A Comparative Study of the Microstructure ‐Property Relationship in Human Adult and Baby Teeth

I.M. Low, N. Duraman, J. Fulton, N. Tezuka Materials Research Group, Dept. of Applied Physics, Curtin University of Technology, Perth, WA 6845, Australia I.J. Davies Materials Research Group, Dept. of Mechanical Engineering, Curtin University of Technology, Perth, WA 6845, Australia ABSTRACT The structure-property relationship in human adult and baby teeth was characterised by grazing-incidence synchrotron radiation diffraction, optical and atomic-force microscopy, in addition to Vickers indentation. Similarities and differences between both types of teeth have been highlighted and discussed. The depth profiling of hardness indicated a gradual change in microhardness from the enamel to dentine, thus confirming the graded nature of human teeth. Vickers hardness of the enamel was load-dependent but load-independent in the dentine. The use of a “bonded-interface” technique revealed the nature and evolution of deformation-microfracture damage around and beneath Vickers contacts. INTRODUCTION Biological materials exhibit many levels of hierarchical structures from macroscopic to microscopic length scales, with the smallest building blocks in biological materials being generally designed at the nano-scale with nanometer-sized hard inclusions embedded in a soft protein matrix.