Small pieces of padding put on top of real, shaved-down teeth are veneers. Almost always, this method is irreversible. There’s no turning back once you decide that veneers are the way to go.

The tooth below remains alive and well. But it does have to be filed down a large portion of it. And that’s a lot for the two most popular veneer forms, composite and porcelain.

Who is a good candidate for veneers?

Generally, veneers are a decorative technique. For teeth that are, they are recommended:

crooked,
irregularly shaped,
worn-down,
affected by decay or disease ,
discolored,
chipped,
misaligned,
or injured in an accident.

If you do not have missing teeth (at the place where you want veneers), serious periodontal disease, or substantial decay, you are a successful candidate. There is a disease, however. Your enamel has to be sufficiently stable to sustain it.

Source: https://www.authoritydental.org/veneers