The dental crown of a tooth is the portion that is covered by enamel. A restorative dental crown replaces this outer part to protect and strengthen the tooth. This protection becomes necessary when a tooth cracks, has its entire structure weakened by decay, or becomes weakened after a root canal. Dental Crowns can also cover dental implants or abutment (adjacent) teeth when fitting a bridge.
Dental Crowns are also used to cover discolored or otherwise aesthetically displeasing teeth. Cosmetic dentistry does not use crowns as much as it once did, since crowns, though aesthetically pleasing, require more radical dental techniques. Dentists are opting for more conservative methods such as bleaching, bonding, or veneers to improve the aesthetic appearance of teeth.
The dentist first removes the decayed portion of the tooth. The tooth is then prepared for a dental crown. It may be tapered on the outside edges to a peg, reinforced with a cast metal core, or rebuilt with both a cast metal core and a post. An impression of the prepared tooth and the teeth next to it is made. A retraction cord is placed around the tooth in order to get the impression medium under the gum where the crown will be fitted.
The dental technician will create a new crown, using a cast made from this impression. The crown may be made of metal with a veneer of tooth-colored porcelain, or of porcelain or resin alone. The finished crown is then placed over the prepared tooth, adjusted, and cemented into place.
When a tooth has had a root canal and the root has been filled, the tooth may not be strong. Post crowns are used in these cases. The tooth is leveled at the gum line and a prefabricated post is fitted into the root canal. This post can then receive the new crown and hold it in place.
Dental Crowns can last 5-15 years or more, if they are well maintained.
All Ceramic Dental Crowns
The predominant material choice for all ceramic crowns today is either Zirconia or aluminous materials. They provide a metal free aesthetic option with a number of benefits.
By eliminating the need for the supportive metal core, an aesthetic all ceramic crown can be created with a reduced thickness of material. This makes them a more favorable treatment choice in areas with limited space. Additionally, the elimination of the metal core allows for light transmission through the porcelain for better optical, life like properties and a higher level of esthetics.
All ceramic materials continue to evolve in strength and durability, but caution should still be exercised for areas of the mouth requiring heavy function. Continuing research is exploring the significant vulnerabilities of the porcelain systems in such areas.