Researchers from the University of Washington and the Pacific Northwest National Laboratory have examined the atomic composition of enamel samples from two human teeth—one from a 22-year-old and one from a 56-year-old.
Their study, published in Communications Materials on− Dec. 19, found that the sample from the older individual contained higher levels of fluoride, particularly in the shell regions of the enamel’s crystalline structure.
Using atom probe tomography
As we age, our teeth become more brittle, especially the outer layer, making them more susceptible to cracking. To understand why this happens, the researchers used a technique called atom probe tomography to create a 3D map of each atom in the enamel samples, Phys.org reported. This method allowed them to observe changes in mineral content at the atomic scale.
“We’re interested in understanding exactly how the mineral content is changing. And if you want to see that, you have to look at the scale of atoms,” lead author Jack Grimm, a UW doctoral student in materials science and engineering and a doctoral intern at PNNL, told Phys.org.
Co-senior author Dwayne Arola, a UW professor of materials science and engineering, added: “In the past, everything that we’ve done in my lab is on a much larger scale—maybe a tenth the size of a human hair. On that scale, it’s impossible to see the distribution of the relative mineral and organic portions of the enamel crystalline structure.”
Despite this detailed analysis, the researchers have not yet determined why the amount of protein found in enamel decreases with age, contributing to increased brittleness in teeth.
