title: Additive effects of TEGDMA and hydrogenperoxide on the cellular glutathione content of human gingival fibroblasts.
abstract: OBJECTIVE
  Only few data are available about cytotoxic effects of leachable dental resin compounds in combination with hydrogen peroxide (H(2)O(2)) segregated from dental bleaching agents. Therefore, the purpose of this study was to evaluate the effects of various concentrations of triethylene-glycol dimethacrylate (TEGDMA) and H(2)O(2) on intracellular glutathione levels (GSH) and viability of human gingival fibroblasts (HGF) that are primary target cells of cytotoxic actions of these substances.
  
  
  METHODS
  HGF were grown in 96-well plates for 24h, treated with various concentrations of TEGDMA (0.5-5.0mM) for 24h and subsequently for 90min with 0.2mM H(2)O(2) or culture medium (control). The relative intracellular GSH concentration was determined using a fluorescence assay with monobromobimane. Readings were normalized to cell numbers, which were determined by a propidium iodide assay. Data were statistically analyzed by t-test and ANOVA with Tukey's post test. A significance level of p<0.05 was used.
  
  
  RESULTS
  Exposure to TEGDMA reduced the viability of HGF at concentrations > or =1.0mM. TEGDMA induced a decrease of the GSH pool in a concentration-dependent manner (p<0.05). The depletion of GSH was correlated with a reduction of viability (p<0.05) and the total cell number. Furthermore, a significant decrease of the intracellular GSH content was found when cells were exposed to TEGDMA in combination with H(2)O(2), compared to experiments without H(2)O(2).
  
  
  CONCLUSIONS
  We conclude from our findings that TEGDMA and H(2)O(2) have additive adverse effects on GSH metabolism and cell viability.
authors.affiliation: Department of Conservative Dentistry and Periodontology, Medical University Hannover, Hannover, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Volk
authors.forename: Gabriele
authors.initials: G
authors.lastname: Leyhausen
authors.forename: Sami
authors.initials: S
authors.lastname: Dogan
authors.forename: Werner
authors.initials: W
authors.lastname: Geurtsen
mesh_terms: D000704:Analysis of Variance; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003188:Composite Resins / Q000737:chemistry / Q000633:toxicity*; D003793:Dental Restoration, Permanent / Q000009:adverse effects; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005881:Gingiva / Q000166:cytology / Q000187:drug effects*; D005978:Glutathione / Q000096:biosynthesis; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity*; D016014:Linear Models; D016877:Oxidants / Q000633:toxicity*; D011092:Polyethylene Glycols / Q000633:toxicity*; D011109:Polymethacrylic Acids / Q000633:toxicity*; D014073:Tooth Bleaching / Q000009:adverse effects
chemical_list: D003188:Composite Resins; D016877:Oxidants; D011109:Polymethacrylic Acids; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D006861:Hydrogen Peroxide; D005978:Glutathione