title: Effect of short LED lamp exposure on wear resistance, residual monomer and degree of conversion for Filtek Z250 and Tetric EvoCeram composites.
abstract: OBJECTIVE
  The latest LED dental curing devices claim sufficient curing of restorative materials with short curing times. This study evaluates mechanical and chemical properties as a function of curing time of two commercial composite filling materials cured with three different LED lamps.
  
  
  METHODS
  The composites were Filtek Z250 (3M ESPE) and Tetric EvoCeram (Ivoclar Vivadent) and the LED curing devices were bluephase 16i (Ivoclar Vivadent), L.E.Demetron II (Kerr) and Mini L.E.D. (Satelec). Control samples were cured with a QTH-lamp (VCL 400, Kerr). The wear resistance after simulated tooth brushing, degree of conversion, curing depth, and amounts of residual monomers were measured after different curing times.
  
  
  RESULTS
  The results of this study show that short curing time with high-intensity LEDs may influence the bulk properties of the materials, resulting in lower curing depth and increased residual monomer content. The measured surface properties of the materials, degree of conversion and wear resistance, were not affected by short curing times to the same extent.
  
  
  CONCLUSIONS
  This study demonstrates that reduced exposure time with high intensity LEDs can result in composite restorations with inferior curing depth and increased leaching of monomers. Dentists are recommended to use sufficient curing times even with high intensity LEDs to ensure adequate curing and minimize the risk of monomer leaching.
authors.affiliation: Nordic Institute of Dental Materials, Sognsveien 70A, Oslo, Norway. hilde.kopperud@niom.no
authors.forename: Hilde M
authors.initials: HM
authors.lastname: Kopperud
authors.forename: Gaute F
authors.initials: GF
authors.lastname: Johnsen
authors.forename: Sébastien
authors.initials: S
authors.lastname: Lamolle
authors.forename: Inger S
authors.initials: IS
authors.lastname: Kleven
authors.forename: Hanne
authors.initials: H
authors.lastname: Wellendorf
authors.forename: Håvard J
authors.initials: HJ
authors.lastname: Haugen
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003188:Composite Resins / Q000737:chemistry / Q000528:radiation effects*; D055117:Curing Lights, Dental / Q000145:classification*; D004867:Equipment Design; D006801:Humans; D055115:Light-Curing of Dental Adhesives / Q000295:instrumentation / Q000379:methods; D008422:Materials Testing; D055595:Mechanical Phenomena; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D058105:Polymerization; D011140:Polyurethanes / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013499:Surface Properties; D053719:Tandem Mass Spectrometry / Q000379:methods; D013997:Time Factors; D014099:Toothbrushing / Q000295:instrumentation
chemical_list: D003188:Composite Resins; C444701:Filtek Z250; D008689:Methacrylates; D011140:Polyurethanes; C501891:Tetric EvoCeram; C029824:urethane dimethacrylate luting resin; C041979:2,2-bis-(4-(2-methacryloxyethoxy)phenyl)propane; D017438:Bisphenol A-Glycidyl Methacrylate
keywords: Composites; Curing lamps; Curing time; Degree of conversion; Depth of cure; LED; Residual monomers; Restorative materials; Wear