title: Influence of different photo-activation distances on cytotoxicity of a dental adhesive model resin.
abstract: OBJECTIVE
  This study evaluated the cytotoxicity of a dental bonding model resin (DBMR) submitted to different photo-activation distances.
  
  
  METHODS
  A monomer mixture based on Bis-GMA and HEMA was used to assess the cytotoxicity in a mouse fibroblast-cell line. To promote different photo-activation distances glass slides were interposed between DBMR surface and halogen light curing unit (LCU) tip. Afterwards, the specimens were immersed in RPMI culture medium for 24 h to obtain extracts. The extracts were incubated in contact with the cells for 24 h. Finally, an MTT colorimetric assay was used to assess the cytotoxicity. The cell viability data (absorbance) were analyzed by one way ANOVA followed by Tukey's test (P<0.05).
  
  
  RESULTS
  The light output decreased according to the increase in the number of glass slides between the halogen LCU tip and DBMR surface. Yet, the distance between the tip of the curing light system and the specimens had significant influence on the cytotoxicity. All extracts produced by groups submitted to different photo-activation distances showed cytotoxic effect after 24h of incubation.
  
  
  CONCLUSIONS
  The photo-activation distance and the interposition of glass slides between LCU tip and DBMR was shown to play an important role in the cytotoxic effect.
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, University of North Parana, Londrina, PR, Brazil - rodrigo.varella@gmail.com.
authors.forename: R V
authors.initials: RV
authors.lastname: De Carvalho
authors.forename: M R
authors.initials: MR
authors.lastname: Fernández
authors.forename: R C
authors.initials: RC
authors.lastname: Poli-Frederico
authors.forename: R D
authors.initials: RD
authors.lastname: Guiraldo
authors.forename: M B
authors.initials: MB
authors.lastname: Lopes
authors.forename: S B
authors.initials: SB
authors.lastname: Berger
authors.forename: S K
authors.initials: SK
authors.lastname: Moura
authors.forename: F F
authors.initials: FF
authors.lastname: Demarco
mesh_terms: D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate / Q000528:radiation effects / Q000633:toxicity*; D002164:Camphor / Q000031:analogs & derivatives / Q000494:pharmacology; D002470:Cell Survival; D055117:Curing Lights, Dental; D006219:Halogens; D057927:Hydrophobic and Hydrophilic Interactions; D055115:Light-Curing of Dental Adhesives / Q000379:methods*; D008422:Materials Testing; D008689:Methacrylates / Q000528:radiation effects / Q000633:toxicity*; D051379:Mice; D041681:NIH 3T3 Cells / Q000187:drug effects*; D010777:Photochemistry; D058567:Photoinitiators, Dental / Q000494:pharmacology; D012117:Resins, Synthetic / Q000528:radiation effects / Q000633:toxicity*; D062366:para-Aminobenzoates / Q000494:pharmacology
chemical_list: D006219:Halogens; D008689:Methacrylates; D058567:Photoinitiators, Dental; D012117:Resins, Synthetic; D062366:para-Aminobenzoates; D017438:Bisphenol A-Glycidyl Methacrylate; C005044:hydroxyethyl methacrylate; D002164:Camphor; C030747:ethyl 4-dimethylaminobenzoate; C553149:camphorquinone