Dental caries is a chronic and progressive disease, if left untreated it will continue to progress. Dental caries is a chronic progressive disease that will continue to progress if left untreated. When caries is left untreated and progresses to the point where the roots are rotten, the food debris and bacterial metabolites within the root residue will often lead to foul odors, and these teeth are usually of no preservation value and are recommended to be extracted. If the root is not extracted, there is a risk of recurrent inflammation and jaw cysts in the mouth for a long period of time. Neighboring teeth will be tilted towards the gap where the root is rotting, and the opposing teeth will elongate, which will affect the restoration. The day before the tooth extraction, pay attention to rest, avoid fasting, women avoid physiological period, some patients with combined systemic basic diseases must inform the physician in advance. After tooth extraction, bite the teeth to stop bleeding for 30min, do not exercise strenuously, do not brush your teeth on the same day. Restorative treatment should be carried out 3 months after tooth extraction. It is recommended to go to the regular hospital stomatology department for consultation.