A Roundup of What We Know About the Oral-Systemic Connection Right Now

Health care and the science of the human body, in general—I dare say science itself, as an endeavor of human discovery—is a field that is increasingly highly specialized. The more we learn, the more we specialize, following promising new leads, creating small teams to pursue tantalizing clues, inventing novel sub-branches of other branches of clinical and investigatory medicine as they go.

That is the nature of pharmacological and medical science. For those of us in the trenches, the usual rhythms of research—hypothesize, test, confirm/deny, revise hypothesis, test again—are as normal as breathing.

But every once in a while, it is helpful to those who are not in the weeds to step back, look at the forest rather than the trees, and tell those outside what we’re finding.

And that brings me to the shape, contours, and overall takeaways we can see now from an emerging body of evidence about the oral-systemic connection.

The Oral Cavity: A Bidirectional Relationship with The Entire Body

It makes intuitive sense that the mouth is the entry point for what happens inside the body, but now science is increasingly validating this hypothesis. And the relationship is not one-way; rather, oral health affects systemic health, which in turn affects oral health, creating a mutually-reinforcing feedback loop.

Take, for example, oral health and diabetes. The American Diabetes Association is aware of the strong bidirectional correlation; tooth loss is higher for those with diabetes. But the relationship also goes the other way. A large-scale clinical review of 690 studies showed statistically significant reductions in HbA1c levels among diabetic patients after dental hygiene (which removes the harmful bacteria and inflammatory response present in periodontal disease and infection).

Inflammation and the inflammatory response, in fact, appear to be deeply implicated in the oral-systemic connection.

The Mouth is the Doorway to Blood, Heart, Kidneys, Brain, Metabolism…and Cancer?

We know the heart and blood vessels are affected by oral bacteria; for years, oral care professionals have been aware of the dangers of invasive oral procedures on patients with compromised cardiac health and have worked with their physician colleagues to manage complex patients.

But there other connections are currently less well-known and just as important to be aware of.

  • Metabolic syndrome. As a constellation of symptoms rather than a “disease” per se, metabolic syndrome has been positively linked with periodontitis. The mechanism of the connection is oxidative stress, which leads to—you guessed it—inflammation.
  • Rheumatoid arthritis. The correlation between oral health and overall health outcomes in those with this autoimmune inflammatory disorder are significant enough that the Arthritis Foundation is now speaking in terms of the Oral-Joint Connection.
  • Cognitive impairment. One of the most startling connections to emerge as we have begun to add more branches and leaves to the tree trunk of oral-systemic connection investigation is its relationship to our brains—and there does appear to be a connection. In 2016, British researchers published a study linking periodontis to the progression of cognitive decline in patients with Alzheimer’s disease, associated with inflammatory processes.
  • Low birth weight. The inflammatory response associated with the oral-systemic does not stop at one person. It has also been correlated with low birth weight in pregnant women with periodontal disease.
  • Periodontis, as a chronic infection, creates oral pockets that have been shown to be potential reservoirs for a host of human-unfriendly microorganisms—from viruses to agents associated with oral cancer.

It’s difficult at times to believe we only started to investigate the new field of preventive dentistry in the late 1960s; we’ve learned so much, so quickly. The implications are considerable for individual patients and practitioners.

For patient populations who have special health concerns, including any of the conditions above, oral health specialists and physicians may want to consider close collaboration and individualized schedules for oral care.