Gum Disease Is Linked to Alzheimer’s and Other Dementias

July 11, 2025

Gum disease isn’t just a disease of the mouth. Infection and inflammation of the gums can negatively affect your overall health, raising the risk of disorders including Alzheimer’s disease and related dementias.

“Poor oral hygiene and chronic gum infections pose potential risk for developing neurodegenerative disorders,” says University Hospitals neurologist Mohamed Elkasaby, MD, who specializes in cognitive neurology.

The human mouth is teeming with bacteria. The most common bacteria that causes gum disease (periodontal disease) is called Porphyromonas gingivalis. The bacterium and an enzyme it produces are believed to promote neuroinflammation and contribute to formation of amyloid-beta plaques that accumulate in the brains of people with Alzheimer’s disease.

“This bacteria has been detected in the brains of individuals with Alzheimer’s disease,” Dr. Elkasaby says. “It is thought to contribute to the pathology of the disease.” Researchers are finding evidence that this bad bacteria in the gums can travel through the blood and penetrate the blood-brain barrier, says University Hospitals oral medicine specialist Andres Pinto, DMD.

“We see people that have progressive periodontal disease and they also have more cognitive issues, Alzheimer’s and other neurodegenerative disorders,” Dr. Pinto says.

What Causes Gum Disease?

Neurodegenerative diseases are complex and can have many causes. “We think Alzheimer’s might be a disease with a mix of genetic factors, environmental exposures, lifestyle, metabolic disorders and vascular risk factors.,” Dr. Elkasaby says. “We try to address as many risk factors as early as possible. One of those is oral hygiene. Frequent tooth brushing and professional dental cleaning are associated with reduced risk of dementia, including Alzheimer’s disease.”

Poor oral hygiene is the key contributor to gum disease. Diet also plays a role, Dr. Pinto says. “High consumption of carbohydrates feeds the bacterial population, so we see more of the inflammatory process,” he says.

Other risks for gum disease include:

Tobacco
Chronic alcohol use
Certain medications
Genetics
Dry mouth

Patients often experience dry mouth because of certain medications, including antihistamines and antidepressants. Many patients use medications containing antihistamines to help them sleep. “I have found people self-medicating for sleep problems for years,” Dr. Elkasaby says. “They often have underlying sleep issues that are not addressed. This is pretty common.”

Older adults are more likely to experience dry mouth from medications. Additionally, the amount of bacteria in the mouth increases with age, making older adults more susceptible to gum infection, Dr. Pinto says.

It’s essential for older adults to maintain good oral hygiene, which often can get overshadowed by other medical issues. “It’s something that caregivers, family and doctors should keep an eye on. It’s a chronic issue with teeth. Make sure even if someone is missing teeth, to keep dental visits and hygiene going,” says Dr. Pinto.

Stages of Gum Disease

Gingivitis is the first stage of gum disease. Symptoms include gum soreness, bleeding with brushing, redness and possible swelling.

Periodontitis is a more advanced form of gum disease that can develop if gingivitis is left untreated. Periodontitis causes permanent damage to gum tissue and bone. Symptoms include receding gums, loose teeth, bad breath, swollen/bleeding gums and painful chewing.

Gum disease is especially prevalent among people age 65 and older. About 70 percent of people that age have some level of gum disease. Advanced gum disease can lead to systemic inflammation and trigger complications in patients with conditions such as heart disease and diabetes.

How to Prevent Gum Disease

Gum disease is common, but it’s not an inevitable part of aging. There are ways to reduce risk:

Brush and floss twice daily.
See a dentist for checkups and cleanings at least every six months. Dental cleanings remove tartar, which is hardened plaque made of bacteria that can lead to inflammation.
Limit or avoid alcohol.
Don’t smoke.
Talk to your primary care doctor about possibly limiting medications that can trigger dry mouth.