Thanks for the info. I use a computer a lot, so it could well be contributing to my problems. I saw a holistic dentist today, who said I probably have a gut/absorption problem which means I have less resistance to mercury than most people. I am getting the fillings replaced - where I don't know! I wasn't happy with this dentist. He was rude and seemed most interested in how much money he could make from me. I don't think those are attributes a dentist should have, not one I want to see anyway as I am dentist phobic.