths when the incisor teeth were 2 mm apart (S2), and another in which the optimal lengths were set for a 12.0 mm interincisal separation (S12). At rest, the jaw attained 3.6 mm interincisal separation in SZ, and 14.8 mm in S12. Activation of the inferior lateral pterygoid (ILP) and digastric (DG) muscles in various combinations always induced passive jaw-closer tensions, and compressive condylar loads. Maximum midline gape (from maximum bilateral co-activation of DG and ILP) was 16.2 mm in S2, and 32.0 mm in S12. When both model states were driven with muscle patterns typical for human mastication, recognizable unilateral and vertical "chopping" chewing cycles were produced. Both states revealed condylar loading in the opening and closing phases of mastication. During unilateral chewing, compressive force on the working-side condyle exceeded that on the balancing side. In contrast, during the "chopping" cycle, loading on the balancing side was greater than that on the working side. In S2, chewing was limited in both vertical and lateral directions. These results suggest that the assumptions used in S12 more closely approximated human behaviour than those in S2. Despite its limitations, modelling appears to provide a useful conceptual framework for developing hypotheses regarding the role of muscle tensions during human jaw function. (C) 1999 Elsevier Science Ltd. All rights reserved.