title: Synergistic interaction caused to human gingival fibroblasts from dental monomers.
abstract: OBJECTIVE
  The toxicity of monomers like bisphenol-A-glycidyldimethacrylate (BisGMA) and urethane-dimethacrylate (UDMA) to cells is well studied. In these studies solubilizers, which have a toxic potential, are used to dissolve the basic monomers in the aqueous medium. In these experiments it is not possible to confidently exclude a synergistic effect of basic monomers and solubilizers in cells. Moreover, less is known about the synergistic interaction between basic- and comonomers (triethyleneglycoldimethacrylate (TEGDMA); 2-hydroxyethylmethacrylate (HEMA)) in cells. We dissolved the basic monomers in the comonomers and incubated human gingival fibroblasts (HGFs) with these binary mixtures in different concentrations.
  
  
  METHODS
  Proliferating HGFs monolayers were cultured in the absence or presence of mixtures of BisGMA/TEGDMA, BisGMA/HEMA, UDMA/TEGDMA and UDMA/HEMA. Twenty-four hours later XTT was added and the formazan formation was quantified. EC(50) values were obtained at half-maximum-effect concentrations from fitted curves.
  
  
  RESULTS
  EC(50) values were (mmol/l; mean±sem; n=5): 0.01 BisGMA/0.48 TEGDMA; 0.04 BisGMA/4.99 HEMA; 0.04 UDMA/1.60 TEGDMA and 0.02 UDMA/2.26 HEMA. All tested mixtures induced a dose-dependent loss of viability in HGFs after 24h.
  
  
  CONCLUSIONS
  The EC(50) values of binary mixtures were significantly (p<0.05) lower compared to the EC(50) values of the pure substances indicating a synergistic interaction of the mixtures on the HGFs. The widely used (co)monomers BisGMA and TEGDMA have the lowest EC(50) values. The highest decrease of EC(50) values, compared with the pure substances, were found in the mixture UDMA/HEMA. Worst case calculations show that the EC(50) values from binary mixtures are at least 6 fold lower compared with known amounts of elutable (co)monomers from polymerized composites.
authors.affiliation: Department of Operative/Restorative Dentistry, Periodontology and Pedodontics, Ludwig-Maximilians-University of Munich, Goethestr 70, 80336 Munich, Germany. juergen.durner@med.uni-muenchen.de
authors.forename: J
authors.initials: J
authors.lastname: Durner
authors.forename: P
authors.initials: P
authors.lastname: Wellner
authors.forename: R
authors.initials: R
authors.lastname: Hickel
authors.forename: F X
authors.initials: FX
authors.lastname: Reichl
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000633:toxicity; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005347:Fibroblasts / Q000187:drug effects; D005881:Gingiva / Q000166:cytology / Q000187:drug effects*; D006801:Humans; D008689:Methacrylates / Q000633:toxicity*; D011092:Polyethylene Glycols / Q000633:toxicity; D011109:Polymethacrylic Acids / Q000633:toxicity; D011140:Polyurethanes / Q000633:toxicity
chemical_list: D008689:Methacrylates; D011109:Polymethacrylic Acids; D011140:Polyurethanes; C029824:urethane dimethacrylate luting resin; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C005044:hydroxyethyl methacrylate