2cheekymonkeys, the tooth could still die if the filling is quite deep and it affects the nerves inside the roots of the tooth and they die. If that happens, she will need to have it pulled out. It's really unusual that they would use that without asking you - IME it was used if people couldn't afford the white filling. I had amalgam fillings from when I was a kid and they were fine, but I had them all replaced with the white ones when I worked as a dental nurse purely because I got it done for free and not because of any issue with them. So it's not a drama to have them, it's more of a cosmetic thing.