Clenching of the teeth is one of the mild forms of oromandibular dystonia, which is a condition in which the muscles contract excessively, resulting in abnormal posture of a part of the body. This is one of the disorders that cause the masticatory muscles to contract continuously and prevent the jaw from opening normally, even to the point of opening the mouth less than one finger across, making it impossible for the patient to chew and eat normally, often combined with vocal difficulties, slurred speech or combined with muscle spasms and contractions in the eyelids. It is often associated with emotional anxiety, depression, nervousness and stress, which leads to an imbalance of excitation and inhibition processes in the cerebral cortex and induces irregular spasms or contractions of the masticatory muscle movements. Currently, the preferred treatment is the application of botulinum toxin for local injection treatment of the masticatory muscle, which serves to reduce the pathological state of involuntary contraction of the masticatory muscle.