Crowns and Bridges
Why is a crown needed?
There are a number of reasons why a crown might be recommended.
These might include:
- Decay – A tooth may be so badly damaged by decay that it becomes impossible to restore it with ordinary filling material.
- Cosmetics – Large fillings – especially old ones may discolour and become unsightly. Crowns also provide a way of improving the appearance of crooked or misshaped teeth.
- Accidents – Teeth can be damaged in accidents and crowns provide a way of rebuilding the tooth after such an accident.
- Missing Teeth – When a tooth is missing crowns may be placed on teeth either side to support an artificial replacement to fill the gap. This is known as a bridge.
What are crowns made of?
This will depend on the individual situation. In the front of the mouth, cosmetic consideration will play an important part as to which material to use, whereas further back, more importance is attached to the ability to withstand the huge forces generated when chewing food. Modern crown material can combine excellent appearance with great strength. Materials used
- Porcelain – This can look very lifelike and is most often used for front teeth.
- Porcelain bonded to metal – This combines the appearance of metal with extra strength and resistance to fracture.
- Gold – This is strong and hard wearing, but its obvious physical appearance means that it is usually only used at the back of the mouth.
What will the dentist do?
The dentist will normally give a local anaesthetic to numb the area. If the tooth has been root treated, this may not be necessary. Then the tooth will be shaped so that with the crown, it will be the same size as a normal tooth. Preparation time will depend on how damaged the tooth is and whether it needs to be built up with a filling first. The dentist will then take an exact “impression” of the tooth that is to be crowned. The material used is a soft mouldable material. This “impression” will then be sent to the dental technician. It is he who will make the crown; the crown will be the exact height, size, shape and colour of your particular tooth. A temporary crown made of plastic is placed over the tooth until the crown is made. This temporary crown won’t be as strong and the colour and appearance will not be as good as the finished one but you can chew on it. There is normally a 10-14 days period between the preparation of the tooth and the fitting of the crown. Before the crown is fitted the dentist will make small adjustments to make sure you can bite comfortably. The crown is tried on first, and then cemented into place.
What will the crown look like and feel like?
Your new crown should feel like a natural tooth and if the crown is made from a tooth coloured material, then it will normally blend in well with the surrounding teeth.
How long will it take?
Two visits will be necessary – one for preparation and one for the fitting.
Do crowns come out and why?
It is important that putting a crown on a tooth does not render it impervious to decay. However, if your oral hygiene is good and maintained at high level then this should not happen. After a number of years it is possible for the cement used for fixing a crown to fail, and the crown comes out. If this happens, the crown can be re-cemented without much trouble. If the crown seems to be coming out rather often, then this is a sign that there is an underlying problem that needs to be fixed.
Private or NHS crowns?
These options can be discussed at your consultation appointment.