The type of crown used will depend on the location of the tooth in need of restoration:
Gold crown: a strong material, used for back teeth responsible for the majority of your chewing.
Full Metal crown: these appear like stainless steel but are made from a non-precious metal alloy, these are strong crowns, used for back teeth (not in the cosmetic zone).
Porcelain-fused-to-metal: offers both aesthetic and strength, therefore, can be done for the front as well as back teeth.
Ceramic / Zirconia: the most cosmetically appealing material. Used for the teeth most visible when you smile (primarily front teeth). But Zirconia crowns are now being made for back teeth as well due to their promising strength.