The purpose of the present study was to investigate the efficacy of autologous Platelet rich fibrin (PRF) or PRF and Simvastatin (SMV) with open flap debridement (OFD) in the treatment of three wall intrabony defects in comparison to OFD alone.

90 systemically healthy subjects were divided randomly into three groups (30 subjects in each group, per subject one site). Control group consisted of the sites treated with OFD and test groups sites were treated with OFD with autologous PRF or PRF with SMV. Site-specific plaque index (PI), sulcus bleeding index (mSBI), probing depth (PD), relative attachment level (RAL) and intrabony defect (IBD) depth reduction was measured at baseline and 9 month after surgery.

Inclusion Criteria:

• Subjects with the diagnosis of chronic periodontitis
• presence of three walled intrabony defects (IBD) ≥ 3 mm deep (distance between alveolar crest and base of the defect on intraoral periapical radiograph [IOPA])
• interproximal probing depth (PD) ≥ 5 mm following scaling and root planing (SRP) in asymptomatic tooth

Exclusion Criteria:

• Subjects, with the diagnosis of aggressive periodontitis,
• with known systemic illness and taking medications known to affect the outcomes of periodontal therapy
• insufficient platelet count (< 200,000/mm3),
• pregnancy / lactation
• use of any form of tobacco
• unacceptable oral hygiene (if plaque index [PI] (Silness & Loe 1964) >1.5) after the reevaluation of phase I therapy
• teeth with furcation defects
• non-vital
• mobility of tooth ≥ Grade II