When was the last time you flossed? Your dental habits could affect more than your smile—they may also influence your brain’s health.
New research suggests that oral health could nearly double your risk of stroke and contribute to brain damage that shows up years later as memory problems and slower thinking.
Two new studies published in Neurology Open Access, the journal of the American Academy of Neurology, link gum disease and cavities to a significantly higher risk of stroke and brain lesions. Both studies draw on the same data.
“We found that people with both cavities and gum disease doubled the stroke risk to people with gum disease alone,” Dr. Souvik Sen, a neurologist at the University of South Carolina School of Medicine and author of both studies, told The Epoch Times.
“These findings suggest that an important part of stroke prevention is the need for regular dental care—brushing, flossing, as well as going to the dentist or dental care provider on a regular basis.”
The Long Reach of Gum Disease
Gum disease—also known as periodontal disease—is one of the most common chronic health problems, affecting roughly half of adults at some point. It starts as gingivitis, when the gum lines become red from inflammation caused by bacteria, and can progress to periodontitis, when gums start shrinking and teeth loosen.
In the first study, Sen and his team found that people with gum disease and cavities had an 86 percent higher risk of stroke as a result of blood clotting and a 36 percent higher risk of heart attacks and heart disease, such as heart failure, compared with those with healthy mouths. In the absence of cavities, having gum disease alone was linked to a 44 percent increase in stroke risk.
Most strokes are caused by blood clots that block blood flow to the brain. When this happens, part of the brain is cut off from oxygen and nutrients, leading to damage.
The researchers followed nearly 6,000 adults—with an average age of 63—for more than two decades from the late 1990s. Stroke rates climbed sharply among the participants as oral health worsened: Slightly more than 4 percent of people with healthy gums suffered a stroke, compared with nearly 7 percent among those with gum disease and 10 percent among participants who had both gum disease and cavities.
“The other very interesting finding from this study,” Sen said, “is if one went to the dentist regularly for preventative care, their risk of having gum disease and cavities was 81 percent lower.”
Clues From the Brain
“There’s a strong link between oral health and small vessel disease in the brain,” Sen said, pointing to his other study that looked directly at the brain.
“The brain has a vast network of blood supply. The major arteries branch into smaller vessels that feed brain pathways, and if those are damaged, subtle changes can occur long before symptoms of stroke or dementia appear.”
In the second study, 1,143 older adults underwent dental exams and brain MRI scans roughly 15 years apart. People with gum disease in midlife were 56 percent more likely to show high levels of white matter hyperintensities—tiny bright spots indicating microscopic brain damage—later in life, even after adjusting for risk factors such as hypertension, diabetes, and smoking.
“These small areas of damage seen in the white matter of the brain are associated with memory loss, balance issues, and slower thinking,” Sen said.
How Oral Inflammation Reaches the Brain
The researchers in both studies point to inflammation as the key link in the mouth-brain connection.
“Inflammation [from the mouth] is what directly affects those small blood vessels and causes small damages in the white matter pathways,” Sen said.
When bacteria from diseased gums enter the bloodstream, the immune system responds by releasing inflammatory molecules that can harm the delicate lining of blood vessels. Over time, this can promote the buildup of plaque in arteries—a process known as atherosclerosis—and make blood more prone to clotting, both major contributors to stroke.
In the brain, inflammation can damage small vessels and reduce oxygen flow, contributing to tiny lesions visible years later on MRI scans. Some oral bacteria have also been found in arterial plaques and blood clots from stroke patients—evidence that what starts in the mouth can directly reach the brain’s circulation.
The mouth is uniquely vulnerable.
“Every time you brush or floss—especially if you have inflammation—you create tiny openings where bacteria can enter the bloodstream,” Dr. Allison Wilson, a dentist in Tennessee, who was not involved in the study, told The Epoch Times.
This becomes particularly concerning in people with gum disease, as they have more harmful bacteria in their mouths.
That does not mean people should stop flossing their teeth, since it would lead to even more growth of these microbes.
The gums are rich in tiny blood vessels, Wilson added, making it easy for microbes to spread throughout the body. “They’ve found oral bacteria all over—head to toe—during autopsies. It gets around.”
The findings do not prove that gum disease or cavities directly cause stroke or brain injury. Still, experts say the evidence points toward an important relationship between oral and vascular health.
In an editorial accompanying the studies, neurologist Dr. Leonardo Pantoni of the University of Milan wrote that the results strongly suggest that maintaining good oral hygiene may help prevent stroke and reduce damage to the brain’s small blood vessels.
What You Can Do
The best ways to lower your risk are simple.
“Bleeding gums aren’t normal—they’re usually the first sign of gingivitis, which is reversible with better brushing and flossing,” Wilson said. “If plaque sits too long, it hardens into calculus [or tartar], and that’s when deeper inflammation and tissue damage begin.”
That hardened buildup traps bacteria under the gumline.
Once plaque has hardened, only a dentist can remove it. If it is left untreated, inflammation creates deep pockets around the teeth where aggressive bacteria thrive.
“When we measure those pockets, one to three millimeters is considered healthy,” Wilson said. “Anything deeper means the toothbrush isn’t reaching, and the bacteria have a chance to take hold.”
Brushing twice daily, careful flossing soon after meals, and regular checkups every six months remain simple but effective tools for keeping your smile bright and your brain’s blood vessels clear.
