Dynamic dentin: A quantitative microscopic assessment of age and spatial changes to matrix architecture, peritubular dentin, and collagens types I and III

Arosha T Weerakoon; Nicholas Condon; Thomas R Cox; Christopher Sexton; Crystal Cooper; Ian A Meyers; David Thomson; Pauline J Ford; Sandrine Roy; Anne L Symons

doi:10.1016/j.jsb.2022.107899

Dynamic dentin: A quantitative microscopic assessment of age and spatial changes to matrix architecture, peritubular dentin, and collagens types I and III

J Struct Biol. 2022 Dec;214(4):107899. doi: 10.1016/j.jsb.2022.107899. Epub 2022 Oct 5.

Authors

Affiliations

¹ School of Dentistry, The University of Queensland, Brisbane, Queensland, Australia. Electronic address: a.weerakoon@uq.edu.au.
² Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia.
³ Garvan Institute of Medical Research & School of Clinical Medicine, UNSW, Sydney, Australia.
⁴ School of Dentistry, The University of Queensland, Brisbane, Queensland, Australia.
⁵ Central Analytical Research Facility, Queensland University of Technology, Brisbane, Queensland, Australia; Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Perth, Western Australia, Australia.
⁶ Translational Research Institute, Brisbane, Queensland, Australia; Olympus Life Science, Australia.

PMID: 36208858
DOI: 10.1016/j.jsb.2022.107899

Abstract

To investigate age and site-related changes to human dentin collagen, sound human teeth collected from donors aged 13-29 (young) and 50-74 (aged) years (n = 9/group) were cut to shallow and deep sites. Dentin collagen orientation and fibril bundling was investigated using the Picrosirius Red (PSR) stain observed under cross-polarized light microscopy (Pol), and collagen distribution was investigated using Confocal Laser Scanning Microscopy (CLSM). Collagen types III to I distribution in peritubular dentin (PTD) was revealed using Herovici stain and brightfield microscopy. Image analysis software and linear mixed modelling quantified outcomes. In situ dentin collagen was observed using Xenon Plasma Focussed Ion Beam Scanning Electron Microscopy (Xe PFIB-SEM). The PSR-Pol analysis revealed less coherently aligned and more bundled collagen fibrils in aged dentin (P = 0.005). Deep inner dentin collagen in both groups were less coherently aligned with reduced bundling. Regardless of age, CLSM showed collagen distribution remained stable; and more collagen type III was detectable in PTD located in inner dentin (Young: P = 0.006; Aged: P = 0.008). Observations following Xe PFIB-SEM cross-sectioning showed apatite-like deposits surrounding large intratubular collagen fibers, and evidence of smaller intertubular dentin collagen fibrils in situ. In conclusion, aging changes collagen network architecture, but not distribution or content.

Keywords: Aging; Collagen; Dentin; Herovici; Picrosirius red; SEM.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Collagen Type I*
Dentin
Humans
Microscopy*

Substances

Collagen Type I