In the past, teeth that were damaged, cracked, or weak were usually covered with porcelain crowns that had a metal foundation. These porcelain-fused-to-metal crowns are strong enough to withstand the pressures of chewing, but they also look opaque and lifeless, without the transparency and sparkle of natural teeth. And even though the metal foundation doesn’t show to begin with, the characteristic dark gum line almost always shows within a few years.
Advances in Porcelain Crowns
Advances in bonding technology have made it possible to create beautiful, lifelike crowns of porcelain without the need for a metal foundation. There are still some situations in the back teeth where the pressures of chewing can make a porcelain-fused-to-metal crown a good choice. But if you need crowns on your front teeth, all-porcelain crowns are one of the best options available. It’s easy to see the difference between crowns with metal foundations and all-porcelain crowns in these photos. The first one above shows the flat, opaque color, thick construction, and dark gum line of porcelain-fused-to-metal-crowns.
All-porcelain crowns are made of feldspathic porcelain, and they are created by stacking and firing thin layers of this materials. This gives the creator a great deal of latitude in working with layers of color and transparency, leading to natural-looking results. This second photo shows the thinner structure, variation in color, and transparency possible with all porcelain crowns on the same patient.
Zirconia and e.max Crowns
Feldspathic porcelain crowns are not the only option available. Many other ceramics have been developed, and they all have different characteristics and advantages. Zirconia crowns are made with a ceramic that is so strong it has earned the name ceramic steel. Crowns made of zirconia are milled from single blocks of ceramic, and the strength of the material means they can be made very thin. This quality adds to the beauty of zirconia crowns because of the translucency it enables.
e.max crowns combine the strength of an inner ceramic core with the esthetics of a porcelain crown. Many different ceramics can be used in this process, but Drs. Murphree and Reed prefer to use zirconia. The zirconia core is milled as it would be for a zirconia crown, and then the front part is ground down and the porcelain is layered and fired over it. Visit our zirconia crowns page to learn more about both zirconia and e.max crowns.
A Porcelain Crown Case Study
The photo to the left shows one of Dr. Murphree’s patients. Her front teeth had been covered with porcelain-fused-to-metal-crowns. You can see the characteristic thickness and opacity, and they also show the beginnings of the dark gum line. The photo to the right here shows the same patient after Dr. Murphree replaced her porcelain-fused-to-metal crowns with all-porcelain crowns. Dr. Murphree entered this case into the American Academy of Cosmetic Dentist’s 2005 International Smile Gallery competition. His peers judged it so successful that they awarded it the competition’s gold medal.
Before you schedule an appointment, you should know that all-porcelain crowns are more expensive than porcelain-fused-to-medal crowns. And in the case of the back molars that bear the full pressure of chewing, it can sometimes be desirable to choose the added strength of porcelain-fused-to-metal crowns.
You can discuss these and other considerations with Dr. Murphree by scheduling a complimentary consultation or a full first appointment. Please call our office or visit our request an appointment page.