Univ. of Pittsburgh, PA (United States). School of Dental Medicine, Swanson School of Engineering, Center for Craniofacial Regeneration, McGowan Inst. for Regenerative Medicine; DOE/OSTI
Univ. of Wisconsin, Madison, WI (United States)
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Lab. for Atomistic & Molecular Mechanics
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.
Beniash, Elia, et al. "The hidden structure of human enamel." Nature Communications, vol. 10, no. 1, Sep. 2019. https://doi.org/10.1038/s41467-019-12185-7
Beniash, Elia, Stifler, Cayla A., Sun, Chang-Yu, Jung, Gang Seob, Qin, Zhao, Buehler, Markus J., & Gilbert, Pupa U. P. A. (2019). The hidden structure of human enamel. Nature Communications, 10(1). https://doi.org/10.1038/s41467-019-12185-7
Beniash, Elia, Stifler, Cayla A., Sun, Chang-Yu, et al., "The hidden structure of human enamel," Nature Communications 10, no. 1 (2019), https://doi.org/10.1038/s41467-019-12185-7
@article{osti_1609806,
author = {Beniash, Elia and Stifler, Cayla A. and Sun, Chang-Yu and Jung, Gang Seob and Qin, Zhao and Buehler, Markus J. and Gilbert, Pupa U. P. A.},
title = {The hidden structure of human enamel},
annote = {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.},
doi = {10.1038/s41467-019-12185-7},
url = {https://www.osti.gov/biblio/1609806},
journal = {Nature Communications},
issn = {ISSN 2041-1723},
number = {1},
volume = {10},
place = {United States},
publisher = {Nature Publishing Group},
year = {2019},
month = {09}}
Yilmaz, Ezgi D.; Schneider, Gerold A.; Swain, Michael V.
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 373, Issue 2038https://doi.org/10.1098/rsta.2014.0130