(a) no systemic diseases as diabetes mellitus or cardiovascular diseases that contraindicated periodontal surgery and could influence the outcome of the therapy; (b) no smoking (c) no medications affecting periodontal tissues; (d) no pregnancy or lactation; (e) a good level of oral hygiene (plaque index < 1, and full mouth bleeding on probing score <20% after initial periodontal treatment), (f) compliance with the maintenance programme and (g) presence of at least one intra-bony defect with a probing depth ≥6 mm, radiographic depth of the defect ≥3 mm as detected on the radiographs.