A crown is a tooth-shaped cover placed over a tooth that is badly damaged or decayed. A crown is made to look like your tooth. Many people call it a cap.
Crowns may be placed for several reasons. Usually the tooth has been broken or damaged. As a result, a filling can't replace enough of the tooth or make the tooth strong enough. A crown may hold together parts of a cracked tooth. It also can be used to hold a bridge in place. Crowns can be used to improve appearance as well. They may be placed to cover misshapen or badly discoloured teeth.
Crowns can be all metal, porcelain fused to metal (PFM), or all ceramic. The all-metal or PFM crowns are strong and can be a good choice for back teeth. PFM and all-ceramic crowns are the same colour as your natural teeth. They look just like normal teeth.
To place a crown, your dentist will file down the tooth to make room for the crown. Then, the dentist will take a mould of the tooth with a rubber-like material. The impression material sets in about three minutes. Then it is removed. Your dentist will also take an impression of the teeth above or below the tooth that will receive the crown. This is to make sure the crown will fit into your normal bite.
The moulds are sent to the laboratory where the crown is made. During that time, you will have a temporary crown placed. These crowns are usually made of plastic and fitted by your dentist with a temporary cement. This is a special cement that is designed to be weak so that the temporary crown can be removed easily when the permanent crown is fitted.
At a second visit, your dentist will remove the temporary crown and test the permanent one. Sometimes crowns need small adjustments before they are placed. Once the crown is ready, it is cemented to your tooth with a very strong adhesive.