After a nerve leakage, the tooth will have pain symptoms. Nerve leakage is mostly caused by a deeper worm tooth, resulting in nerve infection. If it is a mild nerve leakage symptom, the affected tooth usually has long-term symptoms of pain stimulated by cold food and hot food, which may be accompanied by discomfort in chewing, unexplained paroxysmal hidden pain, or dull pain at regular intervals every day. The patient can point out the location of the affected tooth by himself/herself. This symptom is called chronic pulpitis, such as the affected teeth in a short period of time, obvious and severe pain, do not eat all the pain and spontaneous pain, paroxysmal episodes or aggravation of the pain radiates to the affected side of the head and face of the upper and lower jaw, into the cold food, hot food pain aggravation or into the hot food pain aggravation, and cold water can relieve the pain, the pain aggravated at night than the daytime pain is more intense, it is often difficult to sleep or woke up from the pain in their sleep and can not determine the pain of which tooth. It is often difficult to sleep or wake up from sleep with pain, and it is not possible to determine which tooth is in pain, and it is not possible to tell whether it is the upper tooth pain or the lower tooth pain, which is a symptom of acute pulpitis, and it will cause great pain to the patients. Some patients, such as deep caries, pulpitis has long had chronic inflammation, without showing symptoms of pain. When the opening of the crown is blocked, the tooth may show acute nerve pain, considered as an acute attack of chronic pulpitis.