The multi-scale meso-mechanics model of viscoelastic dentin

Area of Science:

• Biomaterials Science
• Mechanics of Materials
• Nanotechnology

Background:

• Human dentin exhibits complex hierarchical micro-/nano-structures.
• Dentin's mechanical properties are crucial for restorative material development.
• Understanding dentin's viscoelasticity requires multiscale analysis.

Purpose of the Study:

• To develop a multiscale micromechanics model for human dentin.
• To investigate the influence of nanostructure on dentin's elastic and viscoelastic properties.
• To analyze the effect of aging on dentin's viscoelasticity.

Main Methods:

• Established a bottom-up micromechanics model from nano- to macro-scale.
• Applied homogenization theories: random platelets composites (HTRPC) and locally-exact homogenization theory (LEHT).
• Used HTRPC for predicting effective modulus of peritubular (PTD) and intertubular dentin (ITD).

Main Results:

• Model predictions showed excellent agreement with experimental data.
• Collagen significantly contributes to dentin's viscoelasticity; hydroxyapatite (HAp) provides strength and hardness.
• Aging primarily affects dentin's loss moduli more than storage moduli.

Conclusions:

• The multiscale model accurately captures dentin's hierarchical mechanical behavior.
• Nanostructural composition dictates dentin's viscoelastic response.
• Aging significantly alters dentin's viscoelastic properties, particularly energy dissipation.