It is not always possible to fill a tooth that is half rotten. It is necessary to consult a doctor for examination, and depending on the depth of the tooth’s rottenness and the amount of remaining tooth tissue, a filling, root canal treatment or extraction will be chosen. 1. If the tooth is half rotten, but does not violate the nerve and has good retention, it can be directly filled, that is, filling treatment, the main steps are: cavity preparation, disinfection, application of adhesive, filling materials. 2. If half of the tooth is rotten and has violated the tooth nerve, but the remaining tooth tissue still has retention value, the tooth cannot be filled directly and needs to be treated with root canal therapy, the main steps are: root canal preparation, rinsing and disinfection, root canal filling, and crown restoration as soon as possible after root canal therapy. 3. If the rotten tooth is deeper, has destroyed the pulp chamber bottom, or bad to the deeper position under the gum, the remaining tooth tissue has no retention value, can not be filled, it is necessary to extract the tooth, after extraction, and actively carry out dental restoration. Whether the rotten tooth rotten half can be filled should be timely hospital consultation, under the guidance of the doctor to judge.