Materials used for crowns include:

	Porcelain - This can look very lifelike and is most often used for front teeth.
	Porcelain bonded to metal - This combines the appearance of porcelain with extra strength and resistance to fracture.
	Gold - This is strong and hard wearing but it's obvious physical appearance means that it is usually only used at the back of the mouth.

How is a crown fixed to the tooth?
There are a number of special adhesives and cements used in affixing crowns. The inside of the crown is filled with a liquid cement and this is then pushed down over the prepared tooth. The cement then sets and any excess material is removed from the edge of the crown and from between the teeth.

Problems with crowns
It is important to remember that putting a crown on a tooth does not render it impervious to decay. Your hygienist will help ensure that problems do not develop. It is also possible for the cement used for fixing the crown to fail, so that the crown comes out. If this happens, the crown can usually be re-cemented without much trouble. If a crown seems to be coming out frequently, this is a sign that there is an underlying problem that needs to be corrected.