Evaluate of the injectable platelet rich fibrin (I-PRF) with xenograft in Intrabony defects of Periodontitis patient stage III versus Xenograft alone.

All surgical procedures will be conducted by a single operator. Following administration of local anesthesia, intrasulcular incisions will beperformed buccally and lingually/palatally on the affected tooth and extended one adjacent tooth mesially and distally, using 15c blades. Following mucoperiosteal flap elevation, thorough debridement will be performed using ultrasonic scalers and curettes until defects are clear from any granulation tissue, and the defect morphology will be visually explored and recorded. In the group1: xenograft alone(Bovin xenograft)will be applied to the intrabony defect area. In the group 2: xenograft (Bovin xenograft) with injectable platelet Rich fibrin (I- PRF) will be applied to the intrabony defect area. Preperation of Injectable platelate Rich Fibrin (I-PRF) : will be prepared for each patient as follows: 5 ml of venous blood will be collected from the patient blood then placed in a plastic tube without any added material or coagulant and centrifuged at 700 rpm for 3 min. then mixed with Xenograft. Finally, the flap will be passively repositioned using interrupted 4-0 silk

Inclusion Criteria:

1. Patient should have localized Periodontitis stage III grade B with pocket depth ≥ 6mm; indicated for periodontal surgery
2. Patient's agreement to the surgical procedure and clinical trial.
3. Age ranged between 30-55 years old.
4. Intrabony defects with depth ≥3mm.
5. Free from any systemic conditions and no previous drug affect bone metabolism

Exclusion Criteria:

1. Smoking.
2. Pregnant women.
3. Patients in variation in anatomical landmarks.
4. Patients with psychological problems.
5. Patients with abnormal habits.