Objective: The possible relationship between internal derangement (ID) and facial asymmetry (FA) has been discussed. Methods: To evaluate the structural characteristics of the condyle in FA patients, 37 subjects (74 joints) were investigated with magnetic resonance imaging (MRI). The temporomandibular joints were classified into normal, anterior disc displace with reduction (ADDR) and without reduction (ADDNR) groups. Axial condylar morphology and horizontal condylar angle were evaluated on axial scanning of MRIs. Condylar spatial and osseous characteristics were measured on sagittal scans in maximum closed and maximum open positions. Differences between TMJs of different DD groups and bilateral sides were analyzed by non-parametric U-tests.
Results: Axial condyle morphology shows statistical difference in different DD groups but no difference was detected between the shifting and the contra side. In the sagittal plane, only condylar angulation was found to be different between the shifting side and the contra side. The condyles of different DD diagnostic groups were found to be significantly different on horizontal position and horizontal translation distance. No differences were found in translation and rotation angle. Condylar bony changes including flattening, erosion and osteophytosis were assessed. 67% of the patients have no condylar bony changes. However, there are relatively more patients with unilateral bony change than bilaterally. The condyle of normal disc status mainly shows no condylar bony change, while that of ADDNR shows more severe osseous change. Bilateral difference of bony change type was not found in this sample.