Trigeminal neuralgia is divided into secondary trigeminal neuropathy and primary trigeminal neuralgia, in which we usually say trigeminal neuralgia refers to primary trigeminal neuralgia. The most important thing about trigeminal neuralgia is first of all the diagnosis, because misdiagnosis of other diseases as trigeminal neuralgia will not be worth the loss. Trigeminal neuralgia” is sometimes called “facial pain” and is easily confused with dental pain. Trigeminal neuralgia is a kind of recurrent severe neuralgia that occurs in the distribution area of the trigeminal nerve in the face, and it is one of the common diseases in neurosurgery and neurology. What are the causes of trigeminal neuralgia? The causes of trigeminal neuralgia have not yet been fully revealed. The more common theories are local irritation theory, compression theory and disorder of the dental system theory. 1.Local stimulation theory Inflammatory lesions occur in the tissues and organs innervated by the trigeminal nerve, such as paranasal sinusitis and odontogenic inflammation, which can cause long-term chronic stimulation, inflammation and fibrosis of the nerve and poisoning of the semilunar ganglion, further causing dysfunction and spasm of the trophoblastic vessels distributed on the trigeminal nerve root, and finally secondary ischemia, resulting in demyelination of the sensory root, and causing trigeminal neuralgia. The demyelination of the nerve roots of the semilunar ganglion causes a short circuit between the adjacent nerves, at this time, the external stimulus is transmitted to the center by the short circuit; the efferent impulses of the center become afferent impulses by the short circuit, and the afferent impulses reach a certain sum and excite the neurons in the semilunar ganglion, producing abnormal impulses and causing pain. 2. Compression theory Trigeminal neuralgia is caused by the compression or pulling of one of the sensory roots of the trigeminal system for various reasons. (1) Vascular compression theory Mechanical compression of the trigeminal nerve, that is, the compression of the trigeminal nerve root by the basilar and superior cerebellar arteries, is an important cause of pain and the most common cause, so the surgical method of vascular decompression is often used to treat the disease. (2) Bone compression theory This type of compression can be divided into two categories: congenital and acquired. The main cause of compression is trigeminal neuralgia due to elevation of the rock bone angle, narrowing of the bone foramen and supratrochlear sinus variation. In contrast, bone foramen stenosis caused by congenital origin is mostly due to skull injury skull base fracture. (3) The theory of disorder of the dental system The dysfunction of the dental system can cause trigeminal neuralgia. These disorders of the dentition relationship can cause spasm and muscle dysfunction of the muscle groups around the joint. This condition creates a small amount of abnormal impulses that are constantly transmitted to the center, causing the center to lose its dynamic balance and become dysfunctional. There are also the ischemic theory, the central etiology theory, the metabolic theory and the family genetic theory.