Experimental arthritis exacerbates periodontal disease but periodontal infection does not exacerbate experimental arthritis

There is a proposed link between periodontal disease (PD) and rheumatoid arthritis (RA). A substantial, although not unanimous, body of epidemiological evidence indicates a bidirectional link, with patients with PD more likely to suffer RA and vice versa. Several mechanisms have been proposed to explain the relationship between PD and RA, including i) periodontal bacterial generating autoantigens, ii) local periodontal inflammation generating autoantigens, ii) direct bacterial insult to the joint, iv) systemic inflammation associated with periodontitis exacerbating inflammation at distant sites, and v) shared risk factors. Previous studies, using experimental models of later stages of arthritis and joint destruction, suggest that periodontal infection may exacerbate arthritis and vice versa. We sought to investigate whether periodontal infection may impact on the initiation of arthritis and therefore used an experimental model of breach of immune tolerance, generation of autoantibodies and synovitis.