Zirconia


A zirconia crown is a popular type of all-ceramic crown which is worn to improve the appearance of a tooth which has become stained or disfigured over the years. They are durable, easy to wear and long lasting.
Plus zirconia crowns have a translucent appearance which means that they are indistinguishable from your own teeth. It is hard to spot a zirconia crown amongst natural teeth.

What is a Zirconia Crown?
This type of crown is made from zirconia, a very strong material which is compatible with the human body. Zirconia is used in many other medical applications such as artificial joints and is known for its strength and durability.


Advantages Of A Zirconia Crown
There are three advantages which are:

  • Strength: zirconia crowns last longer than other types of crowns
  • Aesthetics: these crowns have an attractive translucent colour which blends in well with the other teeth.
  • Retain more of the existing tooth: minimal preparation is required which means more of the original tooth is preserved. This is useful if the crown needs to be removed.

So, a good choice if you are looking for a strong, long lasting and visually appealing crown. They are ideal at covering signs of damage or staining as well as helping to maintain the function of the tooth


Disadvantages Of A Zirconia Crown
The tough, durable nature of a zirconia crown can work against it as well as in its favour. This material has an abrasive quality which can cause friction against the root of the tooth as well as other teeth


How Is A Zirconia Crown Fitted?
The process is similar to that for other crowns. It involves two stages: preparation (first stage) and the fitting of the crown (second stage).


Types of Crown & Bridges


All-METAL CROWN
These crowns, just as their name implies, are fabricated entirely out of metal. The classic all-metal crown has a gold coloration. They can also be made out of "white" (silver color) alloys.


Advantage
Opting for an all-metal crown can make an excellent choice, if you don't mind the fact that it's not tooth-colored. Here's why:

  • Great strength - Having a metal crown break is an extremely rare event.
  • Superior longevity - No other type of crown can be expected to provide more lasting service
  • Less tooth reduction - Slightly less tooth grinding is need for an all-metal as opposed to an all-ceramic or porcelain-fused-to metal crown.

Disadvantage

  • The single disadvantage of this type of crown is its metallic look.
  • Slightly heavy compared to a Ceramic Crown. Especially important in bridges
  • Comparative lack of retention, the cement bonding to the metal crown does not bond with the same strength compared to a ceramic crown

PORCELAIN FUSED TO METAL-(PFM's)
PFM's can be thought of as a hybrid between the two other types of dental crowns, in the sense that they're made out of both metal and porcelain.

  • A metal alloy is used to create a thin thimble-like cap that fits over the tooth.
  • Porcelain is then fused to this metal substructure to form the overall shape of the crown and give it a white, natural-looking appearance.

Advantage
It's easy enough to imagine circumstances where a person would prefer a tooth-colored crown instead of a metallic one. But you might wonder what the advantages of a porcelain-fused-to-metal restoration are over their all-ceramic counterparts. They are:

  • Good strength.
  • Best Balance between Price and Esthetics

Disadvantage

  • Porcelain breakage.

Although relatively rare, the porcelain portion of a PFM crown may fracture or separate from its underlying metal substructure.
Fortunately, this type of mishap doesn't always render a crown useless. Its need for replacement will depend on the magnitude and location of the loss and how much it compromises the crown's function and appearance.
It may be possible that a repair can be made. However, over the long term the failure rate of these types of patches is typically high.