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The hidden structure of human enamel
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...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group UK
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6763454/ https://www.ncbi.nlm.nih.gov/pubmed/31558712 http://dx.doi.org/10.1038/s41467-019-12185-7 |
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author | Beniash, Elia Stifler, Cayla A. Sun, Chang-Yu Jung, Gang Seob Qin, Zhao Buehler, Markus J. Gilbert, Pupa U. P. A. |
author_facet | Beniash, Elia Stifler, Cayla A. Sun, Chang-Yu Jung, Gang Seob Qin, Zhao Buehler, Markus J. Gilbert, Pupa U. P. A. |
author_sort | Beniash, Elia |
collection | PubMed |
description | 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. |
format | Online Article Text |
id | pubmed-6763454 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | Nature Publishing Group UK |
record_format | MEDLINE/PubMed |
spelling | pubmed-67634542019-09-30 The hidden structure of human enamel Beniash, Elia Stifler, Cayla A. Sun, Chang-Yu Jung, Gang Seob Qin, Zhao Buehler, Markus J. Gilbert, Pupa U. P. A. Nat Commun Article 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. Nature Publishing Group UK 2019-09-26 /pmc/articles/PMC6763454/ /pubmed/31558712 http://dx.doi.org/10.1038/s41467-019-12185-7 Text en © The Author(s) 2019 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. |
spellingShingle | Article Beniash, Elia Stifler, Cayla A. Sun, Chang-Yu Jung, Gang Seob Qin, Zhao Buehler, Markus J. Gilbert, Pupa U. P. A. The hidden structure of human enamel |
title | The hidden structure of human enamel |
title_full | The hidden structure of human enamel |
title_fullStr | The hidden structure of human enamel |
title_full_unstemmed | The hidden structure of human enamel |
title_short | The hidden structure of human enamel |
title_sort | hidden structure of human enamel |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6763454/ https://www.ncbi.nlm.nih.gov/pubmed/31558712 http://dx.doi.org/10.1038/s41467-019-12185-7 |
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