VISCOELASTIC PROPERTIES OF DEMINERALIZED HUMAN DENTIN MEASURED IN WATER WITH ATOMIC-FORCE MICROSCOPE (AFM)-BASED INDENTATION

Using an atomic force microscope (AFM) with an attachment specifically designed for indentation, we measured the mechanical properties of de mineralized human dentin under three conditions: in water, in air afte r desiccation, and in water after rehydration. The static elastic modu lus (Eh(r)(h) = 134 kPa) and viscoelastic responses (tau(epsilon) = 5. 1 s and tau(sigma) = 6.6 s) of the hydrated, demineralized collagen sc affolding were determined from the standard Linear solid model of visc oelasticity. No significant variation of these properties was observed with location. On desiccation, the samples showed considerably larger elastic moduli (2 GPa), and a hardness value of 0.2 GPa was measured. Upon rehydration the elastic modulus decreased but did not fully reco ver to the value prior to dehydration (381 kPa). (C) 1998 John Wiley & Sons, Inc.