A crown is a full coverage restoration that is built in a laboratory by a dental technician.
The crown is designed to cover the whole of the tooth so no natural tooth tissue is visible above the gum margin. A porcelain crown can be “all ceramic” which means it is made from porcelain only or “porcelain fused to metal” which means that there is an underlying metal core. The all ceramic type is used where maximum aesthetics are required and where the load on the crown will not be too high. The porcelain fused to metal crowns are used where greater strength is required.
Typically crowns are used to restore very damaged teeth that have already been heavily filled. They can transform the appearance of very damaged or deformed teeth and provide excellent long term solutions. They were used much more in the past to cover dark root filled teeth and very stained teeth before we had whitening techniques available to us.
To make room for the porcelain and metal of these crowns the underlying tooth has to be heavily reduced and adjusted. This adjustment is permanent so once a tooth is prepared for a crown it will always need a crown to restore it. Due to the heavy preparation of already damaged teeth it is estimated that between 15 and 20% of teeth crowned will die of and require root canal fillings within 5 years of treatment.
Crowns can help to create a balanced and natural smile.
Advantages
Complete control of appearance of tooth
Very stable long term aesthetics
Highly predictable result
Minimum of two visits
Easy to clean and maintain
Disadvantages
Extensive preparation of underlying tooth
Higher cost due to laboratory fees
Replacement costs high each time
Unable to repair porcelain in mouth
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