Simvastatin (SMV) is one of the family members of statins, it has been showed in many previous studies that the simvastatin when dissolved with methylcellulose in situ gel with a concentration of 1.2% (SMV) approximately, can have a significant decrease in the pocket depth, regain the clinical attachment loss (CAL), and improve the bone level.

and the platelets concentrate has been introduced which is the injectable plasma rich fibrin (I-PRF), as it contains platelets and leukocytes, stem cells and endothelial cells that why it is called "blood concentrate ". So, it is proposed as treatment option in different periodontal procedures such as treatment of intra-bony defects,

Group I ( Experimental group): will include 12 patients undergoing open flap debridement (OFD) followed by single application of I-PRF. Oral Hygiene measure will be instructed following treatment and maintenance visits will be given to them.

Group II (Control group): will include 12 patients undergoing open flap debridement (OFD) followed by application of 1.2% simvastatin gel. Oral Hygiene measure will be instructed following treatment and maintenance visits will be given to them.

• Oral hygiene instructions will be given to all patients.
• Full mouth Scaling and root planing (SRP) will be performed under local anesthesia.
• 4 to 8 weeks after the non-surgical periodontal therapy patients will be reassessed clinically and radiographically For all patients who are suitable for the study the following clinical and radiographic evaluation parameters will be measured: (All parameters will be recorded Pre-operatively (base line) and 6 months Post operatively by an examiner who will be masked to the type of treatment received by the individuals).

Inclusion Criteria:

• • Age range between 25 and 40 years

  • Patients with severe chronic periodontitis having probing depth (PD) ≥6 mm and clinical attachment loss (CAL) ≥5 mm , or Stage III periodontitis
  • Patient having vertical bone loss ≥3 mm (distance between alveolar crest and base of the defect as confirmed by preoperative intraoral periapical radiographs using standardized parallel technique.)
  • Good compliance with the plaque control instructions following initial therapy
  • Availability for follow up and maintenance program.

Exclusion Criteria:

• • Patient with any systemic disease or conditions

  • Patient using antibiotic, anti-inflammatory, and immunosuppressive therapy during the preceding 3 months before the start of trial and during the study.
  • Patients who have undergone any periodontal treatment in the last 6 months
  • Pregnant and Lactating.
  • Reported allergy to any type of statins
  • Subjects who were tobacco or alcohol users
  • Vulnerable group of patients (e.g.: prisoners , handicapped , or decisionally impaired individuals )