What is the dental science behind porcelain veneers?
Porcelain veneers are the most recent application of the art and science of cosmetic dental bonding. For decades dentists have had available to them materials which can create a durable bond to tooth enamel. Porcelain veneer technique utilizes the bonding capabilities of these materials to securely attach a thin sheet of porcelain (the porcelain veneer) to a tooth. Although porcelain is inherently brittle, when it is firmly bonded to a sturdy substructure (a tooth) it becomes very strong and durable.
One property of this enamel covering is that it's translucent. This means that when light strikes a tooth's surface it is not immediately reflected off, but instead penetrates into the thickness of the enamel. This light will subsequently be reflected off the non-translucent tooth structure that lies beneath the enamel. This property of translucency is an important part of what gives teeth their characteristic appearance.
Historically the cosmetic dental bonding materials dentists have had available to them were only semi-translucent. This means that most of the light striking the tooth did not penetrate into the bonding layer but instead was reflected off the bonding's outer surface. The net result was that while the bonding did give the tooth an improved appearance, there was no sense of depth projected. No sense of a tooth's characteristic translucency.
Porcelain veneers, because they are glass-like, have a great advantage over other types of cosmetic dental bonding by the fact that they are translucent. When they are bonded onto a tooth's surface they mimic the light handling characteristics of enamel.
Light striking a porcelain veneer will penetrate its thickness, and then subsequently be reflected back out once it has reached the opaque cement and tooth structure lying underneath the veneer. This translucency effect provides a sense of depth, and thus a very life-like appearance.
Cosmetic dental bonding materials utilized in the past had the shortcoming of being susceptible to staining and discoloring. This was especially a problem for those people whose teeth had excessive exposure to tea, coffee, red wine, or cigarette smoking.
A significant advantage of porcelain veneers over other types of cosmetic dental
bonding is related to the fact that a porcelain veneer's surface is just that,
porcelain. Since porcelain is a ceramic, and therefore glass-like, its surface
is extremely smooth and impervious. This means that the surface of a porcelain
veneer will not pick up permanent stains.