Surgery
tooth
STERILE
All surgical procedures were conducted by a single operator (MA). Following administration of local anesthesia (2% mepivacaine HCl with 1:20,000 levonordefrin, Alexandria Co. for Pharmaceuticals, Alexandria, Egypt), intrasulcular incisions were performed buccally and lingually/palatally on the affected tooth and extended one adjacent tooth mesially and distally, using 15c blades (TRINON Titanium GmbH, Augartenstraße, Karlsruhe, Germany). Following mucoperiosteal flaps’ elevation, thorough debridement was performed using ultrasonic scalers (Woodpecker Ultrasonic UDS-K Scaler, Zhengzhou, China) and mini-/after-five Gracey curettes (Hu-Friedy, Chicago, USA), until defects were clear from any granulation tissue [In the control group, DFDBA graft material (AlloOss®; demineralized cortical particulates, ACE Surgical Supply Co., Brockton, MA, USA) was placed into the intrabony defect without overfilling. In the test group, 10 mm of fresh blood was withdrawn by venipuncture of the antecubital vein into a sterile 10 ml glass vacuum tube (Voma Med, Chongqing, China) without anticoagulant, and the tube immediately centrifuged (Digital Tabletop Centrifuge, rotor angle: 45° and a maximum radius of 10.6 cm, Velab, VE-4000, TX, USA) at a maximum relative centrifugal force (RCF-max) of 60 g (700 rpm) for 3 min at room temperature [Clinical steps in representative cases of the control (