Tipping the Balance Towards Health with Oral Probiotics

by Lorraine Gambacourt, RDH

Most people understand the benefits of gut probiotics, but fewer individuals and oral health professionals are aware of the preventive and/or supportive health benefits that oral probiotics can provide by reducing the risk or severity of oral disease. Could the addition of this modality to our traditional therapies be a “missing link” that could improve and help sustain treatment outcomes?

Probiotics designed for the oral cavity introduce specific strains of healthy bacteria to the oral environment, which provides the perfect niche for their growth while stopping or interfering with the growth of pathogenic bacteria. Numerous studies have shown that oral probiotics can be extremely useful in the prevention or treatment of oral disease and are also extremely promising as they cause little to no side effects.1

Introduced at the appropriate time, oral probiotics can be another tool in your arsenal to help prevent a destructive biofilm from returning to its “pre-periodontal therapy” state.


After the gut, the oral cavity has the next largest and most diverse microbiota and is home to over 700 different species of bacteria.2 The good or “probiotic” bacteria along with saliva, play an important role in our immune system as a part of our “first line of defense.”

Some bacteria colonize the oral mucosa early on, while others don’t show up until tooth eruption.3 The oral microbiome diversity changes from the time of birth and is influenced by the type of birth (vaginal or cesarian), feeding method (breast or formula) and the bacteria passed on via kissing from family members. Even the oral health of your mother at the time of your birth has an impact. As years progress, other factors influence the oral environment which can tip that beautiful balance, resulting in a dysbiosis and an environment where pathogens can thrive, leading to oral disease.

Within the oral microbiome, certain naturally occurring healthy probiotic bacteria provide protection from disease, while others are more harmful and can initiate disease. Highly prevalent conditions, such as dental decay, periodontal disease and halitosis begin to manifest when shifts in the biofilm occur. Pathogenic bacteria are also responsible for common ailments such as strep
throat, earache, upper respiratory infection, and sinus infection.

Once oral biofilm reaches a level of maturity where pathogenic bacteria are thriving, the potential for periodontal tissue destruction increases. Introducing oral probiotics at the appropriate time can provide significant benefits which include inhibiting oral biofilm development from reaching this level of destruction.


We live in an era when anti-bacterial agents are added to many oral products that we use daily. The effects are compounded with the frequency that we use these products. Other factors include smoking, stress, diet, (including consumption of acidic drinks) and antibiotics. Prescription medications and habits that increase dryness such as snoring, mouth breathing and use of oral appliances, will also change the oral environment.


  1. Colonization is the first necessary step which will occur on oral mucosa and teeth, with migration into periodontal pockets. Adequate colonization is dependent on many factors. Moisture, warmth, and available space in the biofilm are key, as well as timing.
  2. Binding: Probiotics bind to bacteria which decreases their ability to attach to gums and teeth, thus reducing their damaging effects.
    Competitive exclusion: Bacteria, whether good or bad, will compete for nutrients and space, thereby “crowding out” other bacteria.
  3. Natural antimicrobial properties: Some probiotics produce potent antimicrobial compounds such as acids, hydrogen peroxide, or antimicrobial proteins called bacteriocins which are like natural antibiotics that seek out and kill specific harmful pathogens or inhibit their growth.4
  4. Raise pH: Many oral probiotics can neutralize pH or provide a buffering effect on the saliva, which will help to protect from acid erosion and reduce the potential for decay. Having a more neutral pH also helps to keep the balance of good and bad bacteria.
  5. Provide powerful immune support: Certain probiotics have the ability to kill viruses and reduce inflammatory cytokines.5

The following probiotic strains are commonly found in oral probiotic supplements, offering a wide range of benefits to support the management of oral disease, as well as upper respiratory tract health.


S. salivarius K12 (BLIS K12™) inhibits Streptococcus pyogenes,6 which is the most important bacterial cause of pharyngeal infections in humans. It is a highly virulent bacteria that is responsible for strep throat, scarlet fever, rheumatic fever, and impetigo. In addition, PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcus) is a syndrome that can occur in children following an infection involving S. pyogenes.

