Modern industrialized societies are plagued by crowded, ill-aligned teeth, a condition that the dental profession refers to as “malocclusion”—which translates literally to “bad bite.” Survey data from 1998 suggests that as much as a fifth of the U.S. population has significant malocclusion, over half of which require at least some degree of orthodontic intervention. Braces, tooth extractions, and retainers are the bread and butter for all the dentists and orthodontists tasked with setting straight our dental deviations. Having braces as a child has become so common in the Western world that it can seem a rite of passage—today, an estimated 50 to 70 percent of U.S. children will wear braces before adulthood. But what did humans do to fix their teeth before modern dentistry, before Novocain, gauze, and rubber spacers?

As it turns out, our ancestors did not suffer from crooked teeth to the same extent that we do today. Our species’ fossil record reveals a telling story: the epidemic of crooked teeth developed in humans over time. Evolutionary biologist, Daniel Lieberman, notes the pattern in his book, The Story of the Human Body:

Ample evidence abounds in support of Lieberman’s observations. A comparison of 146 medieval skulls from abandoned Norwegian graveyards with modern skulls indicated a trend toward bad bite in our more recent forebears. The skulls of people scored as being in “great” or “obvious” need of orthodontic treatment made up 36 percent of the medieval sample and 65 percent of the modern sample. And evidence of malocclusion in still earlier human fossils is vanishingly rare. The jaws of hunter-gatherers nearly uniformly reveal roomy, perfect arches of well aligned teeth, with no impacted wisdom teeth—a movie star’s dream smile, 15,000 years before the movies!