Trimby, P., Al-Mosawi, M., Al-Jawad, M. et al. (4 more authors) (Cover date: June 2024) The characterisation of dental enamel using transmission Kikuchi diffraction in the scanning electron microscope combined with dynamic template matching. Ultramicroscopy, 260. 113940. ISSN 0304-3991
Abstract
The remarkable physical properties of dental enamel can be largely attributed to the structure of the hydroxyapatite (HAp) crystallites on the sub-micrometre scale. Characterising the HAp microstructure is challenging, due to the nanoscale of individual crystallites and practical challenges associated with HAp examination using electron microscopy techniques. Conventional methods for enamel characterisation include imaging using transmission electron microscopy (TEM) or specialised beamline techniques, such as polarisation-dependent imaging contrast (PIC). These provide useful information at the necessary spatial resolution but are not able to measure the full crystallographic orientation of the HAp crystallites. Here we demonstrate the effectiveness of enamel analyses using transmission Kikuchi diffraction (TKD) in the scanning electron microscope, coupled with newly-developed pattern matching methods. The pattern matching approach, using dynamic template matching coupled with subsequent orientation refinement, enables robust indexing of even poor-quality TKD patterns, resulting in significantly improved data quality compared to conventional diffraction pattern indexing methods. The potential of this method for the analysis of nanocrystalline enamel structures is demonstrated by the characterisation of a human enamel TEM sample and the subsequent comparison of the results to high resolution TEM imaging. The TKD – pattern matching approach measures the full HAp crystallographic orientation enabling a quantitative measurement of not just the c-axis orientations, but also the extent of any rotation of the crystal lattice about the c-axis, between and within grains. Results presented here show how this additional information highlights potentially significant aspects of the HAp crystallite structure, including intra-crystallite distortion and the presence of multiple high angle boundaries between adjacent crystallites with rotations about the c-axis. These and other observations enable a more rigorous understanding of the relationship between HAp structures and the physical properties of dental enamel.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2024 Published by Elsevier B.V. This is an author produced version of an article published in Ultramicroscopy. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Enamel; Hydroxyapatite; Biomineralisation; Transmission Kikuchi Diffraction (TKD); Pattern Matching; Dynamic Template Matching |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst of Geophysics and Tectonics (IGT) (Leeds) |
Funding Information: | Funder Grant number EPSRC (Engineering and Physical Sciences Research Council) EP/V028855/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 20 Feb 2024 15:45 |
Last Modified: | 24 Feb 2025 01:13 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.ultramic.2024.113940 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:209323 |
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Filename: TKD Dental Enamel - Accepted Manuscript.pdf
Licence: CC-BY-NC-ND 4.0