Permanent tooth decay refers to the decay that occurs in children's newly emerged permanent teeth or already replaced permanent teeth. Once decay occurs in a permanent tooth, it is necessary to fill the tooth as soon as possible. Decay is removed by drilling out the decayed hard tissue of the tooth. After removal, direct pulp capping treatment for the tooth is performed. If the decay in the permanent tooth is deep and has reached the tooth nerve, pulp treatment is needed. Vital pulpotomy can be used to retain the root pulp of the root part to promote further development of the tooth root. If the apex of the root has already formed in the permanent tooth and decay occurs, and the tooth nerve cannot be preserved, we can directly proceed with root canal treatment.