Crowns used to be a mess, take an imprint, sned it somwhere, wait a week or so, get it back, and it's not quite perfect, so the dentists adjusts it the best way possible but if it's not a great seal, oh well, it can't be fixed and it's expensive to do it again, so they don't.
I had too many crowns already, and multiple leaked, so they allowed bacteria in and cavities under the crown, where they can't be seen due to the metal, until you have a full blown infection.
I got tired of this and finally changed dentists in 2014 to Dr Todd S Adams got this new 3D printing setup for crowns. He scans your tooh, makes a model, has the software verify it, presses print, and a few minutes later, you get a near perfect tooth
