Korioth T W, Hannam A G
Department of Oral Biology, University of British Columbia, Faculty of Dentistry, Vancouver, Canada.
J Prosthet Dent. 1990 Jul;64(1):62-73. doi: 10.1016/0022-3913(90)90154-5.
The effects of balancing-side tooth contacts on temporomandibular joint loads are unclear. We used a 3-D computer model to calculate the magnitude and direction of temporomandibular reaction forces during simulated clenching on interocclusal acrylic resin shims and between natural teeth. Muscle tensions were proportioned according to the task modeled. Working-side tooth contacts included the canine alone, as well as group function, and occlusal loads were progressively shifted toward a posterior contralateral simple balancing contact. In the acrylic resin shim experiments, group function with simple balancing contact yielded the highest forces at the load point and at both temporomandibular joints. Movement of the occlusal load toward the balancing side produced greater, anteriorly oriented forces on the working condyle. For natural teeth, changes in the angle of resultant tooth force (simulating facet angulation) greatly influenced condylar forces. As the occlusal load moved toward the balancing side, greater and more laterally oriented forces were produced on the balancing condyle. Unilateral clenching on the canine produced the least condylar and bite forces. The simulation involving natural teeth offers a possible explanation for deviations in form and osteoarthrosis at the temporomandibular joints.
平衡侧牙齿接触对颞下颌关节负荷的影响尚不清楚。我们使用三维计算机模型来计算在模拟紧咬咬合间丙烯酸树脂垫片以及天然牙之间时颞下颌反作用力的大小和方向。肌肉张力根据模拟任务按比例设定。工作侧牙齿接触包括仅尖牙接触以及组牙功能接触，并且咬合负荷逐渐向对侧后方的简单平衡接触转移。在丙烯酸树脂垫片实验中，组牙功能与简单平衡接触在负荷点以及两个颞下颌关节处产生的力最大。咬合负荷向平衡侧移动会在工作髁突上产生更大的、向前的力。对于天然牙，合成牙齿力的角度变化（模拟小平面角度）极大地影响髁突力。随着咬合负荷向平衡侧移动，在平衡髁突上会产生更大且更偏向外侧的力。单侧紧咬尖牙产生的髁突力和咬合力最小。涉及天然牙的模拟为颞下颌关节形态偏差和骨关节炎提供了一种可能的解释。
