The prevalence of periodontal disease has doubled among patients with rheumatoid arthritis (RA) when compared to the general population, as stated in a study by Drs. Jean-Marie Berthelot and Benoît Le Goff published in the December 2010 issue of the journal Joint Bone Spine. According to the authors, this increased prevalence is unrelated to secondary Sjögren’s syndrome but instead is related to shared pathogenic mechanisms, including: (1) an increased prevalence of the shared epitope HLA-DRB1-04; (2) exacerbated T-cell responsiveness with high tissue levels of interleukin-17; (3) exaggerated B-cell responses (plasma cells are the predominant cell type found within gingival tissue affected with periodontitis, and B cells are twice as numerous as T cells); (4) receptor activator of NF-B (RANK) overexpression; (5) an increase in the ratio of RANK-Ligand (RANK-L) over osteoprotegerin with a high level of RANK-L expression on gingival B cells, most notably those capable of recognizing Porphyromonas gingivalis. Other factors conducive to periodontitis include smoking and infection with the Epstein-Barr virus or cytomegalovirus; these promote the growth of organisms such as P gingivalis, whose DNA is often found in synovial tissue from RA patients. P gingivalis produces the enzyme peptidylarginine deiminase, which induces citrullination of various autoantigens; levels of anticyclic citrullinated peptide antibodies are considerably higher in RA patients with periodontal disease compared to those without periodontal disease, which suggests that periodontitis may contribute to the pathogenesis of RA. This hypothesis is further supported by evidence that other antigens involved in RA, such as HC-gp39, are also present in gingival tissue. Tumor necrosis factor-α antagonists slow alveolar resorption but may perpetuate infection of periodontal pockets. Therefore, the authors state that rheumatology patients, including those taking biotherapies, are likely to benefit from increased referral to dental care for such treatment as scaling, root planing, and if needed, dental surgery. This is particularly important because periodontitis is also associated with an increased risk of premature atheroma.
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