Gum Disease Bacteria Linked with Alzheimer’s Disease

The study was published in the journal of Science Advances, uncovered a potential link between P. gingivalis, the bacteria associated with periodontal disease (also known as gum disease) and Alzheimer’s.1  P. gingivalis  is a gram-negative pathogenic bacteria found in periodontal disease, in the upper gastrointestinal tract and the colon.

Researchers analyzed brain tissue, spinal fluid, and saliva from Alzheimer’s patients—both living and deceased—and found evidence of P. gingivalis. Specifically, they found “gingipains” the toxic enzyme secreted by P. gingivalis. These toxins were found in 96 % of the 53 brain tissue samples examined, with higher levels detected in those with the pathology and symptoms of Alzheimer’s disease.

What is the Associated Link wth Periodontal Disease?

β-amyloid (green) and tooth bacteria toxins called gingipains (red) in brain tissue from an
Alzheimer’s patient. S. DOMINY ET. AL., SCIENCE ADVANCES
 5, (2019)

Researchers noted that the presence of P. gingivalis increased the production of amyloid beta, a component of the amyloid plaques whose accumulation contributes to Alzheimer’s. The study confirmed via animal testing that P. gingivalis can travel from the mouth to the brain and that the related gingipains can destroy brain neurons.2 These findings are noteworthy in that they suggest a biological mechanism for how periodontal disease bacteria may play a role in the development and progression of Alzheimer’s.

These findings underscore the important role of healthy  teeth and gums have with overall wellness.  There is a plethora of research showing positive links between periodontal disease and other systemic conditions like cardiovascular disease, diabetes, adverse reactions in pregnancy and obesity.  The common link with these systemic conditions is bacterial induced inflammation and the host immune response to them.

Although the study results add to the evidence supporting a link between gum disease and Alzheimer’s, additional research is required to better understand the etiology of Alzheimer’s and how periodontal disease bacteria can exacerbate progression. This was a small study examining only brain tissue samples from only 20 people. Because of that, the association between Alzheimer’s disease and gum disease in this study could have occurred by chance. There is an upcoming FDA Phase II clinical trial that will assess the benefits of using a novel small molecule inhibitor of these P. gingivalis gingipains in hindering the development and progression of Alzheimer’s. This clinical trial may add further insight into the link between gum disease and Alzheimer’s.

Take Home Message

Intra -Oral 3D Scan

From these findings, it is critical that adults’ age 30 or older be seen by a periodontist for a comprehensive examination. You do not have to have a referral by your dentist. A periodontist will conduct a thorough examination of your TMJ, teeth and gums, perform an oral cancer examination and test for gum disease. Additionally, at Prestipino Dental Group : Dr. Tassos Sfondouris will take an intra-oral scan of all of your teeth and gums to obtain a live 3-dimensional picture, so that he can compare them to future scans. This is real time data that can be used to analyze changes to your teeth and gums.

A periodontal examination is critical because according to the literature, 50% the U.S. population age 30 and older have some form of periodontal disease.3 The prevalence increases to 68% for those age 65 and older.3 Routine brushing and flossing twice a day, and visiting a periodontist can help identify, treat and manage the gum disease, potentially decreasing your risk for other systemic medical conditions, like heart attack and strokes.

Contact our practice at 301-652-2300 if you would like to schedule your periodontal and hygiene examinations. We have two highly experienced and skilled hygenists, who are preventively driven to protect your mouth.

Information about the Author: Dr. Tassos Sfondouris is a board certified periodontist and a former clinical assistant professor at the University of Maryland, School of Dentistry. He is passionate about restorative and periodontal therapies that promote the health, comfort, and function of teeth. He welcomes your comments and suggestions and encourages you to like him on Facebook or follow him on Twitter to get the latest unbiased information on dental health topics.


1. S.S. Dominy Porphyromonas gingivalis in Alzheimer’s disease brains: Evidence for disease causation and treatment with small- molecule inhibitors. Science Advances 2019 January;vol 5(1).

2. S. Poole, S. K. Singhrao, S. Chukkapalli et al., “Active invasion of an oral bacterium and infection-induced complement activation in ApoEnull mice brains,” Journal of Alzheimer’s Disease, vol. 43, pp. 67–80, 2015

3.Eke PI  Update on Prevalence of Periodontitis in Adults in the United States: NHANES 2009 to 2012. J Periodontol 2015 May ;86(5):611-22.