1.南昌大学第一附属医院口腔科 江西 南昌;2.乌鲁木齐大为创新信息科技有限公司 新疆 乌鲁木齐
目的：利用三维有限元方法比较双侧颞下颌关节盘可复性前移位患者(anterior disc displacement with reduction, ADDWR)在戴入两种不同厚度稳定性咬合板后紧咬时TMJ内等效应力分布改变。方法：根据患者的CT、MRI影像数据,依次构建ADDWR患者牙尖交错位与戴3mm、5mm稳定咬合板咬合时共3个TMJ有限元模型。分别给以最大肌力加载60s后观察3种工况下关节窝、髁突软骨及关节盘表面最大等效应力变化。结果：各工况左侧TMJ内各结构等效应力均大于右侧。戴3mm咬合板后,双侧关节均未发生复位时,关节盘应力仍旧集中在后带及双板区,双侧关节表面应力显著增加；戴入5mm咬合板后,右侧关节盘复位,关节盘最大应力位于中间带,关节窝、髁突软骨和双板区等效应力降低约40%,左侧关节盘未复位,仅关节窝软骨和双板区等效应力稍低于工况一,但关节软骨、双板区最大应力较工况二时下降明显。结论：TMJ负荷与关节盘移位程度呈正比；只有足够厚度的稳定性咬合板对ADDWR患者才具有减轻关节区应力的作用,关节盘复位是减轻ADDWR患者TMJ负荷的关键；当给ADDWR患者选择稳定性咬合板时,保证舒适前提下,尽可能选择较厚的咬合板。
Objective To compare the stress distribution in TMJ for patients withSbilateral anterior disc displacement with reduction after wearing stabilization splints of two different thicknesses during prolonged clenching using finite element models. Methods Three dimensional finite element(FE)models were constructed based on the CT and MRI image data when the patient was biting in maximum intercuspation, on the splint of 3mm and on the splint of 5mm, respectively .Then the stress distributions in the articular disc and cartilages were analyzed after maximal masticatory force loaded to each model for 60s. Results The value of Von Mises stress of each model in the left TMJ was bigger than the right one. When the disc was not reduced after wearing a 3mm splint, the peak of Von Mises stress was located at the posterior band of the disc. The highest stress in TMJ was bigger than the model without a splint；With a 5mm splint on, the right disc was recaptured, the highest von Mises stress was located at the intermediate zone of the disc. The equivalent stress of articular cartilage and bilaminar zone decreased by about 40%. But the left disc was not reduced after wearing a 5mm splint, the equivalent stress of articular cartilage and bilaminar zone was only slightly lower compared with the model without splints. but decreased significantly compared with the model with a 3mm splint. Conclusion TheSloadSon TMJSmay be directly proportional to the degree of articular disc displacement. Only stabilization splints of enough thickness can reduce TMJ stress in ADDWR patients. Disc recapture is a key factor for ADDWR patients to unload TMJ. When selecting a stabilization splint for the treatment of ADDWR patients, choose a thicker one if possible.