title: Novel light-cured resins and composites with improved physicochemical properties.
abstract: OBJECTIVE
  The aim of this study was to determine the effect of two new diluent agents (Bis-GMA analogues), at different dilution levels and filler contents on relevant physicochemical properties of several novel resins and composites containing Bis-GMA as matrix. Composites using TEGDMA as diluent were used as control.
  
  
  METHODS
  Twenty formulations were prepared combining three monomer mixtures (Bis-GMA/TEGDMA, Bis-GMA/CH(3) Bis-GMA and Bis-GMA/CF(3) Bis-GMA), at three dilution levels (85/15, 10/90, 0/100) and two percentages of filler loading (silanated barium aluminosilicate glass): 0%, 10%, 35%. Preliminary rheological testing was performed in order to obtain the viscosity of the resin samples. Resins and composites were then inserted into molds and light-cured (500mW/cm(2)). The properties evaluated were: (1) homogeneity of curing (HC), using FTIR or Vickers microindentor, (2) microhardness, by a Vickers microindentor, (3) depths of cure and oxygen inhibitor effect (OIE), quantified by scraping, (4) water contact angle on the materials surface, (5) water sorption and solubility, performed by the Oysaed-Ruyter method and (6) scanning electron microscopy analysis of the specimens surfaces. Data were analyzed by ANOVA and Student-Newman-Keuls tests (p<0.05).
  
  
  RESULTS
  Materials with CH(3) Bis-GMA and CF(3) Bis-GMA exhibited less hydrophilicity, water sorption and solubility. Bis-GMA dilution induced an increase in depth of cure and promoted a higher OIE, particularly when the diluent was TEGDMA. Filler loading reduced the OIE and increased hydrophobicity of the resins.
  
  
  CONCLUSIONS
  CH(3) Bis-GMA may be considered as good candidate to be used as diluent because when replacing TEGDMA-induced lower hydrolytic degradation and increase in HC.
authors.affiliation: IST, Departamento de Engenharia de Materiais, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal. soniag.pereira@ist.utl.pt
authors.forename: Sónia G
authors.initials: SG
authors.lastname: Pereira
authors.forename: Raquel
authors.initials: R
authors.lastname: Osorio
authors.forename: Manuel
authors.initials: M
authors.lastname: Toledano
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Cabrerizo-Vílchez
authors.forename: Teresa G
authors.initials: TG
authors.lastname: Nunes
authors.forename: S
authors.initials: S
authors.lastname: Kalachandra
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry*; D006244:Hardness; D011092:Polyethylene Glycols / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry*; D011140:Polyurethanes / Q000737:chemistry*; D012995:Solubility; D014783:Viscosity
chemical_list: D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D011109:Polymethacrylic Acids; D011140:Polyurethanes; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate