Berlin 2015 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 37: Biomaterials and Biological Materials II
MM 37.5: Vortrag
Mittwoch, 18. März 2015, 13:00–13:15, TC 006
Mapping internal mineral strains in human dentine under tension: X-ray diffraction insights into the contribution of the mineral nano-particles to the load-bearing capacity of tooth tissue — •Jean-Baptiste Forien1, Claudia Fleck2, Peter Fratzl3, and Paul Zaslansky1 — 1Julius Wolff Institut, Berlin, Germany — 2Technical University, Berlin, Germany — 3Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
Teeth are hierarchical strong and stiff structures, consisting of a mineralized protein-based composite (dentine). They function under mechanical load, and the nanometer-sized hydroxyapatite mineral particles in the collagen fiber matrix deform as a response to applied external stress (Deymier-Black,2012). In this study, we report on the mineral response in human dentine to mechanical tensile testing. We track mineral particles following changes in the mineral dimension using X-ray diffraction. It is thus possible to compare the stresses experienced by the mineral particles with the stress applied by the external load. We find that the tissue to mineral strain ratios observed increase until they reach a value of 2, which is three times lower than for bone (Gupta,2006), and suggests that a different load-partitioning mechanism exists in teeth. We also find that the Poisson's ratio decreases with increasing load, suggesting that as load increases, there is some dynamic change in the loads transferred to the crystals, similar to what was found for bovine dentine loaded in compression. With increasing load, more strain-energy is orientated along the tensile axis and less is distributed into particles oriented along other orientations.