To explore the role of CGF in the regeneration or preservation of soft and hard tissues during tooth extraction site preservation surgery.

A prospective, randomized controlled trial is designed to explore the role of CGF in the regeneration or preservation of soft and hard tissues in extraction site preservation. Using random number table, 20 patients were randomly divided into 4 groups using different filling materials in the extraction socket and materials for the wound sealing. Group A (5cases): bone powder + collagen membrane; Group B (5 cases): bone powder + collagen membrane + CGF membrane; Group C (5 cases): bone powder mixed CGF gel + collagen membrane + CGF membrane; Group D (5 cases): bone powder + CGF membrane.

Extraction and site preservation surgery were performed by the same physician and clinical follow-up was more than 6 months after surgery. The four groups will be compared on several variables, including the changes in pain score, Landry wound healing index, membrane exposure area, keratinized gingival width, buccolingual gingival width, alveolar crest width and height.

Inclusion Criteria:

Voluntarily participate in this trial and sign a written informed consent; Patients aged 25 ≤ age ≤ 45 years; The combination of intraoral and imaging examinations confirms that the affected tooth has no preservation value, requires tooth extraction, and the patient is willing to use site preservation; No progressive periodontal disease or acute apical periodontitis in the affected teeth; No long-term history of oral bisphosphonates; Non smoking patients； No systemic diseases such as diabetes and hypertension.

Exclusion Criteria:

Patients who have difficulty tolerating surgery; Patients under 25 years old or above 45 years old; The whole body is accompanied by hypertension, diabetes and other serious systemic diseases, which need to be controlled by drugs; Patients who take oral medication that affects bone metabolism for at least one month due to the need for disease treatment; Patients who take medication that may affect platelet function was used within 3 months due to the need for disease treatment; Patients unable to undergo X-ray imaging examination due to pregnancy or preparation after site preservation surgery; Patients who Smoke; The apical and periodontal inflammation is in the acute phase (purulent phase) Regular follow-up or follow-up for more than 6 months is not allowed