Crowns (Porcelain/Gold/Porcelain Fused to Metal)
A dental crown is a restorative oral prosthesis, similar to a thimble over a thumb, and that is shaped and made to look like a real tooth. A crown is usually placed over a tooth that was damaged by eitherdecay or by a fracture, to cover and protect it by reconstructing its shape, its size and its strength. A deteriorated tooth, which requires a dental crown, may be alive or have been treated with a root canal.
Once cemented, a dental crown completely covers the portion of the tooth which is above the gum. Porcelain is the material that is mainly used to make a crown because of its aesthetic qualities, with visual properties that are very similar to dental enamel. Therefore a crown looks like a real tooth in its shape and colour.
Reasons for a crown:
- To protect a weakened tooth (by tooth decay for example) against rupture, or to keep together a cracked tooth.
- To restore an already broken tooth or a severely worn out tooth.
- To restore a tooth that has had a root canal and a post.
- To cover and support a tooth that had a large filling when there isn’t enough healthy tooth structure left to be restored by a new filling.
- To cover a tooth that is malformed or severely discoloured.
- To cover a dental implant.
Types of crowns:
- An all ceramic crown is the most aesthetic crown because it is made of porcelain only and is Dr. Halpin’s preferred material. Its shape and colour can match the qualities of natural teeth very closely. Porcelain only crowns are recommended for anterior (front) teeth to favour beauty and offer a better looking smile. Porcelain crowns are generally fabricated in a dental laboratory.
- A crown made of gold alloy is the one that lasts the longest. It resists very well to chewing forces, it rarely breaks, and it causes very little wear to opposing teeth. The gold’s metallic colour is the main disadvantage of this type of crown and this factor reduces its popularity.
- A crown made of porcelain fused to gold is a more aesthetic crown than the one made of gold alloy. Porcelain can make a crown look very similar to a natural tooth. The gold part, which is located below the porcelain, helps give strength to the tooth. Sometimes the gold under the porcelain may show, especially at the gum level.
- A CEREC crown is also made of porcelain only. This technology allows the dentist to engineer himself the crown following an electronic impression. Even though CEREC’s porcelain is an option today, dental laboratory’s porcelains are still more aesthetic and resemble more the natural appearance of teeth.
A temporary or provisional crown is made by the dentist himself and has a lifespan of a few weeks. It is made of acrylic or stainless steel, and serves as a temporary restoration until the permanent crown is made by a dental laboratory. A temporary crown is not strong and can break easily.