Irrigation of the temporomandibular joint (TMJ), arthrocentesis, has been clinically applied for a long time as the first-choice surgical treatment in patients with temporomandibular disorders (TMD) that are resistant to non-surgical treatments. Its main indication is so-called TMJ closed lock which histopathologically consists of synovitis and osteoarthritis with disc deformity and anterior displacement. In the synovium and synovial fluid of TMJs with the above-mentioned pathologies, various pro-inflammatory mediators have been detected, and it is suggested that they affect the hypoviscosity of the synovial fluid and degenerative changes of the articular cartilage and bone. Consequently, the therapeutic efficacy of arthrocentesis is considered to be mainly brought through the washout of pro-inflammatory mediators in the synovial fluid. On the other hand, we have considered that supplemental intra-articular injection of hyaluronic acid, steroidal drugs, or platelet-rich plasma immediately after arthrocentesis could enhance its clinical outcome. However, the usefulness of supplemental injections has been controversial. Incidentally, the success rate of arthrocentesis is approximately 70-85%. Even in patients who have undergone a successful arthrocentesis, one of the main causative factors for TMD, such as bruxism and/or teeth contacting habit, does not always disappear, and the continuation of intra-articular inflammation has been biochemically and arthroscopically suggested. Even after successful TMJ irrigation, therefore, continuous practice of relaxation, massage, and stretching (maximal mouth opening) of the masticatory muscles is considered to be extremely important to prevent flare-up of TMD symptoms.

Cognitive behavioral therapy is evidence-based psychotherapy, and is the first choice for treatment for mental disorders such as depression and anxiety. Based on research and clinical experience of cognitive behavioral therapy, this paper describes three topics for temporomandibular disorder (TMD) Axis II (psychosocial factors). First, low-intensity cognitive behavioral therapy is recommended for patients with TMD who also have common mental disorders such as depression or anxiety. Second, practitioners consider cognitive behavioral therapy for chronic pain in patients with TMD. Third, 5-minute cognitive behavioral therapy such as the "three good things exercise" from one of the positive psychology interventions or a habit reversal treatment might be used for patients with TMD.

Among condylar head fractures, the level of fracture of the condyle process may present difficulties in deciding whether to pursue conservative or surgical treatment. However, conservative treatment can neither restore the temporomandibular joint morphology nor ease the restriction of lateral movement. A number of reports have described good results by reduction and fixation using a mini plate or lag screw for condylar head fractures. We performed surgical treatment using the lag screw for condylar head fractures at our hospital from 2014 to 2021 (6 cases, 7 TMJs). The postoperative mouth opening was 44.1 mm on average. Postoperative joint noise (click or crepitus) was observed in one joint per case. In addition, the mandibular deviation during mouth opening was observed in one joint per case. These findings suggest that bone fixation with the lag screw can produce good results in patients with mandibular condyle head fractures.

Temporomandibular joint (TMJ) dislocation is generally caused by excessive mouth-opening or trauma, but in rare cases it can be caused by cerebrovascular disease. We report a case of TMJ dislocation that occurred as the first symptom of a brain infarction. The patient, an 82-year-old female, experienced a lacunar infarction of the right capsule in November 2014, and her primary doctor followed it up. In July 2019, when she was yawning, she had difficulty closing her mouth and visited the emergency department of a general hospital. A dislocation of the right TMJ was confirmed on computed tomography (CT), and although manipulative reduction was performed, the dislocation recurred so she visited our hospital the same day for further examination. During her initial visit, the right mandibular condyle was repositioned, and CT showed no abnormal findings in the right TMJ. However, after returning home she began to exhibit gait disturbance, so she visited the Department of Neurology at a general hospital the next day. A close examination revealed a subacute cerebral infarction from the left corona radiata to the posterior limb of the internal capsule and paralysis of the right upper and lower limbs. The patient was admitted, and antithrombotic therapy was administered. Since dislocation of the right TMJ was frequently observed during the patient's hospitalization, manipulative reduction was performed each time, and mouth-opening was suppressed with a chin cap for 10 days after the last dislocation. The patient passed away 2 years and 11 months after onset due to the progression of other diseases, but further dislocation was not observed. In the acute phase of a cerebral infarction, the muscle tension related to TMJ support and movement is reduced, which may be a factor in triggering TMJ dislocation. Therefore, clinicians should be aware that TMJ dislocation may be a sign of cerebrovascular disease.