S. salivarius K12 also inhibits Streptococcus pneumoniae, a key pathogen in the development of pneumonia and ear infections. Numerous studies over the past twenty years have shown the benefits of S. salivarius K12 in the reduction of throat and ear infections in both children and adults.7 One published in 2018 followed 133 children aged 3-14 who received S. salivarius K12 for 90 consecutive days for two periods (Oct-Dec and Apr-June). The outcome showed a 90% reduction of throat infection and a 70% reduction of ear infection (acute otitis media).8

This strain provides powerful immune support9 and may help prevent or reduce symptoms associated with viral infections.10,11 A recent study published in 2020 reveals the potential for S. salivarius K12 to improve oral and lung microbiota and raise defenses against SARS-CoV-2.12

Additional benefits include its ability to inhibit Candida growth13 and to crowd out harmful periodontal pathogens such as Prevotella intermedia and Porphyromonas gingivalis, and many others that contribute to halitosis.14


S. salivarius M18 (BLIS M18 ™) can improve periodontal health,15 reduce the pro-inflammatory cytokine response16,17 and reduce caries risk.18 In addition to producing four potent bacteriocins, it produces two enzymes which include urease (neutralizes lactic acid) and dextranase (breaks down plaque). Its role in the reduction of the development of cavities is in part due to its ability to inhibit Streptococcus mutans (Sm), as well as Actinomyces viscosus (Av) which contributes to plaque formation.

There are also four key significant periodontal pathogens that this probiotic strain inhibits that dental health professionals are very familiar with! Aggregatibacter actinomycetemcomitans (Aa), Prevotella intermedia (Pi), Porphyromonas gingivalis, (Pg) and Fusobacterium nucleatum (Fn).


L. salivarius is a strain that supports both tooth and gum health. Studies show a variety of benefits, including reduction of bleeding on probing, reduction in the virulence of Aa,19 increased resistance to cavities,20 the reduction of Tannerella forsythia (Tf),21 reduced plaque indices and probing pocket depths.22 L. salivarius also produces a small amount of hydrogen peroxide (H2O2) and is also capable of decreasing some of the pathogens that contribute to bad breath.23


L. reuteri DSM 17938 and L. reuteri ATCC PTA 5289 are two strains that are found in a specific product called Prodentis by BioGaia® and have shown many benefits to oral health including reduction of pockets, reduction of periodontal pathogens including Aa, Pg and Pi, as well as Sm, reduction of Candida, and reduction of pro-inflammatory cytokines.24,25,26


L. paracasei can help to reduce the potential for decay through its ability to bind to S. mutans.27 Some studies have shown that L. paracasei can also protect against Candida albicans.28 This strain can be found in some oral probiotic products, including a charcoal toothpaste.


Compare a healthy balanced oral microbiome to a beautifully groomed garden. If you tend to your garden every few days, plucking out any weeds that break through the surface, because they are small and not well rooted, they come out easily. This garden is easy to manage and is thriving.

Now imagine a garden that has not been tended to for years. Weeds are filling every space—tall, dense, and overgrown, blocking many of the lovely plants that were once blooming, blocking the sun, and preventing the flowering plants from blooming. The time and effort needed to bring this garden back to its former glory will be significant, but it can be done!

The beautiful garden can be compared to the mouth that has been restored to health, previously inhabited by many harmful pathogens. Oral probiotics introduced at this time will compete for space and crowd out pathogens, preventing them from reaching the levels that may once again tip the balance toward disease.

While oral probiotics can undoubtedly provide significant benefits to oral health, it is important to point out that the timing of the recommendation is critical for optimal results.


Compare disease in the chronic active state to the analogy of the garden that has not been tended to for years. Whether you are treating tooth decay, periodontal disease, or halitosis, there are certain steps that must be employed before introducing oral probiotics.

