Effects of several temporomandibular disorders on the stress distributions of temporomandibular joint: a finite element analysis.

The aim of this study was to evaluate stress distributions in the temporomandibular joints (TMJs) with temporomandibular disorders (TMDs) for comparison with healthy TMJs. A model of mandible and normal TMJs was developed according to CT images. The interfaces between the discs and the articular cartilages were treated as contact elements. Nonlinear cable elements were used to simulate disc attachments. Based on this model, seven models of various TMDs were established. The maximum stresses of the discs with anterior, posterior, medial and lateral disc displacement (ADD, PDD, MDD and LDD) were 12.09, 9.33, 10.71 and 6.07 times magnitude of the identically normal disc, respectively. The maximum stresses of the posterior articular eminences in ADD, PDD, MDD, LDD, relaxation of posterior attachments and disc perforation models were 21, 59, 46, 21, 13 and 15 times greater than the normal model, respectively. TMDs could cause increased stresses in the discs and posterior articular eminences.