title: Color stability of ceramic laminate veneers cemented with light-polymerizing and dual-polymerizing luting agent: A split-mouth randomized clinical trial.
abstract: BACKGROUND
  The color stability of luting agents influences the esthetics of ceramic laminate veneers. Clinical studies that have evaluated the color changes of veneers cemented to enamel with light- and dual-polymerizing resin cement are lacking.
  
  
  OBJECTIVE
  The purpose of this split-mouth randomized clinical trial was to evaluate the color change and marginal discoloration of dual- and light-polymerizing cement used for cementation of ceramic laminate veneers.
  
  
  METHODS
  In 10 participants, 0.3-mm-thick ceramic laminate veneers were cemented on the buccal surface of the second premolars without tooth preparation. A randomized application of light-polymerized cement was used on one side and a dual-polymerized cement on the contralateral side. The operator and participants were blinded to the activation mode. Color was evaluated by a blinded evaluator with a spectrophotometer at 24 hours and at 2, 6, 12, and 24 months after cementation. The CIELab (ΔE*ab) and CIEDE2000 (ΔE*00) formulas were used to quantify color alteration, and Δa*, Δb*, and ΔL* were calculated between the first and subsequent measurements. US Public Health Service guidelines were used to evaluate the marginal discoloration.
  
  
  RESULTS
  Wilcoxon tests did not show a statistical difference in ΔE*aband ΔE*00between the groups (P>.05). At 24 months, the median ΔE*abwas 2.31 (interquartile ranges [IQR]: 3.34) for the light-polymerizing mode and 1.57 (IQR: 0.41) for the dual-polymerizing mode, while the median ΔE*00was 1.65 for the light-polymerizing mode (IQR: 2.34) and 1.18 for the dual-polymerizing mode (IQR: 0.25). The thresholds for clinically acceptable color changes ΔE*ab>3.46 and ΔE*00>2.25 were found for both curing modes. Marginal discoloration was observed from the 2-year assessment.
  
  
  CONCLUSIONS
  The color stability of ceramic laminate veneers was similar for both of the polymerizing modes for all evaluated periods. Marginal discoloration increased over a 2-year period for both the light- and the dual-polymerizing modes.
authors.affiliation: Doctoral student, Department of Restorative Dentistry, Faculty of Dentistry, Federal University of Santa Maria, Rio Grande do Sul, Brazil. Electronic address: anamarchionatti@hotmail.com.
authors.forename: Ana Maria Estivalete
authors.initials: AME
authors.lastname: Marchionatti
authors.affiliation: Doctoral student, Department of Restorative Dentistry, Faculty of Dentistry, Federal University of Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: Vinícius Felipe
authors.initials: VF
authors.lastname: Wandscher
authors.affiliation: Staff dentist, Department of Restorative Dentistry, Faculty of Dentistry, Federal University of Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: Michele Mirian
authors.initials: MM
authors.lastname: May
authors.affiliation: Titular Professor, Department of Restorative Dentistry, São José dos Campos Dental School, São Paulo State University, São Paulo, Brazil.
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Bottino
authors.affiliation: Adjunct Professor, Department of Restorative Dentistry, Faculty of Dentistry, Federal University of Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: Liliana Gressler
authors.initials: LG
authors.lastname: May
mesh_terms: D002516:Ceramics / Q000627:therapeutic use*; D003116:Color; D003738:Dental Cements / Q000627:therapeutic use*; D003801:Dental Veneers; D004311:Double-Blind Method; D004955:Esthetics, Dental; D006801:Humans; D055115:Light-Curing of Dental Adhesives / Q000379:methods*; D058105:Polymerization
chemical_list: D003738:Dental Cements