title: Cytotoxicity of silica-glass fiber reinforced composites.
abstract: OBJECTIVE
  Silica-glass fiber reinforced polymers can be used for many kinds of dental applications. The fiber reinforcement enhances the mechanical properties of the polymers, and they have good esthetic attributes. There is good initial bonding of glass fibers to polymers via an interface made from silane coupling agents. The aim of this in vitro study was to determine the cytotoxicity of two polymers reinforced with two differently sized silica-glass fibers before and after thermal cycling. Cytotoxicity of the polymers without fibers was also evaluated.
  
  
  METHODS
  Two different resin mixtures (A and B) were prepared from poly(vinyl chloridecovinylacetate) powder and poly(methyl methacrylate) (PMMA) dissolved in methyl methacrylate and mixed with different cross-linking agents. The resin A contained the cross-linking agents ethylene glycol dimethacrylate and 1,4-butanediol dimethacrylate, and for resin B diethylene glycol dimethacrylate was used. Woven silica-glass fibers were used for reinforcement. The fibers were sized with either linear poly(butyl methacrylate)-sizing or cross-linking PMMA-sizing. Cytotoxicity was evaluated by filter diffusion test (ISO 7405:1997) of newly made and thermocycled test specimens. Extracts were prepared according to ISO 10993-12 from newly made and from thermocycled specimens and tested by the MTT assay. The results from the experiments were statistically analyzed by one-way ANOVA and Tukey's test (rho<0.05).
  
  
  RESULTS
  The filter diffusion test disclosed no change in staining intensity at the cell-test sample contact area indicating non-cytotoxicity in all experimental groups. Cell viability assessed by MTT assay was more than 90% in all experimental groups. All are non-cytotoxic.
  
  
  CONCLUSIONS
  It can be concluded that correctly processed heat polymerized silica-glass fiber reinforced polymers induced no cytotoxicity and that thermocycling did not alter this property.
authors.affiliation: Department of Prosthetic Dentistry, Institute of Clinical Dentistry, University of Oslo, Oslo, Norway.
authors.forename: Gökçe
authors.initials: G
authors.lastname: Meriç
authors.forename: Jon E
authors.initials: JE
authors.lastname: Dahl
authors.forename: I Eystein
authors.initials: IE
authors.lastname: Ruyter
mesh_terms: D000179:Acrylates / Q000633:toxicity; D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D004396:Coloring Agents; D003188:Composite Resins / Q000633:toxicity*; D003432:Cross-Linking Reagents / Q000633:toxicity; D003764:Dental Materials / Q000633:toxicity*; D005026:Ethylene Glycols / Q000633:toxicity; D005347:Fibroblasts / Q000187:drug effects; D005898:Glass / Q000737:chemistry*; D008422:Materials Testing; D008689:Methacrylates / Q000633:toxicity; D020366:Methylmethacrylate / Q000633:toxicity; D051379:Mice; D011109:Polymethacrylic Acids / Q000633:toxicity; D019904:Polymethyl Methacrylate / Q000633:toxicity; D011145:Polyvinyls / Q000633:toxicity; D012822:Silicon Dioxide / Q000633:toxicity*; D013499:Surface Properties; D013696:Temperature; D013778:Tetrazolium Salts; D013844:Thiazoles
chemical_list: D000179:Acrylates; D004396:Coloring Agents; D003188:Composite Resins; D003432:Cross-Linking Reagents; D003764:Dental Materials; D005026:Ethylene Glycols; D008689:Methacrylates; D011109:Polymethacrylic Acids; D011145:Polyvinyls; D013778:Tetrazolium Salts; D013844:Thiazoles; C009753:fiberglass; D020366:Methylmethacrylate; C047521:diethylene glycol dimethacrylate monomer; D012822:Silicon Dioxide; C004919:ethylene dimethacrylate; C003080:poly(vinyl chloride)-poly(vinyl acetate) copolymer; C068872:polybutyl methacrylate; D019904:Polymethyl Methacrylate; C022616:thiazolyl blue; C102737:1,4-butanediol dimethacrylate