Tooth whitening is the removal of stains and discolorations from the enamel and dentin. The outer layer of the tooth is enamel, and beneath the enamel is dentin. Enamel is thin and typically much lighter in color, while dentin is darker in color and makes up the bulk of the tooth. Enamel can be discolored over time simply from age, but also from outside sources like coffee, tea, tobacco, and other foods and beverages. Also, as we age, our enamel thins, causing more dentin to show through, making the overall appearance of the tooth look darker. Whitening your teeth removes these stains and discolorations, giving you a whiter, brighter smile.