A strong association exists between periodontal disease and rheumatoid arthritis (RA). The two diseases share common inflammatory pathways, and some research suggests that oral bacteria may actually play a role in triggering RA.
P. gingivalis produces an enzyme called peptidylarginine deiminase (PPAD) that modifies proteins through a process called citrullination. Abnormal protein citrullination is a hallmark of RA — the immune system produces antibodies against citrullinated proteins (ACPA), which is a diagnostic marker for the disease.
This has led researchers to propose that chronic P. gingivalis infection may, in genetically susceptible individuals, trigger the autoimmune response that leads to RA.
P. gingivalis produces PPAD, which citrullinates proteins. In RA, the immune system produces anti-citrullinated protein antibodies (ACPA) that attack joint tissue. The theory: oral bacterial enzymes may initiate this abnormal immune response.
Both periodontal disease and RA involve destructive inflammation driven by similar cytokines (TNF-alpha, IL-6). The chronic inflammatory burden of gum disease may amplify autoimmune joint inflammation.
Some oral pathogens share molecular structures with joint tissue proteins, potentially triggering cross-reactive immune responses (molecular mimicry).
- 1P. gingivalis produces PPAD enzyme — the same protein modification process found in RA.
- 2People with RA are significantly more likely to have periodontal disease.
- 3ACPA (RA diagnostic marker) levels may correlate with periodontal disease severity.
- 4Treating periodontal disease may reduce RA disease activity and inflammatory markers.
- 5Shared genetic susceptibility factors exist between the two conditions.
Produces PPAD enzyme linked to RA protein citrullination
May also contribute to protein citrullination and autoimmunity
Contributes to inflammatory burden; common in both conditions
- Coordinate care between your rheumatologist and dentist
- Treat periodontal disease aggressively — reducing oral inflammation may help reduce joint inflammation
- Get more frequent dental cleanings during RA flares (every 3 months)
- Report oral infections promptly to your rheumatologist
- Consider oral health as part of your autoimmune management strategy
- Salivary testing can identify specific pathogens to target
Consider testing if you have RA or a family history of autoimmune disease. Also valuable if you have persistent gum disease that doesn't respond to standard treatment, or if your RA is not well-controlled.
Wegner N et al. P. gingivalis, PPAD, and rheumatoid arthritis. — Mechanism linking oral bacteria to RA autoimmunity.
Mikuls TR et al. Periodontitis and rheumatoid arthritis. — Association and shared mechanisms.