When a tooth is so broken down that a filling would not last, a crown is recommended.
The crown restoration can be made of different types of ceramic materials. The choice of material is dependent on several factors: how much masking of the discoloration is desired, the strength, the location, etc. An all-porcelain crown, the most esthetic type, is used when there is a desire not to show any metal, especially around the gum line of the front teeth. More severe discoloration and misalignment of teeth can be corrected this way.
The crown (also known as a cap) is a restoration that requires an impression (mold) to be made after the tooth is appropriately prepared, which is then sent to the lab to be fabricated. While it is made, the patient wears a provisional or temporary crown. The crown strengthens the condition of the tooth because it ties all the parts of the tooth together.