Are Probiotics Good for Oral Health?

It’s happened again – something we all knew was good for us now may not be so much.

Spin the wheel—and it’s—


But not because it directly disturbs your oral microbiome (according to one study using Scope®, it really doesn’t), but because if you exercise (and if you’re an avid reader of our blogs, you likely do), continued mouthwash use may disrupt your blood pressure regulation. Exercise is known to promote healthy blood pressure by reducing it. But recently, researchers have shown that when you use an antibacterial mouthwash, a series of biochemical reactions involving your oral bacteria may inhibit the blood pressure-reducing effect of exercise.

So, it’s like this: nitric oxide increases when you exercise, promoting better circulation to muscles. Nitric oxide degrades to a nitrate, and according to the study authors, some bacterial species in the mouth will convert nitrate into nitrite. Blocking nitrate’s ability to convert into nitrite by inhibiting oral bacteria therefore prevents blood pressure from reducing normally during typical exercise. A group of 23 people involve in the study were asked to exercise and use either an antibacterial mouthwash or placebo rinse. The results showed that those in the group who experienced a blood pressure-lowering effect from the antibacterial mouthwash was diminished by 60% after one hour post-exercise, and totally null after two hours.

Lead author Craig Cutler, PhD, commented, "These findings show that nitrite synthesis by oral bacteria is hugely important in kick-starting how our bodies react to exercise over the first period of recovery, promoting lower blood pressure and greater muscle oxygenation. In effect, it's like oral bacteria are the 'key' to opening up the blood vessels. If they are removed, nitrite can't be produced and the vessels remain in their current state.”

We all have big mouths—at least when referring to the resident oral microbiota. Your mouth is not like, say, a state harboring a variety of resident flora-- it’s like the earth, with multiple specific regions and cultures. According to one published scientific article, “The oral microbiome is comprised of over 600 prevalent taxa at the species level, with distinct subsets predominating at different habitats….The oral cavity, or mouth, includes several distinct microbial habitats, such as teeth, gingival sulcus, attached gingiva, tongue, cheek, lip, hard palate, and soft palate.”

The above study suggests that antibacterial mouthwash exerts a similar action as antibiotics in the gut—widespread destruction of both bad and good bacteria. And as with taking probiotics to balance and improve the gut flora habitat, so too is the goal of creating a favorably balanced oral bacterial habitat.

More dentists and oral care surgeons are emphasizing proper oral hygiene that includes taking probiotics. As one expert, Mark Burhenne, DDS, explains, “Numerous diseases have been associated with oral pathogen overgrowth,” wherein there are more harmful bacteria residing in the mouth and not enough good bacteria to crowd them out.

For example, periodontitis, a gum disease characterized as an oral chronic infection-inflammatory condition, has been found to be a causative factor of heart disease, and even Alzheimer’s disease.

According to probiotics experts, a host of research shows that for oral health particularly, probiotics can reduce and/or resolve halitosis infections (bad breath, often caused by bacteria), gingivitis, periodontitis, caries (“cavities”), and candida. According to authors of one study of probiotics applications in oral health, “In medicine, probiotics are used mainly in support therapy for gastro-intestinal diseases. In recent years, probiotics have been used as a treatment to promote oral health. This approach has shown promising results in the oral cavity with respect to control of chronic diseases such as dental caries, periodontitis, and recurring problems such as halitosis and candidal infections.”

There are specific probiotics that thrive in the oral arena, silently keeping you healthy by battling incoming invaders that want to wreak havoc upon your internal person—meaning, make you sick to your stomach, literally—as well as increasing your risk of chronic diseases as mentioned.

The most well known oral health probiotics are Streptococcus salivarius K12 and Streptococcus salivarius M18. These are distinguished by their ability to produce bacteriocin-like inhibitory substances (“BLIS”)—which enhance oral immunity by protecting against pathogenic bacteria that often cause ear infections (Otitis media) and strep throat.

How Probiotics Support Oral Health

Oral health probiotics have both direct and indirect mechanisms of action. Directly, they prevent formation of plaque by competing with pathogenic bacterial adhesion on the surface of teeth. Indirectly, they regulate mucosal permeability (another protective action), and modulate the systemic immune system, impacting local (oral) immune function.

Studies have shown oral probiotics can resolve halitosis (bad breath), help prevent formation of cavities and fight plaque. Halitosis (bad breath) is often caused by volatile sulfur compounds hydrogen sulfide, methyl mercaptan and dimethyl sulfide, which are produced by bacterial degradation of sulfur-containing amino acids in the oropharynx (back of the mouth, upper throat).

A clinical study of 23 subjects by Burton et al., where Streptococcus salivarius K12 was shown to be effective at reducing the levels of volatile sulfur compounds (VSC) in the exhaled breath, which are responsible for chronic oral malodor and halitosis. Another study later confirmed BLIS K12’s ability to inhibit bacteria responsible for the severe bad breath in the oral cavity, known as halitosis, although this study was in-vitro experiment.

Cavities are multifactorial in causes—but it is generally agreed that the pathogen Streptococcus mutans is the main cause of acid demineralization of the tooth enamel. Elevated levels of S. mutans increases risk for developing cavities.

Studies have shown that probiotics L. rhamnosus GG and L. casei or Bifidobacterium DN-173 010, have significantly reduced the growth of oral streptococci and attendant risk of developing cavities. L. rhamnosus GG’s ability to ferment sugars glucose, fructose, mannitol, and trehalose resulted in oral pH values between 5.2 and 6.8 after 24 hours of incubation and resulted in prohibiting S. mutans from decalcifying/eroding teeth.

Gum issues such as gingivitis (a condition characterized by inflammation to gum tissues) and periodontitis (a progressive gum disease) may also benefit from probiotics.

Studies have shown that 14-day consumption of L. reuteri for 14 days led to the establishment of the strain in the mouth and significantly reduced gingivitis and plaque in individuals with moderate to severe gingivitis. L. casei 37 was shown to reduce the number of most common periodontal pathogens and L. salivarius TI 2711 inhibited P. gingivalis when taken for 4 or 8 weeks.

In one study, the authors assert, “With in dentistry, studies with L. rhamnosous GG, L. reuteri have defined their potential in interacting with S. mutans by reducing the number of this caries pathogen, thus suggesting a role of probiotics in caries prophylaxis.”


These authors also stated, “Probiotics have many positive influences in creating better oral health.” Other things you can do to improve and protect oral health include cutting down on eating sugars and simple carbs, drink more water and tea, and brush and floss daily. Get creative—you can make your own natural mouthwashes, which will refresh your mouth and better protect the good bacteria for improved oral health.

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