There are many reasons for difficulty in opening the mouth, and not just because of long wisdom teeth, long wisdom teeth is one of the reasons, as follows: 1. Many people grow wisdom teeth, is not felt, but wisdom teeth are prone to inflammation, will lead to swelling of the face, face swelling and lead to difficulty in opening the mouth, this is because inflammation provoked the corresponding masticatory muscle groups stimulated by inflammatory exudation, clinical many patients with pericoronitis of the wisdom teeth, due to face swelling and hanging saline, after The tooth is no longer painful, but the mouth cannot be opened. If this situation is delayed for a long time, the patient can only go to the hospital for passive opening training, because the original soft muscles and muscle fibers have been fibrosis provoked by inflammation, resulting in difficulty in opening; 2. Tumor infiltration, which invades the surrounding tissues, such as buccal cancer; 3. Diseases of the joints can also cause restricted opening, such as after the patient has a fracture, a broken end The movement of the condyle is compressed, which can also cause restricted opening; 4, hysteria, i.e., psychiatric disease, such patients imagine that the mouth cannot be opened, and only need to relieve his attention, the mouth can be opened. Therefore, the causes of difficulty in opening the mouth go far beyond pericoronitis of wisdom teeth.