Unlike a simple cavity, periodontal disease works quietly beneath the gum line, creating pockets of infection that can persist for years.
Published Oct 29, 2025 | 4:46 PM ⚊ Updated Oct 29, 2025 | 4:46 PM
Representational image. Credit: iStock
Synopsis: US study of 6,000 adults over 21 years shows gum disease plus tooth decay nearly doubles ischemic stroke risk (86% higher vs. healthy mouths). Thrombotic and cardioembolic strokes surge 2-2.6x. Regular dental visits cut combined risk 81%. Oral bacteria fuel systemic inflammation, linking mouth health to brain and heart disease prevention.
People brush their teeth for better oral hygiene, prevent cavities, and to keep their breath fresh. Few realise they might also be protecting themselves from a stroke.
A study from the United States has uncovered a stark reality: People suffering from both gum disease and tooth decay face nearly double the risk of ischemic stroke compared to those who maintain healthy teeth and gums.
The revelation emerged from tracking nearly 6,000 Americans over more than two decades, revealing patterns that connect the mouth to the brain in ways previously underestimated.
The research, published in Neurology in October 2025, began with a simple premise. Researchers from the University of South Carolina and several major US universities wanted to understand what happens when oral health deteriorates. They enrolled 5,986 adults who participated in the Atherosclerosis Risk in Communities study, conducting detailed dental examinations between 1996 and 1998.
At the time of examination, participants averaged 63 years old. Just over half were women. None had experienced stroke or heart disease before the study began, ensuring researchers could track new events accurately.
The researchers divided participants based on what they found during dental examinations. The first group, 1,640 people, had good oral health. The second group, 3,151 people, showed periodontal disease only. The third group, 1,195 people, displayed both periodontal disease and dental caries.
Then came the waiting. Researchers tracked hospital and medical records through 2019, watching for ischemic strokes, heart attacks, and fatal coronary heart disease.
The pattern that emerged told a compelling story. During the median 21-year follow-up period, ischemic stroke struck 67 of the 1,640 patients with good oral health just 4.1 percent. Among those with gum disease alone, 216 of 3,151 patients experienced stroke 6.9 percent. But in the combined group with both conditions, 119 of 1,195 patients suffered strokes a full 10 percent.
“Among 5,986 participants (52 percent female), 1,640 had good oral health, 3,151 had PD only, and 1,195 had PD + caries,” the study documented. “The incidence of ischemic stroke was 4.1 percent, 6.9 percent, and 10.0 percent across groups, respectively.”
Periodontal disease, often shortened to PD in medical literature starts as gum inflammation, where gums become red, swollen, and bleed easily when you brush. Left untreated, it progresses deeper, attacking the bone and tissue that hold your teeth in place.
Unlike a simple cavity you can see or feel, periodontal disease works quietly beneath the gum line, creating pockets of infection that can persist for years. The bacteria trapped in these pockets don’t just stay in your mouth, they can enter your bloodstream, triggering inflammation throughout your body. This chronic infection affects not just your teeth, but potentially your heart and brain as well.
After accounting for traditional stroke risk factors—age, smoking, diabetes, blood pressure—the combined group showed an 86 percent higher risk of ischemic stroke compared to those with healthy teeth and gums. Gum disease alone carried a 44 percent higher risk.
“In fully adjusted models, PD only was associated with a 44 percent increased risk of ischemic stroke , and the combination of PD + caries yielded an even higher risk,” the study reported.
The data revealed even more disturbing patterns when researchers examined specific stroke subtypes. Thrombotic strokes, caused by blood clots forming in arteries, occurred more than twice as often among those with both conditions. Cardioembolic strokes, triggered by clots travelling from the heart, showed a 2.6-fold higher risk.
Beyond stroke, the combination increased the likelihood of broader cardiovascular events including heart attacks and fatal coronary heart disease by 36 percent.
The baseline characteristics painted a revealing picture. Participants without periodontal disease or caries were more likely to be female, White, have higher education, consume alcohol, and maintain higher HDL cholesterol levels.
The group with both conditions told a different story. They were more likely to be male, African American, and carry higher body mass indices and waist-to-hip ratios. Hypertension and diabetes struck them more frequently. Their education levels dropped. Their C-reactive protein levels—a marker of inflammation—climbed higher.
“The PD + caries group was more likely to be male, be AA, and have higher BMI, higher waist-to-hip ratio, hypertension, diabetes, and lower education, as well as higher CRP levels,” the authors noted.
One finding stood out above the rest. People who regularly visited a dentist showed significantly lower odds of developing gum disease or dental decay. Regular care reduced the likelihood of periodontal disease by 29 percent. For the combined condition, the reduction reached a striking 81 percent.
“Regular dental care utilisation lowered the chance of PD and PD + caries, thus lowering the risk of incident ischemic strokes,” the study found.
Scientists have constructed a theory about how oral infections trigger cardiovascular events. Periodontal disease exposes the body to chronic Gram-negative bacteria, driving systemic inflammation higher. Dental caries involves bacteria metabolising sugars to produce acids that demineralise teeth, leading to infection and inflammation.
These inflammatory mediators trigger chronic systemic inflammatory responses, contributing to atherosclerosis—the buildup of fatty plaques in arteries. Previous imaging studies have shown that periodontal inflammation increases arterial inflammation.
The evidence extends beyond correlation. Bacterial DNA from gum and tooth infections has been detected in heart valves and carotid artery plaques. Streptococcus mutans, the main dental caries pathogen, has appeared in heart valve and atheromatous plaques.
“PD pathogens have been found in atheromatous plaques in the carotid and coronary arteries while Streptococcus mutans, the main dental caries pathogen, has been detected in heart valve and atheromatous plaques,” the authors explained.
“Together, these factors likely explain the higher ischemic stroke risk in the PD + caries group.”
The authors acknowledged limitations. Participants were younger, carried lower body mass indices, showed lower rates of hypertension and diabetes, and possessed higher education than those excluded. The study relied on a single dental assessment. Residual confounding may persist despite statistical controls.
Yet the implications remain clear. Regular brushing, flossing, and professional cleaning may help reduce systemic inflammation, thereby lowering stroke and heart disease risk.
“These findings demonstrate that poor oral health, particularly the presence of both periodontitis and dental caries, is significantly associated with elevated risks of MACEs and ischemic stroke, with especially strong associations observed for thrombotic and cardioembolic stroke subtypes,” the authors concluded.
The message extends beyond individual prevention. Integrating dental care into routine medical risk assessment and promoting preventive oral hygiene practices may offer a novel strategy to reduce vascular risk at the population level.
“These results underscore the importance of comprehensive oral health as a modifiable factor in cardiovascular and cerebrovascular disease prevention,” the authors stated. “Integrating dental care into routine medical risk assessment and promoting preventive oral hygiene practices may offer a novel strategy to reduce vascular risk at the population level.”
(Edited by Amit Vasudev)
