Human Dental Pulp Mesenchymal Stem Cells for the Treatment of Chronic Periodontitis Patients

Inclusion Criteria: * Participants are eligible to be included in the study only if all of the following criteria apply: 1)18 to 65 years old (including threshold), unlimited gender; 2)Radiological examination of the periodontal defect site shows angular bone defect; 3)The probing depth (PD) at the periodontal defect site is 4 to 8 mm at baseline; 4)Participants who are willing and able to comply with all scheduled visits, treatment plan, laboratory tests, and other study procedures; 5)Voluntarily participate in the clinical study, understand and sign the informed consent; Exclusion Criteria: * Participants are excluded from the study if any of the following criteria apply: 1. Participants with severe periodontal diseases (alveolar bone resorption exceeds two-thirds of the tooth root length) which affect the investigator's judgment; 2. The grade of studied tooth looseness ≥ grade 3 at baseline (only buccolingual movement is defined as grade 1; buccolingual and mesiodistal movement is grade 2; vertical loosening is grade 3); 3. The studied tooth with occlusal trauma which affect the investigator's judgment; 4. Participants with surgical treatment of previous periodontal defect sites and adjacent periodontal tissues; 5. Participants with non-steroid anti-inflammatory drug, steroid hormone therapy, and/or other hormone (except topical hormones) treatment within past 3 months of the screening visit, and/or previous use of bisphosphonates; 6. Participants with severe systemic infection within past 3 months of the screening visit, or antibiotics treatment within past 72h of the screening visit; 7. Participants with uncontrolled hypertension within 1 month before screening (defined as sitting systolic blood pressure ≥ 160 mmHg or diastolic blood pressure ≥ 100 mmHg after receiving the optimal antihypertensive therapy); 8. Participants with severe or uncontrolled diseases in any system (cardiac, hepatic, renal, respiratory, hematologic, endocrine, nervous, or psychiatric); 9. Participants are known to be allergic to any materials that may be used during surgery (allergy-prone constitution or history of allergy to blood products); 10. Any of the following abnormalities in clinical laboratory tests at screening: ALT \> 3 ULN, total bilirubin \> 1.5 ULN, serum creatinine \> 1.5 ULN, international normalized ratio (INR) ≥ 1.5 ULN or activated partial thromboplastin time (APTT) ≥ 1.5 ULN (except for patients receiving anticoagulation therapy), Hb \< 80 g/L, or PLT \< 75.0×109/L; 11. Positive result for any of the following tests at screening: hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (HCV-Ab), human immunodeficiency virus antibody (HIV-Ab), or Treponema pallidum antibody (TP-Ab); 12. Females who are pregnant or breastfeeding; 13. Participants and their partners who plan to conceive or do not agree to use the effective non-pharmacological method of contraceptive during the trial from screening visit to 6 months after the end of the trial; 14. Participants participated in other clinical studies within past 3 months of the screening visit; 15. Participants with a history of smoking addiction within past 12 months of the screening visit (the number of cigarettes smoked per day ≥ 10); Other circumstances deemed inappropriate by the investigator.