The teeth are innervated by the maxillary and mandibular branches of the trigeminal nerve. The trigeminal nerve travels a short and hidden distance in the neck and is not usually affected by cervical spine degeneration, so most cervical spine diseases do not affect the teeth and cause toothache. However, cervical degeneration, compression of the sympathetic ganglion in the neck located in front of the transverse process of cervical 5 and 6 vertebrae, abnormal stimulation from the middle cervical ganglion and the traffic branch of the upper cervical sympathetic ganglion to the spinal nucleus of the trigeminal nerve, and then from the mandibular branch of the trigeminal nerve to the alveolus, causing severe pain in the left lower teeth, while the teeth themselves are not diseased; once the tension of the sympathetic nerve is relieved after vomiting, the pressure on the trigeminal nerve is also relieved , the toothache is relieved or disappears again. Therefore, if a patient with non-dental disease is encountered clinically, it can be considered whether it is due to cervical spondylosis.