title: Sorption of water, ethanol or ethanol/water solutions by light-cured dental dimethacrylate resins.
abstract: OBJECTIVE
  This work is concerned with the study of the sorption and desorption process of water, ethanol or ethanol/water solution 50% (v/v) or 75% (v/v) by the dental resins prepared by light curing of Bis-GMA, Bis-EMA, UDMA, TEGDMA or D₃MA.
  
  
  METHODS
  A thin resin disc is placed in a bath of time to obtain the sorption curve m(t)=f(t). Then the liquid is desorbed until a constant mass for the disc is reached and the desorption curve is recorded. These experimental curves help in the determination of the sorbed/desorbed liquid amount at equilibrium, the percentage of the extracted mass of unreacted monomer known as "solubility", and the sorption/desorption diffusion coefficient which expresses correspondingly the rate of the liquid sorption/desorption.
  
  
  RESULTS
  The highest liquid uptake by dental resins was 13.3wt% ethanol for Bis-GMA-resin, 12.0wt% ethanol for UDMA-resin, 10.10wt% ethanol/water solution for TEGDMA-resin, 7.34wt% ethanol for D(3)MA-resin and 6.61wt% ethanol for Bis-EMA-resin. The diffusion coefficient for all resins was higher in water than in ethanol/water solution or ethanol. Bis-GMA-resin showed the highest diffusion coefficient (11.01 × 10⁻⁸cm² s⁻¹) followed by Bis-EMA-resin (7.43 × 10⁻⁸ cm² s⁻¹), UDMA-resin (6.88 × 10⁻⁸cm² s⁻¹), D(3)MA-resin (6.22 × 10⁻⁸ cm² s⁻¹) and finally by TEGDMA-resin (1.52 ×10⁻⁸ cm² s⁻¹).
  
  
  CONCLUSIONS
  All studied dental resins, except TEGDMA-resin, absorbed higher amount of pure ethanol than water or ethanol water solution. TEGDMA-resin absorbed higher amount of ethanol/water solution (50/50 or 75/25 (v/v)) than water or ethanol. For all studied dental resins the diffusion coefficient was higher in water than in ethanol/water solution or ethanol.
authors.affiliation: Laboratory of Organic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Greece. siderid@chem.auth.gr
authors.forename: Irini D
authors.initials: ID
authors.lastname: Sideridou
authors.forename: Maria M
authors.initials: MM
authors.lastname: Karabela
mesh_terms: D000042:Absorption; D000180:Acrylic Resins / Q000737:chemistry*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003890:Desiccation; D004058:Diffusion; D000431:Ethanol; D057927:Hydrophobic and Hydrophilic Interactions; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D012995:Solubility; D014867:Water
chemical_list: D000180:Acrylic Resins; D008689:Methacrylates; D011109:Polymethacrylic Acids; D011140:Polyurethanes; C524844:decamethylenediol dimetacrylate; D014867:Water; C029824:urethane dimethacrylate luting resin; C020946:triethylene glycol dimethacrylate; C041979:2,2-bis-(4-(2-methacryloxyethoxy)phenyl)propane; D000431:Ethanol; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate