In the rush to fix people’s smiles, however, troublesome facts about straightening teeth were minimized or ignored — most significant, orthodontia’s astounding rate of relapse. From the early 1960s to the early 2000s, researchers at the University of Washington collected records from more than 800 patients who’d had their teeth straightened to see how they had fared. Orthodontists had long assumed that patients’ teeth shifted slightly but then “stabilized” after the braces came off. But the University of Washington researchers were shocked to find that fully two-thirds of patients’ teeth went crooked again after treatment.
But then, in specimens from people who lived two centuries ago or less, Monge noted a striking change: The edge-to-edge bite completely disappears, and malocclusion suddenly runs rampant. She pointed to a skull on a nearby shelf — that of a woman who lived in 19th-century North America. Unlike the ancient skulls, this postindustrial woman’s maxilla was crinkled and small; the teeth that remained sat crammed together. “I always told my students, ‘Something happened 200 years ago and nobody has an edge-to-edge bite anymore — and I have no freaking idea why,’” Monge said.