You should eat a full meal before tooth extraction, otherwise it will easily cause syncope. There are also some cases where teeth should not be extracted, and patients with blood diseases should try not to have teeth extracted. When patients with hemophilia, thrombocytopenic purpura, leukemia, etc. have teeth extracted, they often bleed uncontrollably and may even be life-threatening. Some patients are eager to have their teeth extracted and deliberately conceal their condition from the doctor. This is very wrong. Patients with high blood pressure and heart disease should be careful when extracting teeth. If you can make preparations before tooth extraction, you can extract teeth. It is only forbidden to extract teeth when there is damage to the brain, heart, kidneys, etc. or during a heart attack. Diabetic patients are prone to wound infection when tooth extraction, and infection can aggravate diabetes. Therefore, antibiotics should be used to control infection before and after tooth extraction. Patients with hepatitis, cirrhosis, liver function damage, and reduced thrombin and fibrinogen in the blood are particularly prone to bleeding. Therefore, it is not advisable to extract teeth during the active stage of hepatitis or severe liver damage. Hepatoprotective measures should be implemented first. After the liver function improves, vitamin K and other coagulation drugs can be used prophylactically before tooth extraction. People with renal failure or severe kidney disease should not have teeth extracted. For mild kidney disease, antibiotics can be injected for 2-3 days before tooth extraction to prevent temporary bacteremia and worsening of kidney disease after tooth extraction. Tooth extraction can be performed during pregnancy, but those with a history of habitual miscarriage should be cautious. Since miscarriage is easy to occur within 3 months of pregnancy and premature birth is easy to occur after 6 months, it is best to extract teeth during 3-6 months of pregnancy, which is safer. There is sometimes heavy bleeding after tooth extraction during menstruation, so tooth extraction should be postponed. Patients with hyperthyroidism may develop thyroid storm due to infection, anxiety, or surgery, and may even die quickly. If a tooth is extracted, a preoperative examination is required. The basal metabolism should be below 20; the pulse should be below 100 beats per minute; epinephrine should not be added to the anesthetic, and anti-inflammatory drugs should be taken before and after tooth extraction. All teeth located within the scope of oral malignant tumors should be removed en masse together with the tumor. Extracting the teeth alone will accelerate the spread of tumor cells. Teeth cannot be extracted from areas that have undergone radiotherapy to avoid causing radiation osteomyelitis. The doctor also reminded the patient that after tooth extraction, they should be careful to bite the cotton roll placed in the patient's mouth gently and spit it out after 30 minutes. On the day of tooth extraction, do not talk or laugh loudly, do not spit or spit hard, do not lick the wound with your tongue, and do not suck on the wound to avoid negative pressure in the wound causing bleeding, and do not touch it with your fingers or toothbrushes. You can eat only two hours after tooth extraction. Do not eat food that is too hot or too hard, drink strong alcohol, smoke, or eat spicy food. Do not rinse your mouth within 6 hours, otherwise it may cause further bleeding or make the wound infected and inflamed. After 6 hours, rinse gently with warm salt water. You can brush your teeth the day after tooth extraction, but you should be careful not to touch the wound with your toothbrush. Within 20 hours, there may be a small amount of blood in the saliva. This is normal, don’t be afraid. Even if there is a lot of bleeding, don't panic. Immediately find a piece of sterilized gauze to bite on the bleeding wound, and then go to the hospital for emergency treatment. On the day of tooth extraction, you should not be overly active. Dangers of tooth extraction: What are the risks of tooth extraction? Since children have not yet completed tooth replacement, they should be particularly cautious when extracting teeth. Experts suggest that deciduous teeth should be retained as much as possible until the normal replacement period. If the deciduous front teeth are not loose before the age of 6 but have dental lesions, they should be treated. If there is pulp gangrene (infectious necrosis), it should be extracted early. In children over 6 years old, most of the roots of the deciduous front teeth have been absorbed, and the function of the teeth has gradually been lost. Therefore, they can be extracted when they suffer from deep caries or most of the crowns are broken. If the first deciduous molar does not have pulp gangrene or loose teeth, but has dental lesions, it should be treated before the age of 8 and should not be removed. The second deciduous molar should be retained as much as possible until normal replacement. If the pulp is gangrenous or infected and cannot be cured, or if there is disease in the root tip, it should be extracted as soon as possible. For some children who have caries on the adjacent surfaces of both their first and second deciduous molars before the age of 8, and the crown damage is severe, it may be considered to extract only the tooth with severe caries and poor periodontal condition, while retaining the other tooth. For those with retained deciduous teeth, the permanent teeth of the same name have erupted and have the appearance of double teeth. At this time, the deciduous teeth should be removed regardless of whether they are loose or not, otherwise the teeth may be misaligned. If the newly erupted or already erupted permanent premolars have occlusal trauma with the opposing deciduous molars, extraction of the deciduous molars should be considered to avoid damage to the permanent teeth. It is not advisable to remove dental disease during the period of acute inflammation or when the body has other acute diseases.

In some cases, such as children with heart disease or blood system diseases, tooth extraction is indeed necessary. The decision should be made by the doctor after comprehensive consideration based on the condition, needs, and conditions