A crown is a restoration that fits over
the part of the tooth that protrudes above the gum
line. Crowns cover, protect, seal and strengthen
a tooth. A crown is needed when a filling
just will not work. A crown may be made of gold, tooth
colored ceramic materials (porcelain), or porcelain
fused to a gold alloy.
There are many situations that may require
a crown:
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Large decay: If a tooth has
decay so deep and large that a filling
will not stay, or if the tooth structure is weakened,
a crown must be placed on the tooth to save it.
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Large old fillings:
When large old fillings break down, or get decay
around them, they usually need to be crowned. It
is important to crown a tooth that has been structurally
weakened to prevent a cracked or broken tooth. Once
a tooth breaks, it may not be possible to save it. |
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Cracked tooth: When a tooth
is cracked, a filling
will not seal the crack. A crown has to be placed
over the tooth to hold it and the crack together.
If a crown is not placed on the tooth, the tooth
will become sensitive to chewing pressure, or will
eventually break. It is important to crown a cracked
tooth before it breaks, because in some cases a
broken tooth cannot be crowned and must be extracted.
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Broken / Fractured tooth: A
tooth that has broken is usually too weak to hold
a filling. A crown will
hold the tooth together and prevent it from breaking
again. If the fracture involves the nerve, Root
Canal Therapy may be required before the tooth
is crowned. In some cases, a broken tooth cannot
be saved and must be extracted.
This patient chose not to have the cracked tooth
above crowned, and it later fractured. This tooth
had to be extracted because it cracked all the way
to the root. |
Sensitive teeth: Teeth that are very sensitive,
either from a lot of "wear," or from receded gums, sometimes
require crowns to seal and protect the teeth from hot
and cold sensitivity.
Root Canal Therapy: In many cases
a tooth that has undergone Root Canal Therapy will need a
crown to properly seal and protect the tooth. A tooth with
Root Canal Therapy is more brittle than a tooth with a healthy
nerve and blood supply. A crown provides the necessary support
to the tooth.
In cosmetic dentistry,
crowns (sometimes called "caps")
are used less frequently since the advent of veneers,
but in some cases a crown may be necessary for a particular
tooth. A tooth with a bad fracture or a large filling
may be a candidate for a crown instead of a veneer.
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Before: This tooth has a large
filling as shown. A crown is needed on this tooth,
instead of a veneer, because there isn't enough
natural tooth left to support a veneer. A crown
will cover and protect the tooth, but will look
the same as a veneer. |
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After: The top teeth now have
veneers, except the one that had the large filling,
which now has a crown. |
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