Towards A 4-D Spatial and Temporal Model of Human Enamel Biomineralisation
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Precise timings and spatial progression of human enamel biomineralisation are still
largely unknown due to scarcity of developing human enamel specimens available for
investigation. This information is crucial for optimising emerging biomimetic
regenerative and reparative dentistry routes.
Five developing permanent incisors were obtained from an archaeological source and
used alongside mature contemporary teeth for comparison. X-ray microtomography
(XMT), synchrotron X-ray diffraction (S-XRD) and quantitative back-scattered
electrons (qBSE) imaging were used to investigate the mineral density distribution, the
crystallites texture magnitude and orientation and the nanostructure of dental enamel at
various developmental stages, respectively.
XMT revealed that there was a bi-directional mineralisation "front" that starts at the
cusp tip and at the enamel-dentine junction (EDJ) travelling cervically and peripherally
until the relative mineral density is uniform in the fully mature tooth (2.75 g/cm3 ±
0.01 g/cm3). S-XRD revealed that within one probed region, two populations of
crystallite orientations exist simultaneously with an angular separation of 20-50°, with
one population being more dominant than the other by a factor of approximately 3:7.
Furthermore, one population displayed a higher degree of crystallite texture than the
other. These phenomena were observed in all stages of tooth development. The
crystallites in both populations were oriented approximately perpendicular to the EDJ
regardless of development stage, indicating initial preferred directions of crystallites
persist from early through to full maturation. The direction and magnitude of
organisation within two distinct populations of crystallites within the developing and
mature enamel has not been quantified previously. qBSE analyses suggested that the
two observed populations are most likely due to prism decussation and revealed that
mineralisation of prism cores precedes that of prism boundaries.
These results provide new insights towards building a quantitative spatio-temporal
model of human enamel biomineralisation in order to inform emerging biomimetic
reparative/regenerative dental technologies.
Authors
Al-Mosawi, MohammedCollections
- Theses [4192]