"Re-instrumentation vs Flap Surgery"

All the sites showing a residual pocket in a sextant allocated to surgery group will receive flap surgery. After the administration of oral local anaesthesia (Articaine 1:100000) an intrasulcular flap will be raised. In order to preserve interdental tissue the flaps will be designed accordingly the principles of papillary preservation flap. Toot root will be carefully debrided using both ultrasonic instruments and Grecey's curettes. Bone recontouring and ostectomy/osteoplasty will be avoided. Single simple sutures will be used to close the flap (Vicryl 5-0).

The sites showing remaining pockets (PD\>4mm), in the sextants allocated to re-instrumentation group, will be treated with subgingival debridement. The subgingival debridement will be performed after the administration of local oral anaesthesia (Articaine 1:100000) using a periodontal tip on ultrasonic instrument (EMS) and Gracey's curettes.