Dental crowns, also known as caps, are a common type of dental restoration used to cover or cap a tooth. A crown is a tooth-shaped cap that is placed over a tooth to restore its shape, size, strength, and appearance. It is cemented into place and cannot be taken out, making it a permanent solution for restoring the function and appearance of a damaged tooth.
Crowns are typically recommended by dentists to restore teeth that have been damaged or weakened due to decay, trauma, or large fillings. They are also used to support a dental bridge, protect a weak tooth from breaking, or cover a dental implant.
Crowns are made of a variety of materials, including porcelain, ceramic, metal alloys, or a combination of these materials. The type of material used depends on the location of the tooth, the extent of the damage, and the patient’s preferences.
During the crown placement procedure, the tooth is first prepared by removing any decay or old filling material. The tooth is then reshaped to make room for the crown. An impression of the prepared tooth is taken and sent to a dental lab where the crown is fabricated. In the meantime, a temporary crown is placed over the prepared tooth to protect it.
Once the permanent crown is ready, the temporary crown is removed and the permanent crown is cemented into place. The fit and bite of the crown are checked and adjusted as necessary to ensure proper function.
After the crown is placed, it is important to maintain good oral hygiene practices, including regular brushing and flossing, to keep the crown and surrounding teeth healthy. It is also important to avoid hard or sticky foods that can damage or dislodge the crown.
Caring for Your Crown
With proper care, a good quality crown could last up to eight years or longer. It is very important to floss in the area of the crown to avoid excess plaque or collection of debris around the restoration.
Certain behaviors such as jaw clenching or bruxism (teeth grinding) significantly shorten the life of a crown. Moreover, eating brittle foods, ice or hard candy can compromise the adhesion of the crown, or even damage the crown.
Different Types of Crowns
Porcelain crowns can be used to build back a smile by restoring the shape, size, and appearance of damaged or decayed teeth.
Porcelain Fused to Metal Crowns
Porcelain can be fused to metal crowns to build back the natural tooth appearance and function for damaged or weakened teeth.
Gold crowns can be used to build back function by restoring the strength and durability of damaged or weakened teeth.
Questions & Answers About Crowns
Crowns are made of three types of materials:
- Ceramic – most like a natural tooth in color
- Gold Alloy – strongest and most conservative in its preparation
- Porcelain fused to an inner core of gold alloy (Porcelain Fused to Metal or “PFM”) – combines strength and aesthetics
Crowns restore a tooth to its natural size, shape and – if using porcelain – color. They improve the strength, function and appearance of a broken down tooth that may otherwise be lost. They may also be designed to decrease the risk of root decay.
In having a crown, some inherent risks exist both to the tooth and to the crown itself. The risks to the tooth are:
- Preparation for a crown weakens tooth structure and permanently alters the tooth underneath the crown.
- Preparing for and placing a crown can irritate the tooth and cause “post-operative” sensitivity, which may last up to 3 months.
- The tooth underneath the crown may need root canal treatment about 6% of the time during the lifetime of the tooth.
- If the cement seal at the edge of the crown is lost, decay may form at the juncture of the crown and tooth.
The risks to the crown are:
- Porcelain may chip and metal may wear over time.
- If the tooth needs a root canal after the crown is permanently cemented, the procedure may fracture the crown and the crown may need to be replaced.
Alternatives to crowns are fillings, such as composite or silver amalgam. These restorations remove decay and may restore teeth to
their original form, but are limited because they do not improve the strength of broken down teeth. They also do not decrease the risk of
root decay or improve the long term function and aesthetics of broken down teeth or crowns.
- Excessive bite forces may lead to the tooth under the crown breaking or loosening.
- Excessive bite forces may lead to the crown chipping, breaking or loosening.
- Porcelain on a crown may have a good color match with adjacent natural teeth when the crown is placed, but less of a match as your natural teeth age.
- Gum recession may lead to unsightly dark roots or crown margins becoming visible.
- A crown may chip or break if used for abnormal activities (e.g. biting fishing line, sewing thread or finger nails, opening bottles).