Abstract: PURPOSE: To introduce a classification of recurrent anterior dislocation of temporomandibular joint(TMJ) based on MRI by analyzing relative position of TMJ disc and condylar; and summarize the experience of different therapeutic methods. Methods: MRI data of 45 patients who suffered from recurrent anterior dislocation of TMJ treated in our hospital during May 2003 to May 2016 were collected. On the basis of MRI findings, four categories were proposed, namely type Ⅰ: proper disc position, type Ⅱ: anterior disc displacement,type Ⅲ: osteoarthritis and type Ⅳ with mental disorders. Different treatments were conducted for different types of lesions. Results: TypeⅠ included 28 cases(62.2%), type Ⅱ included 12 cases(26.7%), type Ⅲ included 2 cases(4.4%) and type Ⅳ included 3 cases(6.7%). Type I was treated for either articular tubercle augmentation or arthroscopic sclerotherapy. Type Ⅱ was treated with TMJ disc reduction and fixation (anchoring), and arthroscopic disc reduction and fixation, assisted with TMJ tubercle enhancement. Type Ⅲ was treated according to clinical symptoms of patients. Type Ⅳ was treated using chiseling of the eminence. During the follow-up period, mouth opening limitation, pain, and dislocation recurrence were not present. Conclusions: The classification of TMJ dislocation based on the features of MRI imaging is instructive for surgeons to make appropriate treatment plan.

Key words: Temporomandibular joint, Recurrent anterior dislocation, Classification, MRI