Clinical and Microbiological Effectiveness of Limosilactobacillus Reuteri in Supportive Periodontal Therapy: Randomized Clinical Trial

Objectives The purpose of the present randomized clinical trial was to evaluate the clinical and microbiological effects of Limosilactobacillus reuteri probiotic therapy as an adjunct to Guided Biofilm Therapy (GBT) during supportive periodontal therapy (SPT) of patients with a history of stage III or IV and grade B or C periodontitis and residual pockets. Materials and Methods Forty-four systemically healthy patients were selected. Complete periodontal assessment was performed including Pocket Probing Depth (PPD), Bleeding on Probing (BOP), Plaque index (PI), Clinical Attachment Loss (CAL) and Recession (REC). Two sites per patient with PPD ≥ 6 mm or PPD of 5 mm with bleeding on probing were selected in two different quadrants as test sites. A session of full-mouth debridement was provided at baseline (T0), and patients were randomized to receive a 3-weeks treatment with lozenges containing probiotic or placebo. Periodontal parameters and microbiological samples from the test sites were taken at baseline (T0), 3 weeks (T1), 3 months (T2) and 6 months (T3). Results 40 patients completed the study. Both groups showed a significant decrease in PPD, BOP, CAL, and number/percentage of residual pockets compared to baseline. However, no inter-group differences were noted. The test group showed a lower percentage of BOP at sites with plaque at T2 and T3. The microbiological analysis detected minimal proportion of L. reuteri in the periodontal pockets. An increase in health-related species such as Streptococcus and Actinomyces was observed at T1 in both groups. However, at T2 and T3 the biofilm composition returned to baseline levels. Conclusion In our cohort of patients, 3 weeks of bi-daily supplementation with lozenges containing L. reuteri in conjunction with a session of SPT did not provide any additional reduction in PPD or number/percentage of residual pockets, and did not have a long-lasting effect on the subgingival biofilm microbial composition. However, patients receiving the probiotic had less bleeding at sites with plaque. Clinical relevance: Whilst L. reuteri cannot be recommended as a standard adjunctive therapy in SPT, it can be considered to reduce BOP levels in patients with poor plaque control.