A crown is a ‘cap’ that fits over the entire surface of the tooth. The process of making a crown involves trimming the tooth down to the desired shape. Impressions of the tooth preparation are then taken and from the impressions the laboratory can construct a crown.
Once fabricated, a crown is fitted over the tooth surface, and is bonded in place using dental cements. The shape, size, colour and surface characteristics of a crown are closely matched to the surrounding teeth. They are fabricated by master ceramists to be of the highest possible standards and once fitted, provide a seamless and permanent restoration to a tooth.
Crowns can last a lifetime and are necessary for a number of reasons.
- To restore heavily broken down teeth
- After root canal therapy to prevent a tooth from fracturing
- To restore heavily filled teeth
- To improve the shape of a broken or unusually shaped tooth
- To treat discoloured teeth
- To realign crowded or spaced teeth
- There are many types of crowns:
Porcelain fused to metal crowns (PFM), all ceramic crowns, and the most durable of restorations, full gold crowns.
All-ceramic crowns are made of porcelain. At the octagon dental suite we use Procera crowns. In many cases, advanced computer technology is used to scan the dimensions of the tooth preparation from which the crowns are constructed.
This provides a perfectly fitting and sealed crown. These crowns are highly biocompatible and avoid the use of metals. They are bonded to the underlying tooth structure in such a fashion that they provide considerable added strength.
Ceramic-metal crowns utilise an alloy as a substructure over which ceramic porcelains are applied. The underlying metal matrix provides strength over which the layering of ceramics can be optimized to imitate the aesthetics of natural teeth.
Full gold crowns are made of a gold alloy. They are very durable and can last for many years.
Bridgework has been used for many decades to replace lost teeth or to restore pre-existing gaps. Put simply, bridgework consists of more than one crown unit joined together. Bridges are fitted over existing teeth to replace toothless spaces.
Other types of bridges do exist; one example is the adhesive bridge which is simply bonded firmly to adjacent teeth.
Bridges are constructed of similar materials to crowns. They are permanent restorations although in many cases, they have now been superseded by the use of dental implants to replace toothless spaces.