The wounds (cavities) after tooth extraction are usually replaced by granulation tissue in about 7 days to achieve the so-called filling and healing. The wound healing after tooth extraction is generally divided into five stages: 1. 15-30 minutes after tooth extraction, a blood clot will first be formed to protect the wound and prevent infection; 2. 24 hours or so, the blood clot will mechanize and gradually form granulation tissue, and in about 7 days, granulation tissue will be formed to reach the clinical wound healing standard; 3. 3-4 days after tooth extraction, connective tissue will gradually replace granulation tissue, and in about 20 days, connective tissue will replace granulation tissue. The basic replacement is complete in about 20 days; 4. Around 38 days, fibrous bone replaces connective tissue; 5. Bone tissue is formed in about 3 months, and normal bone tissue is completely formed in about 6 months. Therefore, it is important to protect the blood clot formed at the initial stage after tooth extraction, do not brush your teeth and rinse your mouth for 24 hours, do not spit or suck the wound (cavity) to prevent the blood clot from falling off and causing poor healing and infection.