Full-porcelain dental crowns
Some dental crowns are fabricated in a manner where their full thickness is porcelain (dental ceramic). These crowns can possess a translucency that makes them the most cosmetically pleasing of all of the different types of dental crowns.
Although they can be very life like in appearance, the overall strength of all-porcelain dental crowns is less than other types of crowns. While they can be a good choice for front teeth, due to the hefty chewing and biting forces that humans can generate, all-porcelain dental crowns may not be the best choice for back teeth. Your dentist's judgement will be required on this point.
Porcelain-fused-to-metal dental crowns
Porcelain-fused-to-metal dental crowns are somewhat of a hybrid between metal crowns and porcelain crowns. When they are made the dental technician first makes a shell of metal that fits over the tooth. A veneering of porcelain is then fused over this metal (in a high heat oven), giving the crown a white tooth-like appearance. Depending on the requirements of your situation, these crowns are sometimes made where the porcelain veneer only covers those aspects of the crown that is readily visible (meaning the other portions of the crown have a metal surface). In other cases these crowns are pretty much fully surfaced with porcelain.
Porcelain-fused-to-metal dental crowns can be a good choice for either front or back teeth. These crowns are strong enough to withstand heavy biting pressures and at the same time can have an excellent cosmetic appearance. There are some disadvantages associated with porcelain-fused-to-metal crowns however (which no doubt your dentist will try to minimize as much as is possible). They are:
- While the cosmetic appearance of these crowns can be excellent, they often are not as pleasing aesthetically as all-porcelain dental crowns.
- The crown's porcelain can chip or break off.
- The porcelain surface of the crown can create wear (sometimes this wear is significant) on those teeth that it bites against.
- The metal that lies underneath a crown's porcelain layer can sometimes be visualized as a dark line found right at the crown's edge. A dentist will usually try to position this dark edge just underneath the tooth's gum line but if a person's gums recede this dark line can show, thus spoiling the crown's appearance.