A dental crown is a tooth-shaped "cap" that is placed
over a tooth. Crowns restore a tooth’s shape and size, strength, and/or improve
its appearance.
Crowns encase the entire visible portion of a tooth –
from top of tooth to the gum line.
Why is a dental crown needed?
A dental crown may be needed to:
- protect a weak tooth (eg, from decay) from breaking or to hold together
parts of a cracked tooth
- restore an already broken tooth or a tooth that has been severely worn down
- cover and support a tooth with a large filling when there isn't a lot of tooth left
- hold a dental bridge in place
- cover misshaped or severely discolored teeth
- cover a dental implant
- cover a tooth that has been endodontically treated (had a root canal)
What materials are used to make crowns? Is one type of
material better suited for specific dental problems?
Permanent crowns can be made from all metal,
porcelain-fused-to-metal, all resin, or all ceramic materials.
- Metals used in crowns include gold alloy, other alloys (for example,
palladium) or a base-metal alloy (for example, nickel or chromium). Compared
with other crown types, less tooth structure needs to be removed with metal
crowns, and tooth wear to opposing teeth is kept to a minimum. Metal crowns
withstand biting and chewing forces well and probably last the longest in
terms of wear down. Also, they rarely chip or break. 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 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.
- 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 may wear down opposing teeth a
little more than metal or resin crowns. All-ceramic crowns are a good choice for front teeth.
- Temporary versus permanent. 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.