Koldsland OC, et al. - Using a multilevel statistical model, the aim of this study was to assess the clinical and radiographic short-term (6 months) effect of surgical treatment of peri-implantitis, as well as to identify prognostic indicators affecting the outcome. According to the findings obtained, resective peri-implantitis surgery appeared to decrease the amount of peri-implant inflammation. However, most of the sites continued on having to bleed on probing/suppuration. Presence of suppuration prior to interception and peri-implant bone loss exceeding 7mm was the prognostic indicators by which the effect of treatment was reduced.