The crowning touch of the extreme dental makeover is the application of veneers that change the color and shape of teeth in a dramatic way. For many people, years of stain and wear, or misalignment are corrected in days with veneers. Veneers are porcelain or composite (a mixture of about 75% glass dust and 25% acrylic) shells that are chemically bonded to the surface of a tooth to repair it or to change the tooth's appearance.
As in many things, good preparation helps to ensure success. Dentists begin to design veneers by taking photographs and making models of their patient's teeth. The models and photos are altered by hand or computer to show the doctor and patient what the result could look like. Changes may be made at this stage depending on the eye of the doctor, patient or the patient's significant other. Nothing is done to change the patient's teeth until everyone likes the design.
Porcelain veneers are usually applied in two visits about two weeks apart. In the first appointment, the teeth are altered to allow for the proper thickness of porcelain (about half a millimeter). When a tooth protrudes beyond the others or is rotated, it is necessary to remove more of the tooth. The dentist makes an impression of the altered teeth to send to the lab. Then, temporary veneers are formed over the teeth to protect them and to keep the patient smiling. Two weeks later, the veneers are bonded to the teeth.
Porcelain veneers seem to last a long time, and porcelain does not stain (cement around the edges does stain). Patients do not usually feel veneers on their teeth. Well-planned veneers are not likely to chip or crack in normal use. Porcelain is hard enough to cause increased wear of teeth that bite against them. Excessive force can break or dislodge a veneer. Do not use a porcelain-veneered tooth to bite a fingernail, open a pistachio, or break fishing line. Broken porcelain veneers are not easy to repair; usually, they are replaced.
There are many techniques for application of composite veneers. Teeth are not always altered as for porcelain. Adhesive is painted on the teeth. Composite paste is formed directly on each tooth often using different colors and translucencies to mimic the look of natural tooth enamel. Then the veneer is hardened with a bright light. Finally, the composite is trimmed and polished
Composite veneers are more likely to stain, chip or break than porcelain. In addition, composite wears faster than natural teeth. Broken composite veneers are easy to repair. Composite veneers cost much less than the porcelain counterpart but usually don't look as good as porcelain veneers. When the length or thickness of the teeth is dramatically changed, it may take a while to become used to speaking with the newly shaped teeth. For example, saying the "f" and "v" sounds brings the edges of the upper front teeth in contact with the lower lip. Changing the size and shape of those teeth will change the distance the lower lip must travel. In a few days to a couple of weeks, lips and tongues retrain themselves to work with the newly shaped teeth.
During the design phase, it is very important for the dentist to be sure that the changes will not harm the patient. It may not be possible to straight teeth that protrude too far are overlapped or very widely spaced with veneers alone. When teeth cannot be straightened with veneers, an orthodontist can make the changes using braces or other devices. These cases may require the orthodontist and the general dentist to work together to obtain the best cosmetic result. As always, you should check with your family dentist and your orthodontist to figure out which technique or combination is best for you.
Dr. David Leader is the Chairman of the Health Advisory Committee of the Lynnfield Schools, a member of the Professional Advisory Committee of Tri-CAP Head Start, and is a member of the Mass Dental Society Council on Dental Care and Benefits Programs.