Structure-function correlative microscopy of peritubular and intertubular dentine

Research output: Contribution to journalArticle

Authors

  • Tan Sui
  • Jiří Dluhoš
  • Tao Li
  • Kaiyang Zeng
  • Adrian Cernescu
  • Alexander M Korsunsky

Colleges, School and Institutes

External organisations

  • Department of Mechanical Engineering Sciences, University of Surrey, Guildford GU2 7XH, UK. t.sui@surrey.ac.uk.
  • TESCAN Brno, s.r.o., Libušina třída 1, 623 00 Brno, Czech Republic. jiri.dluhos@tescan.cz.
  • Department of Mechanical Engineering, National University of Singapore, Singapore 117576, Singapore. peach.fish.b@gmail.com.
  • Department of Mechanical Engineering, National University of Singapore, Singapore 117576, Singapore. mpezk@nus.edu.sg.
  • Neaspec GmbH, Bunsenstr. 5, Martinsried, D-82152 Munich, Germany. adrian.cernescu@neaspec.com.
  • Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK. alexander.korsunsky@eng.ox.ac.uk.

Abstract

Peritubular dentine (PTD) and intertubular dentine (ITD) were investigated by 3D correlative Focused Ion Beam (FIB)-Scanning Electron Microscopy (SEM)-Energy Dispersive Spectroscopy (EDS) tomography, tapping mode Atomic Force Microscopy (AFM) and scattering-type Scanning Near-Field Optical Microscopy (s-SNOM) mapping. The brighter appearance of PTD in 3D SEM-Backscattered-Electron (BSE) imaging mode and the corresponding higher grey value indicate a greater mineral concentration in PTD (~160) compared to ITD (~152). However, the 3D FIB-SEM-EDS reconstruction and high resolution, quantitative 2D map of the Ca/P ratio (~1.8) fail to distinguish between PTD and ITD. This has been further confirmed using nanoscale 2D AFM map, which clearly visualised biopolymers and hydroxyapatite (HAp) crystallites with larger mean crystallite size in ITD (32 ± 8 nm) than that in PTD (22 ± 3 nm). Correlative microscopy reveals that the principal difference between PTD and ITD arises primarily from the nanoscale packing density of the crystallites bonded together by thin biopolymer, with moderate contribution from the chemical composition difference. The structural difference results in the mechanical properties variation that is described by the parabolic stiffness-volume fraction correlation function introduced here. The obtained results benefit a microstructure-based mechano-chemical model to simulate the chemical etching process that can occur in human dental caries and some of its treatments.

Details

Original languageEnglish
Article number1493
Number of pages12
JournalMaterials
Volume11
Issue number9
Early online date21 Aug 2018
Publication statusPublished - Sep 2018

Keywords

  • peritubular dentine (PTD), intertubular dentine (ITD), FIB-SEM-EDS tomography, tapping mode AFM, s-SNOM, parabolic stiffness-volume fraction correlation function