In the case of acute pulpitis, block anesthesia or local infiltration anesthesia can be administered, and the anesthetic will make the gums, alveolar bone and pulp fibers around the affected tooth lose all pain, and the treatment of grinding open the pulp cavity and removing the pulp will not cause any pain. In case of periapical inflammation or chronic pulpitis, the pulp has lost most of its vitality under the action of bacteria, and sometimes liquefied and denatured, so when the pulp cavity is ground open, you can see that the pulp is not shaped and emits a rotten odor, and the nerve fibers lose pain sensation. If the pulp close to the apical foramen still has a residual sensation, you can put anesthetic drops deep into the root canal to anesthetize the residual pulp and then perform the root canal preparation without pain.