A tooth that is so rotten that only a black stump is left needs to go to a hospital dentist and be treated with root restoration or extraction depending on the situation. After examination, if the stump is long and thick, the root can be retained and root canal treatment can be performed on the root as appropriate. Once the inflammation is under control, this residual root is utilized to restore the normal structure of the tooth by performing a prosthetic porcelain crown restoration using the stump-crown method. If the remaining residual root is short, thin, and has significant loosening, the root is not worth preserving. In this case, it is generally recommended to extract the root and wait for the alveolar bone to be completely repaired before making a denture restoration, of which dental implant restoration is more effective. If you find caries or abnormalities in your teeth, you should seek medical attention as soon as possible to avoid progression of the disease.