A dental crown (“cap”) is shaped like a tooth and placed to retain a tooth’s strength, size, and shape, as well as to improve its appearance. The crown covers the entire visible part of the tooth and is cemented into place.
Why May I Need A Dental Crown?
- To protect a tooth that has been cracked or has a large filling/area of decay consisting of 50% or more of the tooth’s structure. Large fillings/areas of decay can make the tooth weak, but a crown restoration can “hold it all together” and prevent future and more severe breaks and cracks in the tooth. These are the most common usage for a dental crown:
- To restore a tooth after it has undergone a root canal. Root canal treated teeth become brittle due to the fact that the blood supply (root/nerve) has been removed from the tooth. It’s important to protect your investment with a crown to protect it from future breaks and cracks. Ideally a crown is placed a month after the tooth has undergone a root canal treatment.
- To make a cosmetic adjustment in various scenarios.
- To go over a dental implant, thus providing a complete tooth replacement.
- To place a dental bridge, as the teeth supporting the dental bridge need to be altered in order to seat the bridge.
Types of Crowns
Stainless steel crowns are usually used on primary teeth or as a temporary solution on permanent teeth. They are prefabricated (not custom made) and don’t require multiple dental visits.
Metal crowns are usually made of gold alloy, other alloys (palladium), or a base metal alloy (chromium or nickel). Metal crowns rarely break or chip and can hold up to biting and chewing forces well. The only drawback to these types of crowns are the color; most of the time they are placed on back teeth that you cannot see.
Porcelain-fused-to-metal crowns look more like teeth and the color can matched to the teeth next to it. The drawback to these crowns are that the porcelain can chip or break and there is more wearing on the opposing natural teeth. It is also possible for the underlying metal to show through at the gum line. They can be used for front or back teeth, and are a good option for a long bridge where more strength is needed.
All-ceramic or all-porcelain crowns are the most natural looking and are usually used for front teeth or for people with metal allergies.
Zirconia or milled crowns are made up of a strong porcelain and digitally constructed in a dental lab.
Temporary crowns are made in the dental office and are usually used to cover the tooth while a custom, permanent crown is being made by the lab. They are made of acrylic or stainless steel and cemented with a temporary cement.
All-resin crowns are usually temporary and are less expensive. Drawbacks are that they are more likely to crack and wear down compared to other crowns.
Preparing a Tooth for a Crown
On your first visit, your dentist will start with numbing the tooth/teeth and the surrounding gums. If your tooth is broken or if there is decay present, your dentist will remove it and place a filling (“build up”). Then the tooth is filed down on all sides to make room for the crown.
After reshaping the tooth, an impression is taken using putty or a digital scanner. These impressions are sent to a dental lab where they are made and returned back to your dentist’s office (usually taking 2 weeks). Your dentist or assistant will also make and place a temporary crown to cover your tooth until your permanent crown can be cemented.
It is important to be careful with your temporary crown. For example, we advise chewing on the opposite side and not flossing on either side of the temporary. If it does come off, don’t panic. Just save the temporary and give your dentist a call; it can be placed back on fairly quickly.
The second visit is quicker than the first one. Your dentist or assistant will remove the temporary crown, clean your tooth and try on your permanent crown. Before it is cemented they will check the fit, color and make sure it can be flossed. If everything looks good it will be placed with permanent cement. Most of the time no anesthetic is needed for this appointment, but it’s not uncommon to use it if the tooth is sensitive. After your crown is cemented, you should avoid chewing on the tooth for about an hour in order to allow the cement to fully set.
Crowns are a common restorative procedure, and on average they can last 5-15 years. Let us know if you have any further questions!