title: Quantitative analysis of adhesive resin in the hybrid layer using Raman spectroscopy.
abstract: The objective was to determine absolute molar concentration of adhesive resin components in the hybrid layer by establishing methods based on Raman spectroscopy fundamentals. The hybrid layer was treated as a three-component system consisting of collagen and an adhesive resin containing two monomers. Adhesive standard specimens and Raman peak area ratios obtained with a 785 nm excitation wavelength were used to construct separate calibration curves for comonomer relative molar concentration and Bis-GMA absolute molar concentration. As collagen and water had no measurable peaks in the fingerprint region, a dilution coefficient K(j) was defined to describe their impact on Raman peak area and to calculate HEMA absolute molar concentration. Methodology was validated using an analogous system containing acetone/ethanol/water. The absolute molar concentration of Bis-GMA and HEMA decreased 87% and 83%, respectively, from the top quarter to the middle of the hybrid layer. Additionally, less Bis-GMA penetrated the hybrid layer than HEMA, as indicated by the approximately 20% decrease in comonomer molar concentration ratio between the adhesive resin layer and the top half of the hybrid layer. Lack of complete monomer infiltration will further challenge dentin-adhesive bond longevity. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.
authors.affiliation: Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zou
authors.forename: Steven R
authors.initials: SR
authors.lastname: Armstrong
authors.forename: Julie L P
authors.initials: JL
authors.lastname: Jessop
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000032:analysis*; D003804:Dentin / Q000737:chemistry / Q000166:cytology*; D017220:Dentin-Bonding Agents / Q000032:analysis*; D008422:Materials Testing; D008689:Methacrylates / Q000032:analysis*; D019279:Resin Cements / Q000032:analysis*; D013059:Spectrum Analysis, Raman / Q000379:methods
chemical_list: D001672:Biocompatible Materials; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D019279:Resin Cements; D017438:Bisphenol A-Glycidyl Methacrylate; C005044:hydroxyethyl methacrylate