All Ceramic Crowns
Traditionally, crowns have been made with a certain amount of metal to give the crown strength, then a layer of porcelain to give the crown its tooth-like appearance. This is known as a porcelain bonded crown. These crowns have disadvantages from a cosmetic point of view.
Firstly, due to the metal layer, the porcelain must be very opaque to block out the underlying grey appearance. This can give the tooth an unnatural appearance as teeth are not naturally this opaque.
Secondly, this metal layer can cause a dark appearance around the gum, which is usually not cosmetically acceptable. Recent developments in ceramic technology have made it possible to make an all-ceramic crown, with no metal layer, that is comparable in strength to the traditional porcelain bonded metal crown.
Due to the lack of a metal layer, these crowns can allow a certain amount of translucency, which gives a very natural appearance. The lack of metal also gives a superior appearance around the gum, removing the dark appearance previously associated with porcelain bonded metal crowns.
Due to these cosmetic advantages, it is common for people to have their old porcelain bonded metal crowns replaced with new all-ceramic crowns to dramatically improve their smile as part of a smile makeover.