If you think the damage done by gum disease is confined to your mouth, think again, say researchers from the University of Louisville School of Dentistry, Oral Health and Systemic Diseases and an international team of scientists from the European Union's Gums and Joints project.

In fact, gum disease, or periodontal disease, not only wrecks teeth and gums, but it can also give rise to a seemingly unrelated ailment: rheumatoid arthritis (RA).

The researchers note that there is a well-established connection among inflammatory diseases, but their research delves deeper into the role of oral bacteria. And RA is not the only disease those with periodontitis should be wary of; Alzheimer’s is among the diseases researchers think may be associated with gum disease.

P. Gingivalis Is the Culprit

Researchers tested bacterial strains of gum disease on mice with collagen-induced arthritis (CIA), which is similar to RA in humans.

They found that the Porphyromonas gingivalis strain, responsible for periodontal disease, worsened arthritis in the mouse models by speeding up onset, progression, and severity, including the breakdown of bone and cartilage. This is because P. gingivalis creates an enzyme called peptidylarginine deiminanse (PPAD), which exacerbates CIA.

The researchers also found high levels of citrullinated proteins at the infection sites of P. gingivalis, which points to more bad news for RA sufferers since the body will attack citrullinated proteins.

“Antibodies against citrullinated proteins are known to be a specific marker [of RA] that can be detected years before the onset of the disease, and their presence and serum levels correlate strongly with disease severity,” the researchers wrote. This defensive mechanism in turn generates more pain and inflammation.

What’s the Link?

Rheumatoid Arthritis isn’t the only inflammatory condition with ties to periodontal disease. Other such diseases include cardiovascular disease and chronic obstructive pulmonary disease, as well as Alzheimer’s and Parkinson's disease (PD).

The exact connection among them is a challenging question for scientists, but the discovery of the effects of protein citrullation does answer many urgent questions.

“Although RA and PD differ in terms of their etiological mechanisms, a link between both diseases has been established in numerous clinical and epidemiological studies,” the researchers wrote. “Compared to the general population, individuals with PD have an increased prevalence of RA and, conversely, PD is at least 2-fold more prevalent in RA patients.”

What Can You Do?

In a perfect world, thorough tooth brushing and flossing would be second nature. It’s important to remember that maintaining oral health keeps gingivitis at bay before it devolves into periodontal disease.

There is a silver lining: Proper dental care, it seems, could hold the key to improved bone and joint health, and a healthier skeleton means fewer trips to the dentist.

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