Effect of Platelet-rich Factor on Implant Stability and Bone Resorption in the Lower Posterior Mandible

Inclusion Criteria: * patients who have 1 or 2 missing teeth in both side of posterior mandible * adequate bone quantity and quality at the implant site * the implant sites with at least 3 months of healing after extraction, * patients well motivated for implant therapy and maintaining good oral hygiene * the implant sites with width and length to installation of an implant of 4.5 mm x 11.5 mm. * Patients who gave written informed consent Exclusion Criteria: * • medically compromised or patients taking any immunosuppressive drugs which may complicate the treatment outcome * infection around the implant site * history of bruxism/parafunctional habits * patients with history of any bleeding disorder or on anti-coagulant therapy. * pregnant patients