1. Good health, no organic diseases of important organs, such as heart disease, hepatitis, nephritis, pneumonia and other diseases.

2. No source of oral infection, such as dental caries, periodontitis, oral ulcers, etc.

3. Female surgery should avoid menstrual period.

4. Routine health checks such as preoperative blood routine, urine routine, chest X-ray and electrocardiogram should also be done.

5. Routine frontal and lateral photos of the face are taken for postoperative comparison and curative effect evaluation, and three-dimensional skull ct can be done if conditions permit. X-ray film of maxilla was taken to understand the development degree of maxillary sinus. In some cases, a facial model should be taken to accurately measure the amount of bone resection of cheekbones.

6. Rinse your mouth with compound borax solution 3 days before operation and clean your mouth if necessary. If the external incision needs to use 1: 1000 new gel defoaming head.

7. Smoking should be stopped before operation. Aspirin, birth control pills and some anti-inflammatory drugs can cause increased bleeding, so these drugs should be stopped for a period of time before surgery.