Forget about the braces, the veneers, the whitening strips and even the breath fresheners.

A study in the journal Globalization and Health reports that a mere eighth of the global population is benefitting from fluoride toothpaste.

Part of the problem, it seems, is the cost. In Zambia, for example, the researchers found that people have to choose between paying for 11 days’ worth of household expenses or buying a year’s worth of toothpaste for just one person.

So while brushing one’s teeth is a great way to ensure morning breath doesn’t last all day, it’s more satisfying to clean one’s mouth after something’s passed through there on its way to the belly.