| Q
What is a crown?
A 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’.
Q Why would I need a crown?
A 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 plac
Q What are crowns made of?
A 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 most crowns are made from. A precious metal base is
made and layers of porcelain are then applied over it.
- Porcelain: these crowns are not as strong as
bonded crowns but they can look very natural and are most often
used for front teeth.
- Porcelain and composite: porcelain and composite
resin materials can sometimes look the most natural. However,
these crowns are not as strong as bonded metal crowns.
- Glass: these crowns look very natural and are
used on both front and back 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.
Q How is a tooth prepared for a crown?
A 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.
Q Who makes the crown?
A 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.
Q Will the crown be noticeable?
A 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.
Q How long does the treatment take?
A 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.
Q Does it hurt to have a tooth prepared
for a crown?
A 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.
Q Are post crowns different?
A 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 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.
Q Are there any alternatives to post
crowns for root-filled teeth?
A 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.
Q How long will a crown last?
A 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.
Q How are crowns fixed to teeth?
A 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.
Q Will the crown feel different?
A 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.
View before and after examples of this treatment>
|