title: Sorption and solubility of composites cured with quartz-tungsten halogen and light emitting diode light-curing units.
abstract: OBJECTIVE
  The objective of this study was to evaluate the effect of light polymerization on water sorption and solubility of hybrid composites.
  
  
  METHODS
  Three composite resins were used to make discs cured with either quartz-tungsten halogen (QTH) or light emitting diode (LED) curing units. The specimens were stored in a desiccator at 37 degrees C and weighted to a constant mass, then immersed in deionized water for different periods of time, and reconditioned until achieving a constant mass. Sorption and solubility were calculated and subjected to analysis of variance (ANOVA) and Tukey tests (p<0.01).
  
  
  RESULTS
  There were no statistically significant differences between the light sources. Water sorption increased with storage time for all the composites. The lowest sorption was observed for Herculite XRV, followed by Tetric Ceram, and Filtek Z250. Increased storage times reduced the solubility of Filtek Z250 but did not affect the solubility of Herculite XRV and Tetric Ceram.
  
  
  CONCLUSIONS
  Water sorption and solubility of composites are not affected by the type of polymerization when the same intensity and exposure times are used. Thus, the differences found are probably related to the composition of the materials.
  
  
  CONCLUSIONS
  Water sorption and solubility of composites can lead to a shortened service life. However, these properties are not correlated to the type of polymerization.
authors.affiliation: Technological School at the Federal University of Parana in Curitiba, PR, Brazil. luci.archegas@ufpr.br
authors.forename: Luci Regina P
authors.initials: LR
authors.lastname: Archegas
authors.forename: Danilo B M
authors.initials: DB
authors.lastname: Caldas
authors.forename: Rodrigo N
authors.initials: RN
authors.lastname: Rached
authors.forename: Sergio
authors.initials: S
authors.lastname: Vieira
authors.forename: Evelise M
authors.initials: EM
authors.lastname: Souza
mesh_terms: D000042:Absorption; D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects*; D003748:Dental Equipment; D006219:Halogens; D008027:Light; D008422:Materials Testing; D044367:Phase Transition; D019279:Resin Cements / Q000737:chemistry / Q000528:radiation effects; D012666:Semiconductors; D012995:Solubility; D018709:Statistics, Nonparametric; D013997:Time Factors; D014867:Water
chemical_list: D003188:Composite Resins; C444701:Filtek Z250; D006219:Halogens; D019279:Resin Cements; C121818:Tetric ceram; D014867:Water; C065770:Herculite XR