Why
Do We Crown Teeth?
The main reasons for restoring teeth with
crowns are:
- To strengthen a badly broken down or weakened tooth,
- To improve the appearance of a badly broken down or
heavily filled tooth,
- To support one end of a bridge which is replacing other
missing teeth.
Crowns come in many forms, the most common
varieties are:
All Porcelain:
These have the most natural appearance for some tooth types,
but they are weaker than metal reinforced crowns. They are
built up of many layers of tooth coloured porcelain and are
translucent and very tooth-like indeed. Unfortunately the
strength of this material usually limits its use to the front
of the mouth.
Porcelain Bonded
to Gold: This type of crown consists of a thin gold
casting, which fits the tooth and reinforces a covering layer
of porcelain, which gives the tooth a very natural appearance.
The majority of crowns for back teeth are made in this way,
however the combination of metal and porcelain is relatively
thick. This can sometimes make using this type of crown difficult
if there is not enough space available between the crowned
teeth and the opposing teeth.
All Gold:
These crowns are made of yellow or white dental golds. They
are very strong and resistant to biting forces, and can be
made very thin. The preparation for this type of crown is
conservative, and full gold crowns can be useful where there
are strong biting forces and there is little space in the
bite.
Before a tooth can be restored with a crown
a strong foundation must be built on what is left of the tooth.
This foundation helps to strengthen the tooth and ensures
that the crown is well retained. The foundation or "Core"
may either take the form of a large filling retained by tiny
pins, or a laboratory-made cast gold post that is cemented
to the prepared tooth. Cast posts are usually used with root
filled teeth, or where very little tooth structure remains.
Teeth that need crowns are usually broken
down and in a poor state of repair. Because of this, there
may be pre-existing inflammation of the dental nerve. An infrequent
problem, which you should be aware of, is that just occasionally
this inflammation may be too advanced to respond. Under these
circumstances further treatment such as root canal therapy
may be required. |
