Our mouth is a veritable microbial paradise: a single 10-second kiss between two people allows the exchange of some 80 million bacteria! Under normal hygienic conditions (regular brushing of the teeth), these bacteria are unable to establish themselves in a lasting way on the teeth and cause little problem; however, when allowed to grow, they can adhere to their surface to form a sort of sticky, whitish coating known as dental plaque.

In addition to causing perforations in the enamel of the tooth (cavities), dental plaque can worsen over time and lead to inflammation of the gums (gingivitis) which causes considerable damage to the tissues surrounding the tooth, including the anchoring bone (periodontitis).

Gateway of bacteria

Another danger of lesions that occur on the gums is that they can be an entry point for plaque bacteria into the bloodstream. The bacterium Porphyromonas gingivalis, for example, is able to squeeze between gum cells and use the bloodstream to establish itself in several places in the body.

The immune system of course tries to eliminate this intruder, but the bacterium has more than one trick up its sleeve and has developed a series of weapons that allow it to circumvent this immunity. As a result, the inflammatory response is powerless to fight off the bacteria and even makes the problem worse by accelerating the destruction of surrounding tissue.

Bacteria: carcinogens

Recent studies suggest that this bacterial infiltration, and the inflammation that accompanies it, could play a role in the development of certain cancers. For example, by comparing the composition of the oral bacterial flora of healthy people and those with pancreatic cancer, a team of New York scientists observed that the presence of P. gingivalis in the mouth was associated with a 59% higher risk of pancreatic cancer, an increase that even reaches 120% for another bacterium responsible for periodontal disease, Aggregatibacter actinomycetemcomitans.

These results are in agreement with an earlier study which observed that people who had high levels of antibodies against P. gingivalis (a marker of the presence of this bacterium in the blood) had twice the risk of developing cancer. of the pancreas.

Finally, another team of scientists observed that 61% of biopsies taken from people with esophageal adenocarcinoma were colonized by P. gingivalis, whereas this bacterium is totally absent from samples from esophagus. healthy. We can think that this bacterial infection has a role in the development of this cancer because of a greater metastatic potential of the tumors containing the bacteria, as well as a reduced survival of the patients.

A healthy mouth, a healthy body

These studies indicate that the health of the teeth can greatly influence the general functioning of the body by acting as a gateway for certain pathogenic bacteria capable of supporting the progression of diseases as serious as cancer. Taking care of your teeth by brushing them regularly and providing them with all the necessary care should therefore be considered a basic hygiene measure, which has a positive impact on the whole body.


(1) Kort R et al. Shaping the oral microbiota through intimate kissing. Microbiome 2014; 2:41.

(2) Fan X et al. Human oral microbiome and prospective risk for pancreatic cancer: a population based, nested case control study. AACR Annual Meeting, New Orleans, April 19, 2016.

(3) Michaud DS et al. Plasma antibodies to oral bacteria and risk of pancreatic cancer in a large European prospective cohort study. Gut. 2013; 62: 1764-1770.

(4) Gao S et al. Presence of Porphyromonas gingivalis in esophagus and its association with the clinicopathological characteristics and survival in patients with esophageal cancer. Infect Agent Cancer. 2016; 11:3.

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