If your dentist took an impression of your teeth before putting in a crown but you did not have the whole procedure done is it legal for your dentist to charge you for a crown and all it entails?

Did you sign an agreement for the procedure? In my experience the impressions are made after the dentist has already built the core and installed a temporary crown. They usually order the permanent crown at that time, which they pay for. So the charge is justified. If this is not the case they should only be allowed to charge for the actual work done (office visit and taking the impression).