Crown

If a tooth is damaged but not lost, a crown can be used to restore its shape, appearance and function. You may need a crown if you have a root canal, a large filling in a tooth or a broken tooth.
A crown, also called a cap, is a hollow, artificial tooth used to cover a damaged or decayed tooth. The crown restores the tooth and protects it from further damage. Crowns can also be used to cover a discoloured or misshapen tooth. A tooth that has been fixed with a crown looks and works very much like a natural tooth.
There is a significant shift towards ceramic crowns. Sometimes gold or porcelain-fused-to-metal (PFM) crowns are used.
On average a ceramic crown costs $1300.
There is an expectation for crowns to last 10+ years, but the length of serviceability will depend on oral hygiene, personal caries risk as well as on dentist's skills.
In general, 2 appointments are needed for a back tooth's crown. Front teeth may require extra appointment as custom color-matching sometimes is necessary to make the crown blend in perfectly. Here are some steps to crown-making.

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Assessment: front tooth is broken and needs a crown

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Adjacent teeth have cavities. Composite fillings will be done to restore them.

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Final crown cemented

Bridge

Bridge is a fixed/permanent structure. You don't need to remove it unlike removable dentures.
Pros:
  • It allows for replacement of missing tooth or teeth very quickly
  • non-removable
  • looks natural
Cons:
  • if replacing only 1 tooth the cost is similar to an implant tooth
  • adjacent teeth needs grinding
  • is one of the abutment teeth fails - the whole bridge fails
  • bridges generally last less that stand-alone crown or implant crowns because of complicated hygiene

Why do some crowns last decades and some fail a lot sooner?

In general, the longevity of any product will depend on how well it is made and how it is used and maintained (cared for).
For a crown or bridge to last a long time at a minimum the following pay role:
  • Dentist's side
    1. tooth needs to be prepared well by a dentist (cleaned from decay,  reduced sufficiently, but not excessively).
    2. dentist need to take a good impression of the tooth so that a lab technician is able to see how to shape the crown.
    3. crown is well made by a dental lab.
    4. quality control by the dentist before a final cementation.
  • Patient's side
    1. good oral hygiene (brush, floss, Waterpik).
    2. catch and treat any other problems in the mouth (regular check ups, not letting adjacent teeth deteriorate). 
    3. be mindful about mechanical limitations - don't use your teeth as tools!

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General guidance for tooth reduction

If we reduce the tooth less than the chosen crown material allows - the crown may break. Gold allows for the smallest "grinding", while ceramic crowns need about 1mm reduction.
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The line where we want a crown to finish (margin) is clearly defined. Reduction to allow enough material thickness is achieved.

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The line where we want a crown to finish (margin) is clearly defined. The tooth is free from decay.


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Good, clear impression allows a lab tech to see where to finish crown. This avoids gaps or overhangs.

Your dentist will check the crown on the model for contour, margin adaptation, contacts etc.
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Before crown is cemented the dentist checks how well it is adapted to the tooth's margin. If all is good the crown is cemented.

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This is an incidental finding while working on another tooth.
The crown on the last tooth has a gap (does not fit the tooth well). The decay will likely develop in that space as it is impossible for the patient to clean that space at home.
This crown will not last long and needs to be redone before tooth starts hurting.

Disclaimer: All above photographs  are of Dr. Andrew Yegorovykh's  patient and treatment. Photographs are for informational purposes only because individual treatment results will vary from patient to patient. Some patients may not be candidates for treatment. It is important for a prospective candidate to engage in detailed discussions with a dentist about treatment options, realistic outcomes, possible complications, costs, informed consent.