One way to whiten teeth with baking soda is to crush a strawberry into pulp and mix it with baking soda. Apply this paste to the teeth and let it sit for five minutes before brushing and rinsing, says Health.com.
When finished, brush teeth thoroughly and use floss to remove any remaining strawberry seeds. This treatment is safe to apply once a week, according to Health.com. The malic acid in the strawberry acts as an astringent and helps remove discoloration on the surface. Baking soda buffs away stains from coffee, wine and other dark beverages. This treatment is not a replacement for professional teeth bleaching but is a cost effective solution to help brighten teeth.
While many people use this solution as a natural teeth whitener, Live Science did an experiment that showed it does not whiten teeth from the inside, explains Live Science contributor Charles Q. Choi. In the experiment, scientists used recently extracted human molars to apply the treatment. The results proved the strawberry and baking soda combination helped remove plaque buildup but did not substantially whiten teeth. The reason for this is the mixture lacks hydrogen peroxide and carbamide peroxide, the main ingredients in commercial whitening products.