Multiscale modelling and diffraction-based characterization of elastic behaviour of human dentine

Area of Science:

• Biomaterials Science
• Nanomechanics
• Dental Tissues

Background:

• Human dentine exhibits a complex two-level hierarchical structure influencing mechanical properties.
• Microscale tubules and nanoscale hydroxyapatite (HAp) crystallites are key structural features.
• Understanding dentine's mechanical response requires considering both micro and nanoscale structural elements.

Purpose of the Study:

• To investigate the in situ elastic strain evolution within HAp crystallites in human dentine under uniaxial compression.
• To develop and validate a multiscale model that incorporates dentine's hierarchical structure.
• To enhance the understanding of mechanical behavior in hierarchical biomaterials.

Main Methods:

• Simultaneous in situ small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) under uniaxial compression.
• Characterization of HAp crystallite strain (WAXS) and nanoscale HAp distribution (SAXS).
• Development and validation of an improved multiscale Eshelby inclusion model.

Main Results:

• WAXS quantified the apparent modulus relating external load to internal HAp strain.
• SAXS provided insights into the nanoscale HAp distribution and arrangement.
• The validated multiscale model accurately reflected dentine's structural arrangement and mechanical response.

Conclusions:

• The developed multiscale hierarchical model effectively captures the mechanical behavior of human dentine.
• This study advances the understanding of hierarchical biomaterials' mechanical properties.
• Knowledge of structure-property relationships is crucial for predicting effects of diseases or treatments on dental tissues.