Veneers are a common cosmetic procedure that allows patients to enhance their smile. Veneers only cover the front, visible part of your tooth; not only can they not address the tooth decay caused by a cavity, but if they are placed over an existing cavity or area of decay, the decay will continue to progress, causing the vener to fail. You may need to have the veneer removed, the cavity treated, then the veneer replaced, or, if it goes on too long, you may need to have the tooth removed entirely.    Prior to adding cosmetic veneers, it is important to first treat any cavities or other oral conditions, like gingivitis. Afterwards, a veneer can be placed for cosmetic purposes. Once you have a veneer, it is important to continue practicing good oral hygiene, including routine dental cleanings and exams, to make sure no decay develops under the veneer.