There have been several threads on these forums about the extent of the danger of mercury fillings, getting them removed, and what might be the best way to go about heavy metal removal afterward.
I looked at the evidence and choose to have my fillings removed. I had over a dozen of them, and most were fairly extensive molar fillings.
If a person chooses to have them removed, there are good protocols and bad protocols. My dentist followed the one here, which among other things calls for using a rubber dam and a high volume evacuator. During the drilling, care is taken to drill around the filling and not across it to avoid releasing mercury vapor.
My dental work was done in four separate sessions, each for a quadrant. The sessions lasted over an hour, except for the last which had only small fillings to remove.
The replacement material was composite (porcelain). It is applied as a liquid, given a rough shape, and cures instantly when hit with a UV light tool. After curing it is drilled and polished to its final shape, and is an area where a good dentist gets to demonstrate their skill.
My dentist has the philosophy of trying to keep as much of the tooth structure as possible. In fact, that was the main reason I chose to go with him (my original dentist said that he would have to put crowns on all of my teeth and would drill across the center of the fillings). Throughout, the dentist I worked with took the time to make sure the procedure was painless (dabbing some numbing gel on the spot where the shot would go, waiting for the first shot to take effect so that the second shot would be painless). He had a couple of large screens on which to display the progress, on which he would use a 300x camera to take snapshots at high resolution. On the other screen I would watch Grateful Dead and U2 concerts. The recovery was steady, some tooth sensitivity that faded over a few weeks' time.
All things considered, I'm very pleased with the results. Cosmetically, my teeth look great; one would never know that I'd had fillings. At a current age of 44, I hope that I will have a long time to benefit from being mercury free.
Stephen