how long does it take baking soda to whiten teeth?

if i brush my teeth with baking soda for two minutes 2 times each day (ive heard this works well) how long will it take to whiten them?
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You need to add a little hydrogen peroxide to the baking soda so it fizzes up into a paste and then brush on. The baking soda is good at removing any stains the the HP oxidizes the teeth to whiten. The combination works well. The results are not dramatic - as you'd expect from a Zoom or other professional teeth whitening.
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