mercury under crowns

i am getting 11 mercury amalgum fillings out. i have one left. the problem is.. i have 3 crowns and don't know if mercury amalgums are underneath them and my dentist doesn't know either because he doesn't have my history of x rays. should i have the dentist removing the amalgums take off the crowns to check it out? it seems logical, but i don't really want to have to do it if there is another way. any suggestions? anyone experience this?