The Differences Of The Temporomandibular Joint Anterior Disc Displacement With Reduction On Magnetic Resonance Imaging

Objectives:The study is to assess the changes in disc position relative to the condyle, disc morphology, and joint effusion with magnetic resonance imaging of the temporomandibular joint anterior disc displacement with reduction to provide useful information regarding early finding of anterior disc displacement which needs treatment.Method:25patients (30side joints) with anterior disc displacement with reduction were collected. A detailed medical history record and TMJ specialized examination were done at first visit, and oblique coronal and sagittal T2and PD weighted MR imaging at open and closed mouth was obtained. According to patients’ feeling and specialized examination results, TMJs were divided into two groups:click and pain group (A group) and asymptomatic group (B group). The angle between disc position and the condyle at closed mouth were measured and recorded disc morphology and joint effusion. SPSS20.0software is used to do T-Test and Fisher’s exact test.Result:Joint effusion presented in both groups, and there was a significant correlation between them. A group has a higher incidence (P=0.025) and moderate joint effusion is more common (P=0.032).The angle of disk anterior displacement in A group is52.56±15.5°, while in B group is36.62±10.9°. There was a significant statistical difference between the angle among these two group (P<0.05). Although disc morphology change is more common in A group, there were no significant differences (P=0.427). In TMJ with anterior disc displacement with reduction, there was a higher prevalence of lengthened discs (47.6%) and thick posterior band (28.6%).Conclusion:It can be concluded that clinical symptoms are associated with joint effusion and the degree of anterior disk.