If you like to keep your teeth enamel, but still wish to whiten your teeth, there are ways besides the products you find in the tooth paste isle. One of the best at home teeth whiteners is Baking Soda!
If you puree two strawberries into a dish and mix with baking soda until you get the consistency of a paste (around 1 tsp), than take a cotton ball and dip in the paste and rub it on your teeth. leave on for 5 min and rinse. After this is done you should always brush your teeth. The strawberries contain natural sugars that could result in cavities if left on the teeth.