Crowns & Bridges
A crown or ‘cap’ is a tooth-shaped piece of porcelain placed over an entire tooth. They are used to restore teeth which are damaged, heavily filled or for some cosmetic situations. They may be made purely of porcelain, of gold, or of porcelain bonded onto metal. They offer an extremely strong, durable restoration and each type has different advantages for particular situations.
Crowns with a metal core are opaque, they often look greyish and sometimes a black line can been seen around the gumline. We prefer to use all-porcelain crowns to solve cosmetic problems whenever possible. This is because the light will pass through them just like real teeth and, therefore, look very natural.
A bridge is a restoration used to replace a missing tooth or teeth. They may either take the form of a series of crowns joined together (a conventional bridge) or a tooth that is attached to existing teeth by means of adhesive tabs (a Maryland Bridge). Both crowns and bridges have been successfully used for many years.
Method:
Crown
The dentist prepares the tooth to be crowned by reducing it just enough to allow a crown to fit over it and not appear bulky. An impression of the teeth is taken and used by the technician to make a plaster cast on which the crown is modelled. A temporary crown is worn for around 14 days whilst the crown is being made. At the next appointment, the dentist will ‘try in’ the crown to check the fit and colour. When both the dentist and client are happy with the overall effect, it will be finally fixed into place.
Conventional Bridge
The preparation required and the procedure used for a bridge is similar to a crown. However, in this case, the teeth either side of the gap are reduced. The bridge is cemented onto the prepared teeth and it carries a dummy crown in the middle to replace the missing tooth. The conventional bridge is most often used but there are variations on the theme e.g. Cantilever, Veneer or Maryland Bridge, which involve less reduction of tooth enamel. These can only be used where stress on the teeth is minimal.
Advantages:
- Looks as good as natural teeth
- Versatile solution to many problems
- Durable and strong
- Do not stain or decay
- Bridges permanently fill gaps, unlike dentures
Disadvantages
- Natural tooth has to be reduced
- Care must be taken to keep the restoration scrupulously clean
Key Facts
- Number of appointments: Usually two
- Life expectancy: Up to 15 years with good oral hygiene
Example Uses
- Replace unnatural looking crowns
- Cover heavily filled or broken teeth
- Replace missing teeth
Aftercare
Regular meticulous brushing and thorough daily flossing, around crowns and under bridges, is needed to eliminate plaque build-up.