Surgical Procedure A non-submerged surgical technique was used for both experimental and control sites. Following administration of local anaesthesia flap elevation procedure included an intra-crevicular incision around the implant. Full thickness mucoperiosteal flaps were raised on the buccal and lingual aspect to gain access to the complete peri-implant defect and to the implant surface. The extent of this incision was determined by supra-crestal incisions extending mesial and distal of the implant site. Vertical incisions into the vestibule at a distance of at least one tooth/implant from the implant were performed as necessary for adequate access. Granulation tissue was removed using titanium curettes (HuFriedy®, Chicago, IL, USA) and the exposed implant surfaces were cleaned mechanically by using a rotary titanium brush (Tigran PeriBrush™, Tigran Technologies, Malmö, Sweden) and decontaminated chemically with 3% H2O2 for 1 minute followed by rinsing with saline for 60 seconds (2 x 20 ml).