Tooth Decay: Risk factors must be assessed and modified. Assessment should also include the use of a disclosing solution, individualized oral hygiene coaching, diet evaluation including the type of water being consumed and sources of acidic food or drink. Recommend the oral probiotics that help to reduce the populations of S. mutans, reduce plaque accumulation and/or neutralize the pH of saliva. You may wish to utilize other modalities such as antimicrobial varnishes, fluoride, and xylitol products.

Periodontal Disease: When considering what to include in a periodontal therapy program, it is important to understand and address the multi-faceted nature of this disease. Treatment should include plaque assessment using disclosing solution, self-care coaching, risk factor assessment, biofilm DNA analysis, reduction of the biofilm burden, and addressing the host response when indicated. Consider implementing oral probiotics in the maintenance phase.

Halitosis: It affects 50% of the population to varying degrees. Although multifactorial in origin, about 90% of breath odour relates to oral conditions and the volatile molecules produced either from pathogens or other sources.29 Some of the more well-known gram-negative anaerobic bacteria that contribute to VSC (volatile sulphur compounds) production include the red complex (Pg, Td, Tf), Fn and Pi.30 Just as in the treatment of periodontal disease, treatment can be complex. Biofilm DNA analysis is ideal and may reveal the need to use various modalities to reduce the overall biofilm burden. The mouth should be evaluated for food trap areas, broken teeth, overhangs etc. which will attract bacteria. Oral self care should be assessed using disclosing solution. Evaluation of diet, water intake, and meal pattern is also important. Daily tongue cleaning should be included in self care as a tongue coating will not only contribute to odours but can also prevent oral probiotics from achieving optimal colonization.31 The use of sodium chlorite mouthwashes, which target gram negative anaerobes and help neutralize VSC’s, are beneficial but may be
required less frequently when oral probiotics are used daily.


Oral probiotics are available via different delivery methods: lozenges, chewing gum, powder, (ideal for infants and toddlers), toothpaste, and a paper-thin strip, ideal for overnight colonization.

The ideal time to begin introducing oral probiotics is after having a hygiene therapy appointment, or comprehensive active periodontal therapy so the bacterial load has been significantly reduced. In the same way that we take vitamins daily, the best way to ensure adequate protection from oral probiotics is to take them daily and ideally as the last step before bed. Consistency and quantity are key. Lozenges should be dissolved slowly to allow for time to colonize. Tooth brushing and mouthwash use should be completed prior to taking the probiotics. Wait at least 30 minutes before eating or drinking.

The persistence of adequate levels of oral probiotics will vary from host to host. Therefore, it is recommended that they are taken regularly and in particular at times of perceived infection risk, such as cold and flu seasons, and air travel.


While introducing oral probiotics in the maintenance phase of treatment is ideal, it does not completely remove the risk of infection. Adding this adjunct to our treatment therapies can most definitely lower risk, help prevent disease, boost our immune defenses, and improve treatment outcomes.

Dental professionals have the privilege of being entrusted with the care of numerous clients daily who look for support, guidance, and recommendations. Recommending oral probiotics can provide therapeutic and preventive benefits and are also safe and effective. Think of the impact we can make by informing parents of the benefits that some oral probiotics can provide in the prevention of ear and throat infections!


Create a handout with some basic information, websites, and product recommendations to give to clients.

Do your own research on various oral probiotic strains as well as the supplements available in your area or online. Products, availability, and options to ship may vary depending on where you live, and your client may want to avoid cross border shopping.

As you converse with parents and grandparents, be an active listener and notice if they mention a child in their life who suffers with throat or ear infections.

Visit your local health food store or naturopathic clinics and inquire about whether they carry or can order oral probiotics. Let’s help make it easier for our clients to access oral probiotics.

Together we can make an impact and help tip the balance towards health!


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About the Author

Lorraine obtained her Dental Hygiene Diploma from George Brown College in 1985. She has presented on a variety of topics and is passionate about the Oral Systemic Connection and promoting medical/dental collaboration. Lorraine also enjoys inspiring others via blogging and writing. Her article, “A Healthy Mouth—A Healthier Heart” was published in Oral Hygiene in February 2018 and she is a co-author of the recently published book, “Get Your Spit Together.”