Minimally-invasive Non-surgical and Surgical Periodontitis Treatment

To compare the efficacy of a modified minimally-invasive non-surgical periodontal therapy (MINST) approach with a surgical approach (M-MIST) in determining bone and clinical attachment changes in intrabony defects

Inclusion Criteria: 1. Age 25-70 2. Diagnosis of 'Periodontitis' stage III or IV (grades A to C) 3. Presence of ≥1 'intrabony defect' (PPD, \>5 mm with intrabony defect depth ≥3mm at screening radiograph), 4. Signed informed consent. - Exclusion Criteria: 1\. Smoking (current or in past 5 years) including e-cigarettes/vaping 2. Medical history including diabetes or hepatic or renal disease, or other serious medical conditions or transmittable diseases 3. History of conditions requiring prophylactic antibiotic coverage prior to invasive dental procedures 4. Antiinflammatory or anticoagulant therapy during the month preceding the baseline exam 5. Systemic antibiotic therapy during the 3 months preceding the baseline exam 6. History of alcohol or drug abuse, 7. Self-reported pregnancy or lactation 8. Other severe acute or chronic medical or psychiatric condition or laboratory abnormality that according to the investigator may increase the risk associated with trial participation, 9. Periodontal treatment to the study site within the last 12 months (excluding not-extensive subgingival debridement as judged by the examining clinician). \-