DIY teeth whitening. Try at your own risk. Wedding-day white teeth! My dentist actually told me about this. Use a little toothpaste, mix in one teaspoon baking soda plus one teaspoon of hydrogen peroxide, half a teaspoon water. Thoroughly mix then brush your teeth for two minutes. Remember to do it once a week until you have reached the results you want. Once your teeth are good and white, limit yourself to using the whitening treatment once every month or two.