Of all the different types of bacteria that live in your mouth, the most pungent, by far, are a kind called "gram-negative
." Not only do they produce gassy-smelling sulfuric compounds, but they also have an extra cell layer that makes them especially resilient. They burrow down below the gum line and hide out in the crevices of the tongue. Flossing helps remove them, but another option is brushing your tongue, which has been shown to reduce bad breath by 70 percent
. Clean your entire tongue, especially the back where more there are more peaks (or papillae) and valleys, as well as the cheeks, recommends Gary H. Westerman DDS, a professor of dentistry at Creighton University. You can also use a toothbrush or a drugstore tongue-brush, but an Orabrush
—yes, the thing you've seen on YouTube—has longer, softer bristles as well as a scraper to collect the bacteria once it's been dislodged.