Acousto-electromagnetic properties of human dentin

Scanning acoustic microscopy (SAM) near-field scanning microwave microscopy (NSMM), micro-Raman spectroscopy (μRS), atomic force microscopy (AFM), and scanning electron microscopy (SEM) were used to study dentin, its demineralization, and its interface and bonding with epoxy and adhesives. SAM yielded information regarding micro-mechanical properties of dentin and its interface while μRS provided information regarding the curing state of the epoxy and presence of contaminants at the dentin/epoxy interface. NSMM, a new technique developed in our laboratory, provided information regarding the interface conductivity and permittivity that are related to density, presence of ionic species and among other factors. Simultaneously performed with AFM, NSMM provided interesting complementary information regarding dentin and epoxy system. Owing to the large penetration depth of its sensing signal in most biological materials, NSMM is capable of imaging sub-surface non-uniformity the scanned surfaces. We report preliminary findings indicating complementary and corroborating natures of SAM, NSMM, μRS, and AFM