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 journalArticlepeer-review

131 Scopus citations


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
Issue number1
StatePublished - Dec 1 2019
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry
  • General Biochemistry, Genetics and Molecular Biology
  • General Physics and Astronomy


Dive into the research topics of 'The hidden structure of human enamel'. Together they form a unique fingerprint.

Cite this