The hidden structure of human enamel

Elia Beniash, Cayla A. Stifler, Chang Yu Sun, Gang Seob Jung, Zhao Qin, Markus J. Buehler, Pupa U.P.A. Gilbert

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

Enamel is the hardest and most resilient tissue in the human body. Enamel includes morphologically aligned, parallel, ∼50 nm wide, microns-long nanocrystals, bundled either into 5-μm-wide rods or their space-filling interrod. The orientation of enamel crystals, however, is poorly understood. Here we show that the crystalline c-axes are homogenously oriented in interrod crystals across most of the enamel layer thickness. Within each rod crystals are not co-oriented with one another or with the long axis of the rod, as previously assumed: the c-axes of adjacent nanocrystals are most frequently mis-oriented by 1°–30°, and this orientation within each rod gradually changes, with an overall angle spread that is never zero, but varies between 30°–90° within one rod. Molecular dynamics simulations demonstrate that the observed mis-orientations of adjacent crystals induce crack deflection. This toughening mechanism contributes to the unique resilience of enamel, which lasts a lifetime under extreme physical and chemical challenges.

Original languageEnglish (US)
Article number4383
JournalNature Communications
Volume10
Issue number1
DOIs
StatePublished - Dec 1 2019
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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    Beniash, E., Stifler, C. A., Sun, C. Y., Jung, G. S., Qin, Z., Buehler, M. J., & Gilbert, P. U. P. A. (2019). The hidden structure of human enamel. Nature Communications, 10(1), [4383]. https://doi.org/10.1038/s41467-019-12185-7