Despite regular brushing, flossing, and professional cleaning, it is challenging to optimally suppress plaque buildup.
In an intriguing development, researchers have discovered two unique strains of bacteria that can prevent the buildup of plaque and biofilm on our teeth.
As we have come to learn, plaque-induced gum disease causes more than just halitosis (bad breath). Chronically inflamed gums lead to a host of degenerative disorders including atherosclerosis, diabetes, and cancer.
After years of study, a new oral probiotic lozenge may change how millions can achieve optimal oral health.
Poor Oral Health Increases Disease Risk
The human mouth is teeming with all kinds of bacteria. Many of those bacteria are harmless or even beneficial, but a sizable handful can cause diseases such as dental caries (cavities) and the much more serious gingivitis and periodontitis.
These conditions tend to be chronic and produce a steady elevation of inflammation in a part of the body that receives a very high blood flow (the mouth). The result of this bacterial “seeding” is the promotion of a host of destructive cytokines.1 These circulating cytokines produce inflammatory responses in tissues far distant from the mouth, including the vascular lining known as the endothelium, and dramatically increase the risk of atherosclerosis, heart attack, and stroke.2,3 Sadly, there is strong evidence that gum disease can also increase the risk of pre-term births and low birth weight.4 Periodontitis has also been linked with diabetes,2,5,6 and periodontal treatment may improve blood sugar control in diabetic patients.7 In short, the mouth is a dangerous place if not kept clean through meticulous hygiene.
The cardiovascular health impact of periodontitis is particularly troubling; people with chronic periodontitis may face an increased risk of heart attacks8 as well as kidney dysfunction related to atherosclerosis.9 Disturbingly, there is direct evidence that some pathogenic oral microbes make it into the bloodstream of people with gum inflammation, and even wind up forming part of the atherosclerotic plaque that causes vascular disease.10-12 Other mouth germs make platelets more sensitive to factors that increase the risk for abnormal blood clot formation.13 The good news is that we may be able to prevent or at least control the growth of those dangerous microorganisms in the first place through the use of a probiotic lozenge in the oral cavity.
Scientists have recently discovered two complementary probiotics that are producing dramatic benefits for oral and periodontal health. By optimizing the health of the oral cavity, these new oral probiotics may provide protection against a broad spectrum of disease issues, ranging from cardiovascular disease to diabetes.
Traditional Oral Health Care: Flossing, Brushing, and Rinsing
Dentists despair that most people fail to engage in the proper daily oral hygiene practices such as brushing, flossing, and mouth rinsing that are currently recommended for the prevention of so many conditions.14,15 Thanks to the work of pioneering scientists, probiotics can now make the mouth itself a contributor to health rather than disease.16-21
Probiotics Fight Plaque, Gingivitis
Probiotics have been defined as “living microorganisms which upon ingestion in certain numbers exert health benefits beyond inherent general nutrition.”22 Scientists have been interested in the makeup of the microbes that live in the mouth (the “oral flora”) for decades, seeking to identify factors that promote the growth of healthy organisms and reduce the growth of those implicated in disease and inflammation.23-26 Probiotics not only improve oral health but can help to change the stubborn composition of dental biofilm and plaque.27,28 While reducing the total amount of plaque through tooth brushing is always a desirable goal, its complete elimination is not possible. Therefore, changing the actual composition of plaque from an inflammatory cytokine-rich environment into a more benign environment dominated by neutral or even helpful organisms can contribute to overall systemic health.29-31
It was a leap of scientific imagination that allowed researchers to realize that the simple use of pro-biotics could make a significant difference in protecting oral health. A powerful demonstration of probiotics’ oral benefits came in 2001, with the publication of a study on tooth decay in children aged one to six.32 The researchers supplemented the children’s milk with a common probiotic bacterium, comparing their rate of cavities with those of kids given normal milk. Researchers examined the children’s oral health status at the beginning and end of a seven-month period. The probiotic group had fewer cavities and lower counts of a hostile bacterium implicated in dental cavities, compared with the control subjects.
