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Nano-Mechanical Properties Across Dentin-Enamel Junction of Adult Human Incisors

Published online by Cambridge University Press:  10 February 2011

H. Fong ,
M. Sarikaya ,
S. N White  and
M. L. Snead
H. Fong
Affiliation:
Materials Science & Engineering, University of Washington, Seattle, WA 98195
M. Sarikaya
Affiliation:
Materials Science & Engineering, University of Washington, Seattle, WA 98195
S. N White
Affiliation:
School of Dentistry, University of California at Los Angeles, Los Angeles, CA 90095
M. L. Snead
Affiliation:
Center of Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA 90033
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Abstract

The structure and mechanical properties of the dentin-enamel junction (DEJ) in human teeth play a critical role in transferring stress from hard enamel to soft dentin efficiently in order to preserve the longevity of this functionally gradient biocomposite. In this investigation, nano-hardness and elastic modulus of incisor teeth were studied across the dentin-enamel junction. It was found that, over a length scale of between 15 to 25 μm, there were decreasing trends in the values of both hardness and elastic modulus across the DEJ zone profiling from enamel to dentin. Images obtained, using atomic force and scanning electron microscopy techniques, from polished surfaces of cross-sectioned teeth samples showed an interpenetrating microstructure of enamel and dentin at the DEJ zone. These results suggest that the nano-mechanical property profiles across the DEJ were due to a continuous variation in the relative amount of enamel and dentin. These characteristics of the DEJ zone could be significant for describing the structural and mechanical coupling of the two structures. By increasing the interfacial contact area across the two mineralized tissues, stresses are dissipated into the softer dentin, thus reducing interfacial stress concentrations at the DEJ. This promotes effective load transfer from the hard enamel to soft dentin.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 599: Symposium DD – Mineralization in Natural & Synthetic Biomaterials , 1999 , 85
Copyright
Copyright © Materials Research Society 2000

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