Comparison of magnetic resonance imaging findings in patients with intermittent closed lock and acute closed lock of the temporomandibular joint: a cross-sectional retrospective study.

Objective: This study aimed to estimate the disc status in intermittent closed lock (ICL) and permanent closed lock (CL) temporomandibular disorders (TMDs) to test the hypothesis that the disc morphology and degree of anterior disc displacement affect the outcomes of these disorders.

Materials and methods: All patients were clinically examined according to the Diagnostic Criteria for Temporomandibular Disorders Axis I protocol, and magnetic resonance imaging (MRI) confirmed ICL and CL. Fifty-six joints of 56 patients with ICL and 110 joints of 110 patients with acute CL with a locking period of less than 3 months were included. Patients with acute CL were further classified into two groups: those with CL that could be successfully manipulated (CLs group) and those with acute CL without the possibility of unlocking (CLu group). MRI was used to assess the degree of anterior displacement, lateral displacement of the disc, disc deformity, and joint effusion. MRI findings were compared among the joints in the ICL, CLs, and CLu groups.

Results: The degree of anterior displacement and disc deformity prevalence significantly differed among the ICL, CLs, and CLu groups. No significant intergroup differences were observed in terms of lateral displacement or joint effusion.

Conclusions: These results suggest that anteriorly displaced discs and deformation of discs associated with TMD progression affect disc reducibility.