Mouth and body
Researchers have studied the mouth–heart connection for decades. Here's where the evidence stands.
Inflammation, oral bacteria in circulation, and shared risk factors all sit in this research, and each carries a different weight.
Periodontitis and cardiovascular disease occur together more often than chance would predict, and that observation has been reproduced across many populations. What remains under study is why. Three explanations are under investigation: chronic inflammation from the gums adding to inflammation elsewhere, oral bacteria entering the bloodstream, and risk factors the two conditions share — smoking, diabetes, age and socioeconomic position. The third is the reason association alone settles little, because those factors raise both risks independently. A 2020 joint consensus of periodontal and cardiology researchers described the association as consistent while stating that the intervention evidence does not yet show that treating gum disease changes cardiovascular outcomes.
Why scientists study oral–systemic connections
Periodontitis is common, it is chronic, and it is inflammatory. Those three properties together make it interesting to researchers studying conditions elsewhere in the body, because a persistent inflammatory source is the kind of thing that might not stay local.
A survey of registered clinical trials in periodontal medicine found investigators studying links to a long list of conditions. Worth reading precisely: that is a map of what is being studied, not a list of what has been shown.
Chronic inflammation
Periodontitis involves a sustained immune response at the gumline, and that response is measurable beyond the mouth — inflammatory markers in blood are elevated in people with periodontitis compared with people without it.
Because inflammation is also part of how atherosclerosis develops, a shared inflammatory pathway is the most examined of the proposed explanations. Examined is not the same as established.
Bacteremia
Oral bacteria enter the bloodstream routinely. Chewing, brushing and dental procedures all produce transient bacteremia, more so when the gumline is inflamed and its barrier is compromised.
That this happens is not in question. Whether it contributes to disease elsewhere is a separate question, and a harder one.
Oral bacterial DNA in cardiovascular research
Studies have reported DNA from oral organisms, Porphyromonas gingivalis among them, in atherosclerotic plaque removed during surgery.
Detecting bacterial DNA in a tissue establishes that the organism's genetic material reached it. It does not establish what the organism did there, or whether it contributed to the lesion — a distinction the researchers themselves draw carefully.
What the epidemiology shows
Across many populations, people with periodontitis have cardiovascular disease more often than people without it. The 2020 joint consensus from the European Federation of Periodontology and the World Heart Federation reviewed this literature and described the association as consistent.
Consistent association is a real finding. It is also the beginning of a question rather than the end of one.
Shared risk factors, and why they complicate everything
Smoking, diabetes, age, obesity and socioeconomic position each raise the risk of periodontitis and of cardiovascular disease, independently.
So two conditions could appear together frequently without either affecting the other, simply because the same things drive both. Studies adjust statistically for known factors, which helps and does not settle it — adjustment can only handle factors that were measured in the first place.
What periodontal-care studies have and haven't shown
Intervention trials are the test that association studies cannot perform: treat the gum disease, and see whether anything changes elsewhere.
Those trials have reported improvements in surrogate markers — inflammatory markers in blood, measures of blood-vessel function. What they have not shown is a reduction in cardiovascular events, which is the outcome that would matter. The 2020 consensus says so directly, and the trials large enough and long enough to answer it have not been done.
Where nitric oxide fits
There is a second, quite different link between the mouth and vascular biology, and it does not run through inflammation at all. Certain oral bacteria convert dietary nitrate to nitrite, the first step of a pathway that human cells do not perform efficiently, and the body uses the product downstream in blood-vessel biology.
That pathway is set out in full on the nitric oxide page. It is mechanistically clearer than the inflammatory route, and it is also a smaller claim.
What this means day to day
Gum health is worth attending to on its own terms: it keeps teeth, and it is treatable. That case stands without reference to anything systemic.
If you have cardiovascular risk factors, your dentist and your physician each hold part of the picture, and they are usually not in touch. Mentioning one to the other costs nothing.
Where the research is
Where the relevant findings sit.
