The Undeniable Link Between Oral and Systemic Health

Recently, oral health studies have been working overtime to further prove a connection between oral and systemic health. As such, the relationship between Alzheimer's disease, colon cancer, diabetes, rheumatoid arthritis, heart disease, and more has shown a link to periodontal disease.

By Genni Burkhart

In 2021, the National Institutes of Health (NIH) released a report emphasizing what Surgeon General David Satcher, MD, PhD stated over two decades ago, as then, this "first-time report" was a public health turning point, insistent on the novel idea that oral health is coupled to overall health and wellness.

Moreover, it highlighted the disparities and inequities regarding disease burden, access to, and affordability of oral health care in the United States. This has highlighted the need for institutional changes to address these issues, such as increasing access to affordable dental care, improving access to preventive care, and providing better education on oral health.(1)

Research has increasingly found a strong correlation between periodontal disease and systemic diseases. As the oral manifestations of systemic diseases negatively impact an individual's quality of life, let's examine some of the latest connections to better educate patients and help them appreciate the link between oral and systemic health.

Alzheimer's Disease

Researchers have recognized for decades that healthy bodies and strong minds are connected. And that research is increasingly tying oral health to Alzheimer's disease and other forms of dementia.

In 2020, an extensive study by the National Institute on Aging (NIA) linked gum disease to dementia and published those findings in the Journal of Alzheimer's Disease. (2)

In these results, scientists found that bacteria from gum disease can travel from the mouth to the brain. Previous studies also found that poor oral health can cause a "cascade of events" leading to dementia.

The NIA team also used a large population study conducted by the CDC's National Center for Health Statistics with data provided by National Health and Nutrition Examination Survey (NHANES).

The team analyzed data from Medicare records and the National Death Index, looking for links between gum disease and infections with oral bacteria and dementia diagnoses and deaths. Among more than 6,000 participants, the team compared different age groups at baseline and up to 26 years of follow-up.

The study showed that Alzheimer's disease was more likely to develop in older adults with gum disease and mouth infections, according to the analysis. Antibodies against P. gingivalis, an oral bacterium that can cluster with Campylobacter rectus and Prevotella melaninogenica, have been associated with an increased risk of Alzheimer's disease diagnoses (and deaths) in people 65 and older.

Cardiovascular Disease

Over the years, studies have repeatedly linked periodontitis to an increased risk of stroke, heart attacks, atherosclerosis, and other cardiovascular events.

In a 2021 article, Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing, Editorial Advisory Board Member, stated at Harvard that one of his most surprising observations in recent years is how study after study shows those who have poor oral health also have increased likelihood of cardiovascular issues such as strokes, heart disease, and heart attacks when compared to people with "good" oral health.

In June of this year, published the article, Not brushing teeth at night may increase the risk of cardiovascular disease. (3)

While the study had no age-based differences among the groups of participants, the study was limited to hospitalized patients whose poor health might have influenced their oral hygiene.

The findings of this study indicated that only brushing in the morning and skipping brushing at night is particularly detrimental and inhibits "good" systemic health. Researchers also showed a link between intestinal bacteria and oral bacteria that could result in cardiovascular events.


It's been suggested the relationship between diabetes and gum disease is circular. Such as those with diabetes are more likely to develop periodontitis, and periodontitis might also increase the risk of diabetes.

Individuals with diabetes are at an increased risk of developing oral issues for several reasons. As high blood glucose level also increases salivary sugar levels, bacteria feed on sugars in plaque leading to tooth decay, cavities, and tooth loss, further increasing the likelihood of periodontitis. These issues can also lead to additional health complications, including gum recession and bone loss. Poorly managed diabetes can also slow dental surgery healing and put patients at an increased risk of infection.

Mental Health

The Incisor recently published an article on a study linking oral and mental health. In this article, Dr. Mehmood Asghar BDS, M.Phil., PhD explains that mental health disorders are bi-directional with other systemic issues, such as cardiovascular disease and diabetes.

In the study by Kisely et al. (2015) (4), people with severe mental illness were found to have a 2.8 times higher risk of losing teeth than the general community. They also had a significantly higher instance of decayed, missing, and filled (DMF) teeth than those without mental disorders.

In Conclusion

The things that are good for our bodies are also good for our mouths, such as a diet low in sugars, exercising, and maintaining mental health. As dentists and hygienists, recognizing underlying diseases in your patients can influence their unique oral hygiene habits, positively impacting their health and quality of life.

When patients understand how oral hygiene impacts bacteria in the mouth, they can better understand how good dental care affects their overall health. In addition to preventing infection, practicing healthy hygiene habits reduces the risks of serious systemic health issues such as diabetes, heart disease, stroke, and Alzheimer's disease, among others.


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Author: With over 13 years as a published journalist, editor, and writer Genni Burkhart's career has spanned politics, healthcare, law, business finance, technology, and news. She resides in Northern Colorado, where she works as the Editor in Chief of the Incisor at DOCS Education.


  1. Oral Health in America. National Institute of Health. December 2021.
  2. Beydoun M, et al. Clinical and bacterial markers of periodontitis and their association with incident all-cause and Alzheimer's disease dementia in a large national surveyJournal of Alzheimer's Disease. 2020;75(1):157-172. doi: 10.3233/JAD-200064.
  3. Isomura, E.T., Suna, S., Kurakami, H. et al. Not brushing teeth at night may increase the risk of cardiovascular disease. Sci Rep 13, 10467 (2023).
  4. Kisely, S., Baghaie, H., Lalloo, R., Siskind, D., & Johnson, N. W. (2015). A Systematic Review and Meta-Analysis of the Association Between Poor Oral Health and Severe Mental Illness. Psychosomatic Medicine, 77(1), 83-92.
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