The Link Between Oral Health and Chronic Diseases

For health professionals

Maintaining good oral health is important for more reasons than just keeping the teeth, gums, throat, and bones around the mouth healthy. Researchers have found evidence that oral health is linked to overall health.1 This link is often called the “oral-systemic connection” or “mouth-body connection.”1

Health care professionals play an important role in helping patients understand this connection so they can improve their health and quality of life.

What is the oral-systemic connection?

A smiling woman sitting in a dental exam chair.

The oral-systemic connection is the idea that poor oral health may contribute to disease in other parts of the body.1,2 Researchers have found links between oral diseases, like periodontal (gum) disease and tooth decay, and chronic diseases such as diabetes, cardiovascular disease (diseases affecting the heart and blood vessels), and dementia and Alzheimer’s disease.1,2,3

For example, one study followed more than 6,000 older adults over time. It found that people with signs of gum disease or mouth infections at the start of the study were more likely to develop Alzheimer’s disease or a related dementia than people with good oral health.4

How does oral health affect overall health?

Researchers have two main theories for how oral health may affect the rest of the body.

  • Bacteria spread through the bloodstream. Bacteria that cause gum disease can enter the bloodstream through small cuts in the gums. These cuts can happen during chewing or dental procedures, such as deep cleanings. The bacteria can then travel to other parts of the body, where it may contribute to disease.1
  • Inflammation. When harmful bacteria from gum disease enters the bloodstream, the body’s immune system responds. Over time, this inflammatory response may contribute to inflammation in other parts of the body and worsen certain diseases.1

Although links between oral health and overall health are clear, more research is needed to explain how preventive oral health behaviors reduce the risk of specific chronic diseases.2

One challenge is that gum disease and many common chronic diseases share the same risk factors. These include tobacco use and consumption of alcohol or foods and drinks that are highly processed or high in sugar. These shared risk factors may contribute to both poor oral health and poor overall health.1

Even so, it’s important to educate patients about the benefits of good oral hygiene and healthy lifestyle changes to support overall health.3

What chronic diseases have connections to oral health?

Many chronic diseases are linked to oral health, both directly and indirectly. The following sections explain how diabetes, cardiovascular disease, and dementias are linked to oral health.

Encourage all patients—especially those with risk factors for developing these chronic diseases—to maintain good oral health habits. These habits include brushing and flossing, eating a balanced diet, and visiting the dentist twice a year.

What’s the link between poor oral health and diabetes?

Insulin is a hormone that controls the amount of sugar in the blood. Diabetes occurs when the body does not make enough insulin or cannot use it well. This leads to high blood sugar.5

Diabetes can worsen oral health.5 People with diabetes are more likely to have gum disease than people without diabetes.5 This may be because high blood sugar levels can also raise sugar levels in saliva. Harmful bacteria in the mouth use this sugar, multiply, and can cause cavities and gum disease. People with diabetes may also take longer to heal from gum disease.5,6

Poor oral health can also worsen diabetes.5 Some research suggests that gum disease is linked to a higher risk of developing diabetes, poorer blood sugar control, and more severe diabetes-related complications. However, the evidence for these connections is not consistent.5

Some evidence suggests that treating gum disease may improve blood sugar control and prevent diabetes-related complications. Encourage patients to continue preventive oral health behaviors.5

Take note of patients with risk factors for developing diabetes, such as a family history of the disease, excess weight, low physical activity, and prediabetes. Prediabetes is a condition in which blood sugar levels, including A1C levels, are higher than normal but not high enough for a diabetes diagnosis.5

What’s the link between poor oral health and cardiovascular disease?

A health care professional measuring a patient’s blood pressure.

Cardiovascular disease includes diseases and conditions that affect the heart and blood vessels. One example is coronary heart disease. This occurs when fatty deposits, called plaques, build up in the arteries and limit blood flow to the heart.7 Risk factors for developing cardiovascular disease include high blood pressure, high cholesterol, and smoking.8

Gum disease may also increase the risk of cardiovascular disease. Bacteria from gum disease can enter the bloodstream and cause inflammation throughout the body. This may irritate the lining of arteries and start the buildup of plaque.1,3

Some studies show that treating gum disease may reduce the risk of cardiovascular disease, but the evidence is mixed. Encourage patients, especially those with high blood pressure, high cholesterol, and who smoke, to maintain good oral health habits.1

What’s the link between poor oral health and dementia and Alzheimer’s disease?

Dementia is the loss of the ability to think, remember, or reason that interferes with daily life. There are many types of dementia, and Alzheimer’s disease is the most common.9,10

Long-term studies have shown that people with signs of gum disease have a higher risk of developing dementia in the future.4 Bacteria that cause gum disease have been found in the brains of people with Alzheimer’s disease. This suggests the bacteria may have traveled from the mouth to the brain.4 These bacteria may contribute to inflammation in the brain, which is common in Alzheimer’s disease.4

There is a clear link between oral health and dementia, but it’s not yet clear how they are connected. Encourage your patients—and their loved ones and caregivers—to practice good oral hygiene.

How can I help my patients find free or low-cost dental care?

Share HRSA's How to Find Low-cost Dental Care page with your patients and caregivers. The page includes information about HRSA-supported health centers, dental schools, Medicaid, Medicare, and other sources of low-cost dental care.

Where can I find more information about the links between oral health and overall health?

Review these resources for more information:

What resources can I share with my patients about the links between oral health and overall health?

Share these resources with your patients:

What resources can I share with my patient’s caregivers to help them provide good oral care?

Share these resources with your patients’ caregivers:

References

  1. National Institutes of Health (NIH), National Institute of Dental and Craniofacial Research (NICDR). (2024). Healthy Mouth, Healthy Body: Decades of NIDCR-funded research reveal the interconnectedness of the mouth and body. Accessed May 7, 2026.
  2. American Dental Association. (2023). Oral-Systemic Health. Accessed May 7, 2026.
  3. National Institutes of Health (NIH), MedlinePlus Magazine. (2024). Your smile (and mouth) can tell you more than you might think. Accessed May 7, 2026.
  4. National Institutes of Health (NIH), National Institute on Aging (NIA). (2020). Research Highlights: Large study links gum disease with dementia. Accessed May 7, 2026.
  5. American Dental Association. (2022). Diabetes. Accessed May 7, 2026.
  6. National Institutes of Health (NIH), National Institute of Dental and Craniofacial Research (NIDCR). (2024). Diabetes & Oral Health. Accessed May 7, 2026.
  7. National Institutes of Health (NIH), National Heart, Lung, and Blood Institute (NHLBI). (2024). What is Coronary Heart Disease? Accessed May 7, 2026.
  8. National Institutes of Health (NIH), National Heart, Lung, and Blood Institute (NHLBI). (2024). Coronary Heart Disease Risk Factors. Accessed May 12, 2026.
  9. National Institutes of Health (NIH), National Institute on Aging (NIA). (2022). What Is Dementia? Symptoms, Types, and Diagnosis. Accessed May 7, 2026.
  10. National Institutes of Health (NIH), National Institute on Aging (NIA). (2025). What Is Alzheimer's Disease? Accessed May 7, 2026.
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