Is it possible to change the shade of an eMax crown after it's been made?

any kind of change after cementation is not possible intra orally. so if u r not happy with your current shade thn only option is new crowns. u have to pay again for that. 

Hi, Brian. I am sorry you are dissatisfied with your new crowns. Emax crowns are very esthetic crowns. Unfortunately you cannot change the shade of the crowns once they have been cemented. You might want to check with your dentist and voice your concerns. Most dentists want you happy with the final result and will do what it takes to satisfy you. When you remake the crowns see if you can get a custom shade from your dentist's lab. That will give you the best chance for a good color match.

Dear Brian:
Unfortunately, there is nothing that can be done at this point.  If your dentist cemented the crowns with temporary cement, he/she might be able to remove them and the crowns can possibly be stained properly by the dentist or his ceramist.  If they were delivered with final (permanent) cement, the only way is to cut them off your teeth and make new ones.
Do not worry about being perceived as a problem patient.  You should get what you paid for and you MUST call your dentist right away to discuss this issue with him/her calmly and peacefully.  
Think about it this way... if you bought a car and you ordered a custom color and it came with the wrong custom color, would you not go back to the dealer???
Best of luck,