Effects of sodium bicarbonate dentifrices on the levels of cariogenic bacteria in human saliva

Caries Res. 1995;29(2):143-7. doi: 10.1159/000262056.


This investigation evaluated the efficacy of two bicarbonate-containing dentifrices (one with fluoride and one without) against one placebo dentifrice (containing neither fluoride nor bicarbonate) in vivo in a panel of human volunteers to determine whether or not sodium bicarbonate would affect salivary mutans streptococci and lactobacilli. Ten caries-inactive adults were divided randomly into three groups, each of which was exposed to all three dentifrices, in a crossover manner, during three 4-week test periods. Saliva samples were taken at 1-week intervals. Samples were stored on ice, and microbiological analyses were conducted. The statistical analyses showed that, over a 4-week period, there was a statistically significant (p < 0.05) reduction in numbers of mutans streptococci with the two bicarbonate dentifrices as compared with the placebo dentifrice. Although not statistically significant, a similar trend was observed with lactobacilli. Longer-term, large-scale studies need to be conducted to investigate the possible mechanisms of action of sodium bicarbonate on these organisms and to relate the results to possible cariostatic effects in humans.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Colony Count, Microbial
  • Cross-Over Studies
  • Dental Caries / microbiology*
  • Dentifrices* / analysis
  • Double-Blind Method
  • Fluorides / analysis
  • Fluorides / pharmacology
  • Humans
  • Lactobacillus / drug effects*
  • Lactobacillus / isolation & purification
  • Placebos
  • Saliva / microbiology
  • Sodium Bicarbonate / analysis
  • Sodium Bicarbonate / pharmacology*
  • Streptococcus mutans / drug effects*
  • Streptococcus mutans / isolation & purification


  • Dentifrices
  • Placebos
  • Sodium Bicarbonate
  • Fluorides