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Energy absorption characterization of human enamel using nanoindentation
Author(s) -
He Li Hong,
Swain Michael V.
Publication year - 2007
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.31051
Subject(s) - materials science , enamel paint , nanoindentation , composite material , nanoindenter , indentation , tooth enamel , penetration depth , optics , physics
Enamel is a natural composite, which has much higher toughness than its major component, crystalline hydroxyapatite. In this study, the energy absorption behavior of human sound enamel was investigated with nanoindentation techniques. A UMIS nanoindenter system as well as a Berkovich and two spherical indenters with nominal tip radii of 5 and 20 μm were used to indent enamel at different loading forces in the direction parallel to enamel prisms. Inelastic energy dissipation versus depth of indenter penetration ( U %– h p curve) as well as a function of indentation strain ( U %– ε curve) of enamel was determined. Enamel showed much higher energy absorption capacity than a ceramic material with equivalent modulus (fused silica). Even at the lowest forces (1 mN) for the 20 μm indenter, inelastic response was found. Additional tests done at different force loading rates illustrated that load rate has little influence on P – h response of enamel. The top surface of enamel has the plastic work of indentation of ∼5.2 nJ/μm 3 . The energy absorbing ability is influenced by the very small protein rich component that exists between the hydroxyapatite nanocrystals as well as within the sheath structure surrounding the enamel rods. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007