Full yellow gold crowns are the best long term value for the most back molars. But because of the gold color many people want more cosmetic alternatives, tooth-colored porcelain
crowns with various materials under the porcelain for a substructure.

All metal crowns, gold or silver, are the strongest. Cosmetic crowns range from porcelain crowns layered over a metal substructure, some with hidden metal substructures, and the most cosmetic without any metal, theycome with a new space-age tooth-colored under structure, called Zirconia.