Late nights and early mornings, Americans on average drink 3.5 cups of coffee a day. Factor in all of the soda, teas, and other delicious drinks your teeth are going through a lot! Any drink that is colored especially coffee & tea have the ability to stain your teeth yellowing them over time.
Mere brushing is not enough to remove the stains. The tannins that are found in coffee, tea, and wine cause color compounds to stick to the enamel on your teeth leaving behind a yellow tint when brushed away.