Twenty-one intra-bony defects in fifteen systemically healthy patients with moderate to severe chronic periodontitis were randomly classified into 3 groups, 7 sites each. Group І treated by MIST alone, group ІІ treated by MIST + ethylenediamine-tetraaceticacid (EDTA) + PRF and group III treated by MIST + EDTA + GEM 21S. The clinical parameters including probing pocket depth (PPD), clinical attachment level (CAL) and bleeding on probing (BOP), were recorded at baseline, 3, 6 and 9 months post-surgery. Cone beam computed tomography (CBCT) was performed at baseline and 9 months post-surgery to evaluate bone level and bone density

: Twenty-one intra-bony defects in fifteen systemically healthy patients with moderate to severe chronic periodontitis were randomly classified into 3 groups, 7 sites each. Group І treated by MIST alone, group ІІ treated by MIST + ethylenediamine-tetraaceticacid (EDTA) + PRF and group III treated by MIST + EDTA + GEM 21S. The clinical parameters including probing pocket depth (PPD), clinical attachment level (CAL) and bleeding on probing (BOP), were recorded at baseline, 3, 6 and 9 months post-surgery. Cone beam computed tomography (CBCT) was performed at baseline and 9 months post-surgery to evaluate bone level and bone density.

Inclusion Criteria:

• Presence of at least one tooth with PPD and CAL loss of ≥ 5 mm associated with an intra-bony defect of ≥ 2 mm according to Cortellini and Tonetti, 2007

Exclusion Criteria:

• Patients with uncontrolled or poorly controlled diabetes, life-threatening conditions, or requiring antibiotic prophylaxis were excluded.
• Smokers
• Pregnant patients.
• Patients with aggressive periodontitis.
• Patients with multiple interconnected vertical defect walls.