Bonding veneers are composed of a resin which is not as durable as the lab processed porcelain veneers and because they are a resin, they do tend to stain/ darken over time. Porcelain veneers are lab processed and are custom made to fit perfectly over the existing tooth. Both procedures require some reduction of the enamel to make room for the veneer or bonding. The porcelain veneers require two visits since lab work is involved; whereas the resin veneers may be performed in one visit.
What is the difference between resin (bonding veneers) and porcelain veneers?