ABSTRACT
Applying 2-hydroxyethylmethacrylate (HEMA) solution to etched dentin enhances the bonding of resin to dentin. However, the principal adhesion mechanisms have not yet been identified. In this study, we examined the dissociation states of the collagen functional groups of the side-chain amino acid residues and their effects on the bond strength of resin to etched dentin primed by the HEMA solution. The bond strength was strongly dependent upon the dissociation state of the collagen functional groups. Inhibiting the dissociation of the carboxylic acid or the amine of a collagen functional group resulted in increased bond strength of resin to collagen. By understanding the significance of inhibiting the dissociation state, we can better design and develop more effective and efficient primer and bonding agents.
Subject(s)
Collagen/chemistry , Dental Bonding , Dentin-Bonding Agents/chemistry , Methacrylates/chemistry , Adhesiveness , Amino Acids/chemistry , Animals , Carboxylic Acids/chemistry , Cattle , Composite Resins/chemistry , Dentin/chemistry , Dentin Permeability , Hydrogen-Ion Concentration , Microscopy, Electron, Scanning , Protein Structure, Secondary , Resin Cements/chemistry , Structure-Activity Relationship , Surface Properties , Tensile StrengthABSTRACT
Amberlite XAD resin and activated carbon columns were tested for their abilities to concentrate trace organic pollutants in chlorinated water. Both XAD-2 and XAD-7 resin columns (20 ml) were capable of adsorbing about 30% of total organic halogen (TOX) present in 20 l of drinking water (pH 7) containing about 100 micrograms/l of TOX, whereas the carbon column (10 ml) adsorbed over 90% of TOX. The adsorption capacity of XAD-7 resin was found to be strongly dependent on the solution pH, as compared with those of XAD-2 and carbon adsorbents. Soxhlet and sonication extractions were also evaluated for their abilities to recover the adsorbed organics from the adsorbents, by measurements of TOX, chromatographable compounds and mutagenicity in the eluates. Soxhlet extraction gave higher recoveries than sonication, as measured with the above indices, but these differences were generally small (ca. 20%), with exception of the carbon extracts. The XAD-2 and XAD-7 extracts of drinking water also showed about 3-4 times higher mutagenic activity than the carbon extracts.
Subject(s)
Water Pollutants, Chemical/analysis , Water Supply/analysis , Acrylic Resins , Adsorption , Chromatography , Chromatography, Gas , Hydrocarbons, Halogenated/analysis , Hydrocarbons, Halogenated/toxicity , Hydrogen-Ion Concentration , Ion Exchange Resins , Mutagenicity Tests , Mutagens/toxicity , Polystyrenes , Salmonella typhimurium/drug effects , Salmonella typhimurium/genetics , Water Pollutants, Chemical/toxicityABSTRACT
The influences of the kinds and concentrations of the aldehydes in the primer on dentin adhesion were investigated. Moreover, the durability of the adhesion to the dentin treated with primer was examined by thermal cycling tests. Among the aldehyde tested here, glutaraldehyde was effective in improving the adhesion to dentin etched with citric acid. When HEMA was substituted with ethanol, the bond strengths decreased. The relationship between the bond strength and the concentration of glutaraldehyde in the primer was studied. In the cases of phosphoric acid or citric acid etching, the bond strengths were affected by the concentration of glutaraldehyde in the primer. The bond strengths decreased after 2000 thermocycles in phosphoric acid etching.
