Lactobacillus reuteri and Reduced Plaque Index

Research synthesisLow evidenceMixed effect size4 studies · 3 beneficial · 1 neutral · 0 harmful

Across 4 studies, 3 reported beneficial effects on plaque index, but the highest-quality RCT (evidence score 5) found no effect. The predominant effect size among beneficial studies was mixed (small to large). Evidence is limited by small sample sizes, inconsistent findings, and poorly reported doses.

Caveats: Evidence base is small (only 4 studies) — conclusions should be considered preliminary. The highest-quality study (RCT with evidence score 5) showed no significant effect, while lower-quality studies reported benefits. Effects may be population-specific (e.g., peri-implantitis, adolescents with betel quid chewing) and not generalizable. Doses were poorly reported, limiting dose-response assessment.

Generated Jul 9, 2026

Doses used in studies

day: 2 (median 2, IQR 2–2) — 1 study
lozenge/day: 1 (median 1, IQR 1–1) — 1 study

Time to effect

Median: 4.5 months · IQR 3.8 months–5.3 months · Range 3 months–6 months — Reported in 2 of 4 studies

4 of 4 papersPopulation:

Effect of adjuvant probiotic therapy (Lactobacillus reuteri) in the treatment of periodontitis associated with diabetes mellitus: clinical, controlled, and randomized study.
- 2024-01-06
- RCT · n = 20
- Clinical oral investigations 28(1)
- - Maria Aparecida Neves Jardini
  - Juliana Fatima Pedroso
  - Camila Lopes Ferreira
  - Camilla Magnoni Moretto Nunes
  - Cadiele Oliana Reichert
  - Marlene Nunez Aldin
  - Antonio Martins Figueiredo Neto
  - Debora Levy
  - Nagila Raquel Teixeira Damasceno
- PubMed: 38183505
- DOI: 10.1007/s00784-023-05441-0
15 Insights on
- Reduced Plaque Index
- High evidence
- Clinical
The use of L. reuteri probiotics had no additional effects compared with the placebo
Effect
Neutral
Effect size
Small
Significant
No
Dose
not specified
Impact of Subgingival Lactobacillus reuteri Probiotic Therapy on Clinical Outcomes and Porphyromonas gingivalis Quantification in Peri-Implant Disease: A Prospective RT-PCR-Based Clinical Study.
- 2026
- RCT · n = 26
- Journal of long-term effects of medical implants 36(1)
- - Karthick Kamalakannan
  - Arvina Rajasekar
- PubMed: 41662654
- DOI: 10.1615/jlongtermeffmedimplants.2025060737
5 Insights on
- Reduced Plaque Index
- High evidence
- Clinical
Group 2 exhibited significantly greater reductions in PI, GI, PPD, CAL, and P. gingivalis levels compared with Group 1 (P = 0.00)
Effect
Beneficial
Effect size
Large
Significant
Yes
Dose
not specified
Correlation of probiotic consumption with plaque index, salivary pH, and streptococcus mutans: A clinical experimental study.
- 2025-11-11
- Clinical Trial · n = 40
- The Saudi dental journal 37(10-12)
- - Rista Lewiyonah
  - Heriandi Sutadi
  - Eva Fauziah
- PubMed: 41214230
- DOI: 10.1007/s44445-025-00010-5
4 Insights on
- Reduced Plaque Index
- High evidence
The correlation coefficient between Lactobacillus reuteri probiotics consumption and plaque index is 0.672
Effect
Beneficial
Effect size
Moderate
Significant
Yes
Dose
one lozenge daily
Effectiveness of Lactobacillus reuteri Probiotics on Plaque Index, Gingival Index, and Bleeding on Probing in Adolescents with Betel Quid Chewing Habit: Study in Children Aged 13-15 Years in Alor Regency, East Nusa Tenggara.
- 2026-02-12
- Observational
- International journal of clinical pediatric dentistry 19(2)
- - Labiba Idzni Marjani
  - Margaretha Suharsini
  - Eva Fauziah
- PubMed: 41800014
- DOI: 10.5005/jp-journals-10005-3411
4 Insights on
- Reduced Plaque Index
- Low evidence
There was a significant difference in PI, GI, and BOP scores before and after consuming L. reuteri for 7 and 14 days (p < 0.05).
Effect
Beneficial
Effect size
Small
Significant
Yes
Dose
twice a day for 14 days

Lactobacillus reuteri and Reduced Plaque Index

Effect of adjuvant probiotic therapy (Lactobacillus reuteri) in the treatment of periodontitis associated with diabetes mellitus: clinical, controlled, and randomized study.

Impact of Subgingival Lactobacillus reuteri Probiotic Therapy on Clinical Outcomes and Porphyromonas gingivalis Quantification in Peri-Implant Disease: A Prospective RT-PCR-Based Clinical Study.

Correlation of probiotic consumption with plaque index, salivary pH, and streptococcus mutans: A clinical experimental study.

Effectiveness of Lactobacillus reuteri Probiotics on Plaque Index, Gingival Index, and Bleeding on Probing in Adolescents with Betel Quid Chewing Habit: Study in Children Aged 13-15 Years in Alor Regency, East Nusa Tenggara.