Relationship between Degenerative Bone Changes of Condylar Surface and Articular Disc Disorders in Symptomatic Osteoarthrosis of Temporomandibular Joints

AbstractPurpose: We investigate the relation of bone changes of the condylar surface to disc displacement and discuss the development of joint symptoms in osteoarthrosis of temporomandibular (TM) joints.Subjects and Methods: Seventy‐seven patients with an image diagnosis of degenerative bone changes of the unilateral condylar surface accompanied with joint symptoms were studied. The bone changes were assessed by panoramic radiographs and classified into two groups: pathologic bone changes (PBC) including erosion, osteophyte and deformity, and adaptive bone changes (ABC) including flattening and concavity. Magnetic resonance imaging was performed on the subjective TM joints to examine the configuration and position of articular discs. A visual analogue scale was used for evaluation of joint pain.Results: Erosion and deformity showed significantly higher prevalence than the other three kinds of bone changes in the joints with anterior disc displacement without reduction (ADWoR) as compared to those with anterior disc displacement with reduction (ADWR). The cases with the vertical disc position to the condyle ranging from 60° to less than 150° were more frequent than those ranging from 0° to less than 60° in the PBC group, whereas the cases with the vertical disc position to the condyle ranging from 0° to less than 6° were more frequent than those ranging from 60° to less than 150° in the ABC group. The average degree of joint pain when chewing but not jaw opening was higher in the joints with ADWoR than in those with ADWR, and in the PBC group than in the ABC group.Conclusion: The bone changes of the condylar surface diagnosed as PBC tended to induce more advanced disc displacement and chewing pain than those diagnosed as ABC.