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’.
An ‘Anterior Crown’
is a crown fitted to the front eight
teeth.
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 place.
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
not usually used at the front of
the mouth, where they are highly
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 your 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.
Q> Is there an alternative to
a crown?
A> A veneer may be an alternative
to having an anterior crown. Your
dentist will advise you of any suitable
alternatives.
