The statistical association is clear: tooth decay and infected gums are associated with higher rates of heart disease and all-cause mortality. The question, then, is whether the association is causal? Can you actually increase your life expectancy just by taking better care of your teeth? Spoiler alert: I find the causal link convincing. 

A prospective NHANES cohort of 15,030 US adults followed a median of 9 years found all-cause mortality was 22% higher among people with infected gums (periodontal disease). This represents about a year and a half of life expectancy. The association with cardiovascular risk is most talked-about, but surprisingly, in this study, the greatest increase was for type-2 diabetes (up 66%). [ref]

In a typical study, the researchers may start by categorizing a test group according to their oral health, then following the people for a number of years to see who dies and who contracts chronic diseases. Measures of oral health include the number of teeth that have been lost, number that have active decay, and number that have fillings.  Theoretical connection is with heart disease, and via heart disease, all-cause mortality. But there are surprising links to other aspects of health.

The major effect on mortality and lifespan comes from inflammation. Bacteria from the mouth find their way into the bloodstream and the body responds with inflammatory cytokines which have a destructive effect overall, increasing risk of heart disease, cancer, and dementia. [Bida, 2025] It’s hard to quantify. This review of 19 studies found that people with periodontitis had blood C-Reactive Protein (CRP) levels 2.3 standard deviations higher compared to people without periodontitis. The theory proposed by authors of the review is that bacteria from the mouth contribute to chronically higher levels of inflammation, which eventually lead to inflamed arterial plaques and heart disease. 

One study reported a 31% increase in atrial fibrillation (?) in patients with periodontal disease which could plausibly have come from increased inflammation. 

“In order to let microbes into the bloodstream, species including P. gingivalis, T. denticola, and F. nucleatum release exotoxins and proteolytic enzymes that break down proteins in the extracellular matrix and at the junctions between the cells of the epithelium.” [ref]. 

This Japanese study showed large reductions in inflammatory markers (IL-6 and CRP) from routine dental cleaning and regular flossing. Not surprisingly, metabolic syndrome (Type 2 diabetes) was found to be inversely correlated oral health. But the natural causal interpretation would be that people whose health is declining because of T2D end up with compromised oral health. It was surprising, therefore, that fixing the periodontitis with routine dental procedures actually improved T2D, as measured by blood levels of leptin (in addition to the improvements in markers of inflammation).

“The transmission of bacterial DNA isn’t the only mechanism that connects periodontal infection to circulatory dysfunction; microbial compounds including lipopolysaccharides (LPSs) and short-chain fatty acids (SCFAs) also play a role. Oral microbial load is a modifiable systemic risk factor because these compounds can circulate at subclinical levels, contributing to chronic endothelial activation, systemic inflammation, and metabolic imbalance.” [ref]

Drug side effects

Xerostomia is a fancy word for dry mouth, which is associated with poor oral health and possible downstream consequences. Xerostomia can be caused by ACE inhibitors, diuretics, beta blocks, and calcium channel blockers — all common prescriptions for the elderly. 

Swelling of the gums (gingiva overgrowth) is a common side effect of calcium channel blockers. Regardless of the cause, enlarged gingiva causes teeth to loosen and creates space below the gumline where food is commonly trapped, leading to chronic low-grade infection in the mouth and systemic inflammation. 

People who are on long-term prescriptions of anticoagulants such as warfarin tend to experience chronic bleeding in the mouth. Anticoagulants are valuable for reducing blood clots which are the triggering event for most heart attacks and strokes, but chronic use of warfarin or xarelto or eliquis lead to low-level oral bleeding as a side-effect. I used to recommend aspirin as a safer alternative, but in recent years, I’ve discovered nattokinase, which reduces heart risk with the fewest side effects. 

(all this from the review cited above). 

Oral probiotics

We know about the importance of the gut microbiome, but the skin microbiome and the mouth microbiome are less well studied. The most common bacteria in oral probiotics is Streptococcus salivarius M18. In this study, once-nightly lozenges of S. salivarius improved gum health after just a few weeks.  S. salivarius is said to stimulate the immune system as well. In this study, S. salivarius defended against dental plaques, which are precursors of cavities and gum disease. 

Mercury fillings

For decades, cavities were filled exclusively with an “amalgam” or “silver filling” which in fact contained no silver, but a good deal of mercury. The mercury is mostly locked into the amalgam, but the process of putting in the filling (or taking it out!) can lead to systemic mercury exposure. We all know that mercury is a neurotoxin, and that it contributed to late-life insanity in Isaac Newton and countless mad hatters. 

Children are especially susceptible to mercury and neurotoxicity in general. Children should not be getting fillings with mercury amalgam. 

Today, there are good alternatives to mercury fillings. For new cavities or repair of old fillings, there is no need to use mercury. Is it worthwhile to have all the mercury removed from your mouth? Probably not, for most people. But if your naturopath (or ReCODE doc) tells the mercury leeching slowly from your fillings is causing a problem, listen to him.

Root canals

A root-canal-treated tooth is dead tissue retained in the body. It cannot mount an immune response. It’s sealed, but sealing is not perfect. There is some indication that root canals are associated with higher levels of inflammation and with higher risks of heart disease. 

My advice: If you have existing root canals, don’t fret. If you are facing a choice, consider extraction followed by a bridge or an implant as a safer alternative to a root canal. 

 

The good news

This is the easiest risk to mitigate. You don’t have to take drugs that have side effects. You don’t have to change your exercise habits or (God forbid) lose weight. You don’t have to eat healthier foods, although that is a plus for oral health and other factors of life expectancy.

  • Don’t let foods linger in the mouth after you’ve eaten
  • Brush more often and more thoroughly, but not with more force or a stiffer brush
  • Floss and use a waterpik to eliminate food lodged between the teeth before it can begin to decay within the mouth
  • Professional cleanings at least twice yearly can reach below the gum line to remove plaque that is the beginning of gum disease 
  • If you wear a night guard or orthodontic retainer, more frequent professional cleanings are indicated.
  • Oral probiotics can help with gum health and possibly immune health more broadly. Look for S. salivarius M18 as ingredient.