I just got an implant for my front tooth a month ago; the A1 color does not match the A1 color of the rest of my upper crowns.

Different porcelains have a different look. A1 is slightly different from manufacturer to manufacturer  and material to material. Porcelain over metal is different from porcelain over zirconia or alumina, two common substructures in crowns. An all zirconia crown, very popular now because they do not break so easily if at all, is even more different....since it is not a porcelain laminate. Making front teeth match is very difficult and only the best dentists and ceramists in the laboratory can do it well. Many tryins and remakes may be needed to get an exact match. That is one reason for higher costs of some crowns over others....care, skill and judgement along with artistic excellence.

I have run into the same problem as your dentist, where the manufacturer changed the formula and we had some challenges matching crowns or veneers done now to adjacent ones done a few years ago.Also, it would depend on what type of crowns are placed.  If your implant crown and other crowns are all "porcelain fused to metal" then I would expect that a pretty close match could be done for you.  However, if your other crowns are all-ceramic (with no metal understructure) and they are trying to match an implant crown to the other all-ceramic crowns, there will be some issues that aren't under the control of the dentist....i.e. metal or white zirconia abutment which will not allow light to pass into and through the implant in the same manner as the all-ceramic crowns.  This can be a real challenge even by some of the very best dentists and ceramists.  The question is "can they work the porcelain to make it a little better" or will you have do be satisfied with the best they can do today based on the realities of esthetics and dental materials.

There are multiple factors that lead to a different appearance in shade. One of the most common causes is what we call "metamerism," which is the appearance of different objects under different light sources. Under a soft light setting, your teeth may appear the same color as your metal crown-- but may look entirely different under light, such as a camera flash. Unfortunately, this situation is one of the biggest hurdles in dentistry and can be difficult to resolve, with no absolute answer. I wouldn't necessarily just blame the metal coping under the crown, since you seem to have other existing crowns, which I'm guessing have metal copings as well. As the other Dr. mentioned, it's difficult to say what's the actual cause of the "grey" appearance.There is a possibility that the laboratory technician who made the crown cross-compared your crown to its corresponding shade tab under a light source where everything looked the same. Your best course of action is to bring this up to your provider and vet out the options presented. If you opt for a re-make, you can ask for a custom shade match. The absolute best way would be if you happen to have your old crown available; if you send that in, a good lab tech can usually match it.Hope that helps!

Hard to know why crown looks gray without seeing case and knowing what was done.  Crowns should be able to be matched to others even if they are made at different times.  One possibility is if a metal abutment was used under the crown that you are getting some show through of the abutment and creating a gray appearance.  If that is the case a nonmetal abutment of zirconium can be used to solve that issue.