Commentary: Periodontitis and Rheumatoid Arthritis: What Do We Know?

Background: Currently, in the field of rheumatology, there is much attention given towards the possible causality between periodontitis and rheumatoid arthritis (RA), specifically regarding the role of Porphyromonas gingivalis (Pg). This bacterium is unique, having a citrullinating enzyme. Antibodies against citrullinated proteins are rather specific for RA.Methods: Because causality is ultimately tested in longitudinal cohort studies which currently do not exist for periodontitis and RA, this commentary applied Bradford Hill criteria on the existing literature to assess causality as the most likely interpretation of this association.Conclusions: From an epidemiologic point of view, patients with RA have a higher incidence of periodontal disease than individuals without RA. In addition, there is a dose-response pattern in the association between the severity of periodontitis and RA disease activity. There are indications that periodontitis precedes RA, but there is no evidence yet available to show that P...