A crown (sometimes called a "cap") is a shell that your dentist makes to fit right over the top of a tooth, strengthening it.
Why would I need a crown?
Probably because a tooth has been weakened by extensive dental decay, large fillings, accidental damage or root canal treatment. A crown holds together the remaining tooth and any dental filling material, making it stronger. A crown can also be used to greatly improve the appearance of a tooth that is damaged, discoloured, mis-shapen or misaligned.
What types of crown are there?
There are several different types of crown that your dentist might recommend:

• Porcelain bonded to precious metal crown. Good aesthetics and strong, too.
• All-porcelain crown: made from porcelain alone. Excellent aesthetic results - very suitable for front teeth.
• Precious metal crown: made from gold and palladium. Extremely strong but have poor aesthetics.
How much does a crown cost?
Private crowns cost from £440.00. The exact price depends on type of material used and whether your dentist advises that a core/post is needed to anchor the crown in place.
How does a dentist prepare a tooth for a crown?
Your dentist will shape the tooth by removing some of the outer surface. Sometimes the dentist may have to "build up" the core of the tooth (particularly if a lot has broken off) with filling material or put a post into the tooth so that the crown has something to sit on. Next, they will take an "impression" (i.e. make a mould) of your teeth and take a measurement of how you bite together.

The dentist will record the shade of the adjacent teeth so that the new crown (note: not for a metal crown) is an exact match for the other teeth. Your dentist will fit a temporary crown while the permanent crown is being made so that the tooth looks and feels the same between visits.
Will the dentist use anaesthetic?
When the tooth has already been root treated it isn't necessary, but in most cases your dentist will need to anaesthetise the tooth before working on it so that you don’t feel anything.
What happens next?
The impression, bite measurements and shade information are passed to a specialist dental laboratory. The laboratory makes a model of your mouth: the crown will be constructed on this to ensure that it fits in perfectly with your other teeth.

About a week or two after your first appointment your dentist will see you for a second time to check that your new crown is a good fit and that the shade is a good match for your other teeth. The crown is then fixed in place using special dental cement.
Are there any alternatives to crowns?
If your dentist has suggested a crown then this is probably because the tooth is weak (see above). It is unlikely that alternative treatments such as fillings, inlays or veneers would be effective – the tooth may well break after they have been placed. If alternatives are viable in your case then your dentist will discuss the options with you.