
AsianScientist (Sep. 14, 2016) – Researchers from Australia have identified some nanoscale elements that govern the mechanical behavior of our teeth. The study has been published in Science Advances.
Human dental enamel, the hardest tissue in the body, plays a vital role in protecting teeth from wear and tear. Its mechanical strength and fatigue resistance are derived from its periodically arranged bundles of hydroxyapatite (HAP) nanorods. However, scientists do not fully understand how HAP crystallizes to form this structure, nor how magnesium (Mg2+) ions, which regulate HAP crystallization, are distributed within the HAP nanorods.
In the present study, a team of engineers and dentists led by Professor Julie Cairney from the University of Sydney used a relatively new microscopy technique called atom probe tomography to map the exact composition and structure of tooth enamel at the atomic scale.
The researchers found magnesium-rich elongated precipitates and nanoscale ‘clumps’ of organic material distributed between the HAP nanorods in mature human dental enamel, indicating that proteins and peptides are distributed within the enamel, rather than along all the nanorod interfaces.
“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. What we have found are the magnesium-rich regions between the hydroxyapatite nanorods that make up the enamel,” said Cairney.
Their findings, which suggest that decay occurs via dissolution of this magnesium-rich region, may help in tooth remineralization research, the researchers say.
The article can be found at: La Fontaine et al. (2016) Atomic-scale Compositional Mapping Reveals Mg-rich Amorphous Calcium Phosphate in Human Dental Enamel.
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Source: University of Sydney; Photo: Pixabay.
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