M. D. D'Emic et al., PLoS ONE (2013); (Illustration, bottom) Dmitry Bogdanov/Creative Commons

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ScienceShot: Hard Food Better for Your Teeth

When people say "use it or lose it," they're usually not referring to your teeth. But a specific pattern of dental wear and tear has increased dramatically over the past hundred years, and new research suggests that, paradoxically, the soft, highly refined diet of today may be to blame. "Noncarious cervical lesions," or wedge-shaped divots at the gum line (pictured), are found in up to 85% of dental patients. Although not always troublesome, the lesions can be unsightly and painful and can set the stage for tooth decay. Based on archaeological evidence, this type of lesion is a uniquely modern problem: Human teeth from prehistoric and preindustrial times rarely show such damage. While some experts blame erosion from cola drinking or even zealous tooth brushing, others feel that modern teeth simply don't get the workout that they were designed for. Researchers tested the latter theory by creating casts of 19th century molars, which they put through a variety of computer-simulated chewing scenarios. They then used fingerprinting imaging techniques to scan the pattern of wear. When the teeth were artificially worn down, the stress was distributed across the surface of the tooth (inset), resulting in a lighter load overall. The study confirms the idea that the crunchier, less refined diet of earlier times—including more whole foods, nuts, seeds, and general grit— was actually easier on the teeth and may have even influenced the way human teeth evolved.

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