title: Effect of a third-generation LED LCU on microhardness of tooth-colored restorative materials.
abstract: OBJECTIVE
  To assess the effects of different modes of a third-generation light-curing unit (LCU) (VALO) on the microhardness of restorative materials.
  
  
  METHODS
  A microhybrid composite resin (Filtek(™) Z550), a giomer (Beautifil II), a compomer (Dyract eXtra) and a RMGIC (Photac(™) Fil) were used in the study. Three different modes of VALO were tested and a second-generation LCU (Elipar S10) was used as a control. The microhardness (VHN) was measured using a Vickers Hardness tester. Data were analyzed using two-way anova and post hoc Tukey's test (P < 0.05).
  
  
  RESULTS
  The Filtek Z550 group had the highest VHN values followed by Photac Fil, Beautifil II and the Dyract eXtra at both top and bottom surfaces, however the difference between Filtek Z550 and Photac Fil was not statistically significant for the bottom surfaces (P > 0.05). Of the different curing protocols tested, the VALO LCU in Mode 3 resulted in the lowest VHN values at both top and bottom surfaces (P < 0.05).
  
  
  CONCLUSIONS
  Based on the results of this study, it can be concluded that the high-power mode of the VALO LCU can be recommended for clinical applications especially in pediatric patients, as it can shorten the time required to adequately polymerize resin-based tooth-colored restorative materials.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey.
authors.forename: Nihan
authors.initials: N
authors.lastname: Gonulol
authors.affiliation: Department of Pediatric Dentistry, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey.
authors.forename: Sezin
authors.initials: S
authors.lastname: Ozer
authors.affiliation: Department of Pediatric Dentistry, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey.
authors.forename: Emine Sen
authors.initials: ES
authors.lastname: Tunc
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry / Q000528:radiation effects; D020770:Compomers / Q000737:chemistry / Q000528:radiation effects; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects*; D055117:Curing Lights, Dental / Q000145:classification*; D003764:Dental Materials / Q000737:chemistry* / Q000528:radiation effects; D003793:Dental Restoration, Permanent; D004867:Equipment Design; D005899:Glass Ionomer Cements / Q000737:chemistry / Q000528:radiation effects; D006244:Hardness / Q000528:radiation effects; D008029:Lighting / Q000295:instrumentation*; D008422:Materials Testing; D019279:Resin Cements / Q000737:chemistry / Q000528:radiation effects; D012117:Resins, Synthetic / Q000737:chemistry / Q000528:radiation effects; D013499:Surface Properties; D013997:Time Factors
chemical_list: C470433:Beautifil composite resin; D020770:Compomers; D003188:Composite Resins; D003764:Dental Materials; C088486:Dyract; C000612973:Filtek Z550; D005899:Glass Ionomer Cements; C081144:Photac-Fil; D019279:Resin Cements; D012117:Resins, Synthetic; D017438:Bisphenol A-Glycidyl Methacrylate