PurposeTo evaluate the adjunctive clinical effects of a chloramine to non-surgical treatment of peri-implantitis. Material and methodsEighteen individuals diagnosed with peri-implantitis (clinical signs of inflammation and progressive bone loss) on at least two implants were included. Clinical variables; plaque accumulation (Pl), probing depth (PD), clinical attachment level (CAL) and bleeding on probing (BoP), were recorded at baseline and at 3-month follow-up. Primary clinical efficacy variable was the change in the number of sites with BoP. The implants were randomized into two different treatment groups: test and control. Both implants received supra- and submucosal debridement by ultrasonic instrumentation supplemented with hand instruments. The implants assigned to the test group first received local applications of a chloramine gel (Perisolv; RLS Global AB, Gothenburg, Sweden) followed by mechanical instrumentation. The oral hygiene was checked at 6weeks. ResultsAfter 3months, implants of both groups showed statistically significant reduction (P<0.001) in the number of BoP-positive sites compared with baseline. The reduction of BoP-positive sites in the test group changed from 0.97 (SD0.12) to 0.38 (SD +/- 0.46), and in the control group from 0.97 (SD +/- 0.12) to 0.31 (SD +/- 0.42). Between-group comparisons revealed no statistically significant differences at baseline and after 3months, for BoP or any of the other variables. ConclusionIn the present randomized clinical trial of peri-implantitis therapy; non-surgical mechanical debridement with adjunctive use of a chloramine is equally effective in the reduction of mucosal inflammation as conventional non-surgical mechanical debridement up to 3months.