title: Characterization of urethane-dimethacrylate derivatives as alternative monomers for the restorative composite matrix.
abstract: OBJECTIVE
  The aim was accomplished by a comparative analysis of the physicochemical properties of urethane-dimethacrylate (UDMA) monomers and their homopolymers with regard to the properties of basic dimethacrylates used presently in dentistry. The homologous series of UDMA were obtained from four oligoethylene glycols monomethacrylates (HEMA, DEGMMA, TEGMMA and TTEGMMA) and six diisocyanates (HMDI, TMDI, IPDI, CHMDI, TDI and MDI).
  
  
  METHODS
  Photopolymerization was light-initiated with the camphorquinone/tertiary amine system. Monomers were tested for viscosity and density. Flexural strength, flexural modulus, hardness, water sorption and polymerization shrinkage of the polymers were studied. The glass transition temperature and the degree of conversion were also discussed.
  
  
  RESULTS
  HEMA/IPDI appeared to be the most promising alternative monomer. The monomer exhibited a lower viscosity and achieved higher degree of conversion, the polymer had lower water sorption as well as higher modulus, glass temperature and hardness than Bis-GMA. The polymer of DEGMMA/CHMDI exhibited lower polymerization shrinkage, lower water sorption and higher hardness, however it exhibited lower modulus when compared to HEMA/TMDI. The remaining monomers obtained from HEMA were solids. Monomers with longer TEGMMA and TTEGMMA units polymerized to rubbery networks with high water sorption. The viscosity of all studied UDMA monomers was too high to be used as reactive diluents.
  
  
  CONCLUSIONS
  The systematic, comparative analysis of the homologous UDMA monomers and corresponding homopolymers along with their physico-mechanical properties are essential for optimizing the design process of new components desirable in dental formulations. Some of the studied UDMA monomers may be simple and effective alternative dimethacrylate comonomers.
authors.affiliation: Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, M. Strzody 9, 44-100 Gliwice, Poland. Electronic address: Izabela.Barszczewska-Rybarek@polsl.pl.
authors.forename: Izabela M
authors.initials: IM
authors.lastname: Barszczewska-Rybarek
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D003510:Cyclohexanes / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent; D055119:Elastic Modulus; D019855:Ethylene Glycol / Q000737:chemistry; D005026:Ethylene Glycols / Q000737:chemistry; D006244:Hardness; D017953:Isocyanates / Q000737:chemistry; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D009570:Nitriles / Q000737:chemistry; D018583:Pliability; D011092:Polyethylene Glycols / Q000737:chemistry; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry*; D013499:Surface Properties; D014051:Toluene 2,4-Diisocyanate / Q000737:chemistry; D044366:Transition Temperature; D014783:Viscosity; D014867:Water / Q000737:chemistry
chemical_list: C459089:2,2,4-trimethylhexanediisocyanate; C404812:4,4'-methylene dicyclohexyl diisocyanate; D003188:Composite Resins; D003510:Cyclohexanes; D003764:Dental Materials; D005026:Ethylene Glycols; D017953:Isocyanates; D008689:Methacrylates; D009570:Nitriles; D011109:Polymethacrylic Acids; D011140:Polyurethanes; D014867:Water; C015262:1,6-hexamethylene diisocyanate; C029824:urethane dimethacrylate luting resin; C020946:triethylene glycol dimethacrylate; D014051:Toluene 2,4-Diisocyanate; C028914:triethylene glycol; D011092:Polyethylene Glycols; C015301:isophorone diisocyanate; C013484:diethylene glycol; C005044:hydroxyethyl methacrylate; D019855:Ethylene Glycol
keywords: Alternative monomers; Composite resin; Degree of conversion; Glass temperature; Mechanical properties; Polymerization shrinkage; Urethane-dimethacrylate; Viscosity; Water sorption