Unfortunately, Dr. Oz’s method, a mixture of lemon juice and baking soda has two problems:
1) It doesn’t whiten your teeth
2) It can destroy your tooth enamel and make you much more susceptible to decay and tooth errosion.
Lemon juice has a PH near 2, which is as acidic as the stuff in your car battery. Acid is the mortal enemy of tooth enamel. In fact, tooth decay is caused by the acids produced by oral bacteria.
When you combine the acid and the baking soda, their effects are magnified. The lemon acid starts to dissolve the outer layer of tooth enamel, making it easier for the abrasive baking soda to erode the surface.
The whitest part of your tooth is the enamel. The layer below, the dentin, is a deep yellow color. If you thin your enamel with abrasives and acid, more of the yellow dentin will show through from below.