Is There Any Difference Between a Regular Crown and an Implant Crown?

Authors

I really need to understand what the difference is between a dental crown and a crown that is “a prosthetic device used in conjunction with an implant”. Are they not constructed with the same material, and are not the same methods used to make one as the other? It seems to me that the only difference is how the crown is anchored in the mouth. While I can fully understand a dental insurance company not covering the surgical procedure for the implant, it is beyond me why the “dental device” is not covered. Can you help explain the difference between a regular crown and a crown on an implant? Thanks!