After necrosis of the nerve, the tooth will become brittle and the color of the tooth will darken to a dark gray or brownish-black. Regardless of whether the tooth is painful or not, it is necessary to go to the stomatology department of the regular hospital in time to treat the tooth. Specific treatment steps, divided into the following steps: 1, with a high-speed water drill to remove corrupt caries tissue, various contaminated materials, and then use specialized instruments to remove the nerve and infected material, and make the root canal of the tooth shaped, and then sealing medicine, temporary sealing. 2, on top of the first treatment, with a professional root canal filling materials, dental adhesive, so that the root canals are filled closely. 3, on top of the filling, to fill in the decayed parts of the tooth to Make the tooth body complete. 4, If there are conditions, it is recommended to do crown restoration to prevent the tooth body from splitting.