Q. What are they?
A. Crowns are made of metal, or porcelain, or porcelain with metal inside for strength. If a tooth has been weakened a lot by decay or other damage, a crown can protect it. It completely covers the tooth above the gum line.
A crown can also improve appearance if a tooth is misshapen or discoloured.
Q. What does the dentist do?
A. The tooth is shaped first. The crown needs to fit over the tooth easily without making it bulky; preparation time will depend on how damaged the tooth is. If there is not much natural tooth left, the tooth might be root-filled - this is sometimes called 'removing the nerve'. Then the tooth is built up with a filling, which might be held in place by a peg in the root canal. Preparation would then take more than one visit;
Soft material like putty is used to record the exact shape of the tooth to be crowned and the nearby teeth. A dental technician uses this 'impression' to make the crown the right size and height. The edge of the crown will normally be very close to the gum. A thin cord is used to hold the gum away from the neck of the tooth so that the impression is accurate round the edges;
A temporary crown will be put over the tooth until the crown is made. You can chew on a temporary crown but it won't be as strong as the permanent crown. Temporary crowns are made of plastic or metal;
When the permanent crown is fitted, small adjustments will be made to ensure that you can bite comfortably. The crown is tried on, first, and then fixed permanently.
Q. What are the benefits?
A. A crown is strong and can look and feel almost exactly like a natural tooth.
The colour and shape can be matched to your own teeth.
Depending on the strength of the tooth underneath, a crown can last for many years if your oral hygiene is good and the crown is not accidentally damaged.