Thanks for writing antonette458@. First, let me say that for you safety, we cannot give medical advice over the internet. It is completely understandable that you would be concerned by any procedure that you thought could contribute to a condition such as RA.
RA is an autoimmune condition (as are other conditions, such as type 2 diabetes, plaque psoriasis, psoriatic arthritis, lupus, and others). The exact cause is unknown. This article looks at some of the hypothesized causes, including looking at genetics, infections, and leaky gut: https://rheumatoidarthritis.net/living/hypothesized-causes-rheumatoid-arthritis/.
The research on amalgam fillings has largely focused on mercury and the body's absorption of it. There has been some research finding mercury absorption, but not a real connection to mercury and RA. Most of the claims linking amalgam fillings and RA are from holistic and natural healing sites. The research that has been done has largely focused on bacteria and it is true that people with RA are more prone to periodontal disease. However, it appears to be the RA that is causal. This article looks at RA and periodontal disease: https://rheumatoidarthritis.net/living/oral-hygiene-protect-yourself-against-periodontal-disease/.
You may also want to ask your dentist about the type of fillings they use and about mercury. Also, remember that it is always your right to ask for a second opinion.
Hope this answer is helpful. If you would like more opinions you may want to take your question to our Facebook page at https://www.facebook.com/RheumatoidArthritisDotNet/. Best, Richard (RheumatoidArthritis.net Team)