Fillings are designed to kill the nerve in order to avoid problems such as persistent pain and inflammation. When the tooth damage is already deep into the dentin or when there is already a leakage of the nerve, the direct use of resin and other materials for filling will lead to persistent pain or even cause pulp necrosis, apical inflammation and other problems. Only when the nerve inside the tooth is completely removed, and the contents are cleaned and sterilized before a tight filling is made, can the patient avoid persistent recurring pain, and at the same time there is no infected material left inside, which can effectively avoid problems such as pulp necrosis as well as periapical inflammation. Fillings to kill the nerve is mainly for relatively serious patients, the general situation is not serious, the damaged part of the tooth will be removed, and then directly for filling can be. Killing the nerve is not necessary for everyone, and it is recommended to follow the doctor’s instructions.