Research & Education

The Oral Microbiome


Functional and integrative medicine focuses much attention on the gut microbiome as the root of many chronic health conditions. This exciting new field of research has allowed us to understand the significance of the relationship between human health and the microorganisms that exist in our body.

As we continue to focus on optimizing the microbial balance within the gut we may neglect to consider the microbiome of the first organ of the gastrointestinal tract. The mouth possesses a microbiome that not only influences the microbiome downstream but the entire body. In fact many of the microorganisms found in the gut are endemic to the oral cavity. As with the gut microbiome the oral microbiome is significant in the development of dysbiosis systemic inflammation immunity and chronic health conditions. Research now supports the fact that our oral microbiome can also be a causative agent in the pathogenesis of bronchitis pneumonia diabetes heart disease inflammatory bowel disease arthritis dementia and cancer. This association should draw our attention to oral health alongside gut health.

More than 700 bacterial species are found in the oral cavity. As in the gut the mouth can harbor fungal bacterial and viral infections that are common to dysbiosis. Likewise the biofilms produced by many of these organisms create an obstacle for overcoming these pathogenic organisms and reestablishing a healthy microbial balance. Diet genetics lifestyle choices immune health and inflammation can impact the oral microbiology as they do in the gut; therefore rebalancing this environment requires similar methods as are utilized for the gut. Antibiotic resistance is causing practitioners to turn to selective botanicals essential oils and probiotics to reestablish a healthy bacterial balance. Current chemical agents used to maintain oral health are increasingly unsatisfactory and are raising concerns about adverse effects which include fluorosis dental chromatism oral lesions and ulcers and enamel erosion. With nearly 90% of all individuals exhibiting dental caries stemming from an unhealthy oral microbiome alternative methods of oral hygiene may be necessary. Routine brushing and flossing remain the most effective means of maintaining general oral health but essential oils and probiotics can help preserve the delicate microbial environment.

Essential oils offer selective antimicrobial activities that promote the growth of beneficial bacteria while inhibiting pathogenic organisms and their biofilms. Streptococcus mutans is the principal agent associated with dental caries due to its acidogenic and aciduric properties that allow it to survive in the oral cavity. A study published in the Journal of Ethnopharmacology found the essential oils of lemongrass (Cymbopogon citratus) and Lippia alba were effective against S. mutans biofilms. The major components of both oils geraniol and citral showed a 95% efficacy against the biofilms. Similarly a 2015 systematic review of over 30 essential oils showed essential oils of turmeric (Curcuma longa) coriander (Coriandrum sativum) peppermint (Mentha piperita) and rosemary (Rosmarinus officinalis) inhibited S. mutans biofilm formation. Many were more effective than traditional chlorhexidine mouth rinses. 

Various essential oils also showed very strong or strong direct antibacterial activity against several Streptococci and planktonic Lactobacilli strains common in oral dysbiosis. Some of the more common essential oils include rosemary clove sacaca sugi yarrow camphor lemon balm and tree basil. Together the studies could point to effective botanical combinations to address both pathogenic bacteria and their biofilm.

Staphylococcus aureus Escherichia coli Enterococcus fecalis and Candida albicans are not only common pathogenic organisms found in the mouth but especially in the root canal environment. Root canals are increasingly being targeted as infection-harboring environments leading to systemic inflammation and chronic immune suppression. A study published in the European Journal of Dentistry found tea tree thyme peppermint and clove essential oils displayed significant inhibitory effects against these organisms. It was suggested these essential oils can be used as antiseptic solutions for root canals as well as general oral health maintenance.          

Finally probiotics can offer a supportive solution to oral health. Just as the gut must be repopulated with friendly bacteria to achieve microbial balance so the mouth must maintain a healthy number of beneficial organisms. Toothpastes containing probiotics are becoming more popular and supported by in vitro studies. When toothpaste containing Lactobacillus paracasei or Lactobacillus acidophilus was tested against common oral pathogens including Candida albicans both showed better inhibitory effects against pathogens compared to toothpaste without added probiotics. They also showed greater antimicrobial activity than mouth rinses with and without essential oils. 

As the first organ of the gastrointestinal tract the mouth plays an important role in preventing dysbiosis establishing good immunity and guarding against systemic inflammation that can lead to chronic disease and illness. Essential oils and probiotics may be just as important to use in the mouth as they are for the gut and certainly have proven to be equally effective and vital in maintaining whole body health.