Tanne K, Tanaka E, Sakuda M
Department of Orthodontics, Hiroshima University, School of Dentistry, Japan.
J Orofac Pain. 1995 Spring;9(2):153-60.
This study was designed to investigate stresses in the TMJ during clenching in patients with skeletal discrepancies in the vertical direction. A three-dimensional model of the mandible including the TMJ was used for finite element analysis for the stresses. The model, referred to as a standard model, consists of 2,088 nodes and 1,105 solid elements, comprising the cortical and cancellous bones, articular disc and cartilage layer, and periodontal ligament. The standard model was modified by varying the gonial and mandibular plane angles to simulate vertical discrepancies between the maxilla and mandible observed in open and deep bites. Stresses were analyzed on the surfaces of the condyle, the glenoid fossa, and the articular disc, and the values were compared to those found with the standard model. Stresses increased substantially for the condyle, the glenoid fossa, and the articular disc with greater gonial and mandibular plane angles, and those changes were more obvious in association with the divergent mandibular plane. Thus, the nature of stress distributions in the TMJ was substantially affected by vertical discrepancies of the craniofacial skeleton. It is also suggested that these changes in stresses produce a lack of biomechanical equilibrium in the TMJ, which may have some association with temporomandibular disorders.
本研究旨在调查垂直方向骨骼差异患者紧咬牙时颞下颌关节（TMJ）的应力情况。使用包含TMJ的下颌骨三维模型进行应力的有限元分析。该模型称为标准模型，由2088个节点和1105个实体单元组成，包括皮质骨和松质骨、关节盘和软骨层以及牙周韧带。通过改变下颌角和下颌平面角对标准模型进行修改，以模拟开咬和深咬中观察到的上颌和下颌之间的垂直差异。分析髁突、关节窝和关节盘表面的应力，并将这些值与标准模型中的值进行比较。随着下颌角和下颌平面角增大，髁突、关节窝和关节盘的应力大幅增加，且这些变化在下颌平面发散时更为明显。因此，颅面骨骼的垂直差异对TMJ应力分布的性质有显著影响。还表明，这些应力变化会导致TMJ生物力学平衡失调，这可能与颞下颌关节紊乱症有一定关联。
