A dental crown is a tooth-shaped “cap” that is placed over a tooth. The cap restores the tooth’s shape and size, strength, and appearance.
The crowns, when cemented into place, cover the visible portion of a tooth.
When would a dental crown be needed?
A dental crown may be needed to:
- protect a weak tooth (for example, from decay) from breaking or to hold together parts of a cracked tooth
- restore a broken tooth or a severely worn down tooth
- cover and support a tooth with a large filling and not much tooth remaining
- hold a dental bridge in place
- cover misshaped or severely discolored teeth
- cover a dental implant
- cover a tooth treated with a root canal
What types of crown materials are available?
Permanent crowns can be made from all metal, porcelain-fused-to-metal, all resin, or all ceramic.
- Metals used in crowns include gold, palladium, nickel, or chromium. Metal crowns rarely chip or break, last the longest in terms of wear down, and only require a small amount of tooth to be removed. They can also withstand biting and chewing forces. 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 matched to the color of the teeth beside them. They have a more natural tooth color. However, sometimes the metal under the crown’s porcelain cap shows through as a dark line. Other drawbacks are that the crown’s porcelain portion can chip or break off and there is more wearing down of the teeth opposite them in the mouth. (The top and bottom tooth that come into contact when the mouth is closed.) These crowns can be a good choice for front or back teeth.
- All-resin dental crowns are less expensive than other crown types. However, they wear down over time and are more likely to break than porcelain-fused-to-metal crowns.
- All-ceramic or all-porcelain dental crowns provide the best natural color match than any other crown type. They are also a good choice for people with metal allergies. However, they are not as strong as porcelain-fused-to-metal crowns. They also may wear down the teeth opposite them in the mouth a little more than metal or resin crowns. All-ceramic crowns are a good choice for front teeth.
- Pressed ceramic crowns have a hard inner core. They replace the metal liner that is used in the all-ceramic crown-making process. Pressed ceramic crowns are capped with porcelain, which provides the best natural color match. They are also more long-lasting than an all-porcelain crown.
What steps are involved in preparing a tooth for a crown?
Two visits to the dentist are usually needed.
At the first visit, the tooth to receive the crown is examined and prepared. X-rays are taken of the tooth and bone around it. If decay is found or there is a risk of infection or injury to the tooth’s pulp, a root canal treatment may need to be done first. (Pulp is the soft tissue inside your teeth containing blood vessels, nerves, and connective tissue.)
To make room for the crown, the tooth to receive it is filed down across the top and sides. The amount of tooth filed away depends on the type of crown selected. All-metal crowns are thinner and don’t need as much tooth structure removed compared with all-porcelain or porcelain-fused-to-metal crowns. If too much tooth is missing, due to damage or decay, a filling material is used to “build up” enough tooth structure for the crown to cover.
After reshaping the tooth, a paste or putty is used to make a copy (also called impression) of the tooth that will be receiving the crown. Impressions of the teeth above and below the tooth to receive the dental crown are also made. This is done to make sure that the crown will not affect your bite.
The impressions are sent to a dental laboratory. The laboratory makes the crowns and usually returns them to the dentist’s office in 2 to 3 weeks. During this first office visit your dentist will make a temporary crown to cover and protect the prepared tooth while the permanent crown is being made.
At the second visit, the permanent crown is placed. First, the temporary crown is removed and the fit and color of the permanent crown is checked. If everything is okay, a local anesthetic (“numbing” drug) is sometimes used to numb the tooth and the new crown is permanently cemented in place.
Same day crowns made in a dental office. Crowns can also be made in a dentist’s office if your dentist has the equipment. Like the traditional way to prepare a tooth for a crown, the first steps are to remove decay and shape the tooth for a perfect fit inside the crown. After these steps, the making of a crown is different. In this procedure, a scanning device (a “wand”) is used to take digital pictures of the tooth inside the mouth. The computer’s software creates a 3D model of the tooth. The digital design is sent to another in-office machine that carves the shape of the crown from a block of ceramic. This method of making a crown is called computer-aided design/computer-aided manufacturing (CAD/CAM). In less than 15 minutes, the crown is ready to be cemented into place.
What problems could develop with a dental crown?
- Discomfort or sensitivity. A newly crowned tooth may be sensitive immediately after the procedure as the anesthesia begins to wear off. If the crowned tooth still has a nerve in it, there may be some heat and cold sensitivity. Your dentist may recommend that you brush your teeth with toothpaste designed for sensitive teeth. Pain or sensitivity that occurs when you bite down usually means that the crown is too high on the tooth. If this is the case, call your dentist. He or she can easily fix this problem.
- Chipped crown. Crowns made of all porcelain can sometimes chip. Small chips can be repaired and the crown could remain in the mouth. The crown may need to be replaced if the chip is large or when there are many chips.
- Loose crown. Sometimes the cement washes out from under the crown. Not only does this allow the crown to become loose, it allows bacteria to leak in and cause decay to the tooth that remains. If your crown feels loose, contact your dentist’s office.
- Crown falls off. Sometimes crowns fall off. Usually this is due to an improper fit or a lack of cement. If this happens, contact your dentist’s office immediately. He or she will give you specific instructions on how to care for your tooth and crown until you can be seen by your dentist. Your dentist may be able to re-cement your crown in place; if not, a new crown will need to be made.
- Allergic reaction. Because the metals used to make crowns are usually a mixture of metals, an allergic reaction to the metals or porcelain used in crowns can occur. However, this is extremely rare.
- Dark line on crowned tooth next to the gum line. A dark line next to the gum line of your crowned tooth is normal, particularly if you have a porcelain-fused-to-metal crown. This dark line is simply the metal of the crown showing through.
What are “onlays” and “3/4 crowns?”
Onlays and 3/4 crowns are crowns that don’t cover as much of the underlying tooth as traditional crowns. Traditional crowns cover the entire tooth.
How long do dental crowns last?
On average, dental crowns last between 5 and 15 years. The life span of a crown depends on the amount of “wear and tear” the crown is exposed to, how well good oral hygiene practices are followed, and your personal mouth-related habits (you should avoid such habits as grinding or clenching your teeth, chewing ice, biting your fingernails and using your teeth to open packaging).
Does a crowned tooth require any special care?
A crowned tooth does not need any special care. However, the underlying tooth still needs to be protected from decay or gum disease. Therefore, continue to follow good oral hygiene practices, including brushing your teeth at least twice a day and flossing once a day -- especially around the crown area where the gum meets the tooth. Also avoid biting on hard surfaces with porcelain crowns (for example, chewing ice and popcorn hulls) to prevent cracking the porcelain.
How much do crowns cost?
Costs vary depending on where you live and the type of crown chosen (for example, porcelain crowns are typically more expensive than gold crowns, which are typically more expensive than porcelain-fused-to-metal crowns). Generally, crowns can range in cost from $800 to $1,500 or more per crown. The cost of crowns is not usually fully covered by insurance. To be certain, check with your specific dental insurance company.
© Copyright 1995-2015 The Cleveland Clinic Foundation. All rights reserved.
This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 4/15/2015…#10923