Streptococcus salivarius K12:
NOW Foods - OralBiotic® Lozenges

Contains a powerful strain of Streptococcus salivarius (BLIS K12®) which colonizes your mouth and defends you against bacteria attacking your teeth and gums. By crowding out bad bacteria, S. salivarius K12 also actively suppresses one major cause of bad breath when used regularly.[2]

Lactobacillus salivarius WB21

Lactobacillus salivarius is a probiotic bacteria species inhabiting the alimentary canal where among other things it works to suppress pathogenic bacteria. The WB21 strain has shown promise against cavities, bad breath and even periodontitis.[3]

Lactobacillus reuteri against cavities and gum disease

The study Decreased gum bleeding and reduced gingivitis by the probiotic Lactobacillus reuteri was able to show that patients with moderate to severe gingivitis saw both their gum disease and plaque go down when taking Lactobacillus reuteri. This probiotic appears to efficiently crowd out bacteria which cause plaque and gingivitis.

Another study "Effect of chewing gums containing xylitol or probiotic bacteria on salivary mutans streptococci and lactobacilli" ( showed that chewing gums containing two strains of Lactobacilli reuteri significantly reduced the levels of Streptococcus mutans in the saliva, i.e. one of the main culprits that cause cavities.

Streptococcus A12

A novel Streptococcus strain dubbed A12 was found to effectively arrest the growth of Streptococcus mutans such as by producing high amounts of hydrogen peroxyde.[4]

How to combine oral probiotics with xylitol/erythritol rinses

Rinsing with xylitol/erythritol is a powerful way to crowd out cavity- and gum-disease-causing microorganisms in your mouth. Xylitol however not only suppresses S. mutans but also (to a minor and less permanent degree) beneficial bacteria such as S. salivarius K12.

If you want to use both, make sure to give the probiotics several days time to really implant themselves in your mouth before using xylitol rinses again.

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1 For general background on probiotics, see Probiotics and Lactic Acid Bacteria.

2 See A preliminary study of the effect of probiotic Streptococcus salivarius K12 on oral malodour parameters,and

3 See Effects of Lactobacillus salivarius WB21 combined with green tea catechins on dental caries, periodontitis, and oral malodor and Effect of a Lactobacillus Salivarius Probiotic on a Double-Species Streptococcus Mutans and Candida Albicans Caries Biofilm.

4 A Highly Arginolytic Streptococcus Species That Potently Antagonizes Streptococcus mutans

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