Efficacy of different nonsurgical treatments for peri-implantitis: a multi-arm randomized controlled clinical trial.

Peri-implantitis remains a challenging biofilm-associated condition, and the comparative effectiveness of adjunctive nonsurgical decontamination approaches is still unclear. This randomized, assessor-blinded, multi-arm clinical trial evaluated the clinical performance of different local submarginal decontamination protocols used alone or in combination with mechanical instrumentation in the management of early peri-implantitis lesions. Eighty implants from 26 patients were allocated to five treatment groups: mechanical instrumentation alone, mechanical instrumentation combined with chlorhexidine irrigation, ozone application, or glycine powder air abrasion, and glycine powder air abrasion as monotherapy. Clinical parameters, including probing pocket depth, bleeding on probing, and modified plaque index, were assessed at baseline, 3 months, and 6 months, and analyzed using linear mixed-effects models accounting for clustering at the patient level. All treatment modalities resulted in significant clinical improvements over 6 months. The greatest numerical reductions in probing depth, bleeding on probing, and plaque index were observed when mechanical instrumentation was combined with glycine powder air abrasion; however, no statistically significant differences were detected among treatment groups. These findings suggest that nonsurgical mechanical instrumentation, with or without adjunctive approaches, can provide meaningful short-term improvements in early peri-implantitis, while adjunctive glycine powder air abrasion may offer additional clinical benefits without demonstrating clear overall superiority.