A Healthy Oral Microbiome: The Key to Systemic Health

Is there more than one microbiome?

oral microbiome smiling with curly hair, laughs while has morning routines, shows bright smile, holds toothbrush, stands with bare shoulders over blue background

When we think of the human microbiome, we typically think of the gut microbiome in the lower gastrointestinal tract. However, thanks to many years of research, we have discovered many unique microbiomes throughout the body, such as the mouth, the urogenital tract, and even the skin. Each of these microbiomes exists to serve the body by providing a protective health benefit for their specific location and are considered to be well-balanced when the beneficial bacteria effectively compete with pathogenic bacteria. Additionally, our microbiomes exist to provide support to the immune system by decreasing inflammation from elevated cytokines.[1]

As science continues to explore the various microbiomes throughout the human body, the oral microbiome, in particular, has fascinated researchers. Besides being the second-largest microbiome (after the gut), the oral microbiome presents an incredibly biodiverse collection of microorganisms. With the advancement of genomic technologies, we can learn even more about the importance of this complex microbiome and its significant implications for our health.[2]  A healthy oral microbiome is a key component of our overall health. To understand how to properly support the oral microbiome, let us first examine its uniqueness in relation to the rest of the body.

How is the oral microbiome unique?

The primary uniqueness of the oral microbiome is its diversity. This microbiome features a vast array of bacteria, viruses, yeast, archaea (species of methanogen producers), and protozoa. There are more than 1,000 species of bacteria within the oral microbiome. Though this microbiome includes some familiar groups such as actinobacteria, bacteroides, and firmicutes, many species remain unidentified.[8] These groups include the commonly known lactobacillus, bifidobacteria, and streptococcus bacteria. These beneficial probiotic bacteria work to keep the oral biofilm healthy and balanced. The balance of the microbiome acts as a preventative measure against the overgrowth of pathogenic bacteria.

An imbalance of beneficial bacteria and pathogenic bacteria, as well as environmental factors (such as diet and smoking) can cause dysbiosis, which leads to a broad array of dental health complications.

How does a healthy oral microbiome contribute to healthy teeth and gums?

Because there is a delicate balance of probiotic and pathogenic microbiota within the oral cavity, even a slight change in diet can have profound health implications. One such example is the bacteria Streptococcus mutans. S. mutans is a typical inhabitant of the oral microbiome and does not necessarily pose a threat when the microbiome is healthy and balanced. However, under certain conditions and when the amount of S. mutans becomes excessive, it is the most common bacteria contributing to periodontal and dental caries. S. mutans and other bacteria form biofilms on the teeth, commonly known as dental plaque.[11] The bacteria within the biofilm metabolize sugars and produce acids that break down or demineralize tooth enamel and dentin, leading to dental caries. Therefore, a person’s diet, specifically the amount of sugar in their diet, can create an environment where pathogenic bacteria thrive, causing an imbalanced microbiome and increasing the risk of developing dental caries. Supporting a healthy oral microbiome goes beyond a healthy mouth, research has found significant correlations between dental health and systemic health.

Are there supplements that support the oral microbiome?

Research has demonstrated clear indications that a healthy oral microbiome supports over all health. One method of supporting the oral microbiome is supplementation with probiotics. Research has shown improved oral microbiome health when supplementing with various probiotics. For example, oral tablets containing Lactobacillus salivarius have been shown in clinical studies to improve the balance of the oral microbiome.[20] Furthermore, when EGCG (of the form found in green tea), which is an antioxidant, was administered alongside L. salivarius, the beneficial effect was even more substantial. Lactobacillus reuteri, also a probiotic strain of bacteria, produces organic acids, hydrogen peroxide, and a bacteriocin-like compound that support microbial balance.[22] As with L. salivarius, the use of oral tablets containing L. reuteri, were found to provide tangible benefits.[23] Indeed, based on this cited research, oral tablets appear to be an extremely effective way to target and support a healthy oral microbiome.


Because the human body relies on beneficial bacteria to maintain proper health and functioning of our microbiomes, their may be benefits to supporting these essential organisms. In the case of the oral microbiome, research suggests that specific probiotic supplements may play a role in maintaining a healthy microbial balance.  Because the oral microbiome plays a crucial role in the health of the entire body, supporting a healthy oral microbiome may also support broader systemic health.


[1] Haukioja A. Probiotics and oral health. Eur J Dent. 2010;4(3):348-355

[2] Deo PN, Deshmukh R. Oral microbiome: Unveiling the fundamentals. J Oral Maxillofac Pathol. 2019;23(1):122-128. doi:10.4103/jomfp.JOMFP_304_18

[3] Seymour, G. J., P. J. Ford, M. P. Cullinan, S. Leishman, and K. Yamazaki.2007. Relationship between periodontal infections and systemic disease. Clin. Microbiol. Infect.13(Suppl. 4):3-10.

[4] Beck, J. D., and S. Offenbacher.2005. Systemic effects of periodontitis: epidemiology of periodontal disease and cardiovascular disease. J. Periodontol.76:2089-2100.

