A dental crown is a tooth-shaped "cap" that is placed over a tooth – covering the tooth to restore its shape, size and strength, and/or to 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 when at least one of the following occurs:
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 misshaped or severely discolored teeth
to cover a dental implant
What types of crown materials are available?
Permanent crowns can be either all metal, porcelain-fused-to-metal, all resin, or all ceramic.
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.
This innovative system combines the durability of porcelain fused to metal bridges with the aesthetic appearance of metal–free crowns. This system is based on the material zirconium-oxide.
Nowadays we can hear more and more about the probable allergic effects of metals applied in dentistry. Therefore the use of a material having the same good mechanical properties as metals but doesn't affect allergic reactions in human organism became necessary. While zirconium oxide does not have any allergic effects described in scientific publications, this material can be told as "biocompatible". It appertains to his good qualities that it conducts heat very badly, so the patients do not complain about cold or heat sensitiveness. This material is produced with the help of the most modern CAD/CAM computer technologies. Zirconium oxide crowns and bridges are the most aesthetic solutions.
The traditional crowns have a porcelain layer burnt on a metal cap, so its light permeability is weak. The light permeability of porcelain crowns burnt on zirconium oxide look like the own natural teeth. Because there aren't any metal caps, the dark metal frame-edge of the crown will not be visible if the gums may draw back in after years.
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 the best natural color match than any other crown type and may be more suitable for people with metal allergies. However, they are not as strong as porcelain-fused-to-metal crowns and they wear down opposing teeth a little more than metal or resin crowns. All-ceramic crowns are a good choice for front teeth.
Temporary crowns can be made in your dentist's office whereas permanent crowns are made in a dental laboratory. Temporary crowns are made of acrylic or stainless steel and can be used as a temporary restoration until a permanent crown is constructed by the dental laboratory.