title: Influence of light-curing mode on the cytotoxicity of resin-based surface sealants.
abstract: BACKGROUND
  Surface sealants have been successfully used in the prevention of erosive tooth wear. However, when multiple tooth surfaces should be sealed, the light-curing procedure is very time-consuming. Therefore, the aim of this study was to investigate whether reduced light-curing time (while maintaining similar energy density) has an influence on resin-based surface sealant cytotoxicity.
  
  
  METHODS
  Bovine dentine discs were treated as follows: group 1: untreated, groups 2-5: Seal&Protect and groups 6-9: experimental sealer. Groups 2 and 6 were light-cured (VALO LED light-curing device) for 40 s (1000 mW/cm2), groups 3 and 7 for 10 s (1000 mW/cm2), groups 4 and 8 for 7 s (1400 mW/cm2) and groups 5 and 9 for 3 s (3200 mW/cm2). Later, materials were extracted in culture medium for 24 h, and released lactate dehydrogenase (LDH) activity as a measure of cytotoxicity was determined photometrically after cells (dental pulp cells and gingival fibroblasts) were exposed to the extracts for 24 h. Three independent experiments, for both sample preparation and cytotoxicity testing, were performed.
  
  
  RESULTS
  Overall, lowest cytotoxicity was observed for the unsealed control group. No significant influence of light-curing settings on the cytotoxicity was observed (p = 0.537 and 0.838 for pulp cells and gingival fibroblasts, respectively). No significant difference in the cytotoxicity of the two sealants was observed after light-curing with same light-curing settings (group 2 vs. 6, 3 vs. 7, 4 vs. 8 and 5 vs. 9: p > 0.05, respectively).
  
  
  CONCLUSIONS
  Shortening the light-curing time, while maintaining constant energy density, resulted in no higher cytotoxicity of the investigated sealants.
authors.affiliation: Clinic for Preventive Dentistry, Periodontology and Cariology, University of Zurich, Plattenstrasse 11, 8032 Zürich, Switzerland. florian.wegehaupt@zzm.uzh.ch.
authors.forename: Florian J
authors.initials: FJ
authors.lastname: Wegehaupt
authors.forename: Tobias T
authors.initials: TT
authors.lastname: Tauböck
authors.forename: Thomas
authors.initials: T
authors.lastname: Attin
authors.forename: Georgios N
authors.initials: GN
authors.lastname: Belibasakis
mesh_terms: D000818:Animals; D002417:Cattle; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D055117:Curing Lights, Dental / Q000145:classification; D003764:Dental Materials / Q000528:radiation effects / Q000633:toxicity*; D003782:Dental Pulp / Q000166:cytology / Q000187:drug effects; D003804:Dentin / Q000187:drug effects*; D005347:Fibroblasts / Q000187:drug effects; D005881:Gingiva / Q000166:cytology / Q000187:drug effects; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000032:analysis / Q000187:drug effects; D055115:Light-Curing of Dental Adhesives / Q000295:instrumentation / Q000379:methods*; D008689:Methacrylates / Q000633:toxicity; D010895:Pit and Fissure Sealants / Q000528:radiation effects / Q000633:toxicity*; D011409:Propylene Glycols / Q000633:toxicity; D019279:Resin Cements / Q000528:radiation effects / Q000633:toxicity*; D013997:Time Factors
chemical_list: D003764:Dental Materials; D008689:Methacrylates; D010895:Pit and Fissure Sealants; D011409:Propylene Glycols; D019279:Resin Cements; C442646:Seal and Protect resin cement; D007770:L-Lactate Dehydrogenase