Abstract: PURPOSE : To summarize the clinical and imaging characteristics of idiopathic condylar resorption (ICR) and investigate the pathogenic factors and susceptible factors of ICR. METHODS : Forty-six ICR patients were included who were treated between 2007 and 2012. The clinical data was collected. The facial type, condition of TMJ and occlusion were recorded. On X-ray films, the ramus height, destruction of condyle, craniofacial features were evaluated. Correlation between condylar resorption and the position relationship between the disc and the condyle were assessed by arthrography with Cone-beam CT (CBCT). RESULTS : Idiopathic condylar resorption often occurred in females (42 cases, 91.30%) and teenagers. The patients had a common facial morphology including skeletal and occlusal high-angle Class II deformity, anterior open bite, high occlusal plane angle and mandibular plane angle, progressively retruding mandible. The patients always had TMJ symptoms, such as joint sound. X-ray film showed extreme thinness or loss of continuity of cortical bone on the head of the condyle and vertical height of the ramus decreased. TMJ disc perforation could be observed by arthrography with CBCT. The position of perforation was always on the posterior of disc. CONCLUSIONS : ICR has its own unique pathogenesis and clinical features. There is correlation between TMJ disc displacement and ICR, Disc displacement may reinforce and promote ICR, and vice versa.

Key words: Temporomandibular joint, Condyle, Idiopathic resorption, Disc perforation