The thing about the mercury amalgam fillings is: why even bother any more? Modern resin fillings are mercury-free, plus they look far better and are nearly indistinguishable from real tooth. They're stronger too: I have a resin "filling" that's actually filling in a chip on one of my front teeth, meaning this filling is actually shaped into a sharp biting edge. It's been there for a year now and works fine. You can't make tooth repairs like that with amalgam.
Amalgam is just plain obsolete, regardless of how safe it may or may not be. So why anyone still uses it, I have no idea; I can only guess they're cheaper than the resin fillings, so they're used for low-income patients, or by shitty (or old-timer) dentists trying to improve their bottom line.
Price, yes. I got mine when I was a student and had no cash; I had a hole in my tooth and had to get it filled for the lowest cost I could.
If I have to get more... It'll be resin. The amalgam ones I've got have lasted a long time though, and I don't seem to have any new holes now that I've quit drinking so much soda every day :)
Amalgam is just plain obsolete, regardless of how safe it may or may not be. So why anyone still uses it, I have no idea; I can only guess they're cheaper than the resin fillings, so they're used for low-income patients, or by shitty (or old-timer) dentists trying to improve their bottom line.