New research documents lower inflammation after deep gum cleanings
Study: Dysbiosis-Mediated Inflammation: A Pathophysiological Link Between Rheumatoid Arthritis and Periodontitis (DOI: 10.1111/jcpe.70063)
EXPERT Q&A
It's well established that gum disease and rheumatoid arthritis are strongly linked. But what wasn't known, until a recent study, was that the two churn through a vicious cycle, feeding off each other and triggering damaging inflammation.
The study, led by the University of Birmingham in the U.K. in collaboration with the University of Michigan, also sought to answer another critical question: Which comes first, gum disease or RA?
RA is an autoimmune disorder that attacks the joints and other parts of the body and affects some 1.5 million Americans and about 23 million people worldwide. It is also a leading cause of disability.
The study, published in the Journal of Clinical Periodontology, adds to a growing understanding that oral health is closely tied to overall health.
Purnima Kumar, professor and chair of the Department of Periodontics and Oral Medicine at the U-M School of Dentistry, is the senior and corresponding author of the study. She explains the significance of the findings.
What did you and your fellow researchers learn about the unhealthy relationship between gum bacteria and RA?
An unhealthy community of bacteria living under the gumline can stoke local (gum) and systemic (body-wide) inflammation, serving as a mechanistic link between periodontitis and rheumatoid arthritis. The presence of these bacteria and their byproducts appears to worsen autoimmune responses in RA, while RA itself can make the oral environment more prone to dysbiosis and disease-a vicious cycle.
Can you say which comes first: RA or gum disease and why it matters?
The body is an interconnected system, and as I tell my patients, "the mouth is not an island." This study really highlights that fact, since patients with RA exhibit detrimental changes to the oral bacterial communities that normally protect them. Once they get gum disease, this virulent community and the inflammation it creates spills out of the mouth into the blood stream. While it is important to know that RA predisposes patients to gum disease, and that these patients require frequent monitoring and care to prevent gum disease, our data supports a "vicious cycle" model, where periodontitis and RA have a complex, mutually reinforcing relationship. This makes it vital for clinicians to integrate dental and rheumatological care for affected patients.
The study used information from plaque samples and bloodwork from volunteers, correct? Can you sum up the details it provided?
Yes, about 150 volunteers were enrolled, including individuals with rheumatoid arthritis, RA, those with periodontitis, PD, patients with both conditions and healthy controls with neither condition. Our first discovery was that patients with RA but no PD already demonstrated a virulent group of bacteria living under their gumline, and a much more florid inflammation of their gums, suggesting that the inflammation induced by RA can negatively impact oral health. Then, we randomized patients to one of two groups. This is, to my knowledge, the first randomized controlled trial, which means that we randomly assigned patients with RA and PD to two groups. One group received a deep cleaning; That is to either receive a deep cleaning. That is, treatment of the deep pockets hidden under the gumline to remove plaque, tartar and unhealthy root surface tissue followed by continued monitoring and cleaning at three-month intervals. Or to receive instructions on how to clean their teeth. To be clear, those randomized to the second group that received cleaning instructions only did receive the deep cleaning after a six-month period, when their participation in the study ended. We found that the group that received treatment for their gum disease demonstrated much greater improvement of their RA status-when compared to those who received instructions only.
The study seems to strongly advise RA patients, and perhaps everyone, to consider deeper teeth and gum cleanings?
Yes, indeed. Our oral cavity hosts a real estate that is about the size of our palm for bacteria to live on. These bacteria are highly skilled and exquisitely adapted to live in the mouth and to provide huge benefits in terms of breaking down complex foods, providing protection against foreign pathogens, and educating our immune system. Therefore, the least we can do is protect them, and allow them to thrive as a healthy, health-compatible community. This means that we don't expose them to chemicals such as from smoking or vaping or indiscriminately destroy them through antimicrobials. Maintaining this community in a healthy state also requires frequent cleanings, monitoring the health of the community and intervening at the first sign of dysbiosis, which is loss of balance within the microbial community.
The gum cleanings we're talking about go beyond typical teeth and gum cleanings, correct? Could you describe what they entail?
These patients had active gum disease. This means that the tissues that anchor the teeth to the jawbone were being destroyed, leaving a large, inflamed and infected pocket between the teeth and the gums. The gum cleanings are the first step in restoring health. They are typically performed under local anesthesia and involve removal of plaque, tartar, necrotic root surface and other tissues, in general, creating an environment that can begin the healing process. The oral health care expert might also fix cavities, broken fillings/crowns and perform other procedures to improve the patient's ability to keep these areas free of plaque at home. This is most often the first step in the treatment sequence which can also involve surgical reduction of these pockets or procedures to reconstruct lost tissues. A very important part of this process is regular monitoring of gum health and intervening at the earliest sign of change in health status.
Was there anything surprising or unexpected in the findings?
We have known, from our own work, and through work from other groups, that RA and PD are interlinked. Previous work was largely focused on a single oral pathogen and its ability to hijack our immune system to aggravate RA. We now show that this is more of a community-level event, what is known as dysbiosis, rather than a single culprit. And the magnitude of response to deep cleaning that we observed signposts the need to treat the body as an integrated system of organs rather than each system separately.
What's your advice to anyone concerned about or living with inflammation or related health issues?
Inflammation is our body's protective response mechanism, and can occur due to various factors, from injury to infection. Controlling the triggers of inflammation and resolving inflammation as quickly as possible are important for health. These triggers range from habits such as smoking and vaping to higher body mass index to poor oral hygiene-and personal hygiene.
As with most smaller studies, which this one was, do you and the research team plan to investigate on a larger sample? Or encourage anyone in this area of study to do so?
Absolutely. We need more randomized trials with larger populations. We are now exploring other related diseases, for example Scleroderma and Lupus, to see if similar mechanisms of circular relationships exist.
Co-authors of the study also included Iain Chapple, Thomas Dietrich, Melissa Grant, Paola de Pablo and Praveen Sharma, University of Birmingham; Isabel Lopez-Olivia, University of Birmingham and Birmingham Dental Hospital; Karim Raza and Andrew Filer, NIHR Birmingham Biomedical Research Centre in Inflammation; Stefan Serban, University of Leeds School of Dentistry; Akshay Paropkari, Clear Labs Inc.; and Shweta Saraswat, Ohio State University.
