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New crowns mimics look of real teethDear Dr. Reitz: One summer, when I was in my teens, a bicycle accident resulted in the fracture of my two front teeth. The broken teeth were fixed with crowns. The dentist did a good job, but the crowns never looked natural. I am now 45 years old and would like a better smile. - Bob Dear Bob: If the first thing saying hello when you smile are the crowns on your front teeth, it's time for an upgrade. Based on your age, I would say your crowns were likely made using a process of baking porcelain on a core of metal. The metal core was necessary for strength; however technology at the time made it difficult to hide the metal, which often resulted in a dark area at the gum line. Although your current crowns are not aesthetically pleasing, you should feel good that they lasted for many years. Advancements in ceramics now allow dentists to fabricate crowns that are metal free while retaining the strength necessary to withstand the forces of chewing. An all-ceramic crown reflects and absorbs light similar to a real tooth, making it look more natural than your current crown. Today's dentists have multiple ceramic crowns from which to choose. Some crown manufacturers use zirconia (a white crystal) as the substitute for the metal core. You have likely heard of the cubic crystalline form of zirconia, called cubic zirconia, which is sold as a synthetic diamond. Another method involves using a computer to mill the crown from a solid block of porcelain. Although it lacks the zirconia core, this type of crown works well when bonded onto the tooth with present-day adhesives and looks exactly like a natural tooth. Regardless of which method is used, your new crowns are going to look natural and less noticeable. Unfortunately, the materials have only been in use for a few years, so only time will tell if they last as long as the old porcelain to metal crowns, so expect to replace those crowns again in the future. Even though the new ceramics are an improvement from the past, they are still a man-made substitute for the original tooth. Future dentists will restore a broken tooth with materials that mimic nature, a concept referred to as biomimetic dentistry. Current porcelains that mimic nature in strength and appearance are improvements over the old material; however, biomimetic dentistry's goal is to use tissue-engineering to regenerate the broken or decayed tooth using the same material as nature. The column is written by John Reitz, DDS, and does not represent the opinion of the Pennsylvania State Dental Board. Dr. Reitz answers questions from readers. E-mail them via his Web site at reitzdds.com or mail to John Reitz, DDS, 30 Commerce Drive, Wyomissing PA 19610 John
V. Reitz, D.D.S., F.A.G.D. Copyright
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