Inclusion Criteria:  The age of the patient is 18-80 years old. selection of affected teeth: there is still at least one site of periodontal probing depth ((PD) ≥ 5mm) at 6-8 weeks after initial periodontal treatment,and the degree of mobility is less than grade II or II-III degree but without mobility after fixation.Imaging evaluation shows that the tooth has a Intrabony defect which is larger than 3mm, and there is no history of periodontal surgery at this site, and the affected tooth has no obvious symptoms of discomfort. The patient has good compliance, good plaque control after basic treatment (bleeding index and plaque index < 20%). He/She can understand the purpose of the test and is willing to cooperate with surgical treatment and follow-up. He/She voluntarily participates in the trial and signs informed consent.  Exclusion Criteria:  In the past 6 months, patients who chewed smokeless tobacco, smoked a pipe or cigar once a week, or smoked more than 20 cigarettes per week (1 pack per week); Patients took any drug affecting platelet function or had a platelet count less than 200000/mm3 3 months before blood collection. Patients have taken antiepileptic drugs, antihistamines, antidepressants, sedatives, sedatives, anti-inflammatory drugs or daily analgesics within 1 month before operation; Patients with a history of diabetes or patients with abnormal blood glucose test (fasting blood glucose ≥ 7mmol/L); Liver and renal dysfunction (AST, ALT ≥ 1.5 times ULN, creatinine ≥ 1.5 times ULN); Patients with severe endocrine and metabolic diseases. Those with a history of grade 3 hypertension; Those with a history of osteoporosis; Those with a history of autoimmune diseases; Those with a history of malignant tumor or other serious diseases who are not suitable for surgery or cause observation of tooth loss; Pregnant or lactating women; Patients with local anesthetic allergy. Clinical or radiological findings showed acute infection, apical lesions, root fractures, severe root deformities, cementum beads, indelible enamel protuberances, untreated caries at the enamel or root boundary, and restoration reaching subgingival and/or below CEJ or marginal incongruity All kinds of subjects who can cause artifacts in oral imaging examination, such as: the study teeth and their adjacent teeth are metal dentures and porcelain teeth; The affected teeth have root furcation lesions