[5] Joshipura, K. J., E. B. Rimm, C. W. Douglass, D. Trichopoulos, A. Ascherio, and W. C. Willett.1996. Poor oral health and coronary heart disease. J. Dent. Res.75:1631-1636.

[6] Joshipura, K. J., H. C. Hung, E. B. Rimm, W. C. Willett, and A. Ascherio.2003. Periodontal disease, tooth loss, and incidence of ischemic stroke. Stroke34:47-52.

[7] Awano, S., T. Ansai, Y. Takata, I. Soh, S. Akifusa, T. Hamasaki, A. Yoshida, K. Sonoki, K. Fujisawa, and T. Takehara.2008. Oral health and mortality risk from pneumonia in the elderly. J. Dent. Res.87:334-339.

[8] Wade WG. The oral microbiome in health and disease. Pharmacol Res. 2013 Mar;69(1):137-43. doi: 10.1016/j.phrs.2012.11.006. Epub 2012 Nov 28. PMID: 23201354.

[9] Dewhirst FE, Chen T, Izard J, Paster BJ, Tanner AC, Yu WH, Lakshmanan A, Wade WG. The human oral microbiome. J Bacteriol. 2010 Oct;192(19):5002-17. doi: 10.1128/JB.00542-10. Epub 2010 Jul 23. PMID: 20656903; PMCID: PMC2944498.

[10] Seminario-Amez M. et al. Probiotics and oral health: A systematic review. Med Oral Patol Oral Cir Bucal. 2017;22(3):e282-e288.

[11] Bowden GH. The Microbial Ecology of Dental Caries. Microbial Ecology in Health and Disease. 2000. 12:3, 138-148.

[12] Pitts, N., & Zero, D. White Paper on Dental Caries Prevention and Management: A summary of the current evidence and the key issues in controlling this preventable disease. FDI World Dental Press Ltd. 2016. https://www.fdiworlddental.org/sites/default/files/2020-11/2016-fdi_cpp-white_paper.pdf

[13] Kumar PS. From focal sepsis to periodontal medicine: a century of exploring the role of the oral microbiome in systemic disease. J Physiol. 2017 Jan 15;595(2):465-476. doi: 10.1113/JP272427. Epub 2016 Aug 28. PMID: 27426277; PMCID: PMC5233655.

[14] Tonetti MS. Et al. Treatment of periodontitis and endothelial function. N Engl J Med. 2007. 356: 911–920.

[15] Linden GJ, Herzberg MC; Working group 4 of joint EFP/AAP workshop. Periodontitis and systemic diseases: a record of discussions of working group 4 of the Joint EFP/AAP Workshop on Periodontitis and Systemic Diseases. J Clin Periodontol. 2013 Apr;40 Suppl 14:S20-3. doi: 10.1111/jcpe.12091. PMID: 23627330.

[16] Grau AJ. Et al. Periodontal disease as a risk factor for ischemic stroke. Stroke 2004.35, 496–501.

[17] Beck JD. Et al. Associations between IgG antibody to oral organisms and carotid intima-medial thickness in community-dwelling adults. Atherosclerosis. 2005. 183, 342–348.

[18] Scher JU. Et al. Microbiome in inflammatory arthritis and human rheumatic diseases. Arthritis Rheumatol. 2016. 68, 35–45.

[19] Hendler A. Et al. Involvement of autoimmunity in the pathogenesis of aggressive periodontitis. J Dent Res. 2010. 89, 1389–1394.

[20] Nishihara T. Et al. Effects of Lactobacillus salivarius-containing tablets on caries risk factors: a randomized open-label clinical trial. BMC Oral Health. 2014.

[21] Higuchi T.  Effects of Lactobacillus salivarius WB21 combined with green tea catechins on dental caries, periodontitis, and oral malodor. Archives of Oral Biology. 2019. 98: 243-247.

[22] Kang MS. Et al.  Inhibitory effect of Lactobacillus reuteri on periodontopathic and cariogenic bacteria. J Microbiol. 2011. 49, 193–199.

[23] Caglar E, Cildir SK, Ergeneli S, Sandalli N, Twetman S. Salivary mutans streptococci and lactobacilli levels after ingestion of the probiotic bacterium Lactobacillus reuteri ATCC 55730 by straws or tablets. Acta Odontol Scand. 2006 Oct;64(5):314-8. doi: 10.1080/00016350600801709. PMID: 16945898.

[24] Wiwattanarattanabut K, Choonharuangdej S, Srithavaj T. In Vitro Anti-Cariogenic Plaque Effects of Essential Oils Extracted from Culinary Herbs. J Clin Diagn Res. 2017;11(9):DC30-DC35.

[25] Gupta C, Kumari A, Garg AP, Catanzaro R, Marotta F. Comparative study of cinnamon oil and clove oil on some oral microbiota. Acta Biomed. 2011 Dec;82(3):197-9. PMID: 22783715.

[26] Kanth MR, Prakash AR, Sreenath G, Reddy VS, Huldah S. Efficacy of Specific Plant Products on Microorganisms Causing Dental Caries. J Clin Diagn Res. 2016;10(12):ZM01-ZM03.