title: Water sorption of CH3- and CF3-Bis-GMA based resins with additives.
abstract: OBJECTIVE
  To evaluate the effect of additives on the water sorption characteristics of Bis-GMA based copolymers and composites containing TEGDMA, CH3Bis-GMA or CF3Bis-GMA.
  
  
  METHODS
  Fifteen experimental copolymers and corresponding composites were prepared combining Bis-GMA and TEGDMA, CH3Bis-GMA or CF3Bis-GMA, with aldehyde or diketone (24 and 32 mol%) totaling 30 groups. For composites, barium aluminosilicate glass and pyrogenic silica was added to comonomer mixtures. Photopolymerization was effected by 0.2 wt% each of camphorquinone and N,N-dimethyl-p-toluidine. Specimen densities in dry and water saturated conditions were obtained by Archimedes' method. Water sorption and desorption were evaluated in a desorption-sorption-desorption cycle. Water uptake (%WU), water desorption (%WD), equilibrium solubility (ES; µg/mm³), swelling (f) and volume increase (%V) were calculated using appropriate equations.
  
  
  RESULTS
  All resins with additives had increased %WU and ES. TEGDMA-containing systems presented higher %WU, %WD, ES, f and %V values, followed by resins based on CH3Bis-GMA and CF3Bis-GMA.
  
  
  CONCLUSIONS
  Aldehyde and diketone led to increases in the water sorption characteristics of experimental resins.
authors.affiliation: Department of Clinical Sciences, Restorative Dentistry, Faculty of Dentistry, University of Toronto, Toronto, Canada. anuradha.prakki@dentistry.utoronto.ca
authors.forename: Anuradha
authors.initials: A
authors.lastname: Prakki
authors.forename: Renato
authors.initials: R
authors.lastname: Cilli
authors.forename: Ian Matos
authors.initials: IM
authors.lastname: Vieira
authors.forename: Kristina
authors.initials: K
authors.lastname: Dudumas
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Pereira
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry*; D003931:Diacetyl / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D058105:Polymerization; D012995:Solubility; D013997:Time Factors; D014867:Water / Q000737:chemistry*
chemical_list: D000447:Aldehydes; D003188:Composite Resins; D014867:Water; D017438:Bisphenol A-Glycidyl Methacrylate; C005556:propionaldehyde; D003931:Diacetyl