Micromechanics of the dentin/adhesive interface.

Scanning acoustic microscopy (SAM) was used in the burst mode at 400 MHz, nominal lateral resolution 2.5 microm, to study the micromechanical properties of the dentin/adhesive interface. Corresponding specimens from the same tooth were investigated using mu Raman spectroscopy, light microscopy, and scanning electron microscopy.12 The elastic moduli of the components of the dentin/adhesive interface were determined by comparing the recorded acoustic impedance values to a calibration curve generated on standard materials. The standard materials, which include polypropylene, Teflon, PMMA, pyrex glass, aluminum, titanium, and stainless steel, provide the appropriate range of acoustic impedance values. The elastic moduli of the components of the dentin/adhesive interface are: partially demineralized dentin, 13 Gpa; mineralized dentin, 28 GPa; adhesive, 5.0 GPa; and unprotected protein at the interface < 2.0 GPa. Copyright 2001 John Wiley & Sons, Inc.