crowns
When very extensive fillings break or need replacing, it may be that a more complex restoration such as a crown is required.
What is a crown?
A crown, sometimes known as a cap, is a custom-made covering that fits over a tooth that has perhaps been damaged or weakened by decay or a very large filling. In addition, some people have them to improve the appearance of their teeth.
What is a crown made of?
Crowns can be made of metal, porcelain or a combination of the two. Alternatively, composite resins, glass and combinations of all these may be used and can be designed to look natural, as well as being gentle to the surrounding tissue. However, the composite resin, glass or combination crowns may be more liable to fracture than the metal and porcelain options.
Why would I need a crown?
- If a tooth has been weakened by a large filling
- If you broke or damaged a tooth
- To protect a tooth that has had a root filling
- To improve the appearance of the tooth, e.g. if you have discoloured fillings
- To hold a bridge or denture in place
What does fitting a crown involve?
- The dentist prepares the tooth to be crowned by shaving off sufficient amounts of the outer surface of the tooth for the crown to fit neatly over the remaining tooth and to reproduce the correct contour and shape.
- The dentist may need to build up new foundations and fit a post in a root-filled tooth.
- Having shaped the 'core', the dentist takes impressions (or moulds) of the teeth, which are sent to the technician to make the plaster casts, on which the crown is then modelled.
- Shades required to match the crown to the other teeth are also sent to the technician.
- A temporary crown is constructed at the chairside and cemented in lightly, enabling the dentist to remove it to fit the final crown. (Some care is needed to avoid dislodging the temporary crown with sticky foods).
- At your next appointment, the dentist ‘tries in’ the crown and, if the dentist and you are both satisfied with the fit and the match to the other teeth, the crown is bonded into place. You should not then be able to remove it.
Is the procedure painful?
No, a local anaesthetic can be used while the tooth is prepared and it should feel no different from a filling. However, if the crown is to go over a root canal filling, the tooth has no nerve and an anaesthetic may not be necessary. Once fitted, the crown should feel very much like the original intact tooth, although it may feel slightly strange at first. If it continues to be uncomfortable, it may need adjustment - ask your dentist.
How do I care for a crown?
A crown or bridge should be cleaned in the same way as natural teeth, though to clean a bridge you may need special miniature bottle brushes or floss handlers to clean under the false tooth. Flossing is particularly important to clean the edge where a brush cannot reach.
How long can a crown be expected to last?
This depends on the material used, but you can expect a crown to last many years. Problems tend to occur in the surrounding gums and the tooth root, rather than the crown itself and, over time, the appearance of the surrounding teeth may change, making the crown more noticeable. The prime danger to the crown is decay or gum disease occurring where the edge of the crown meets the tooth or gums, so good oral hygiene is very important.
