A crown fits over the entire top of the tooth above
the gum line. Crownscover, protect, seal and strengthen
a tooth. A crown is needed when a filling just will not work. A crown may be made of gold, white
porcelain, or porcelain fused to gold. There are many
situations that may call for a crown:
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.
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.
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
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. 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.
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.
After: The top teeth now have veneers, except
the one that had the large filling, which now has a crown.