Objective: The aim of this double-blind randomized placebo-controlled trial was to evaluate the effects of probiotic supplements in adjunct to conventional management of peri-implant mucositis.

Methods: Forty-nine adult patients with peri-implant mucositis were consecutively recruited after informed consent. After initial mechanical debridement and oral hygiene instructions, the patients received a topical oil application (active or placebo) followed by twice-daily intake of lozenges (active or placebo) for 3 months. The active products contained a mix of two strains of Lactobacillus reuteri. Patients were clinically monitored and sampled at baseline and after 1, 2, 4, 12 and 26 weeks. The clinical end-points were pocket-probing depth (PPD), plaque index (PI) and bleeding on probing (BOP). In addition, the subgingival microbiota was processed with checkerboard DNA-DNA hybridization and samples of gingival crevicular fluid (GCF) were analyzed for selected cytokines with the aid of multiplex immunoassays.

Results: After 4 and 12 weeks, all clinical parameters were improved in both the test and the placebo group. PPD and BOP were significantly reduced compared with baseline (p < 0.05), but no significant differences were displayed between the groups. The clinical improvements persisted 3 months after the intervention. No major alterations of the subgingival microflora were disclosed and the levels of inflammatory mediators in GCF did not differ between the groups.

Conclusions: Mechanical debridement and oral hygiene reinforcement resulted in clinical improvement of peri-implant mucositis and a reduction in cytokine levels. Probiotic supplements did not provide added benefit to placebo.