title: Ternary phase diagram of model dentin adhesive exposed to over-wet environments.
abstract: When adhesives and/or composites are bonded to the tooth, water in the environment can interfere with proper interface formation. Formation of water blisters and phase separation at the adhesive/dentin interface have appeared as new types of bond defects. To better understand this problem, we determined the near-equilibrium partition of the hydrophobic/hydrophilic components when exposed to over-wet environments. Model methacrylate-based adhesives were mixed with different amounts of water to yield well-separated aqueous and resin phases. It was found that less than 0.1% BisGMA but nearly one-third of the HEMA diffused into the aqueous phase, leaving the remaining resin phase relatively hydrophobic. A partial phase diagram was created for the ternary BisGMA/HEMA/water system. All the experimental phase partitioning data were plotted, and the points lay on a binodal curve that separated the single-phase region from the two-phase region. We obtained the 3 tie lines by connecting the 2 points of each conjugate pair of the phase partitioning data from the 3 sets of tripartite mixtures. Information about solubility, water miscibility, distribution ratio, and phase partitioning behavior could be obtained quantitatively. This type of phase diagram will provide a more thorough understanding of current adhesive performance and elucidate directions for further improvement.
authors.affiliation: Bioengineering Research Center, University of Kansas, Lawrence, KS 66045-7609, USA. yeq@ku.edu
authors.forename: Q
authors.initials: Q
authors.lastname: Ye
authors.forename: J
authors.initials: J
authors.lastname: Park
authors.forename: J S
authors.initials: JS
authors.lastname: Laurence
authors.forename: R
authors.initials: R
authors.lastname: Parthasarathy
authors.forename: A
authors.initials: A
authors.lastname: Misra
authors.forename: P
authors.initials: P
authors.lastname: Spencer
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000032:analysis; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D008689:Methacrylates / Q000032:analysis; D008956:Models, Chemical; D012995:Solubility; D014867:Water / Q000032:analysis
chemical_list: D017220:Dentin-Bonding Agents; D008689:Methacrylates; D014867:Water; D017438:Bisphenol A-Glycidyl Methacrylate; C005044:hydroxyethyl methacrylate