Veneers are very thin shells that are attached to the front part of the teeth. They are often made out 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 two dental visits to apply and composite veneers can be done in one visit. Porcelain veneers generally last longer than composite veneers.