The main contraindications for tooth extraction are as follows: I. Heart disease, heart function grade 3-4 or jugular vein anger, telangiectatic breathing, lower limb venous edema, etc., are not allowed to extract teeth. Hypertension, blood pressure higher than 180/100mmHg is not allowed to extract teeth. Diabetes mellitus, blood glucose value higher than 8.88mmol/L is also not allowed to extract teeth. Acute hepatitis and acute nephritis are also not allowed to extract teeth. V. Tooth extraction is not allowed during menstruation in women. Tooth extraction is not allowed during early and late pregnancy, that is, the 1st, 2nd, 3rd and 7th, 8th and 9th months of pregnancy. VII. Patients who have been taking anticoagulant drugs for a long time need to stop the drugs before tooth extraction. The extracted teeth should not be extracted around malignant tumors because of the possibility of tumor spread. Patients with local radiotherapy of the maxillofacial region should not have their teeth extracted. In addition, there are many other cases where tooth extraction is not allowed.