title: Probiotics reduce mutans streptococci counts in humans: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Systematically review the available literature regarding the caries-preventive effect of probiotics.
  
  
  METHODS
  An electronic search was conducted in three databases (PubMed MEDLINE, ISI Web of Science and Cochrane Library) to identify all suitable studies. The outcomes had to be presented as the effect of probiotics on the incidence of caries or on the levels of mutans streptococci and/or Lactobacillus species. Human studies, written in English, with at least 15 participants, comparing a probiotic product with a placebo/no probiotic were included. Where possible, a meta-analysis was performed to obtain quantitative data.
  
  
  RESULTS
  Since only two articles presented useful data on the caries incidence, we focused on the surrogate endpoints: mutans streptococci and/or Lactobacillus counts. The meta-analysis showed that when the probiotic and control group are compared after treatment, significantly more patients in the probiotic group had low mutans streptococci (<10(5) CFU/ml) counts and significantly less patients had high (>10(6) CFU/ml) counts. Regarding the Lactobacillus counts, comparing the probiotic and control group at the end of the probiotic use, no significant differences could be observed, neither in low (<10(4) CFU/ml) nor in high Lactobacillus (>10(6) CFU/ml) counts.
  
  
  CONCLUSIONS
  Within the limitations of the available data, it may be concluded that probiotics decrease the mutans streptococci counts. This suggests that probiotics could have a positive effect in the prevention of caries.
  
  
  CONCLUSIONS
  There is insufficient evidence that probiotics can prevent caries, but they can reduce the mutans streptococci counts.
authors.affiliation: Department of Oral Health Sciences, KU Leuven & Dentistry, University Hospitals Leuven, Kapucijnenvoer 33, 3000, Leuven, Belgium.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Laleman
authors.forename: Valentine
authors.initials: V
authors.lastname: Detailleur
authors.forename: Dagmar Else
authors.initials: DE
authors.lastname: Slot
authors.forename: Vera
authors.initials: V
authors.lastname: Slomka
authors.forename: Marc
authors.initials: M
authors.lastname: Quirynen
authors.forename: Wim
authors.initials: W
authors.lastname: Teughels
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D015169:Colony Count, Microbial; D006801:Humans; D007778:Lactobacillus / Q000302:isolation & purification; D008875:Middle Aged; D019936:Probiotics; D013295:Streptococcus mutans / Q000302:isolation & purification*; D055815:Young Adult