Crowns

9/11/08
By: Larry J. Cook

Crowns or "caps" have been used in dentistry in some form for hundreds of years. In general, crowns are recommended for teeth that are so badly broken down by caries, wear, or trauma or some combination of the three that other restorative methods (such as fillings) are not appropriate. When certain strategic portions of the tooth are gone or already replaced by "filling" or restorative material, the tooth becomes too weak to be statistically likely to withstand biting and chewing forces.
Unlike "fillings" which rest within the confines of the tooth, a crown fits over and around the tooth like a thimble over the finger. The importance of the crown is that it fits over and around the tooth far and reinforces it like a ring reinforces and contains the staves of a barrel. In short, it makes the tooth less likely to break while replacing the missing tooth structure. This has important implications for both the form and function of the newly restored tooth. It is strong enough to with stand biting forces, and when constructed of porcelain by a skilled technician, can look exactly like the teeth around it.
Originally, most crowns were constructed of gold, which is a very strong material, but not the most cosmetically pleasing. In the 1960’s a method of fusing porcelain to gold was perfected and most crowns for the last 45 to 50 years have been constructed of porcelain fused to a gold coping or core. Technicians have now developed a way to make cores out of zirconium, which act like metal as far as strength, but does not have the metallic color and can in fact be shaded to different tooth colors. These core now even are strong enough for bridge work. With such beautiful materials to work with, it is a wonderful time to be a dentist.
The one downside to performing this type of dentistry is that in some circumstances, some healthy tooth structure must be sacrificed in order to create the shape of the preparation so the resulting crown is beautiful, strong, and long-lasting. Only you, in consultation with your dentist, can decide if a crown is appropriate for any given dental problem you might have.