Teeth whitening is a simple process. Whitening products contain one of two tooth bleaches (hydrogen peroxide or carbamide peroxide). These bleaches break stains into smaller pieces, which makes the color less concentrated and your teeth brighter.

No, which is why it’s important to talk to your dentist before deciding to whiten your teeth, as whiteners may not correct all types of discoloration. For example, yellow teeth will probably bleach well, brown teeth may not respond as well and teeth with gray tones may not bleach at all. Whitening will not work on caps, veneers, crowns or fillings. It also won’t be effective if your tooth discoloration is caused by medications or a tooth injury.