Hirose Miho, Tanaka Eiji, Tanaka Masao, Fujita Reiji, Kuroda Yukiko, Yamano Eizo, van Eijden Theo M G J, Tanne Kazuo
Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan.
Eur J Oral Sci. 2006 Oct;114(5):441-8. doi: 10.1111/j.1600-0722.2006.00389.x.
In the temporomandibular joint (TMJ), overloading induced by prolonged clenching appears to be important in the cascade of events leading to disc displacement. In this study, the effect of disc displacement on joint stresses during prolonged clenching was studied. For this purpose, finite-element models of the TMJ, with and without disc displacement, were used. Muscle forces were used as a loading condition for stress analysis during a time-period of 10 min. The TMJ disc and connective tissue were characterized as a linear viscoelastic material. In the asymptomatic model, large stresses were found in the central and lateral part of the disc through clenching. In the retrodiscal tissue, stress relaxation occurred during the first 2 min of clenching. In the symptomatic model, large stresses were observed in the posterior part of the disc and in the retrodiscal tissue, and the stress level was kept constant through clenching. This indicates that during prolonged clenching the disc functions well in the asymptomatic joint, meanwhile the retrodiscal tissue in the symptomatic joint is subject to excessive stress. As this structure is less suitable for bearing large stresses, tissue damage may occur. In addition, storage of excessive strain energy might lead to breakage of the tissue.
在颞下颌关节（TMJ）中，长时间紧咬牙引起的过载似乎在导致盘移位的一系列事件中起着重要作用。在本研究中，研究了长时间紧咬牙期间盘移位对关节应力的影响。为此，使用了有和没有盘移位的TMJ有限元模型。在10分钟的时间段内，将肌肉力用作应力分析的加载条件。TMJ盘和结缔组织被表征为线性粘弹性材料。在无症状模型中，通过紧咬牙在盘的中央和外侧部分发现了较大应力。在盘后组织中，紧咬牙的前2分钟内发生了应力松弛。在有症状模型中，在盘的后部和盘后组织中观察到较大应力，并且通过紧咬牙应力水平保持恒定。这表明在长时间紧咬牙期间，盘在无症状关节中功能良好，同时有症状关节中的盘后组织承受过大应力。由于该结构不太适合承受大应力，可能会发生组织损伤。此外，过多应变能的储存可能导致组织破裂。
