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.
- Stainless steel crowns are prefabricated crowns that are used on permanent teeth primarily as a temporary measure. The crown protects the tooth or filling while a permanent crown is made from another material. For children, a stainless steel crown is commonly used to fit over a primary tooth that’s been prepared to fit it. The crown covers the entire tooth and protects it from further decay. When the primary tooth comes out to make room for the permanent tooth, the crown comes out naturally with it. In general, stainless steel crowns are used for children’s teeth because they don’t require multiple dental visits to put in place and so are more cost-effective than custom-made crowns and prophylactic dental care needed to protect a tooth without a crown.
- Metals used in crowns include alloys that have a high content of gold or platinum, or base-metal alloys (for example, cobalt-chromium and nickel-chromium alloys). Metal crowns withstand biting and chewing forces well and probably last the longest in terms of wear down. Also, metal crowns rarely chip or break. The metallic color is the main drawback. Metal crowns are a good choice for out-of-sight molars.
- Porcelain-fused-to-metal dental crowns can be color-matched to your adjacent teeth (unlike the metallic crowns). However, more wearing to the opposing teeth occurs with this crown type compared with metal or resin crowns. The crown’s porcelain portion can also chip or break off. Next to all-ceramic crowns, porcelain-fused-to-metal crowns look most like normal teeth. However, sometimes the metal underlying the crown’s porcelain can show through as a dark line, especially at the gum line and even more so if your gums recede. These crowns can be a good choice for front or back teeth as well as long bridges where the metal is needed for strength.
- All-resin dental crowns are less expensive than other crown types. However, they wear down over time and are more prone to fractures than porcelain-fused-to-metal crowns.
- All-ceramic or all-porcelain dental crowns provide better natural color match than any other crown type and may be more suitable for people with metal allergies. All-ceramic crowns can be used for front and back teeth.
- Temporary versus permanent. Temporary crowns can be made in your dentist’s office, whereas most permanent crowns are made in a dental laboratory. Typically, temporary crowns are made of an acrylic-based material or stainless steel and can be used as a temporary restoration until a permanent crown is constructed by a lab.
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 treatment may first be performed.
Before the process of making a crown begins, your dentist will anesthetize (numb) the tooth and the gum tissue around the tooth. 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. 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 typically will use a paste or putty to make an impression of the tooth to receive the crown. Sometimes, though, impressions are made with a digital scanner. 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 or scans 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.
We love our patients and love to help them form healthy dental life that will last them a lifetime. For more information call us today to answer all of your questions so get an appointment today.