Investigating the intrinsic factors related with anterior disc displacement in temporomandibular disorder: a preliminary MRI study

To observe the structure of temporomandibular joint (TMJ) in patients with TMD by magnetic resonance imaging (MRI), and to investigate the related factors of anterior disc displacement in patients with TMD.Which were classified into TMD without displacement group (97 TMJs), anterior displacement (147TMJs, including anterior displacement with reduction 69 TMJs and without reduction 78 TMJs), the observed variables were focused on the bone structures of TMJ ( the depth, the anteroposterior diameter, the index of TMJ fossa, the morphology, location, medial-lateral diameter, anteroposterior diameter and the index of TMJ condyle) and the other structures indexes involved in the temporomandibular movement (mouth opening movement range, soft tissue of bilaminar region, superior band of the bilaminar zone, morphology and signal of the lateral pterygoid muscle(LPM), joint effusion, osteoarthritis). The three groups were subjected to one-way analysis of variance and chi-square test, while binary logistic regression analysis was employed to establish a regression model and construct the receiver operating characteristic curve. The present study demonstrated that various structural and clinical factors, particularly the altered bone structure of the TMJ, hypertrophy of the LPM, and joint effusion, significantly contribute to the ADD in patients with TMDs.