Objectives: This prospective, parallel-group, examiner-blinded, multicentre, randomized, controlled clinical trial aimed to assess the efficacy of an oscillating chitosan brush (OCB) versus titanium curettes (TC) on clinical parameters in the non-surgical treatment of peri-implantitis. Material and Methods:In five dental specialist clinics, 39 patients with one implant with mild to moderate peri-implantitis, defined as 2-4 mm radiographic reduced bone level, bleeding index (BI) ≥ 2, and probing pocket depth (PPD) ≥ 4 mm were randomly allocated to test and control groups, receiving OCB or TC debridement, respectively.Treatment was performed at baseline and three months. PPD, BI, and Plaque index (PI) were measured at six sites per implant and recorded by five blinded examiners at baseline, one, three, and six month(s). Pus was recorded as present/not present.Changes in PPD and BI were compared between groups and analysed using multilevel partial ordinal and linear regression.Results: Thirty-eight patients completed the study. Both groups showed significant reductions in PPD and BI at six months compared with baseline (p < .05). There was no statistically significant difference in PPD and BI changes between the groups.Eradication of peri-implant disease as defined was observed in 9.5% of cases in the OCB group and 5.9% in the TC group.Conclusions: Within the limitations of this six-month multicentre clinical trial, nonsurgical treatment of peri-implantitis with OCB and TC showed no difference between the interventions. Eradication of disease was not predictable for any of the groups.

Objectives To study clinical and radiographic outcomes after non‐surgical treatment of peri‐implantitis using either an oscillating chitosan brush (OCB) or titanium curette (TC) and to observe changes in clinical signs of inflammation after repeated treatment. Methods Thirty‐nine patients with dental implants (n = 39) presented with radiographic bone level (RBL) of 2–4 mm, bleeding index (BI) ≥ 2, and probing pocket depth (PPD) ≥ 4 mm were randomly assigned to mechanical debridement with OCB (test) or TC (control). Treatment was performed at baseline and repeated at 3, 6, and 9 months in cases with > 1 implant site with BI ≥ 1 and PPD≥4 mm. Blinded examiners recorded PPD, BI, pus, and plaque. The radiographic bone level change between baseline and 12 months was calculated. A multistate model was used to calculate transitions of BI. Results Thirty‐one patients completed the study. Both groups exhibited a significant reduction in PPD, BI, and pus at 12 months compared to baseline. Radiographic analysis showed stable mean RBL in both groups at 12 months. There was no statistically significant difference in any of the parameters between the groups. Conclusions Within the limitations of this 12‐month multicenter randomized clinical trial, non‐surgical treatment of peri‐implantitis with OCB or TC showed no statistically significant differences between the groups. Clinical improvements and, in some cases, disease resolution, was observed in both groups. However, persistent inflammation was a common finding which further puts emphasis on the need for further treatment.