title: Distance and protective barrier effects on the composite resin degree of conversion.
abstract: BACKGROUND
  The food wrap films are used to cover the tip of curing light units in order to avoid contamination and prevent damage to the light guide. However, their effects on resin polymerization are not fully known.
  
  
  OBJECTIVE
  We investigated the effects on restoration efficiency of a food wrap protective barrier used on the tip of curing light units.
  
  
  METHODS
  For each treatment, five replications were performed, a total of 60 bovine incisor. The degree of conversion (%DC) of restorations with the composite resin Opallis EA2 was evaluated using 3 curing light devices (Optilux 501, Optilight and Ultra LED) and 2 curing distances (0 and 5 mm). The composite resin was tested for restoration of cavities in bovine crowns. %DC values were measured by the Fourier transform infrared spectroscopy-attenuated total reflectance technique.
  
  
  METHODS
  The data were analyzed using 3-way ANOVA and Tukey's test.
  
  
  RESULTS
  Use of the protective film lowered %DC (F = 4.13; P = 0.05), and the effects of curing distance were associated to the curing light device (F = 3.61; P = 0.03).
  
  
  CONCLUSIONS
  The distance from the light curing tip and use of a translucent protective barrier on the light-cure device can both impair composite resin %DC.
authors.affiliation: Federal University of Mato Grosso do Sul, School of Dentistry Albino Coimbra Filho, Campo Grande, MS, Brazil.
authors.forename: Margareth
authors.initials: M
authors.lastname: Coutinho
authors.forename: Natália Carvalho
authors.initials: NC
authors.lastname: Trevizam
authors.forename: Renata Nakase
authors.initials: RN
authors.lastname: Takayassu
authors.forename: Ariene Arcas
authors.initials: AA
authors.lastname: Leme
authors.forename: Giulliana Panfiglio
authors.initials: GP
authors.lastname: Soares
keywords: Composite resin; Fourier transform infrared spectroscopy; dental curing lights; dental infection controls; polymerization