Gum disease treatment slows the thickening of arteries, clinical trial shows

Research has long pointed to a link between poor gum health and a higher risk of cardiovascular disease — and now, a new trial suggests that treating severe gum disease may reduce the narrowing of a major artery over time in otherwise healthy people.

Likely by reducing inflammation, this routine oral hygiene procedure may be an unsung way of minimizing declines in blood vessel functioning.

"I was very overwhelmed when I looked at the data the first time," study co-author Dr. Marco Orlandi, a clinical research periodontist at University College London, told Live Science.

Around 40% of U.S. adults ages 30 and older have some level of gum disease, known as periodontitis, a chronic inflammatory condition whose progression leads to wobbly teeth, tooth loss and persistent bad breath. As the disease worsens, small pockets around the teeth that cannot be reached by a toothbrush or floss expand and fill with plaque and bacteria.

There is now an abundance of research linking periodontitis to a higher risk of various health outcomes, including Alzheimer's disease, colon cancer and rheumatoid arthritis. A key area with mounting evidence is the association between severe gum disease and cardiovascular disease, with previous studies finding that the management of gum disease is linked to improved blood vessel function.

Now, a clinical trial published Aug. 19 in the European Heart Journal has found that treating periodontitis slows the thickening of the inner two layers of the carotid arteries, found on each side of the neck, in otherwise healthy adults. The thickness of those artery walls is a key marker for cardiovascular disease risk.

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By targeting inflammation rather than other artery health factors, like cholesterol, "the impact of what we are doing comes without going through the classic risk pathway" for cardiovascular disease, Orlandi said.

To test whether treating periodontitis actually causes the carotid arteries to thicken less over time, Orlandi and his team of periodontists and cardiologists conducted a gold-standard trial at a dental hospital in central London. The trial was randomized, meaning participants were randomly placed in a treatment group or a comparison group that didn't receive the intensive gum treatment.

First, the researchers took ultrasounds of the carotid arteries of 135 people with severe periodontitis, to establish a baseline level of thickness. They also measured how much the arteries dilated when blood flow increased — a measure of blood vessel functioning — and took blood samples to pinpoint markers of inflammatory and oxidative stress. All of the individuals were healthy besides having gum disease.

Next, the participants were randomly divided into either the treatment group or the control group. Care was taken to ensure there was a roughly even split between the two groups in terms of the participants' periodontitis severity, smoking status and family history of cardiovascular disease.

In the treatment group, patients received intensive periodontitis treatment: a thorough clean of the whole mouth and a deep clean below the gumline to remove plaque and tartar. The control group received a simple scale and polish, more akin to a regular dental cleaning that doesn't include a deep clean of the gums.

The participants were then followed for two years, and they each received further dental treatments at regular intervals throughout that time. The researchers also reassessed the carotid artery at the one-year and two-year marks, and took blood samples and measured blood-vessel function at five time points.

They found that the thickness of the carotid arteries' innermost linings was lower for individuals who received intensive treatment than for those in the control group. This difference was "comparable to what has been seen with lifestyle interventions and some pharmacological agents in similar populations," study co-author Dr. Francesco D'Aiuto, a clinical research periodontist at University College London, told Live Science in an email.

The treated patients also had better blood vessel function and lower levels of inflammatory and oxidative stress markers in their blood, which are known to contribute to the narrowing of artery walls — a condition called atherosclerosis.

Although many factors drive atherosclerosis, "our results reinforce the view that untreated periodontitis is a modifiable risk factor for vascular ageing and possibly cardiovascular events," D'Aiuto said.

However, a key limitation of the research is that it was conducted in only one location, so there is a chance that the findings partly come down to quirks of the location or the people in the sample, Orlandi said.

Another limitation, said Dr. Maurizio Tonetti, a clinical and research periodontist at the University of Hong Kong who was not involved in the research, is that all of the participants in the trial were healthy other than having periodontitis. As such, these results should not be interpreted as evidence that if someone with atherosclerosis has their gum disease treated, the health of their arteries will improve, he told Live Science.

Even so, the findings "are bringing the concept of these [intensive gum disease] interventions into the preservation of wellness," Tonetti said.

"For many, many years, dentists have been focusing on the teeth, forgetting the rest of the body, and physicians have been focusing on the body, forgetting that there are teeth," he said. "They are really two worlds that have been separated and need to go back together for the benefit of patients."