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Tooth Veneers |
In dentistry, a veneer is a thin layer of restorative material placed over a
tooth surface, either to improve the aesthetics of a tooth, or to protect a
damaged tooth surface. There are two types of material used in a veneer,
composite and porcelain. A composite veneer may be directly placed (built-up in
the mouth), or indirectly fabricated by a dental technician in a dental
laboratory, and later bonded to the tooth, typically using a resin cement such
as Panavia. In contrast, a porcelain veneer may only be indirectly fabricated.
The advantages of using a veneer to restore a tooth are many. Very good
aesthetics can be obtained, with minimal tooth preparation (i.e. drilling).
Normally a reduction of around 0.5 mm is required for a porcelain veneer on a
labial tooth surface. Composite veneers are becoming more popular as they are
easy to repair, and porcelain veneers have a tendency to fracture. It can be
very difficult to match the shade of an individual veneer to the remaining
teeth, hence the tendency to place several veneers. Veneers may be used
cosmetically to resurface teeth such as to make them appear more straight and
possess a more aesthetically pleasing alignment. This may be a quick way to
improve the appearance of malposed teeth without need to use orthodontics.
However, the amount of malposition of teeth may be such that veneers alone may
not be enough to correct the esthetic imbalance. Instead, orthodontics would
need to be used, or orthodontics combined with veneers. The dentist who places
veneers must be careful since veneers could increase the thickness of the front
face of the teeth. If the teeth are too thick on the face they may appear to
stand out and push out the lips. The effect may be enough to give the patient a
full or chipmunk appearance when the lips are closed. Veneers must also be
created such that the patient bites into them with minimal force.
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Otherwise, they may chip off. So, patients whose lower jaw protrudes out farther
than their upper jaw, otherwise known as a class III bite, may not be good
candidates for veneers because the teeth of the lower jaw may bite into the
teeth of the upper jaw such as to dislodge the veneers. Veneers were invented in
the 1930s by a dentist named Pincus. At the time, they fell off in a very short
time as they were held on by denture adhesive. They were, however, useful for
temporarily changing the appearance of movie actors'/ actresses teeth. Research
started in 1982 by Simonsen and Calamia revealed that porcelain could be etched
with Hydrofluoric Acid and bond strengths could be achieved between composite
resins and porcelain that were predicted to be able to hold porcelain veneers on
to the surface of a tooth permanently. This was confirmed by Calamia in an
article describing a technique for fabrication, and placement of Etched Bonded
Porcelain Veneers using a refractory model technique and Horn describing a
platinum foil technique for veneer fabrication. Today, with improved cements and
bonding agents, they typically last 10-15 years. But patients who receive
veneers should understand that they may only last 10-15 years and then may have
to be replaced. | |
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