If you’re an adult human, odds are you already know a thing or two about tooth regeneration. Around age six, most of us begin to lose baby teeth in a process called eruption, exchanging our delicate, first set for more burly, permanent teeth. The phenomenon calls to mind the critters that continuously regrow their chompers — for example, sandbar sharks, which sprout tens of thousands of serrated teeth over time; and rabbits, whose incisors grow continuously as they’re worn down by roughage. If fish, bunnies, and kiddos do it in their sleep, then why don’t adults naturally expel their aging molars with shiny, new replacements? And on that note, just how close is science to making such a feat a reality? Please, I feel a toothache coming on…
Off the bat, why don’t we do this already? To better understand what we’re up against in this toothy quest, Dr. Ophir Klein—a professor of orofacial sciences and pediatrics at the University of California, San Francisco—offered Popular Science a brief history lesson.
Long ago, before celebrity veneers, bleach kits, or even dental floss, “animals diverged into invertebrates and vertebrates,” explained Klein. At the time, hundreds of millions of years ago, “the earliest vertebrates [were] sort of reptile-like creatures,” and “mammals came out of that, as did dinosaurs and birds and amphibians.”
[ Related: Why do humans have toenails? Because we’re evolutionary ‘weirdos.’ ]
As fate would have it, Klein explained, “teeth became an integral part of the vertebrate mouth,” but it’s “not exactly clear where they originated,” he added—“whether they started inside the mouth or whether they started as scales, like fish have, that migrated from outside to inside.” Okay, gross! We know these early teeth were simple, and they might’ve been somewhat like the teeth we see in fish today. “If you open a salmon’s mouth, all the teeth are the same and they’re…
Read the full article here
