How can poor oral health and periodontitis raise your blood pressure?
Gum disease is clearly associated with higher blood pressure, and there is good evidence that it genuinely contributes to it. Intensive gum treatment can lower blood pressure, but that effect has not been confirmed across all studies; taking good care of your teeth remains worthwhile in any case.
Gum disease measurably increases the risk of high blood pressure. People with moderate periodontitis are 22% more likely to have hypertension; with severe periodontitis that figure rises to 49%. Systolic blood pressure (the upper reading) is on average about 4.5 mmHg higher in people with periodontitis than in those without it. This association held up after adjustment for smoking, body weight and diabetes across several large studies. The worse oral health is in general, the greater the risk of hypertension: people who rate their oral health as 'poor' are 48% more likely to have high blood pressure compared with people who have excellent oral health.
There are three biological pathways that explain this association. First, bacteria from the gum pockets travel through the bloodstream to the walls of blood vessels, where they trigger greater inflammation and reduce the vessels' ability to dilate, pushing blood pressure up. Second, the chronic inflammation in the gums activates the immune system throughout the entire body: inflammatory markers and certain immune cells are demonstrably elevated in the blood of people with periodontitis. Third, in a randomised trial, intensive gum treatment reduced the levels of these inflammatory markers in the blood at the same time as producing a substantial fall in blood pressure. This suggests that the inflammation is a genuine link in the chain, not a side effect.
The case that the relationship is causal rather than merely coincidental is supported by a genetic analysis involving around 750,000 people. In that analysis, genetic variants that determine a person's predisposition to periodontitis were also found to raise blood pressure. This is an indication that it is not other lifestyle factors that explain the association.
The most striking treatment outcome comes from a single randomised trial involving 101 people who had both high blood pressure and periodontitis. Intensive gum cleaning reduced systolic blood pressure by 11 mmHg after two months, and the blood vessels also became more flexible. That is comparable to the effect of some blood-pressure-lowering medications. At the same time, it should be noted that when all available treatment studies are considered together, only slightly more than half show a positive effect; the other half do not. The overall picture for treatment as a blood pressure strategy is therefore not yet complete and calls for larger studies.
Finally, there is also a reverse interaction. People with high blood pressure in turn appear to have more gum inflammation than people without it. This association is less well established and a great deal remains unclear about the exact direction of the relationship. If you have both high blood pressure and gum problems, it is certainly worth discussing with your dentist and doctor to ensure both are properly treated.
This answer draws on several large population studies (including an analysis of nearly 750,000 people and a study of more than 21,000 Americans), a review of twelve treatment studies, one randomised trial involving 101 patients, and multiple review articles on the biological mechanisms. The association between periodontitis and hypertension is well documented in the large population studies. The treatment evidence is mixed: one randomised trial shows a large reduction in blood pressure, but the broader collection of treatment studies is not consistent. The causal mechanism (inflammation as the linking factor) is biologically plausible but is largely based on animal and laboratory research supplemented by indirect human evidence.