Treatment of Intrabony Defects With L-PRF Membrane With or Without Collagen Membranes

* Patients having 2-3 osseous bony wall infrabony periodontal lesions are enrolled in the present study. They have to be free from any systemic disease that contraindicates periodontal surgeries. * Baseline data are obtained including the GI, PI, PD, CAL and preoperative paralleling periapical radiographs. * Full thickness mucoperiosteal flaps are elevated and thorough debridement of the periodontal bony defect is performed. * for OFD group; following debridement and saline irrigation, wound closure proceeds. * for the L-PRF group; L-PRF is prepared and applied within the defect before primary closure. * for the L-PRF + CM: similar procedure like the second group is performed but with an additional protective layer of collagen membrane on top of the defect before wound closure. * from the second day postoperative; Periopaper strips are used to obtain a crevicular fluid sample from the sulcus * At 6 months postoperative: the same baseline clinical measurements are obtained.