A dental crown
is a tooth-shaped "cap" that is placed over a tooth
– covering the tooth to restore its shape and size, 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 in the following situations:
To protect a weak tooth (for instance, from decay) from breaking
or to hold together parts of a cracked tooth
2. To restore an already broken tooth or a
tooth that has been severely worn down
3. To cover and support a tooth with a large
filling when there isn't a lot of tooth left
4. To hold a dental bridge in place
5. To cover misshaped or severely discolored
6. To cover a dental implant
What Types of Crown Materials Are Available?
can be made from all metal, porcelain-fused-to-metal, all resin,
or all ceramic.
• 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
• 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
• 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 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.
What Steps Are Involved in Preparing a
Tooth for a Crown?
tooth for a crown usually requires two dentist visits, the first
step involves examining and preparing the tooth, the second
visit involves placement of the permanent crown.
Visit: Examining and preparing the tooth.
At the first
visit, your dentist may take a few X-rays to check the roots
of the tooth receiving the crown and surrounding bone. If the
tooth has extensive decay or if there is a risk of infection
or injury to the tooth's pulp, a root canal treatment may first
Before the process
of making your crown is begun, your dentist will anesthetize
(numb) your tooth and the gum tissue around the tooth. Next,
the tooth receiving the crown is filed down along the chewing
surface and sides to make room for the crown. The amount removed
depends on the type of crown used (for instance, all-metal crowns
are thinner, requiring less tooth structure removal than all-porcelain
or porcelain-fused-to-metal ones). If, on the other hand, a
large area of the tooth is missing (due to decay or damage),
your dentist will use filling material to "build up"
the tooth to support the crown.
the tooth, your dentist will use impression paste or putty to
make an impression of the tooth to receive the crown. Impressions
of the teeth above and below the tooth to receive the dental
crown will also be made to make sure that the crown will not
affect your bite.
are sent to a dental laboratory where the crown will be manufactured.
The crown is usually returned to your dentist's office in 2
to 3 weeks. If your crown is made of porcelain, your dentist
will also select the shade that most closely matches the color
of the neighboring teeth. During this first office visit your
dentist will make a temporary crown to cover and protect the
prepared tooth while the crown is being made. Temporary crowns
usually are made of acrylic and are held in place using a temporary
Second Visit: Receiving the permanent
At your second
visit, your dentist will remove your temporary crown and check
the fit and color of the permanent crown. If everything is acceptable,
a local anesthetic will be used to numb the tooth and the new
crown is permanently cemented in place.
Should I Care for My Temporary Dental Crown?
dental crowns are just that – a temporary fix until a permanent
crown is ready, most dentists suggest that a few precautions
be taken with your temporary crown. These include:
• Avoid sticky, chewy foods (for example, chewing gum, caramel),
which have the potential of grabbing and pulling off the crown.
• Minimize use of the side of your mouth with the temporary
crown. Shift the bulk of your chewing to the other side of your
• Avoid chewing hard foods (such as raw vegetables), which could
dislodge or break the crown.
• Slide flossing material out-rather than lifting out-when cleaning
your teeth. Lifting the floss out, as you normally would, might
pull off the temporary crown.
What Problems Could Develop With a Dental Crown?
• Discomfort or sensitivity. Your newly crowned tooth may be
sensitive immediately after the procedure as the anesthesia
begins to wear off. If the tooth that has been crowned still
has a nerve in it, you may experience some heat and cold sensitivity.
may recommend that you brush your teeth with toothpaste designed
for sensitive teeth. Pain or sensitivity that occurs when you
bite down usually means that the crown is too high on the tooth.
If this is the case, call your dentist. He can easily fix this
• Chipped crown. Crowns made of all porcelain can sometimes
chip. If the chip is small, a composite resin can be used to
repair the chip with the crown remaining in your mouth. If the
chipping is extensive, the crown may need to be replaced.
• Loose crown. Sometimes the cement washes out from under the
crown. Not only does this allow the crown to become loose, it
allows bacteria to leak in and cause decay to the tooth that
remains. If your crown feels loose, contact your dentist's office.
• Crown falls off. Sometimes crowns fall off. Usually this is
due to an improper fit or a lack of cement. If this happens,
clean the crown and the front of your tooth. You can replace
the crown temporarily using dental adhesive or temporary tooth
cement that is sold in stores for this purpose. Contact your
dentist's office immediately. He or she will give you specific
instructions on how to care for your tooth and crown for the
day or so until you can be seen for an evaluation. Your dentist
may be able to re-cement your crown in place; if not, a new
crown will need to be made.
• Allergic reaction. Because the metals used to make crowns
are usually a mixture of metals, an allergic reaction to the
metals or porcelain used in crowns can occur, but this is extremely
• Dark line on crowned tooth next to the gum line. A dark line
next to the gum line of your crowned tooth is normal, particularly
if you have a porcelain-fused-to-metal crown. This dark line
is simply the metal of the crown showing through.
What Are "Onlays" and "3/4 Crowns?"
These are variations
on the technique of dental crowns. The difference between these
crowns and the crowns discussed previously is their coverage
of the underlying tooth - The "traditional" crown
covers the entire tooth; onlays and 3/4 crowns cover the underlying
tooth to a lesser extent.
Long Do Dental Crowns Last?
dental crowns last between 5 and 15 years. The life span of
a crown depends on the amount of "wear and tear" the
crown is exposed to, how well you follow good oral hygiene practices,
and your personal mouth-related habits (you should avoid such
habits as grinding or clenching your teeth, chewing ice, biting
your fingernails and using your teeth to open packaging).
a Crowned Tooth Require any Special Care?
While a crowned
tooth does not require any special care, remember that simply
because a tooth is crowned does not mean the underlying tooth
is protected from decay or gum disease. Therefore, continue
to follow good oral hygiene practices, including brushing your
teeth at least twice a day and flossing once a day-especially
around the crown area where the gum meets the tooth.