Crowns and Bridges
A crown is a type of dental restoration which completely caps or encircles a tooth or dental implant. Crowns are often needed when a large cavity threatens the ongoing health of a tooth. They are typically bonded to the tooth using a dental cement. Crowns can be made from many materials, which are usually fabricated in a dental labortary. Crowns are often used to improve the strength or appearance of teeth.
The most common method of crowning a tooth involves using a dental impression of a tooth that has been prepared by the dentist in order to fabricate the crown outside of the mouth. The crown can then be inserted at a subsequent dental appointment using a strong restorative cement.
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: this is what most crowns are made from. A precious metal base is made and then porcelain is applied in layers over it.
Porcelain: these crowns are made entirely out of porcelain and are not as strong as bonded crowns. But they can look very natural and are most often used for front teeth.
All-ceramic: this modern technique offers a metal-free alternative, which can give the strength of a bonded crown and the appearance of a porcelain crown. Therefore it is suitable for use in all areas of the mouth.
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 very hardwearing. These crowns are silver or gold in colour.
What is a post crown?
In root-filled teeth it may be necessary to insert a post into the tooth root before placing a crown. A post gives support and helps the crown to stay in place. The surface of the tooth may be removed down to the level of the gum.
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 a 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.
Why should I replace missing teeth?
Your appearance is one reason. Another is that the gap left by a missing tooth can mean more strain is put on the teeth at either side. A gap can also mean your ‘bite’ is affected, because the teeth next to the space can lean into the gap and change the way the upper and lower teeth bite together. This can then lead to food getting packed into the gap, which causes tooth decay and gum disease.
How are missing teeth replaced?
This depends on the number of teeth missing and on where they are in your mouth. The condition of the teeth you still have also affects the decision.
There are three main ways to replace missing teeth. The first is with a removable false tooth (or teeth) – called a partial denture. The second is with a fixed bridge. A bridge is usually used when there are fewer teeth to replace, or when the missing teeth are only on one side of the mouth. The third way is by the use of dental ‘implants’. This is where an artificial root is placed into the bone of the jaw and a crown or bridge placed on top of this.
See our leaflet ‘Tell me about Dental implants’