Beavers have a pigmented enamel containing iron built into the chemical structure of their teeth that could provide insight into understanding human tooth decay, according to a new Northwestern study.

McCormick Prof. Derk Joester, lead author of the study, found the enamel’s acid resistance is controlled by the material surrounding nanowires, the core structure of enamel that has small amounts of iron and magnesium.

“We have made a really big step forward in understanding the composition and structure of enamel — the tooth’s protective outer layer — at the smallest length of scales,” Joester said in a news release.

Joester and his team imaged the structure that surrounds nanowires using atom-probe tomography to create a detailed map of the enamel’s structure. When they subjected teeth to acid exposure, they found the area around the nanowires dissolved, not the nanowires themselves.

They then identified the minerals in the enamel and saw how they helped protect against acid.

“A beaver’s teeth are chemically different from our teeth, not structurally different,” Joester said in a news release. “Biology has shown us a way to improve on our enamel.”

This strategy of “grain boundary engineering,” focusing on the area surrounding the nanowires, provides more information on how scientists can improve fluoride treatment, Joester said.

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