title: Light polymerization-dependent changes in color and translucency of resin composites.
abstract: OBJECTIVE
  To determine the influence of type of polymerization light on changes in color and translucency of resin composites.
  
  
  METHODS
  16 shades of commercial composites were analyzed. Specimens were polymerized with quartz-tungsten-halogen (QTH) and light-emitting diode (LED) polymerization light. Color of non-polymerized and polymerized composites was measured against white and black backgrounds using a spectroradiometer. Changes in color (deltaE'), translucency (deltaTP') and color parameters (deltaL', deltaC' and deltah') were calculated for each polymerization light. The differences among deltaE' values and among deltaTP' values obtained for each device were analyzed by two-way ANOVA. Multiple regression analysis was used to determine the influence of color parameters on deltaE' and deltaTP'.
  
  
  RESULTS
  The results indicated that there was significant difference among the deltaE' and deltaTP' values obtained using QTH and LED light polymerization (P< 0.05). The prediction equations for deltaE' and deltaTP' based on the multiple regression analyses indicated that deltaE' was mainly caused by deltaC' for both lights. However deltaTP' was mainly caused by deltah' for LED light and by the deltaC' for QTH light. Changes in translucency significantly influenced the overall color changes after polymerization.
authors.affiliation: Department of Optics, Faculty of Sciences, University of Granada, 18071 Granada, Spain. mmperez@ugr.es
authors.forename: Maria
authors.initials: M
authors.lastname: del Mar Pérez
authors.forename: Arafa
authors.initials: A
authors.lastname: Saleh
authors.forename: Rosa
authors.initials: R
authors.lastname: Pulgar
authors.forename: Rade D
authors.initials: RD
authors.lastname: Paravina
mesh_terms: D003116:Color; D003124:Colorimetry; D003188:Composite Resins / Q000737:chemistry*; D055117:Curing Lights, Dental; D006219:Halogens; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D044367:Phase Transition; D012044:Regression Analysis; D012666:Semiconductors
chemical_list: D003188:Composite Resins; D006219:Halogens