A crown is a dental restoration that covers the
entire tooth. While fillings just fill cavities
and fit inside the tooth, a dental crown will
cover the entire tooth and will replace the
entire chewing surface of the tooth. It called a
"cap."
A crown is placed to prevent a tooth from
breaking. If a tooth has a large filling, it is
more prone to cracking or breaking. A crown,
especially if it has metal in it, will help
protect a tooth against breaking.
Types of dental crowns:
- Porcelain fused to metal ( Noble without
Nickel )
- Porcelain fused to gold
- Full ceramic (porcelain crowns)
- Zirconium crowns
The metal that is preferred for dental crowns is
gold. When they are made of porcelain fused to
metal, the underlying metal is often an alloy
containing either gold, palladium, or platinum,
or a combination of these. When the crown is a
metal crown, gold is used for three reasons:
First, it is a very workable metal. It can be
burnished tightly to the tooth, and nothing fits
better to the tooth.
Second, it can be cast very accurately. Margins
can be made very thin if necessary, and will
meet the teeth precisely.
Third, it will not corrode. For these reasons,
dental crowns made of gold can last for many
years. They are a protection for your teeth and
can help insure that you keep your teeth for all
your life.
A crown is a dental restoration that covers the
entire tooth. While fillings just fill cavities
and fit inside the tooth, a dental crown will
cover the entire tooth and will replace the
entire chewing surface of the tooth. It called a
"cap."
Second, it can be cast very accurately. Margins
can be made very thin if necessary, and will
meet the teeth precisely. 
