What is causing the horrible taste in my mouth after recent eMax crown?

Foul, metallic taste that is very unpleasant and certainly causing halitosis. I have other crowns, but this is my only e-max crown. I've had no problems with my other crowns. Bite wing and a periapical x-ray show no problems, and the crown margin is sealed. The dentist who placed the crown is a superb dentist. What can be done to eliminate this terrible taste and smell?