What is a Crown?
Crowns, sometimes called “caps”, are restorations that are placed to repair or significantly re-contour natural teeth. They are used to prevent cracked teeth from progressing to catastrophic failure, to reinforce teeth with compromised tooth structure due to existing large and failing fillings, to support partial dentures, to reconstruct a proper bite, and for significant esthetic changes. Crowns are also usually indicated for back teeth that have had root canal therapy because when a tooth has had root canal therapy, it is more brittle.
All crowns are not created equal. There are many different types and qualities of crowns that depend on the individual needs of each patient, the laboratory that is used to make the crowns, the choice of metal used, whether or not porcelain or acrylic is used, etc.
Sometimes, even plastic crowns are made that are “temporary” in nature designed to last from a few months to a few years. There are also variations in the amount of tooth a crown will cover; so, there are such things as ¾ crowns, partial crowns, and onlays, all of which the same information about crowns discussed here applies.
In general, crowns that are made with porcelain closely resemble natural tooth color. Since teeth naturally come in many variations of “white,” accurate shading is a skill that must be mastered by each dentist, and each dentist’s abilities are unique. This shade must then be communicated to a laboratory technician who can accurately and artistically duplicate it in porcelain. Just like buying a painting, better artists usually get paid much better than average artists. Therefore, the fee charged for a crown should probably reflect the skills and abilities of both the dentist and the laboratory. Therefore, it would be unrealistic to expect the same esthetic quality from a crown that costs $900 as one that costs $2000.
Gold alloys are often used to provide strength for crowns. They can be used alone to provide very durable crowns that are metallic in color. Covering the metal with porcelain is also common practice. The amount and types of metals used in these alloys also can affect the shade of the porcelain. The skill of the technician is a critical factor in the appearance of ceramic as well.
With modern dental materials, all ceramic crowns are an esthetic option. Materials like zirconia and lithium disilicate can provide extremely durable, esthetic crowns without the need for metal. Today, most of the crowns done in our office are metal-free. They can be done conventionally with impressions that are sent to an outside dental laboratory for fabrication, or they can be made in our office (see Single Visit CEREC® Dentistry).
Crown therapy is one of the best services that dentists can provide, if done properly and if done in the right patient. All restorations will likely break down with time and need to be replaced. However, crowns are one of the best and probably the most durable of dental treatments available.