Inclusion Criteria:  1) no systemic diseases which could influence the outcome of therapy; 2) good compliance with plaque control instructions following initial therapy; 3) teeth involved were all vital with no mobility; 4) each subject contributed a single predominately 2 or 3-wall intrabony interproximal defect around premolar or molar teeth without furcation involvement; 5) selected intrabony defects (IBD) measured from the alveolar crest to the defect base in diagnostic periapical radiographs of ≥ 3 mm, the width of ≥ 3 mm at its most coronal part, with no cratering that involve both mesial and distal surfaces of adjacent teeth; 6) selected probing depth (PD) ≥ 6 mm and clinical attachment loss (CAL) ≥ 4 mm at the site of intraosseous defects four weeks following initial cause-related therapy; 7) availability for the follow-up and maintenance program; 8) absence of periodontal treatment during the previous year  Exclusion Criteria:  1) Pregnant females