Crowns
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Why a crown?
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A crown can be done for any number of reasons:
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- broken tooth
- root canal treated tooth (to protect it from breaking)
- large old filling (that can no longer support the tooth)
- reshape tooth (for appearance and/or improved bite)
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A filling really only repairs a small hole. To rebuild, reshape, or
protect a substantial part of your tooth, a filling just won't do the job, and
a crown is preferred. A crown is also called a cap.
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Sometimes, a filling is not sufficient for long-term strength, yet there is
quite a bit of healthy tooth. In this instance a partial crown or inlay
is appropriate.
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A bridge is constructed to replace a missing tooth, and is made of
crowns that are invisibly joined together.
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Making a Crown
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The tooth is reshaped or "prepared", often including rebuilding
part of the tooth with a crown buildup. The amount of enamel removed is
exactly the thickness of the crown (about 0.5-2 mm, depending on materials used:
less with all metal, more with porcelain). A mold is made of this tooth
(the mold usually includes adjacent teeth and the teeth that this one bites
against). From this mold the laboratory constructs your crown (the
porcelain color is matched to your tooth). While the crown is being
constructed you have a temporary crown on your tooth. It takes about 10
working days before your crown is back from the laboratory. At the second
appointment, the crown is bonded on your tooth (you may need to have anesthesia
and/or nitrous oxide if your tooth is sensitive).
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What is a crown made of?
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A crown can be made from different materials: all porcelain, gold alloy
(white or yellow), porcelain and gold alloy, other metal combinations (I only
use noble or high noble metals). Different situations often suggest
different materials to be used depending on durability, esthetics, and physical
limitations - this is determined in concert with your wishes. When
a porcelain crown is made, I match the shade(s) of your adjacent teeth for the
new crown, so that it is indistinguishable.
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Classification of Metals: The noble metal
classification system has been adopted as a more precise method of
reporting various alloys in dentistry commonly used in crowns, bridges
and dentures. These alloys contain varying percentages of gold,
palladium and/or platinum.
- high noble contains more than 60% of gold, palladium,
and/or platinum (with at least 40% gold)
- noble contains more than 25% gold, palladium and/or
platinum
- predominantly base contains less than 25% gold, palladium
and/or platinum
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Care of your temporary crown
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The temporary crown is usually made of plastic (it can also be metal), and is
not intended for long-term wear - usually for 2-6 weeks (longer in
certain situations). It is to protect the tooth from sensitivity
(temperature, touch), protect the gums, and to hold the bite (keep the adjacent
and opposing tooth from shifting). A temporary crown is like a temporary
tire, it is sufficient for short-term, careful use.
Brush, floss, Water-Pik, clean, etc. as usual, except, when you
floss pull the floss through instead of up/down, so as not to dislodge the
temporary crown. Avoid sticky things that could pull off your temporary
crown.
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Care of your tooth and gum
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The gum is often a little irritated next to the crown. A salt water rinse is
very helpful - a teaspoon of salt in a warm glass of water, rinsed gently a
couple times a day, until your gum feels better. Advil, aspirin, or
Tylenol before the anesthesia wears off is always helpful.
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What if the temporary crown comes off?
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If it is only a day or two before your visit to try in your new
crown, and the tooth is not sensitive, you can leave it out - BUT save it!
If the time is greater before your appointment, you can put it back in
temporarily with Vaseline, but call to have it recemented. Without the
temporary crown on, adjacent and opposing teeth can shift, sometimes so much
that the permanent crown won't fit.
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What's next?
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At your next appointment, the temporary crown is gently removed. If
your tooth is sensitive, you may require some anesthesia (or laughing gas).
Your new crown is tried in to check it for: fit, color, shape and appearance,
bite, fit between teeth, seal against your tooth. If everything is correct
and it meets your approval, it is cemented with a long-term cement. Treat
the crown as if it is your own tooth, especially for cleaning. It is not
uncommon to experience a little sensitivity to cold after getting a new crown,
but this should diminish quickly (over a couple weeks).
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| There is a process available for making a
permanent crown in one-visit. At this time I feel that this type of
crown (Cerec) does not yet meet the accuracy and esthetics that my
laboratory can create. If and when it does, I look forward to offering
this service. |
