Human dental caries is transmissible bacterial disease, which dissolves the inorganic component

from the dental hard tissues (enamel, dentine and cementum), influences the micro- and nanostructure

and mechanical properties of the teeth. To understand the change in the mechanical

properties of the teeth caused by natural and laboratory-based artificially induced dental caries,

firstly it is vital to understand how the structural arrangement at nanoscale resolution relates to the

organic/inorganic component of dental hard tissues. For this purpose, numerous studies has been

conducted using cutting-edge X-rays imaging techniques for the dental hard tissues structure

investigation. However, due to the complex 3D hierarchical structure organisation of the dentine,

there is still an understanding gap, primarily due to field of view and spatial resolution limitations.

To address these challenges, in this study first UK based advanced 3D Small-angle X-ray

scattering tensors tomography (SASTT) technique has build-up at beamline I22, Diamond Light

Source to investigate the 3D dentine structural variation due to dental caries a with a high imaging

resolution at nanoscale. 3D SASTT findings show well-defined organic/inorganics component

distribution into dentine, pronounced caries region and structure alterations. Additionally, to

explore the 3D dentine structure alteration effect on the mechanical properties of the dentine, in

situ compression micro-mechanical testing was performed on healthy and demineralised dentine.

The results of the study indicated that the strength of the demineralised dentine decreases three

times more than healthy dentine.

By understanding this relationship, the next goal was to design a new ceramic-based composites

for dental restorative applications and analyse their 3D structure distribution at the nanoscale.

Overall, this study provides valuable insight into dentine structure and mechanical properties,

which will facilitate development of high strength restorative materials to treat dental caries and

demineralised teeth in dentistry.