Citric Acid Passivation on Implant Abutments for the Prevention of Peri-implant Disease

The implant surgery will be performed by 3rd year residents of the Postgraduate Program in Periodontology at UIC, supervised by a board-certified periodontist (J.V). Under local anaesthesia, a mid crestal incision will be performed and a full thickness flap will be raised. Implants will be placed following the manufacturer's recommendations. Implant shoulder (IS) will be placed 1 mm subcrestally, and a distance of ≥ 1.5 mm from adjacent natural tooth and ≥ 3 mm between implants will be always respected. Implant stability will be measured with Ostell ISQ. Straight definitive abutments (2 mm height) will be tightened to 25 N respecting the previous randomization procedure. One of the implants will receive an antibacterial- coated abutment (citric acid), while the other implant will receive a non-coated abutment (C). A protector cap will be screwed manually. Implant sites will be sutured with polypropylene 5/0 (Prolene Ethicon, USA) by simple stitches.