As a person who has struggled to afford dental care over other life expenses I would strongly believe that the Mercury only stays in place in optimal conditions. I had a chipped tooth which I didn't treat right away which lead to the tooth decaying. Then it cracked in half. There was a filling that was split in half during this. It was a month later before I could afford work on the tooth. I don't know if that filling had Mercury or not but if it did, my mouth was definitely exposed to it.