|
|
|
Crowns
Crowns are caps shaped like natural teeth that are placed on top of teeth to cover their entire surface. They are used to restore single teeth that are seriously damaged and can no longer be preserved with fillings or inlays. Crowns can preserve the function of these teeth and restore their size, appearance and strength. Teeth also become weaker after root canal treatment and crowns are used to preserve their function and prevent fractures. In some cases, healthy teeth are crowned when they are used as an anchor for a removable partial denture or bridgework. Crowns are also used when smile needs to be aesthetically improved and veneers would not be an option because there is a need to alter size, shape or shade of teeth.
When is a crown used?
To cover a dental implant
In case of severely broken, damaged tooth restoration when there is not enough tooth structure left to support a filling or inlay
In case of a seriously decayed tooth
To protect a tooth after root canal treatment
If the teeth have undergone acid erosion as a consequence of poor diet
To improve appearance of a tooth that is misshaped or discoloured
To hold a dental bridge or partial denture in place
For cosmetic reasons to improve the aesthetics of smile
The procedure
To place a crown, teeth have to be prepared. During the first visit the dentist removes the decay and outer layers of the tooth structure using a dental drill and then takes moulds. The dental technician fabricates the crown and during the next visit the dentist permanently cements it into the mouth. It usually requires 2-3 visits in a 7-10 day period. During this period you will be fitted with a temporary crown.
Types of crown materials
-metal
Usually gold alloys are used. They have several advantages, they are very workable, a precise fit can be achieved with the tooth surface, less tooth structure needs to be removed, very durable, withstand biting forces, do not chip and do not break. They have the same wear rate as tooth enamel, so they are less abrasive to the opposing tooth. Their aesthetic appearance is their only disadvantage and for this reason they are recommended for molars. It is also advantageous for those patients who grind their teeth during night. They generally require less work to fabricate and last longer than other restorations.
-porcelain-fused-to-metal
They provide a more aesthetic solution for teeth that show when you smile. They have a metal core and covered with tooth colour matched porcelain. Some amount of wearing and chipping can occur, but in case of good quality materials and dental work they can last for up to 15 years. Their disadvantage is that if the gum recedes over time, some metal can show at the gum line and since they have a metal core they are not as transparent as full porcelain crowns.
-all porcelain
They are generally not as durable as porcelain fused to metal crowns but are more aesthetic in appearance and ideal for front tooth restorations and for patients with metal allergies.
-all ceramic restoration
They are either made of zirconia or aluminous materials.
They provide a metal free aesthetic restoration with numerous advantages. They do not need a metal core they are thinner and less of the tooth structure has to be removed during preparation. The absence of the metal core allows light transmission through them providing a more natural solution. They are not as durable as gold or porcelain fused to metal restorations and for this reason they should be avoided at sites where the biting forces are heavy.
How long do crowns last?
If you take care of them as your own teeth, maintain good oral hygiene, and do not chew on very hard surfaces such as nutshell they can last up to 15 years.
Back to Home Page
|
