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Influence of the probiotic Streptococcus salivarius strain M18 on indices of dental health in children: a randomized double-blind, placebo-controlled trial.

  • 2013-06-01
  • Journal of Medical Microbiology 62(6)
    • J. Burton
    • B. Drummond
    • C. Chilcott
    • J. Tagg
    • W. Thomson
    • J. Hale
    • P. Wescombe


The prevalence of dental caries continues to increase, and novel strategies to reverse this trend appear necessary. The probiotic Streptococcus salivarius strain M18 offers the potential to confer oral health benefits as it produces bacteriocins targeting the important cariogenic species Streptococcus mutans, as well as the enzymes dextranase and urease, which could help reduce dental plaque accumulation and acidification, respectively. In a randomized double-blind, placebo-controlled study of 100 dental caries-active children, treatment with M18 was administered for 3 months and the participants were assessed for changes to their plaque score and gingival and soft-tissue health and to their salivary levels of S. salivarius, S. mutans, lactobacilli, β-haemolytic streptococci and Candida species. At treatment end, the plaque scores were significantly (P = 0.05) lower for children in the M18-treated group, especially in subjects having high initial plaque scores. The absence of any significant adverse events supported the safety of the probiotic treatment. Cell-culture analyses of sequential saliva samples showed no differences between the probiotic and placebo groups in counts of the specifically enumerated oral micro-organisms, with the exception of the subgroup of the M18-treated children who appeared to have been colonized most effectively with M18. This subgroup exhibited reduced S. mutans counts, indicating that the anti-caries activity of M18 probiotic treatments may be enhanced if the efficiency of colonization is increased. It was concluded that S. salivarius M18 can provide oral health benefits when taken regularly.

Research Insights

SupplementHealth OutcomeEffect TypeEffect Size
Streptococcus salivariusNo Significant Adverse EventsNeutral
Streptococcus salivariusReduced Mutans Streptococcus CountsBeneficial
Streptococcus salivariusReduced Plaque ScoreBeneficial
Streptococcus salivarius BLIS M18Improved Oral HealthBeneficial
Streptococcus salivarius BLIS M18Reduced Formation of Dental PlaqueBeneficial
Streptococcus salivarius BLIS M18Reduced Mutans Streptococcus CountsBeneficial
Streptococcus salivarius M18Maintained Soft-Tissue HealthNeutral
Streptococcus salivarius M18Reduced Mutans Streptococcus CountsBeneficial
Streptococcus salivarius M18Reduced Plaque ScoreBeneficial
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