Crowns can be made from porcelain, porcelain fused to metal, or a full gold crown. To maintain a natural look and feel a porcelain finished crown is best, as it can be matched to the shade of your other teeth. This will allow it to blend in and appear just like one of your natural teeth.
A dental crown is a tooth-shaped "cap" that is placed over a tooth -- to cover the tooth to restore its shape and size, strength, and improve its appearance.
The crowns, when cemented into place, fully encase the entire visible portion of a tooth that lies at and above the gum line.
Why Is a Dental Crown Needed?
A dental crown may be needed in the following situations:
To protect a weak tooth (for instance, from decay) from breaking or to hold together parts of a cracked tooth
To restore an already broken tooth or a tooth that has been severely worn down
To cover and support a tooth with a large filling when there isn't a lot of tooth left
To hold a dental bridge in place
To cover misshapened or severely discolored teeth
To cover a dental implant
To make a cosmetic modification
For children, a crown may be used on primary (baby) teeth in order to:
Save a tooth that has been so damaged by decay that it can't support a filling.
Protect the teeth of a child at high risk for tooth decay, especially when a child has difficulty keeping up with daily oral hygiene.
Decrease the frequency of general anesthesia for children unable because of age, behavior, or medical history to fully cooperate with the requirements of proper dental care.
In such cases, a pediatric dentist is likely to recommend a stainless steel crown.
What Types of Crowns Are Available?
Permanent crowns can be made from stainless steel, all metal (such as gold or another alloy), porcelain-fused-to-metal, all resin, or all ceramic.
What Steps Are Involved in Preparing a Tooth for a Crown?
Preparing a tooth for a crown usually requires two visits to the dentist -- the first step involves examining and preparing the tooth, the second visit involves placement of the permanent crown.
First Visit: Examining and preparing the tooth.
At the first visit in preparation for a crown, your dentist may take a few X-rays to check the roots of the tooth receiving the crown and surrounding bone. If the tooth has extensive decay or if there is a risk of infection or injury to the tooth's pulp, a root canal may first be performed.
Before the process of making a crown begins, your tooth and gum tissue will be anesthetized (numbed). Next, the tooth receiving the crown is filed down along the chewing surface and sides to make room for the crown. The amount removed depends on the type of crown used (for instance, all-metal crowns are thinner and require less tooth structure removal than all-porcelain or porcelain-fused-to-metal ones). If, on the other hand, a large area of the tooth is missing (due to decay or damage), your dentist will use filling material to "build up" the tooth to support the crown.
After reshaping the tooth, your dentist will use a paste or putty to make an impression of the tooth to receive the crown. Impressions of the teeth above and below the tooth to receive the dental crown will also be made to make sure that the crown will not affect your bite.
The impressions are sent to a dental lab where the crown will be manufactured. The crown is usually returned to your dentist's office in two to three weeks. If the crown is made of porcelain, your dentist will also select the shade that most closely matches the color of the neighboring teeth. During this first office visit your dentist will make a temporary crown to cover and protect the prepared tooth while the crown is being made. Temporary crowns usually are made of acrylic and are held in place using a temporary cement.
Second Visit: Receiving the permanent dental crown.
At the second visit, your dentist will remove the temporary crown and check the fit and color of the permanent crown. If everything is acceptable, a local anesthetic will be used to numb the tooth and the new crown is permanently cemented in place.