If the tooth is rotten and only the root is left, you need to go to the hospital to take an apical radiograph of the tooth to see if there is inflammation at the tip of the tooth. If there is inflammation and the root is short, it is recommended to extract the tooth. If there is no inflammation and the root is long, it can be retained for restoration. 1. Extraction: If the tooth is rotten and only the stump is left, and there is inflammation at the root tip of the tooth, and the root is relatively short and difficult to be preserved, it is recommended that the stump of the tooth be extracted. After extraction, the tooth can be restored with a denture to restore a complete tooth. 2. Retention restoration: If the tooth is rotten and only the stump is left, but there is no inflammation at the root tip of the tooth, and the root length of the stump is good, the tooth can be restored with a dental crown, so that the tooth can be made complete again. The specific treatment of the tooth is recommended to go to the hospital, the dentist combined with the actual situation to develop a treatment plan.