Mandibular disorders are related to the following factors: 1. Long-term loss of multiple teeth causes the habit of chewing on the lateral side, which causes asymmetric wear of the temporomandibular joint and symptoms such as skewed mouth opening and jaw movement disorders. 2. The presence of twisted teeth, misaligned teeth and misalignment in the dental row can form a misaligned occlusal relationship and induce mandibular dysfunction. 3. Mental tension, lack of sleep or habits such as clenching and night grinding of teeth. The masticatory muscle group is in spasm for a long time, which will easily lead to mandibular disorder.4. The occurrence of trauma that damages the temporomandibular joint, or the occurrence of misaligned bite due to fractured teeth in the mandible, will cause disorder of the mandible.