Correlation of condylar mobility and arthrotomography in patients with internal derangements of the temporomandibular joint

Arthrography of the temporomandibular joint is a useful method of demonstrating the tissue abnormalities related to disc dysfunction. In this study, 19 asymptomatic joints, 31 joints with anterior disc displacement with reduction, 31 joints with anterior disc displacement without reduction which were classified by arthrotomography under fluoroscopy were evaluated to determine the linear measurement of anterior recess of inferior joint space and the relationship between the condylar anterior translation and the severity of the internal derangements. Their fluoroscopic images were also evaluated to describe the characteristics of condylar paths in internal derangements of the temporomandibular joints. The results were as follows; 1. The mean lengths of the anterior recess in asymptomatic group, reduction group, and non-reduction group were 8.7 ± 1.6 mm, 11.2 ± 1.7 mm, 12.8 ± 1.7 mm respectively. The length of the anterior recess was increased according to the severity of the internal derangements (P<0.05). 2. Linear measurements if anterior movement of condyle on maximum mouth opening were 13.1 ± 4,2 mm, 15.9 ± 4,1 mm, 5.0 ± 3.7 mm in asymptomatic group, reduction group, and non-reduction group respectively. Compared with asymptomatic group, reduction group showed hypermobility of the condyle and not-reduction group showed hypomobility. 3. Condyles moved beyond the crest of articular eminence in 80% of reduction group and did not it in 70% of not-reduction group. 4. The condyle moved mainly superiorly in reduction group (66%)and horizontally in asymptomatic group (47%). There were no cases to move superiorly in not-reduction group.