Effect of Disc Position for Acute Closed Lock of the Temporomandibular Joint

In this manuscript, the authors have studied the Disc Displacement (DD) status of patients with acute Closed Lock (CL) to determine differences between DD with Reduction (DDwR) and DD without Reduction (DDwoR). Among the acute CL patients who visited our hospital within 2 weeks of the onset of CL, we studied 10 patients whose CL was released (DDwR) and 13 patients whose CL was not released (DDwoR). The DDwoR group was significantly older than the DDwR group. Although the mouth opening distance was significantly greater in the DDwoR group than in the DDwR group, the two groups were identical in the duration of CL. Sagittal MRI images showed no significant differences between the two groups in disc length and disc thickness (anterior band, intermediate zone, and posterior band). Multisection sagittal and coronal images identified lateral DD in 7 of the 10 patients in the DDwR group, although no specific direction of the DD was observed in the DDwoR group. Furthermore, deformation of the medial disc was common in the DDwoR group but uncommon in the DDwR group.