In a more compelling study, Swedish scientists showed in 2006 that they could reverse symptoms of gingivitis through the use of another probiotic species in adults with moderate-to-severe inflammation.33 After just two weeks, subjects who received pro-biotics demonstrated a reduced amount of plaque and inflammation, compared with the placebo group.
Numerous clinical and laboratory studies have confirmed and clarified the ways in which probiotic organisms contribute to a reduction in plaque and hostile organism colonization.34-38
Discovering Advanced Forms of Probiotics
A microbiologist from New Zealand, Dr. John R. Tagg, is credited with advancing the science of using probiotics to enhance oral health. Dr. Tagg began his work with the 1981 publication of a paper on the role of mysterious compounds called bacteriocins on the formation of dental plaque.39 Dr. Tagg and his colleagues found that certain “friendly” oral bacteria were producing substances that inhibit the growth of other microbes. Because these microbes had no known use as drugs in humans they were given the name bacteriocins.40
What was remarkable about Tagg’s work was that the species of friendly Streptococcus salivarius bacteria that produced the bacteriocins can also be found to occur naturally in the mouth. Unlike other probiotic species, these strep organisms lived in benign symbiosis with the human oral cavity.18 Even more remarkable, the bacteriocin produced by Streptococcus salivarius (S. salivarius) bacteria had powerful inhibitory actions against other strep species, most notably those that cause dental cavities as well as serious human infections such as strep throat, deep tissue infections, and even rheumatic fever.18,19,41,42 By the end of the 1980s, Tagg’s group knew enough about their molecules to name them bacteriocin-like inhibitory substances, or BLIS.20,43
Dr. Tagg and his investigative team studied these bacteriocins intensively over the subsequent decade, determining their structures, mechanisms of action, and the means by which the S. salivarius germs were controlling bacteriocin production.44-47 Their work culminated in the 2003 publication of a landmark paper entitled “Bacterial replacement therapy: adapting ‘germ warfare’ to infection prevention.”17
In this article, Tagg and colleague Karen P. Dierksen review what they describe as an “ongoing battle” between oral microbes, some of which may pose an infectious threat to the host, and others of which confer protection. They propose further exploration of the use of probiotic organisms to colonize human tissues with health-promoting effector strains of beneficial bacteria that can out-compete disease-causing germs. Finally, they focus on recent progress in application of so-called avirulent (non-dangerous) S. salivarius species in the control of dental cavities, strep throats, and even childhood ear infections. Let’s take our own look at the evidence for these oral probiotics.
Beneficial microorganisms such as those studied by Dr. Tagg may contribute to improved dental health. In laboratory studies, the probiotic S. salivarius helped inhibit the formation of the sticky biofilm that can contribute to oral disease.41 Building on these results, a study in animals showed that the S. salivarius probiotic helped displace biofilm from the teeth, displacing cavity-causing bacteria and inhibiting tooth decay.42
Another in vitro experiment demonstrates how effectively a second oral probiotic protects oral health.48 In this experiment, a form of Bacillus coagulans (known as GanedenBC30™) was shown to competitively inhibit the cariogenic (cavity-inducing) bacterium Streptococcus mutans, which contributes to significant tooth decay. The photo below shows a Petri dish that was incubated at body temperature for two days after the left side was streaked with GanedenBC30 and the right side with S. mutans. You can see a large zone of inhibition between the two cultures, indicating that the S. mutans culture died as it approached the GanedenBC30 culture. This is indicated by the solid red line at the edge of the GanedenBC30 growth. The final zone of inhibition was 6 mm, which showed GanedenBC30 to be effective at inhibiting the growth of S. mutans.
Together, these findings suggest that both S. salivarius and B. coagulans probiotics can help prevent harmful bacteria from colonizing teeth and contributing to dental cavities.