Tanaka Eiji, Hirose Miho, Koolstra Jan Harm, van Eijden Theo M G J, Iwabuchi Yasunori, Fujita Reiji, Tanaka Masao, Tanne Kazuo
Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan.
J Oral Maxillofac Surg. 2008 Mar;66(3):462-8. doi: 10.1016/j.joms.2007.06.640.
The effect of the frictional coefficient in the temporomandibular joint on the disc during prolonged clenching was examined.
For this purpose, a finite element model of the temporomandibular joint based on magnetic resonance images from a volunteer subject was used. Muscle forces applied for clenching were used as a loading condition for stress analysis during 10 minutes. With respect to the frictional coefficient between articular surfaces, 3 different values ranging from micro = 0.001 to micro = 0.1 were established.
At the onset of clenching, large stresses were found in the central and lateral part of the intermediate zone in the disc, and its stress distribution was not markedly changed during 10 minutes of clenching. In the retrodiscal tissue, stress relaxation occurred during the first 2 minutes of clenching. When the frictional coefficient between articular surfaces increased, the anterior, lateral, and central points in the disc moved further forward. At the end of 10 minutes of clenching, the disc showed a more anterior position as the frictional coefficient increased.
This result indicates that increase of the frictional coefficient between the articular surfaces may be a major cause for the onset of the disc displacement.
研究颞下颌关节摩擦系数在长时间紧咬过程中对关节盘的影响。
为此，使用了基于一名志愿者受试者磁共振图像构建的颞下颌关节有限元模型。将紧咬时施加的肌肉力用作10分钟应力分析的加载条件。关于关节面之间的摩擦系数，设定了3个不同的值，范围从μ = 0.001到μ = 0.1。
紧咬开始时，在关节盘中间带的中央和外侧部分发现较大应力，且在10分钟紧咬过程中其应力分布无明显变化。在盘后组织中，紧咬的前2分钟出现应力松弛。当关节面之间的摩擦系数增加时，关节盘中的前、外侧和中央点向前移动得更远。在紧咬10分钟结束时，随着摩擦系数增加，关节盘显示出更靠前的位置。
该结果表明关节面之间摩擦系数的增加可能是关节盘移位发生的主要原因。
