What is a crown?
Crowns are an ideal way to rebuild teeth which have been broken, or have been weakened
by decay or a very large filling. The crown fits right over the remaining part of the
tooth, making it strong and giving it the shape and contour of a natural tooth. Crowns
are sometimes also known as ‘caps’.
Why would I need a crown?
There are a number of reasons. For instance:
the tooth may have been weakened by having a very large filling
you may have discoloured fillings and would like to improve the appearance of the
tooth
you may have had a root filling which will need a crown to protect it
you may have had an accident and damaged the tooth
it may help hold a bridge or denture firmly in place.
What are crowns made of?
Crowns are made of a variety of materials and new materials are being introduced all the
time. Here are some of the options available at present:
Porcelain bonded to precious metal: this is what many crowns are made from. A precious
metal base is made and layers of porcelain are then applied over it.
Porcelain, Ceramic and Composite: these crowns can look very natural and are most often
used for front teeth.
Precious metal (gold and palladium): these crowns are very strong and hard-wearing, but
are usually used at the back of the mouth, where they are not visible.
How is a tooth prepared for a crown?
The dentist will prepare the tooth to the ideal shape for the crown. This will mean
removing most of the outer surface, and leaving a strong inner ‘core’. The
amount of the tooth removed will be the same as the thickness of the crown to be fitted.
Once the tooth is shaped, the dentist will take an impression of the prepared tooth, one
of the opposite jaw and possibly another to mark the way you bite together. The
impressions will be given to the technician, along with any other information they need
to make the crown.
Who makes the crown?
The impressions and information about the shade of your teeth will be given to a dental
technician who will be skilled in making crowns. They will make models of your mouth and
make the crown on these to be sure that the crown fits perfectly.
Will the crown be noticeable?
No. The crown will be made to match your other teeth exactly. The shade of the
neighbouring teeth will be recorded, to make sure that the colour looks natural and
matches the surrounding teeth. A temporary crown, usually made in plastic, will be
fitted at the end of the first appointment to last until the permanent one is ready.
These temporary crowns may be more noticeable, but they are only in place for about two
weeks.
How long does the treatment take?
You will need to have at least two visits: the first for the preparation, impression,
shade taking and fitting the temporary crown, and the second to fit the permanent crown.
Does it hurt to have a tooth prepared for a crown?
No. A local anaesthetic is used and the preparation should feel no different from a
filling. If the tooth does not have a nerve, and a post crown is being prepared, then
local anaesthetic may not be needed.
Are post crowns different?
Post crowns may be used when the tooth has been root filled. The weakened crown of the
tooth is drilled off at the level of the gum. The dentist makes a double-ended
‘post’ to fit into the root canal. This can be either prefabricated
stainless steel, reinforced fibreglass or custom made of gold. One end of the post is
cemented into the root canal, and the other end holds the crown firmly in place.
Are there any alternatives to post crowns for root-filled
teeth?
If a root-filled tooth is not completely broken down, it may be possible to build it up
again using filling material. This
‘core’ is then prepared in the same way as a natural tooth and the
impressions are taken.
How long will a crown last?
The life of a crown will depend on how well it is looked after. The crown itself cannot
decay, but decay can start where the edge of the crown joins the tooth. It is very
important to keep this area as clean as your other teeth, or decay could endanger the
crown. Properly cared for crowns will last for many years – your dentist will be
able to tell you how long.
How are crowns fixed to teeth?
Once the fit and appearance of the crown has been checked – and approved by you
– it will be cemented in place with special dental cement. The cement also forms a
seal to help hold it firmly in place.
Will the crown feel different?
Because the shape of the crown will be slightly different from the shape of you tooth
before it was crowned, you may be aware of it to begin with. Within a few days it should
feel fine, and you will not notice it. The crown may need some adjustment if it feels
higher than the surrounding teeth. If it is at all uncomfortable ask your dentist to
check and adjust it.