title: In vitro cytotoxicity of dental composites based on new and traditional polymerization chemistries.
abstract: The biological response to dental restorative polymer composites is mediated by the release of unpolymerized residual monomers. Several new composite formulations claim to reduce unpolymerized residual mass. The current study assessed the cytotoxic responses to several of these new formations and compared them with more traditional formulations. Our hypothesis predicted that if these new polymerization chemistries reduce unpolymerized residual mass, the cytotoxicity of these materials also should be reduced relative to traditional formulations.
  
  
  METHODS
  Materials (HerculiteXRV, Premise, Filtek Supreme, CeramxDuo, Hermes, and Quixfil) were tested in vitro in direct contact with Balb mouse fibroblasts, initially, then after aging in artificial saliva for 0, 1, 3, 5, or 8 weeks. The toxicity was determined by using the MTT assay to the estimate SDH activity. Knoop hardness of the materials also was measured at 0 and 8 weeks to determine whether surface breakdown of the materials in artificial saliva contributed to cytotoxic responses.
  
  
  RESULTS
  Materials with traditional methacrylate chemistries (Herculite, Premise, Filtek Supreme) were severely (>50%) cytotoxic throughout the 8-week interval, but materials with newer chemistries or filling strategies (Hermes, CeramXDuo, and Quixfil) improved over time of aging in artificial saliva. Hermes showed the least cytotoxicity at 8 weeks, and was statistically equivalent to Teflon negative controls. Hardness of the materials was unaffected by exposure to artificial saliva.
  
  
  CONCLUSIONS
  Newer polymerization and filling strategies for dental composites show promise for reducing the release of unpolymerized components and cytotoxicity.
authors.affiliation: School of Dentistry, Medical College of Georgia, Augusta, Georgia 30912-1100, USA.
authors.forename: M Goël
authors.initials: MG
authors.lastname: Brackett
authors.forename: S
authors.initials: S
authors.lastname: Bouillaguet
authors.forename: P E
authors.initials: PE
authors.lastname: Lockwood
authors.forename: S
authors.initials: S
authors.lastname: Rotenberg
authors.forename: J B
authors.initials: JB
authors.lastname: Lewis
authors.forename: R L W
authors.initials: RL
authors.lastname: Messer
authors.forename: J C
authors.initials: JC
authors.lastname: Wataha
mesh_terms: D000818:Animals; D041702:BALB 3T3 Cells; D003188:Composite Resins / Q000737:chemistry* / Q000633:toxicity*; D066298:In Vitro Techniques; D008422:Materials Testing; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D019279:Resin Cements / Q000737:chemistry / Q000633:toxicity; D012463:Saliva
chemical_list: D003188:Composite Resins; C474035:Filtek Supreme; C516831:Hermes Composite Resin; C510379:QuiXfil; D019279:Resin Cements; C507210:premise composite resin; C065770:Herculite XR