Tooth rotten only the root of the tooth need to take pictures to check whether the root of the tooth has the value of retention, can be retained roots for root canal treatment after the pile core crown repair, can not be retained, as soon as possible after the extraction of prosthetic restoration. 1. Preserve the root. If the crown loss caused by dental caries only leaves the root, if the root caries is mild and can be retained by root canal treatment, it is recommended to carry out root canal treatment, and then pull out part of the root through gingival cutting or orthodontics to carry out denture crown restoration. 2. Extraction of roots. If most of the caries has been caused by the root of the tooth, and the condition of the root is not good enough to be preserved, it is recommended to extract the root as soon as possible, and then restore it with prosthesis later on. If the tooth is decayed and only the root is left, it is recommended to go to the hospital in time to check the oral condition and judge according to the X-ray, and deal with it as soon as possible to avoid the inflammation further affecting the oral health.