Treating gum disease also relieves the symptoms of rheumatoid arthritis, researchers say.
For people with both conditions, gum care plus arthritis drugs was the best combination treatment, according to a Journal of Periodontology study.
In the study, according to the BBC, patients who had dental treatments such as scaling also saw their arthritis symptoms lessened.
Gum disease and rheumatoid arthritis go hand in hand. In both conditions, soft and hard tissues are destroyed. Rheumatoid arthritis is an incurable disease caused by dysfunction of the immune system.
Researchers from the School of Dental Medicine at Case Western Reserve University and University Hospitals of Cleveland studied 40 patients who had both moderate to severe periodontal disease and a severe form of rheumatoid arthritis.
Dr. Nabil Bissada, head of the department of periodontics at the dental school, said: "It was exciting to find that if we eliminated the infection and inflammation in the gums, then patients with a severe kind of active rheumatoid arthritis reported improvement on the signs and symptoms of that disease. It gives us a new intervention."