It takes three times to kill the nerve of the tooth specifically you can consult your own dentist because different doctors will have different programs based on different patients. Some people’s teeth due to excessive fluid leakage, the first visit needs to be open pulp drainage treatment, the second time some doctors may use pulp inactivation drugs to make the pulp inactivation, and then the third time for the extraction of the pulp treatment root canal preparation, depending on the circumstances of the second time may be directly after local anesthesia for the extraction of the pulp treatment, and the third time, if the remaining pulp will also carry out the extraction of the pulp. The exact number of follow-up visits depends on the treatment of the tooth. The number of times the nerve is killed is affected by the method used by the doctor, the patient’s oral conditions and the local level of medical care, the number of times and the content of the operation vary from person to person.