Good oral hygiene can lower a person's risk of developing arthritis, it has been claimed.
Studies conducted at the University of Louisville's School of Dentistry in Kentucky found a link between the bacteria which causes gum disease and the early onset of rheumatoid arthritis.
The bacterium was also found to cause the condition to progress at a faster and more severe rate.
Known as Porphyrmonas gingivalis, it produces an enzyme which the body reads as intruders, causing an attack on the immune system.
For people with arthritis, this causes chronic inflammation in the joints and can cause bone damage.
Dr Jan Potempa, who led the study, said: "Taken together, our results suggest that bacterial PAD may constitute the mechanistic link between P. gingivalis periodontal infection and rheumatoid arthritis."
However, he added that further research is need before the findings can be verified.
Previous studies have found higher levels of gum disease in arthritis patients.