Pre-operative preparation 1. First of all, you can understand the danger of the obstructed tooth and know why the obstructed tooth is extracted, so that you can have an idea. 2. Before extraction, it is necessary to perform oral panoramic film examination, which helps the extraction surgeon to understand the relationship between the root of the blocked tooth and the inferior alveolar nerve and maxillary sinus, and to understand how complex and risky the extraction is, which is of great value to the surgeon for smooth extraction. In some cases, oral 3D CT examination is needed to understand the relationship between the root and the inferior alveolar nerve and maxillary sinus. 3. It is recommended that if a patient has a complex blocked tooth that requires surgical extraction, he or she should choose a professional oral surgeon to remove it. The extraction of complex blocked teeth is risky, such as jaw bone fracture, lower alveolar nerve and lingual nerve damage, root displacement, bleeding, infection, etc. Oral surgeons are relatively familiar with anatomy, and with professional training, they can effectively reduce the risk. 4. Tooth extraction has high physical requirements for patients, and major diseases such as hypertension, diabetes and heart disease need to be excluded. 5. Avoid fasting, cold, dizziness and discomfort during tooth extraction. Women need to avoid menstruation and pregnancy. 6. Patients should know the method of tooth extraction and the difficulties and risks, so that they can have a good understanding and have a certain psychological tolerance.