Clinical and microbiological effectiveness of limosilactobacillus reuteri in supportive periodontal therapy: randomized clinical trial

Objectives: 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 PPD, BOP, PI, CAL and REC. Two sites per patient with PPD≥6 mm or PPD of 5 mm with BOP were selected 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 were taken at baseline (T0), 3 months (T2), and 6 months (T3). Microbiological samples from test sites were taken at T0, 3 weeks (T1), T2, and T3. Results: Forty patients completed the study. Both groups showed 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 lower percentage of BOP at sites with plaque at T2 and T3. Microbiological analysis detected minimal proportion of L. reuteri in the periodontal pockets. No significant inter-group differences were detected in the red complex at any observation time. The SMDI revealed a decrease in dysbiosis from T0 to T1, followed by a slight increase towards T3 for both groups. Conclusions: In our cohort, 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.