Periodontitis and Rheumatoid Arthritis: the Common Thread

Periodontitis (PD) and rheumatoid arthritis (RA) are immuno-inflammatory diseases where leukocyte infiltration and inflammatory mediators induce alveolar bone loss, synovitis and joint destruction, respectively. One percent of the human population is affected by RA which is an autoimmune disease that target modified self-epitopes while 11% of the global adult population are affected by severe chronic periodontitis in which commensal microflora on the tooth surface is replaced by a dysbiotic consortium of bacteria that promote the chronic inflammatory destruction of periodontal tissue. Despite differences in aetiology, RA and periodontitis show similarity in terms of pathogenesis; both diseases involve chronic inflammation fuelled by pro-inflammatory cytokines, connective tissue breakdown and bone erosion. The two diseases also share risk factors such as smoking and ageing and have strong epidemiological, serological and clinical associations. In this review aetiology, clinical and experimental evidence supporting this association is discussed and the potential mechanisms involved in linking periodontitis to RA are presented.