Spectroscopic and morphologic characterization of the dentin/adhesive interface

The potential environmental risks associated with mercury release have forc ed many European countries to ban the use of dental amalgam. Alternative ma terials such as composite resins do not provide the clinical function for t he length of time characteristically associated with dental amalgam. The we ak Link in the composite restoration is the dentin/adhesive bond. The purpo se of this study was to correlate morphologic characterization of the denti n/adhesive bond with chemical analyses using mitro-Fourier transform infrar ed and micro-Raman spectroscopy. A commercial dental adhesive was placed on dentin substrates cut from extracted, unerupted human third molars. Sectio ns of the dentin/adhesive interface were investigated using infrared radiat ion produced at the Aladdin synchrotron source; visible radiation from a Kr + laser was used for the micro-Raman spectroscopy. Sections of the dentin/a dhesive interface, differentially stained to identify protein, mineral, and adhesive, were examined using light microscopy. Due to its limited spatial resolution and the unknown sample thickness the infrared results cannot be used quantitatively in determining the extent of diffusion. The results fr om the micro-Raman spectroscopy and light microscopy indicate exposed prote in at the dentin/adhesive interface. Using a laser that reduces background fluorescence, the micro-Raman spectroscopy provides quantitative chemical a nd morphologic information on the dentin/adhesive interface. The staining p rocedure is sensitive to sites of pure protein and thus, complements the Ra man results. (C) 1999 Society of Photo-Optical Instrumentation Engineers. [ S1083-3668(99)00201-4].