Well, don’t expect it to clear away 20-years’ worth of yellow from cigarettes, but it can scrub away daily coffee and wine stains. That’s from the UCLA School of Dentistry. A lot of whitening gums contain baking soda, which polishes teeth. But really, ANY gum can help erase superficial stains. Because it’s really your saliva doing most of the work. Chewing gum increases the output of saliva – and saliva is antimicrobial – so it kills bacteria and washes away debris that can stain teeth.