Went in for a routine cleaning last week, my dentist treatment planned for me to have a crown put in on #18 -- she did tons of work since the Fall and I also had two root canals but NOT on this tooth. She had previously opened up some metal fillings from the 90s on a few other teeth and now I have terrible sensitivity -- she said a few visits ago that she wouldn't open this tooth up because it will "certainly then need a root canal" -- why does she suddenly want to then put a crown on it? It is the only tooth left with a metal filling (from 20 years ago) but if she does this won't I just need to then get an unnecessary root canal and then have her put on the crown again? Doesn't make sense to me. The tooth has a filling down the side of it and on top (if that matters). I just don't want to have to drop $600 on a crown after insurance to then find out that I will need a root canal for another $1000 and then more unexpected expense because the crown was done then a root canal and then another crown? Thanks for any advice!!!