Several imaging techniques occasionally contribute to correct diagnosis of temporomandibular joint (TMJ) diseases or disorders. Panoramic radiography may play an important role clinically owing to its universal use in dental clinics. However, there have been few reports on panorama image reading of TMJ diseases. The present paper reports on typical panorama images and findings of TMJ diseases or disorders including: 1) osteoarthritis of TMJ, 2) trauma, 3) ankylosis of TMJ, 4) hyperplasia of tendon and aponeurosis of masticatory muscles, 5) synovial chondromatosis of TMJ, and 6) calcification or ossification surrounding the mandibular condyle. These diseases were selected by the following criteria for whether CT and/or MRI seemed to be useful for the diagnosis and the frequency of encounter was probably not so low. CT and MRI findings are also described and contrasted with panorama image findings. Feedback from CT and MRI images to panorama images is expected to improve understanding of panorama image findings and the precision of detecting TMJ diseases by panoramic radiography.

Multiple factors are involved in the onset of temporomandibular disorder (TMD) including sleep disorder, although the precise nature of the relationship remains unknown. We studied the correlation of TMD with sleep disorder in TMD patients, especially those with masticatory muscle pain, using a questionnaire. The subjects were 40 female TMD patients with masticatory muscle pain who visited our department for consultation between April 1, 2015 and March 31, 2016, and 30 female subjects without TMD symptoms (control group). Masticatory muscle pain was assessed using the Japanese version of the Pittsburgh Sleep Quality Index (PSQI-J). The items investigated were "masseter tenderness", "pain on opening the jaw", "maximum unassisted pain-free jaw opening", and "interference with daily life". The PSQI-J score was significantly higher in the TMD group. As for significant correlations between TMD symptoms and items on the PSQI-J, "masseter tenderness" showed a correlation with "sleep quality" (p = 0.036) and "sleep-onset time" (p = 0.009), "interference with daily life" was correlated with "sleep duration" (p = 0.021), and both "pain on opening the jaw" (p = 0.026) and "masseter tenderness" (p = 0.024) were correlated with "use of a soporific". Moreover, in the TMD group, a correlation was observed between the total PSQI-J score and "masseter tenderness" (p = 0.003). Our results suggested strongly that bruxism, possibly caused by sleep disorder, was correlated with TMD development, especially masticatory muscle pain, in affected patients.