Veneers are used on teeth with uneven surfaces or that are chipped, discolored, oddly shaped, unevenly spaced or crooked. Little or no anesthesia is needed. Veneers may have a longer life expectancy and color stability than bonding, and will likely resist permanent staining from coffee, tea, or even cigarette smoking better than bonding.
Veneers are usually irreversible because in most cases it is necessary to remove a small amount of enamel from your teeth to accommodate this thin shell. When using veneers to close a gap or replace a fractured corner, the additional area being filled in is simply solid porcelain with the shell portion being what actually holds it to the tooth. When used to change the color of a tooth, the veneer is made lighter than the final shade selected such that what shows through, tooth and bonding composite, when combined with the shade of the veneer shell gives the desired outcome.
Typically, veneers entail at least three appointments: diagnosis and treatment planning, preparation/impression, and placement/bonding. The veneer itself is generally made at a dental laboratory off premises. Bonding, in which tooth colored filling material only is used, can be done in two visits as the preparation and placement appointments are the same.
During the placement appointment, slight modifications can be made in color by varying the shade of the bonding resin after first trying in just the veneer with water or glycerin. Adjustments to shape are done after being bonded into place. Until it is bonded to a solid substructure, the veneer isn’t very strong. Veneers are held in place by a tooth colored composite filling material sandwiched between the enamel of the tooth and the veneer itself. When both surfaces were properly prepared, each has a microscopic surface roughness that allows the bonding material to flow into and once cured it is locked into place.
One thing to keep in mind with veneers is that just like natural tooth, they can fracture or the bonding composite can fail and the entire veneer comes off. All is not necessarily lost should you find yourself in this situation. Sometimes they can be cleaned up and re-bonded or repaired.