Unilateral Finite Element Modeling And Biomechanical Analysis Of Temporomandibular Joint Disc Anchorage

Objective: To establish a model of one sided ADDwo R and a model of TMJ disc anchorage,and to compare and analyze the biomechanical changes of bilateral TMJ disc and condyle before and after surgical treatment and their effects.Methods: Among the patients with temporomandibular joint disease and related diseases who were admitted to the Department of Oral and Maxillofacial Surgery of our hospital from December 2018 to June 2020,50 patients meeting the criteria were selected according to the inclusion and exclusion criteria,including 17 males and 33 females,aged between12 and 42 years,with an average age of(22.65±7.71)years.There was also a healthy volunteer.Medical finite element software was used to compare the model of unilateral ADDWo R with the model of DA.The changes of articular disc and condylar process in different models were analyzed from the perspective of biomechanics.Results: In the preoperative model,the maximum stress of the pathological articular disc was located in the lateral intermediate region,and the maximum contact stress and contact area of the lower interface of the articular disc were greater than that of the upper interface.The maximum contact stress occurred between the anterior inclined plane of the condylar process and the lower surface of the middle area of the articular disc,and between the upper surface of the middle area of the articular disc and the posterior inclined plane of the articular nodules.Compared with the preoperative and postoperative models,the maximum von Mises stress calculated in the joint disc of the healthy side before surgery was 0.265 MPa,and the maximum von Mises stress calculated in the joint disc of the affected side was 0.568 MPa.In the postoperative model,the calculated maximum von Mises stress was 0.146 MPa in the articular disc of the uninjured side and 0.294 MPa in the articular disc of the affected side.Compared with the preoperative model,the maximum Von-Mises stress was reduced by 44.90%.The affected side was reduced by 48.24%.In the preoperative model,the calculated maximum stress of condylar bone on the healthy side was 0.438 MPa,and the calculated maximum stress of condylar bone on the affected side was 0.764 MPa.In the postoperative model,the stress on the condylar bone on the healthy side was calculated to be 0.365 MPa,and the maximum stress on the condylar bone on the affected side was calculated to be 0.621 MPa.Compared with the condylar stress of the preoperative and postoperative model,the stress of the postoperative model of the affected side was 18.72% lower than that of the preoperative model.The healthy side was reduced by 16.67%.Conclusions:(1)When the unilateral ADDWOR,both the articular disc and condyle bone of the patient were in a state of stress imbalance.(2)Unilateral ADDWOR can increase the load on the joint disc and condyle of the contralateral natural joint.(3)Comparison of preoperative and postoperative models showed that unilateral articular disc anchorage significantly improved the loading state of bilateral joint disc and the loading state of the upper condylar process,suggesting that DA can effectively treat unilateral ADDWOR.