Veneers are very thin shells that are attached to the front part of teeth. They are often made of porcelain or composite resin. Porcelain veneers are stronger than composite resin veneers and do not change colour or stain. Generally, porcelain veneers take at least 2 dental visits to apply and composite resin veneers can be done in 1 visit. Porcelain veneers generally last longer than composite resin veneers.