Mandibular joint dislocation, commonly known as "mandibular ptosis". It is characterized by pain and discomfort in the preauricular joint area and abnormal mandibular movement. After "mandibular descent", it should be reset in time, and the mandibular movement should be limited after reset. Before resetting, the operator should make the patient mentally prepared, the spirit should not be tense, the muscles should be relaxed, and sedatives can be given before resetting if necessary. Both thumbs are obviously dislocated bilaterally or unilaterally, so as to coordinate the force when resetting. There are three commonly used manual reduction methods: intraoral reduction, extraoral reduction and intermaxillary reduction.