Bonding and veneers are similar though distinct cosmetic dental procedures that can repair damaged, decayed or misshapen teeth, as well as improve the appearance of healthy teeth.
Both procedures may be done by dentists or by prosthodontists – dentists who specialize in replacement of healthy tooth enamel and tissue with manmade materials.
Bonding, the less-invasive procedure, is done to whiten, to make minor repairs to teeth, and to reduce spaces between teeth using a tooth-coloured composite resin. Usually accomplished in a single visit, resin application is done after the dentist applies a mild phosphoric solution to roughen the surface of the tooth or teeth to be bonded.
The rougher surface allows the resin to adhere, or bond, more solidly to the tooth. The resin is molded to the desired shape and hardened using a high-intensity light. The dentist will carefully choose a shade of resin that matches the other teeth.
Veneers are extremely thin shields, often made of porcelain or composite resin, that cover the top and front of the tooth. Porcelain veneers are stronger than composite resin veneers, last longer, resist staining and discolouration, and require less enamel removal for placement. Porcelain veneers are more expensive than their resin counterparts, and their application usually takes two or more visits, compared to one visit to apply composite resin veneers.
When porcelain veneers are applied, the dentist removes a very thin layer of enamel from the front of the teeth under a local anesthetic, in order to make sufficient room for the veneers. A mold of the teeth is then cast, and thin, delicate temporary veneers are placed for the patient to wear until the custom-made porcelain veneers are ready.
The temporary veneers must be worn and treated with care, as they are much more delicate than the permanent porcelain veneers that will be the end product.
At the following visit, the dentist takes off the temporary veneers and chemically roughens the enamel surface, much like during the bonding process. Strong dental cement is then used to glue the permanent porcelain veneers tightly to the teeth one at a time, so precisely that a they should be undetectable to a layperson.
Some people are better candidates for veneers than others. Those who are suffering from decay or gum disease in the treatment area need to address those problems before having veneers placed.
Others who may want to avoid veneers include those with significant enamel loss, who may not have enough enamel left to attach the veneers properly – crowns may be a better choice for those who are missing too much of a natural tooth. Those who grind or clench their teeth may damage the veneers in the process.
Veneer application is not a reversible process, because of the removal of enamel in order to place them onto the teeth. Damaged veneers will need to be replaced, rather than removed entirely. When applied to healthy teeth, veneers may actually increase their overall strength.