Skip the Floss, Risk the Clot? The Surprising Link Between Oral Health and Heart Disease

We spoke with Dr. Souvik Sen, Professor and Chair of the Department of Neurology at the University of South Carolina School of Medicine, to explore the connection between oral health and cardiovascular risk, including how something as simple as flossing might play a role. His recent study suggests a potential link between regular flossing and lower stroke risk, though the findings are still preliminary and haven't been published in a peer reviewed journal.

Further research is needed to confirm whether improving oral hygiene can truly help prevent strokes. "Flossing is a simple habit, but it appears to have a significant impact on reducing inflammation and the risk of clot-related strokes," Dr. Sen explained.

Your mouth is home to a mix of helpful and harmful bacteria. Normally, these bacteria maintain balance, aid digestion, and support oral health. However, poor oral hygiene allows harmful bacteria to grow, leading to gum disease and inflammation. Over time, bacteria from the mouth can enter the bloodstream, triggering an immune response.

“We know that gum disease and tooth decay have been linked to heart disease for a long time," said Dr. Sen. We think inflammation plays a key role. When inflammation is chronic, it could lead to hardened arteries, blockages, and possibly blood clots, increasing the risk of strokes and heart attacks."

How Gum Disease and Inflammation Affect Heart Health

When bacteria build up on the teeth and gums, they form dental plaque. If left untreated, plaque can lead to periodontitis, a chronic condition that damages gum tissue. Inflamed gums become an easy entry point for bacteria into the bloodstream. Everyday activities like brushing or chewing food can dislodge bacteria, allowing them to enter your body.

Once in the bloodstream, bacteria trigger inflammation, affecting blood vessels in ways that increase cardiovascular risk:

• Artery narrowing: Inflammation damages blood vessel walls, making them stiffer and more prone to blockages.

• Plaque buildup: Some bacteria release toxins that contribute to fatty deposits in the arteries, making clots more likely.

• Increased clot formation: Inflammation can promote platelet aggregation, increasing the risk of clots that block blood flow to the heart or brain.

Researchers have even found oral bacteria inside artery plaques, meaning they can travel through the blood. These bacteria can worsen plaque buildup by triggering inflammation and immune responses, making plaques weaker and more likely to rupture. If a plaque ruptures, it can cause a blood clot, which may lead to a heart attack or stroke.

Can Flossing Help Prevent Stroke?

Dr. Sen’s research suggests that flossing at least once a week is associated with a 22% lower risk of all types of strokes. Even after considering other habits like brushing and regular dental visits, flossing had an independent protective effect.

"We found that even after adjusting for other oral hygiene habits, flossing had an independent effect," Dr. Sen explained.

He also noted that flossing regularly may help reduce the risk of atrial fibrillation (Afib), a common irregular heartbeat that increases the risk of stroke.

Flossing and Stroke Risk: What the Research Shows

Stroke can be divided into two main types:

• Ischemic stroke (87% of strokes): Caused by a blood clot blocking a vessel.

• Hemorrhagic stroke (13% of strokes): Caused by bleeding in the brain.

A cardioembolic stroke is a type of ischemic stroke caused by a clot that forms in the heart and travels to the brain. AFib increases the risk of these clots forming. If a clot breaks loose, it can travel to the brain and cause a stroke.

When looking at specific types of stroke, cardioembolic stroke showed the most significant reduction, with a 44% lower risk. While more research is needed, these findings suggest that a simple habit like flossing could have a meaningful impact on stroke prevention.

Why More Research on Oral Health and Stroke Matters

Dr. Sen said his next step is to review the data carefully, making it easier to compare to a clinical trial. A large trial would be hard to do, but ongoing studies could help give clearer answers. "It’s hard to do a clinical trial where half of the participants floss, and the other half don’t for 25 years. But the next step is to refine our data and see how we can match groups to get clearer results," he explained.

Flossing Early and Often: A Simple Habit for Better Heart Health

While flossing alone isn’t a guarantee against cardiovascular disease, maintaining good oral hygiene, including brushing, flossing, and seeing a dentist regularly may help. “Flossing is very affordable. It's also easily done at home. Somebody doesn’t need access to a dentist to be flossing regularly,” said Dr. Sen.

He also emphasizes the importance of starting early. "Flossing should be part of early education, just like other good hygiene habits," he explained. Teaching good oral health practices at a young age could help more people adopt lifelong habits that may reduce health risks later.”

Learn More About Oral Hygiene

Looking for more guidance on maintaining good oral hygiene? Trusted resources from the American Dental Association (ADA) and the National Institute of Dental and Craniofacial Research (NIDCR) offer evidence-based recommendations on brushing, flossing, and preventing gum disease.

Frequently Asked Questions

1. How does oral health affect heart disease?

Poor oral health, like gum disease or tooth loss, can raise your risk of heart disease. Heart disease includes blocked arteries, heart attacks, and strokes. Gum disease causes inflammation and lets bacteria enter the bloodstream, which can damage blood vessels and help plaque buildup in the arteries

2. Is brushing enough if I don’t floss?

Brushing helps, but it doesn’t reach between your teeth like flossing does, where bacteria build up the most.

3. Should kids floss too?

Yes! Kids should floss with help from a parent or caregiver. Experts recommend that adults help children floss until they can do it well on their own, usually around age 10. Good flossing habits early may help protect oral health and lower health risks later in life.

References

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American Stroke Association. Let’s talk about hemorrhagic stroke. American Heart Association. https://www.stroke.org/en/help-and-support/stroke-resource-library/lets-talk-about-stroke-fact-sheets/hemorrhagic-stroke. Accessed April 2, 2025.

American Stroke Association. Ischemic stroke (clots). American Heart Association. https://www.stroke.org/en/about-stroke/types-of-stroke/ischemic-stroke-clots. Accessed April 2, 2025.

Church L, Franks K, Medara N, et al. Impact of oral hygiene practices in reducing cardiometabolic risk, incidence, and mortality: A systematic review. Int J Environ Res Public Health. 2024;21(10):1319. doi:10.3390/ijerph21101319

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