title: Resin-composite cytotoxicity varies with shade and irradiance.
abstract: OBJECTIVE
  The study was aimed at investigating the cytotoxicity of different composites as a function of composite shade and the light curing unit (LCU) employed.
  
  
  METHODS
  Non-polymerized and polymerized samples of the composites Grandio(®) (VOCO, Cuxhaven), Solitaire(®) (Heraeus Kulzer, Hanau) and Filtek Z 250(®) (3M/Espe, Seefeld) in two markedly differing shades (A2, C2) were prepared. Polymerization was performed with two LCUs: Heliolux II (Ivoclar/Vivadent, Ellwangen) and Swiss Master Light (EMS, Nyon, Switzerland). To obtain composite extracts, the samples were immersed in cell culture medium (DMEM--Dulbecco's Modified Eagle Medium), which was replaced daily up to the 7th day of the experiment, and then on the 14th, 21st and 28th day. After incubation of human gingival fibroblasts (HGF) with the extracts obtained, cytotoxicity was determined using the MTT test.
  
  
  RESULTS
  With the non-polymerized samples, essentially no influence of the composite shades investigated on HGF viability was detected, with the exception of the Solitaire material, where a higher cytotoxicity of the shade C2 in the non-polymerized state was found at the end of the observation period. After polymerization of the different composites, the cytotoxic reaction observed for the extracts of shade C2 was stronger than that observed for A2. After polymerization with the Heliolux II (HLX) LCU, the extracts of composites Grandio and Solitaire C2 were significantly more toxic than those of the A2 shade (p<0.01). Polymerization with the Swiss Master Light (SML) reduces this cytotoxic effect. The extracts of the Grandio composite showed the least cytotoxic effect throughout the observation period, irrespective of the LCU used. For the extracts of the Z250 specimens, the cytotoxicity observed was generally higher.
  
  
  CONCLUSIONS
  The results show that the shade of the composite has an influence on its cytotoxicity and that this cytotoxicity is also influenced by the light curing unit used. It was observed that composites of the darker shade (C2) had a higher cytotoxicity, which varied with the LCU employed.
authors.affiliation: Department of Conservative Dentistry, Jena University Hospital, Friedrich-Schiller-Universität Jena, An der alten Post 4, Jena D-07743, Germany. Bernd.W.Sigusch@med.uni-jena.de
authors.forename: Bernd W
authors.initials: BW
authors.lastname: Sigusch
authors.forename: Torsten
authors.initials: T
authors.lastname: Pflaum
authors.forename: Andrea
authors.initials: A
authors.lastname: Völpel
authors.forename: Kerstin
authors.initials: K
authors.lastname: Gretsch
authors.forename: Sandra
authors.initials: S
authors.lastname: Hoy
authors.forename: David C
authors.initials: DC
authors.lastname: Watts
authors.forename: Klaus D
authors.initials: KD
authors.lastname: Jandt
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003116:Color; D003188:Composite Resins / Q000633:toxicity*; D055117:Curing Lights, Dental; D005260:Female; D005347:Fibroblasts / Q000187:drug effects; D005881:Gingiva / Q000166:cytology / Q000187:drug effects*; D006801:Humans; D055115:Light-Curing of Dental Adhesives / Q000295:instrumentation / Q000379:methods*; D018709:Statistics, Nonparametric
chemical_list: D003188:Composite Resins; C509998:Grandio; C113049:Solitaire composite resin