What's the Science Behind Teeth Whitening? Over the years, your teeth can become discolored by things such as poor dental hygiene, teeth grinding, tobacco, and dark-colored drinks like coffee, red wine, and soda. As you age and consume foods and beverages that are sugary or acidic, your enamel (the outer layer of teeth) weakens and thins, which allows your dentin (the underlying yellow layer of teeth) to show through. Teeth whitening agents can solve your discoloration woes by either removing surface stains from the hard shell enamel or by changing the color of the dentin. Whitening toothpastes contain mild abrasives that help remove surface stains from enamel. But to change the color of dentin and achieve a more dramatic result, your smile will require bleach-based whiteners that contain carbamide peroxide or hydrogen peroxide. These chemicals release oxygen into the teeth as they break down, making the teeth appear lighter and more like the smile of your dreams. What ...