Purpose: Numerous approaches have been proposed for the treatment of peri-implantitis, but to date, none has been identified as the most effective. This study compared the efficacy of implantoplasty and glycine air polishing for the surgical treatment of peri-implantitis. Materials and Methods: This prospective, randomized, parallel-group trial included 31 patients presenting with 42 implants with peri-implantitis. Patients underwent surgical treatment by implantoplasty (test group, n = 22) or glycine air polishing (control group, n = 20). Clinical parameters (Plaque Index), bleeding on probing (BOP), suppuration on probing (SOP), probing pocket depth (PPD), relative attachment level (RAL), and mucosal recession were assessed before surgery (baseline), and at 3 months and 6 months after surgery. Bone loss was recorded at baseline and 6 months. Two composite outcomes were also evaluated, according to the following definitions: (1) mean PPD reduction ≥ 0.5 mm + no further loss of bone; (2) PPD ≤ 5 mm, absence of BOP/SOP, and no additional mean bone loss ≥ 0.5 mm. Results: Plaque Index remained low ( 0.5) in both groups for the duration of the study. Mean BOP, SOP, PPD, and RAL were greatly reduced at 3 months in both groups, and remained low between 3 months and 6 months. Bone loss was stable in the implantoplasty group, and slight bone gain (0.5 mm) was observed in the glycine airpolishing group. There were no significant differences between the two groups in any parameter, and composite treatment outcomes were similar in both groups, irrespective of the definition. Conclusion: Within the limitations of this 6-month follow-up study, implantoplasty is as effective as glycine air polishing for the surgical treatment of peri-implantitis. Keywords: clinical research, oral infection, peri-implantitis, periodontology, surgical procedure, treatment, wound healing