Researchers Map Enamel at the Atomic Level to Stop Decay

Richard Gawel


Dentists can use today’s latest imaging technologies to spot tooth decay in its earliest stages. But researchers at the University of Sydney may have them beat with atom probe tomography, producing the first 3-D maps showing the positions of critical atoms in the composition and structure of enamel during the decay process.

“The dental professionals have known that certain trace ions are important in the tough structure of tooth enamel, but until now it had been impossible to map the ions in detail,” said Julie Cairney, PhD, a material and structures engineer with the faculty of engineering and information technologies at the university.

“The structure of human tooth enamel is extremely intricate, and while we have known that magnesium, carbonate, and fluoride ions influence enamel properties, scientists have never been able to capture its structure at a high enough resolution or definition,” Cairney said.

The researchers have found the magnesium-rich regions between the hydroxyapatite nanorods that make up the enamel, providing the first direct evidence of an amorphous magnesium-rich calcium phosphate paste that plays an essential role in governing tooth behavior.

“We were also able to see nanoscale ‘clumps’ of organic material, which indicates that proteins and peptides are heterogeneously distributed within the enamel rather than present along all the nanorod interfaces, which was what was previously suggested,” said Alexandre La Fontaine, PhD, of the university’s Australian Centre for Microscopy and Microanalysis.

“The mapping has the potential for new treatments designed around protecting against the dissolution of this specific amorphous phase,” said La Fontaine. “The new understanding of how enamel forms will also help in tooth remineralization research.”

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