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Graded microstructure and mechanical properties of human crown dentin
W Tesch1, N Eidelman, P Roschger
1Ludwig Boltzmann Institute of Osteology, 4th Medical Department, Hanusch Hospital, Vienna, Austria.
Calcified Tissue International
|October 31, 2001
Summary
Human coronal dentin exhibits varying mechanical properties, with mineral content and crystal thickness predicting hardness. This gradient material structure near the dentin-enamel junction optimizes crack resistance.
Area of Science:
- Biomaterials Science
- Dental Biomechanics
- Materials Science
Background:
- Intertubular dentin is a collagen-mineral composite.
- Significant local variations in mechanical properties exist within dentin.
Purpose of the Study:
- To investigate correlations between local mechanical properties and mineral characteristics in human coronal dentin.
- To understand how mineral density, size, and crystallinity influence dentin's mechanical behavior.
Main Methods:
- Utilized complementary techniques: Fourier-transform infrared microspectroscopy in reflectance mode (FTIR-RM), small-angle X-ray scattering (SAXS), quantitative backscattered electron imaging (qBEI), and atomic force microscope Nanoindentation.
- Performed area scans on human coronal dentin specimens.
Main Results:
- Mineral content decreased, while mineral crystal thickness increased towards the dentin-enamel junction (DEJ).
- Hardness and elastic modulus showed a decrease towards the DEJ.
- Mineral content and, notably, mineral crystal thickness were identified as key predictors of hardness.
Conclusions:
- Dentin exhibits a gradient material structure near the DEJ, with decreasing hardness and elastic modulus.
- This gradient configuration effectively impedes crack propagation.
- Crown dentin is optimized for mechanical function through variations in its structural and mechanical properties.