Oral bacteria enter the bloodstream transiently during chewing, brushing and dental procedures.
Periodontitis involves a sustained inflammatory response measurable in markers beyond the mouth.
Smoking, diabetes, age and socioeconomic position raise the risk of both periodontitis and cardiovascular disease.
Across many populations, periodontitis and cardiovascular disease occur together more often than chance would predict.
DNA from oral organisms has been reported in atherosclerotic plaque.
Whether the association reflects one condition affecting the other, or shared causes acting on both.
Whether treating periodontitis changes cardiovascular outcomes. Trials have reported changes in surrogate markers, not in events.
What oral bacterial DNA found in vascular tissue was doing there.
In context
Your physician
Cardiovascular risk is assessed with blood pressure, lipids, glucose, family history and more. None of that is a saliva measurement, and none of it is replaced by one.
Your dentist
Probing, attachment levels and radiographs establish whether periodontitis is present. That determination is your dentist's, and a microbial result sits alongside it.
Shared risk factors
Smoking and diabetes sit in both stories at once, which is why they are the hardest part of this research to reason about.
Time
This literature is decades old and still open. The evidence labels on this page reflect where it currently sits, not where it will settle.
How OraPath measures this
OraPath sits at the oral end of this research. The Oral Balance Test detects and quantifies the organisms associated with periodontal disease, the protective commensals competing with them, and the nitrate-reducing capacity — the part of the picture that can be sampled and tracked.
What it describes is the bacterial community in your mouth. Cardiovascular questions belong to your physician, and the measurements that answer them are different measurements entirely.
See what's happening at the oral end.
Curious what your oral microbiome looks like? The Oral Balance Test measures targeted organisms and microbial functions from a saliva sample processed in our Norman, Oklahoma laboratory.
Common questions
Does gum disease cause heart disease?
The research describes an association, not a causal relationship. The two occur together more often than chance would predict, and several explanations remain under investigation — including risk factors the two conditions share.
Can an oral microbiome test tell me about my heart?
It measures the bacterial community in your mouth. Cardiovascular assessment uses entirely different measurements, and belongs with your physician.
Has oral bacteria been found in arteries?
Studies have reported DNA from oral organisms in atherosclerotic plaque. That establishes the genetic material reached the tissue; what the organisms were doing there is still being studied.
Will treating my gum disease protect my heart?
Intervention trials have reported improvements in surrogate markers such as inflammatory markers and blood-vessel function. They have not shown a reduction in cardiovascular events.
Why is this so hard to study?
Smoking, diabetes and age raise the risk of both conditions independently, so the two can appear together without either affecting the other. Statistical adjustment helps, but only for factors that were measured.
Should I tell my doctor about my gum health?
Your dentist and physician each hold part of the picture and are usually not in contact. Mentioning one to the other is a reasonable thing to do.
References
- Sanz M, Marco del Castillo A, Jepsen S, et al. Periodontitis and cardiovascular diseases: Consensus report. J Clin Periodontol. 2020;47(3):268–288.
- Hajishengallis G. Periodontitis: from microbial immune subversion to systemic inflammation. Nat Rev Immunol. 2015;15:30–44.
- Paul O, Arora P, Mayer M, Chatterjee S. Inflammation in periodontal disease: possible link to vascular disease. Front Physiol. 2020;11:609614.
- Monsarrat P, Blaizot A, Kemoun P, et al. Clinical research activity in periodontal medicine: a systematic mapping of trial registers. J Clin Periodontol. 2016;43(5):390–400.
- Hezel MP, Weitzberg E. The oral microbiome and nitric oxide homeostasis. Free Radic Biol Med. 2015;105:48–57.
- Kilian M, Chapple ILC, Hannig M, et al. The oral microbiome — an update for oral healthcare professionals. Clin Microbiol Infect. 2016;22:657–666.
Laboratory developed test · for adjunctive clinical use · not FDA cleared.