Structure-Function Correlative Microscopy of Peritubular and Intertubular Dentine

Area of Science:

• Biomaterials Science
• Nanotechnology
• Dental Research

Background:

• Peritubular dentine (PTD) and intertubular dentine (ITD) are key structural components of human dentine.
• Understanding their microstructural differences is vital for dental health and treatment.

Purpose of the Study:

• To investigate the microstructural and chemical differences between PTD and ITD.
• To correlate these differences with mechanical properties.
• To develop a microstructure-based model for dental caries simulation.

Main Methods:

• 3D correlative Focused Ion Beam (FIB)-Scanning Electron Microscopy (SEM)-Energy Dispersive Spectroscopy (EDS) tomography.
• Tapping mode Atomic Force Microscopy (AFM).
• Scattering-type Scanning Near-Field Optical Microscopy (s-SNOM) mapping.

Main Results:

• PTD shows higher mineral concentration than ITD via SEM-BSE imaging.
• Ca/P ratio is similar between PTD and ITD.
• AFM reveals larger hydroxyapatite (HAp) crystallites in ITD (32 ± 8 nm) than in PTD (22 ± 3 nm).
• The primary difference lies in nanoscale crystallite packing density, with a moderate chemical composition contribution.

Conclusions:

• Dentine's structural heterogeneity arises from nanoscale crystallite arrangement and packing density.
• This structural difference dictates mechanical properties, explained by a novel stiffness-volume fraction correlation.
• Findings support microstructure-based modeling for simulating dental caries and treatments.