Probiotic effects of orally administered Lactobacillus salivarius WB21-containing tablets on periodontopathic bacteria: a double-blinded, placebo-controlled, randomized clinical trial

J Clin Periodontol. 2009 Jun;36(6):506-13. doi: 10.1111/j.1600-051X.2009.01392.x. Epub 2009 Apr 22.


Aim: This study was designed to evaluate whether the oral administration of lactobacilli could change the bacterial population in supra/subgingival plaque.

Material and methods: Sixty-six healthy volunteers without severe periodontitis were randomized into two groups to receive lactobacilli or placebo for 8 weeks (8W): the test group (n=34) received 2.01 x 10(9) CFU/day of Lactobacillus salivarius WB21 and xylitol in tablets; the control group (n=32) received placebo with xylitol. Supra/subgingival plaque samples were collected at the baseline and after 4 weeks (4W) and 8W. The bacterial amounts in plaque samples were analysed by quantitative real-time polymerase chain reaction.

Results: The numerical sum of five selected periodontopathic bacteria in the test group was decreased significantly in subgingival plaque at 4W [odds ratio (OR)=3.13, 95% confidence intervals (CI)=1.28-7.65, p=0.012]. Multivariate analysis showed that significantly higher odds were obtained for the reduction of Tannerella forsythia in subgingival plaque of the test group at both 4W (OR=6.69, 95% CI=2.51-17.9, p<0.001) and 8W (OR=3.67, 95% CI=1.45-9.26, p=0.006).

Conclusion: Oral administration of probiotic lactobacilli reduced the numerical sum of five selected periodontopathic bacteria and could contribute to the beneficial effects on periodontal conditions.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aggregatibacter actinomycetemcomitans / isolation & purification
  • Bacteroides / isolation & purification
  • Colony Count, Microbial
  • Dental Plaque / microbiology
  • Dental Plaque Index
  • Double-Blind Method
  • Female
  • Follow-Up Studies
  • Gingival Hemorrhage / microbiology
  • Humans
  • Lactobacillus*
  • Male
  • Middle Aged
  • Periodontal Index
  • Periodontal Pocket / microbiology
  • Periodontitis / microbiology*
  • Placebos
  • Porphyromonas gingivalis / isolation & purification
  • Prevotella intermedia / isolation & purification
  • Probiotics / administration & dosage
  • Probiotics / therapeutic use*
  • Smoking
  • Tablets
  • Treponema denticola / isolation & purification
  • Xylitol


  • Placebos
  • Tablets
  • Xylitol