How Bonding Responds to Color
Almost everyone has dealt with stains on their teeth at one time or another. Surface stains are caused by contact with common, everyday foods and beverages like tea or coffee. If you smoke regularly, your teeth may have either brown or yellow stains from contact with nicotine. Teeth whitening is an effective and simple way to remove these types of imperfections.
Whitening bonded teeth, however, comes with its own set of exceptions. The resin used for bonding, as described by the University of Iowa College of Dentistry, neither stains nor whitens as easily as natural enamel, but it can suffer discoloration over a period of time. Why doesn't it respond as well to tooth-whitening treatments? Because the bonding resin is nonporous, unlike tooth enamel. Stains form when the staining agents penetrate the pores of the teeth, and because porcelain and bonding resin are both nonporous, they don't change color, however, they can become stained. So although bonded teeth can stain, they also don't whiten. If the bonded portion of your tooth does become discolored, you may find it more difficult to treat successfully.