 Root and bone defect debridement The bone defect was meticulously debrided with surgical curettes and ultrasonic instruments with special effort to remove all the inflammatory granulation tissue, but with no intention to perforate the cortical bone walls. Thorough root planing was performed with hand Hu-Friedy, IL, USA, rotary Intensiv, Grancia, Switzerland and ultrasonic instruments Cavitron, Dentisply, USA, to remove subgingival plaque and calculus until all root surfaces attained a hard glassy surface. During the instrumentation, the flaps were slightly elevated, carefully protected with periosteal elevators, and frequently irrigated with saline. 