Patients are often found to have tooth pain, spontaneous pain, hot and cold stimulation will aggravate the pain, and some are painful conditions at night, called dental nerve pain, inflammation of the nerve, treatment is root canal treatment. The first step is to put nerve-killing drugs to kill the nerve to stop the pain; the second step is to clean the necrotic nerve which contains bacteria; the third step is to seal the clean root canal with material to seal it tightly, and then fill up the tooth to repair it. The third step is to clean the root canal, seal it tightly with material, fill it up and restore it to prevent the bacteria in the mouth from infiltrating again and prevent future inflammation.