title: Influence of additives on the properties of Bis-GMA/Bis-GMA analog comonomers and corresponding copolymers.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the effect of two additives: propionaldehyde (aldehyde) and 2,3-butanedione (diketone) on the properties of Bis-GMA diluted with TEGDMA and the synthesized Bis-GMA analogs, propoxylated Bis-GMA (CH(3)Bis-GMA) and propoxylated fluorinated Bis-GMA (CF(3)Bis-GMA).
  
  
  METHODS
  Nine experimental comonomers were prepared combining Bis-GMA and TEGDMA, CH(3)Bis-GMA, CF(3)Bis-GMA, with aldehyde (32mol%) and diketone (32mol%). Photopolymerization was effected by using Camphorquinone (0.2wt%) and N,N-dimethyl-p-toluidine (0.2wt%). Experimental comonomer viscosity (Brookfield viscometer), polymerization shrinkage (gravimetrically), degree of conversion (FT-IR) and contact angles (contact angle goniometer) were determined. Comonomer and copolymer T(g)s (DSC and Fox equation) were also evaluated. Data were analyzed by one-way ANOVA and Tukey test (alpha=0.05).
  
  
  RESULTS
  Bis-GMA/CH(3)Bis-GMA and Bis-GMA/CF(3)Bis-GMA with additives exhibited lower viscosities (p<0.01). Inclusion of additives into the comonomer systems did not produce significant increase in polymerization shrinkage (p>0.05). A significant increase in degree of conversion was shown for Bis-GMA/TEGDMA and Bis-GMA/CH(3)Bis-GMA with additives (p<0.01). Additives reduced contact angle and comonomer T(g) values, whereas the corresponding copolymers with additives showed an increase in T(g).
  
  
  CONCLUSIONS
  Use of novel comonomer systems with the addition of aldehyde and diketone functional groups would improve dental resin composite properties.
authors.affiliation: Department of Operative Dentistry, Endodontics and Dental Materials, University of São Paulo, Bauru, São Paulo, Brazil.
authors.forename: Anuradha
authors.initials: A
authors.lastname: Prakki
authors.forename: Padmavathy
authors.initials: P
authors.lastname: Tallury
authors.forename: Rafael Francisco Lia
authors.initials: RF
authors.lastname: Mondelli
authors.forename: Sid
authors.initials: S
authors.lastname: Kalachandra
mesh_terms: D000447:Aldehydes / Q000494:pharmacology*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry*; D003931:Diacetyl / Q000494:pharmacology*; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D014783:Viscosity / Q000187:drug effects
chemical_list: D000447:Aldehydes; D011109:Polymethacrylic Acids; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C005556:propionaldehyde; D003931:Diacetyl