The number of years a tooth with a killed nerve will last is based on the patient’s condition after the root canal treatment, depending on the patient’s condition. If the treatment effect is good, it can last 10-20 years. 1. If the patient’s tooth after removing the nerve to do the root canal treatment is good, and the root tip of the tooth is no longer inflamed. And the patient is able to carry out the necessary crown restorations or crowns according to the area of the tooth loss. Then, under normal circumstances, the service life is about 10-20 years. 2. If the tooth does not have an intact root canal, probably because the infection is not controlled, and the periapical infection reappears within 1-2 years, it will need to be re-treated. Although the nerve is gone, the peripheral tissues of the tooth are still healthy and still maintain the normal function of the tooth, and can be used normally as long as it is treated in a timely manner. 3. If the tooth is not restored in time after root canal treatment, it may split under the action of biting force, resulting in the tooth not being retained. Patients maintain oral hygiene in daily life. Meanwhile, regular oral checkups, minimize the intake of sugary foods and eat more fiber-rich foods.