A crown is an artificial restoration that fits over the remaining part of a prepared tooth, making it strong and giving it the shape of a natural tooth. A crown is sometimes known as a “cap”.
Why have a crown? A crown can:
Improve the colour, shape and position of your teeth. A precise shade of porcelain can be chosen to give the right colour to improve a single discoloured tooth or to lighten the front teeth.
The lower teeth have been cleaned to remove the majority of the staining, then the three lower teeth have been straightened and the colour improved by crowning.
The old porcelain bonded crowns had visible grey margins and appeared false, they have been changed to all ceramic crowns giving a vibrant natural appearance.
Replace heavily restored teeth, that need additional strength and support.
The premolar tooth has a new composite filling and the 2nd premolar and 1st molar have been crowned, thus the amalgam fillings are no longer visible when the patient smiles.
Be used to support a bridge or denture
In this example the previously crowned upper right lateral tooth has been used to support the new bridge for the missing central; the upper right canine has had the crown replaced and the upper left central and lateral have been veneered to give an aesthetically pleasing, regular and natural appearance.
What are crowns made from?
Porcelain Bonded Crown
All Ceramic Crown
Crowns can be made of a variety of different materials and new materials are continually being introduced. Some of the most popular options are listed below.
Porcelain bonded to precious metal: these crowns have a precious metal base that are covered with layers of porcelain, they are strong and good for back teeth but can look dull and lifeless on front teeth. These used to be the cheapest option but this is no longer the case because of the high cost of precious metal today.
All-ceramic crowns: this modern technique offers a metal-free alternative, which are stronger than porcelain bonded crowns, therefore they are suitable for use in all areas of the mouth. In addition they are much more aesthetically pleasing and lifelike.
Gold alloy crowns: gold is one of the oldest filling materials. Today it is used with other metal alloys to increase its strength, which makes it a very hardwearing restoration. These crowns are silver or gold in colour, and are only used on back teeth.
How is a crown prepared?
What is a post crown?
In root-filled teeth it may be necessary to insert a post before placing a crown. A post provides support and helps the crown stay in place. The weakened crown of the tooth may be shortened to gum level
A post can be made of prefabricated stainless steel which the dentist can fit directly into the root canal, or a custom-made post can be constructed by the dental technician to accurately fit the shape of the prepared root canal. The post is placed into the root canal and cemented in position, ready for the crown to be attached.
How long will a crown last?
Properly cared for crowns should last for many years but this depends on how well you look after it. The crown itself cannot decay, but decay can start where the edge of the crown joins the tooth. Therefore, to prevent decay it is important to keep this area clean, by using interdental brushes or floss. Your dentist will be able to advise you on what suits you best.