Tooth drilling to kill the nerve is also known as clinical root canal treatment, this treatment process is under local infiltration anesthesia treatment, so in the whole process is painless. Local anesthesia is used to inject a small dermatome at the root of the gums near the root of the tooth, and the anesthetic is gradually infiltrated into the internal nerve of the tooth to block the pain sensation of the tooth, thus preventing discomfort to the patient during the treatment process, and therefore is painless throughout the entire root canal treatment process. The first step of root canal treatment is to remove all the infections in the hard tissues of the tooth, and at the same time open the pulp chamber to unblock the root canals, release the pressure of the pulp chamber, and seal in the pulp chamber to inactivate the nerves of the tooth, that is, the pulp inactivator, after this step of the treatment by the pulpitis caused by the pain will be largely relieved, or even completely disappeared, when the pulp inactivator with the pulp role of the pulp for a period of time, the pulp has been After the pulp inactivator has worked with the pulp for a period of time, the pulp is completely inactive, and then the second step of root canal treatment is carried out, and naturally, there will be no pain.