A crown, also known as a cap, is a covering that fits on to the remaining tooth, restoring the strength and shape of the tooth.
Crowns/caps are used to repair or restore:
- severely broken teeth
- heavily filled teeth
- on a root treated tooth to prevent further damage
- to close gaps in teeth
- on discoloured teeth or to restore a tooth to its natural shape
There are different types of materials that a crown can be made from. The most commonly used are:
- Porcelain bonded to metal, these give a natural appearance and are good for teeth heavily filled with amalgam. They have a metal base and layers of porcelain on top.
- All porcelain crowns, these crowns are made from slightly stronger porcelain, giving it the strength so no metal base is required. These are very good for front teeth as they can give a more natural look. The tooth only needs to be reduced by a small amount.
- All ceramic crowns, and one of the newest techniques, they are just as strong as a porcelain bonded crown but look as good as an all porcelain crown. These are suitable for use on any tooth in the mouth. Like the all porcelain crowns the tooth needs minimal preparation!
- Gold/silver alloy crowns. These crowns are very strong and work extremely well on the molar teeth and the tooth only needs to be reduced a small amount as with the all porcelain and all ceramic crowns.
The tooth is prepared to the desired shape and size by the dentist. Most of the outer structure of the tooth will be removed leaving the core. The crown that will be fitted will be the same size as the amount of tooth removed. The dentist will then take an impression or mould of the prepared tooth, and one of the opposing arch to note the way the teeth bite.
For teeth that have been root treated (so they have a root filling) and to give the tooth added strength in the core a post may be constructed and fitted. Posts are usually made from prefabricated stainless steel which the dentist can fit directly into the root canal, or a impression can be taken of the root canal so that a custom-made post can be made to fit in the prepared root canal. The post would be cemented into place, and the finished crown cemented on top. A temporary crown will be fitted so the tooth will be protected and can be used. This is only temporary so care needs to be taken, it may also be slightly more noticeable as it can pick up stains easily.
Both the patient and the dentist must be happy with the crown’s shape and colour before it is cemented into place permanently. The crown has to be looked after as you would your natural teeth, because although the porcelain cannot decay or discolour, the tooth under the crown can! The main area that needs special attention is at the gum line where the crown meets the gum.
The expectant life of a crown can vary from tooth to tooth and from patient to patient, but as long as the crown and the tooth underneath it is cared for it should last a long time!
Costs will vary according to the type of crown and material used. It is advisable to get a written estimate and treatment plan before beginning any dental treatment.