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

2025-08-26
Clinical oral investigations 29(9)
- Magda Mensi
- Eleonora Scotti
- Silvia Marchetti
- Annamaria Sordillo
- Gianluca Garzetti
- Stefano Calza
- Mark J Buijs
- Egija Zaura
- Bernd W Brandt

PubMed: 40856866
DOI: 10.1007/s00784-025-06508-w

Study Design

Type: Randomized Controlled Trial (RCT)
Population: 44 systemically healthy patients with a history of stage III or IV and grade B or C periodontitis and residual pockets
Methods: randomized clinical trial, full-mouth debridement at baseline, 3-weeks treatment with lozenges containing probiotic or placebo as adjunct to Guided Biofilm Therapy during supportive periodontal therapy
Blinding: Double-blind
Duration: 3 weeks
Funding: Unclear

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), Presence of supragingival plaque (PI), Clinical Attachment Loss (CAL) and Recession (REC). Two sites per patient with PPD ≥ 6 mm or PPD of 5 mm with BOP 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 were taken at baseline (T0), 3 months (T2), and 6 months (T3). Microbiological samples from the test sites were taken at baseline (T0), 3 weeks (T1), 3 months (T2), and 6 months (T3).

Results

Forty 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. No significant inter-group differences were detected in the red complex at any observation time. The subgingival microbial dysbiosis index (SMDI) revealed a decrease in dysbiosis from T0 to T1, followed by a slight increase in dysbiosis towards T3 for both groups. However, no significant differences were noted between the groups.

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.

Research Insights

Lactobacillus reuteri→Reduced Bleeding on Probing
The test group showed a lower percentage of BOP at sites with plaque at T2 and T3.
Effect
Beneficial
Effect size
Small
Dose
3 weeks of bi-daily supplementation with lozenges containing probiotic (specific CFU not stated in abstract)
Lactobacillus reuteri→Reduced Bleeding on Probing (BOP)
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.
Effect
Neutral
Effect size
Small
Dose
3 weeks of bi-daily supplementation with lozenges containing probiotic (specific CFU not stated in abstract)
Lactobacillus reuteri→Reduced Clinical Attachment Loss
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.
Effect
Neutral
Effect size
Small
Dose
3 weeks of bi-daily supplementation with lozenges containing probiotic (specific CFU not stated in abstract)
Lactobacillus reuteri→Reduced Periodontal Pocket Depth
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.
Effect
Neutral
Effect size
Small
Dose
3 weeks of bi-daily supplementation with lozenges containing probiotic (specific CFU not stated in abstract)
Lactobacillus reuteri→Reduced Probing Pocket Depth
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.
Effect
Neutral
Effect size
Small
Dose
3 weeks of bi-daily supplementation with lozenges containing probiotic (specific CFU not stated in abstract)
Lactobacillus reuteri→Reduced Red Complex Bacteria Count
No significant inter-group differences were detected in the red complex at any observation time.
Effect
Neutral
Effect size
Small
Dose
3 weeks of bi-daily supplementation with lozenges containing probiotic (specific CFU not stated in abstract)
Lactobacillus reuteri→Reduced Subgingival Microbial Dysbiosis Index
The subgingival microbial dysbiosis index (SMDI) revealed a decrease in dysbiosis from T0 to T1, followed by a slight increase in dysbiosis towards T3 for both groups. However, no significant differences were noted between the groups.
Effect
Neutral
Effect size
Small
Dose
3 weeks of bi-daily supplementation with lozenges containing probiotic (specific CFU not stated in abstract)