A rotten tooth nerve can produce pain. When the tooth decay has involved the dental nerve, it will produce severe pain. This is because the main trunk of the dental nerve is the trigeminal nerve dental nerve, which is the end of the trigeminal nerve. Usually the pain will not be produced until the dental nerve is in the case of necrosis. The rest usually produce chronic pulpitis, acute pulpitis this time will produce hot and cold irritation pain, and tend to have night pain or appear severe pain. Generally, we choose to take out the nerve and remove the part of the nerve connected with the trunk to avoid the phenomenon of sleeplessness at night, and after taking out the nerve, we need to do the filling of the root canal of the tooth to facilitate the closure of the tooth and avoid secondary caries.