A new long-term study suggests that using dental floss at least once a week may help reduce the risk of certain types of stroke and atrial fibrillation, a common heart rhythm disorder that can lead to strokes.
The findings were presented at the International Stroke Conference 2025 in Los Angeles and shared on the American Heart Association (AHA) website.
While the results are promising, researchers say they should still be considered preliminary until published in a peer-reviewed journal.
Flossers Show Lower Stroke Risk
The study tracked over 6,200 adults for 25 years. Participants were asked about their flossing habits, and researchers followed them to see who developed strokes or heart rhythm problems.
Those who reported flossing at least once a week showed:
22% lower risk of ischemic stroke (caused by blocked blood flow to the brain)
44% lower risk of strokes caused by blood clots from the heart
12% lower risk of developing atrial fibrillation (AFib)
But the study did not find a reduced risk for thrombotic stroke, which happens when a blood clot forms directly in a blood vessel in the brain.
How Oral Health Affects the Brain
Lead author Dr. Souvik Sen, speaking to the AHA, said flossing might not be the only factor, but it seems to support overall brain and heart health.
“I wouldn't say that flossing alone prevents strokes,” said Sen. “But our findings suggest it plays a role in a healthy lifestyle.”
Previous research has shown that oral infections and gum disease can trigger inflammation, which may damage blood vessels and increase the risk of heart problems and strokes. Flossing reduces bacteria and inflammation in the mouth, which could help lower the body's overall inflammation levels, Sen explained.
Is It About Flossing — or Lifestyle?
Not all experts agree that flossing itself is the key.
Dr. Karen Furie, a neurologist at Brown University Health, told the AHA she’s not surprised by the findings but added that flossing may be a sign of broader healthy habits.
“People who floss may also be more likely to follow medical advice, eat better, and take better care of their health in general,” she said.
Still, she agreed that flossing plays an important role in oral hygiene by removing food particles and preventing gum inflammation — and that could, in turn, support better cardiovascular health.
While more research is needed, this study adds to growing evidence that oral health and heart health are connected. And flossing — a quick and inexpensive habit — might offer surprising long-term benefits.
For those already brushing twice a day, adding flossing to the routine could be one more way to protect not just your teeth, but your brain and heart too.
