title: Chemical profile of adhesive/caries-affected dentin interfaces using Raman microspectroscopy.
abstract: In clinical practice, dentists must frequently bond adhesives to caries-affected dentin substrates, but the bond that characteristically forms with these substrates does not provide the durability necessary for long-term clinical function. The purpose of this study was to characterize and compare the interfacial chemistry of adhesive with caries-affected and noncarious dentin using micro-Raman spectroscopy. The results indicated that the differences in the Raman spectra between noncarious and caries-affected dentin could not be accounted for by simple decreased mineralization. Both the structure of collagen and mineral in the caries-affected dentin has been altered by the caries process. The differences in structure and composition not only interfered with acid-etching process but also subsequent resin monomer penetration. It was shown that the interface between the adhesive and caries-affected dentin was wider and more complicated than that of the adhesive and noncarious dentin. As a result of adhesive phase separation, a structurally integrated hybrid layer did not form at the interface with either caries-affected or noncarious dentin. Using chemical imaging techniques, this study provides the direct evidence of adhesive phase separation at the interface with caries-affected dentin. Although our group previously reported adhesive phase separation at the interface with noncarious dentin, the chemistry of caries-affected dentin leads to greater variability and a more highly irregular composition along the length and breadth of the interface.
authors.affiliation: Department of Oral Biology, University of Missouri-Kansas City School of Dentistry, Kansas City, MO, USA. Wangyo@umkc.edu
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Paulette
authors.initials: P
authors.lastname: Spencer
authors.forename: Mary P
authors.initials: MP
authors.lastname: Walker
mesh_terms: D000328:Adult; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003731:Dental Caries / Q000378:metabolism* / Q000628:therapy; D003804:Dentin / Q000737:chemistry*; D017220:Dentin-Bonding Agents / Q000737:chemistry* / Q000627:therapeutic use; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D013059:Spectrum Analysis, Raman
chemical_list: D017220:Dentin-Bonding Agents; D008689:Methacrylates; D017438:Bisphenol A-Glycidyl Methacrylate; C005044:hydroxyethyl methacrylate