Thursday April 4, 2002
Dear Dr. Mady: I recently visited my dentist and she told me that I need three crowns on my back teeth. She said I could have them made from porcelain, porcelain and metal or all metal. Why do I need them, what are the differences and what do you think would be the best? -Kim in South Windsor.
Dear Kim: Crowns are a restorative dental treatment option that consist basically of a complete covering or cap over your tooth or teeth. They are used to restore teeth that are worn, badly broken down, structurally compromised, cosmetically unpleasant and often teeth that have had root canal treatment.
These restorations are usually composed of metal, porcelain or a combination of both. Metal crowns are probably the oldest style, but still an excellent choice with respect to fit and function. This type is mostly, but not always used on posterior or back teeth. Crowns made of porcelain are a more esthetic choice, but can be placed anywhere in the mouth and are the most widely utilized today. The ceramic porcelain can be fabricated any color to match the shade of your existing teeth.
When individuals choose metal crowns, the lab technicians and doctors usually use cast gold. It is not one hundred percent pure gold because if it were, it would be much too soft. Rather it is usually comprised of approximately eighty percent gold with small percentages of copper, zinc, silver and sometimes a few other non-corrosive, biocompatible metals. The high content of precious metal limits the occurrence of an allergic reaction in most cases. Although an excellent choice in terms of wear, longevity and effect on opposing teeth, it is often declined as a treatment option due to the fear that it may show when one is talking or opening their mouth.
Porcelain crowns can be created from solid porcelain or from porcelain fused to precious, semi-precious or non-precious metal. More and more often, patients are requesting tooth colored crowns for back teeth also and they are now stronger than ever. Some types are even fabricated over a computer generated ceramic coping made from scanning a die of the crown-prepped tooth and these have unbelievable strength to withstand biting forces. These porcelain crowns are practically invisible, blending with your other teeth but still have a possibility of fracture greater than metal, and may wear the opposing teeth more than metal.
Overall, the type of crown you and your dentist choose will depend on your eating habits, esthetic desires, and on whether or not you grind your teeth. If you like to chew hard candies, ice cubes or grind your teeth, then porcelain is probably not a good option for you. However, if you don't have any of these habits and you are concerned about esthetics, then porcelain is probably a better choice. There are many factors that can increase or decrease the possibility of damage to your crown(s) or their lifespan, but your dentist and his lab technician should be able to explain all the options to you and help you determine the best course of action.
This column is reprinted with the permission of the author and The Windsor Star. "Ask the Dentist" is written by Windsor dentist (and ECDS member), Dr. David Mady Jr.. The column appears the first Thursday of each month in the Windsor Star. Readers with questions can write to "Ask The Dentist", c/o The Windsor Star, 167 Ferry St., Windsor Ontario, N9A 4M5