Porcelain Crowns & Veneers
A closer look at two innovative techniques and strategies to improve your smile
New Ceramic Materials
Problems with porcelain restorations in the past have been in those composed of high concentrations of glass particles. They were brittle and had low tensile strength, and like glass, they were prone to fracture. One way of overcoming this has been to incorporate a core or substructure material made out of metal, i.e. cast gold, with porcelain facings. Unfortunately, while strengthening the crown, the metal tends to detract from the glass-like translucence of the porcelain and from its life-like appearance — not so bad for back teeth but not so great for front teeth.
Recently, the newest category of all-ceramic crowns make use of an internal ceramic “core” made from “Zirconia” which adds significant strength as well as esthetic beauty. This polycrystalline ceramic core (poly – many, crystalline – a crystal-structure which imparts greater strength) is the same material that forms the basic structure of fake diamonds.
|Figure 11: A milling machine sculpturing a restoration from CAD-CAM technology.|
CAD-CAM (Computer Aided Design – Computer Aided Manufacturing) technology is another innovation in dentistry which allows extraordinary accuracy of fit and contour of crown restorations. Using a special wand to scan a tooth that has been modified for a new crown, information is beamed from a computer to a milling machine that sculpts an exact fitting “ceramic core” of the crown [Figure 11]. Porcelain is then baked on top of this core to mimic tooth form and color as well as impart its traditional brilliance and translucence. The result of this computer-aided system is a crown composed of a strengthened core which is permanently cemented to the remaining natural tooth.
Secrets of Success — Veneers or Crowns?
In many instances porcelain veneers and crowns can produce pleasing and excellent results but these two types of dental restorations do have different structural characteristics. Ultimately, the precise terminology is unimportant. The secret to a successful outcome is to know what to use and when to use it. This is the province of the dental professional, who combines knowledge, skill and experience. Whether veneers or crowns are used to enhance your smile, the truth of the matter is that no one should know that you've had anything done, just that you look great!