〔摘要〕 目的：观察人体颞下颌关节盘在拉伸和压缩状态下的超微结构改变，探讨机械应力导致关节盘破坏的有关机理。方法：用扫描电镜观察关节盘不同应变水平(2%、3%、4%、6%)拉伸试件及不同时间(150 s，3 h)围限压缩试件的变化。结果：关节盘在2%～4%应变下结构正常，6%应变产生中、后带局部胶原原纤维横向拉伸剪切破坏。150 s压缩，盘表面波纹尚存；3 h压缩，蛋白多糖大量丢失，胶原网暴露，胶原—蛋白多糖网状支架受压变形不能再复原。结论：关节盘可承受的最大横向拉应变为5%(约0.22 MPa拉应力)。持续长时压缩可造成关节盘内部构筑不可复性改变。推测机械因素可能是导致关节盘破坏的重要病理机理。
Response of the human temporomandibular joint (TMJ)disc to mechanical
stress.I. Scanning electronic microscope investigation
Kang Hong,Yi Xinzhu,Xu Xiaochuan,et al.
College of Stomatology,West China University of Medical Sciences,Chengdu,610041
〔Abstract〕 Objective:To observe the ultrastructural changes of the TMJ disc in response to tension and compression and to study the mechanism of disc failure by mechanical stress.Methods:SEM was used to observe the morphologic feature of TMJ disc samples in stress relaxation at different strain rate (2%,3%,4%and 6%)and in compression for 150 seconds and 3 hours.Results:Tensile and shear destruction of local collagen fibrils was observed in intermediate zone (IZ) and posterior band (PB) in the samples in 6% strain.Changes of wave-like structure in the samples treated with 150 seconds compression were reversible;severe deformation of collagen architecture in those with 3-hours compression was irreversible.Conclusion:The maximal physiological tensile strain of the TMJ disc in mediolateral direction may be 5%(nearly 0.22 MPa of tenlile stress).Long-time compression may result in unrecoverable disc fail
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