How quickly can using baking soda whiten teeth?

I use baking soda right after brushing about 2-4 time a week. Will my teeth whiten slowly? Should I use the baking soda more often without brushing my teeth? How does baking soda take off stains anyway, the abbrasiveness?
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Baking soda can be very abrasive & only works on the stain on the top layer of your teeth. It cannot alter the stain that exists in the multiple layers of enamel or deep with the tubules that make up the enamel. Only professional whitening products will alter the whiteness & remove the deep stains that were created years ago.
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