title: Effect of accelerated aging on the color stability of cemented laminate veneers.
abstract: OBJECTIVE
  The effect of the aging process on color stability of light-cure, dual-cure, and self-cure resin cements used for luting laminate veneers was investigated in this study.
  
  
  METHODS
  Dyract Cem (self cure), Twinlook (dual cure), and En Force (light cure) cements, 0.30 mm thick, were polymerized on laminate veneers that were 13 mm in diameter and 0.50 mm thick in an A2 shade. Five specimens were made for each material. The specimens were subjected to an accelerated aging process in a Weather-Ometer for 900 hours. Spectrophotometric analyses were made after 300, 600, and 900 hours of accelerated aging time. Overall color difference (delta E*ab) was determined using the CIE-LAB system for measuring small color differences. Chroma changes (delta C*ab) and hue differences (delta H*ab) were also determined. delta E*ab, delta C*ab, and delta H*ab were analyzed by one-way analysis of variance, t test for dependent samples, and Tukey honestly significant difference (HSD) tests.
  
  
  RESULTS
  delta E*ab values determined for the materials in this study varied in the acceptable range of 1.9 to 2.7. Different aging times caused no significant differences in delta E*ab, delta C*ab, or delta H*ab values for any of the materials. There were no significant differences in the amount of overall color change among the 3 resin cements at the same aging period. Twinlook material showed the greatest chroma change at each aging time. The greatest hue change was determined for Dyract Cem material.
  
  
  CONCLUSIONS
  The light-cure resin cement tested can be proposed as a suitable material for luting laminate veneers, but long-term clinical studies are necessary to verify these experimental findings.
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey. hkoray@isbank.net.tr
authors.forename: C
authors.initials: C
authors.lastname: Hekimoğlu
authors.forename: N
authors.initials: N
authors.lastname: Anil
authors.forename: I
authors.initials: I
authors.lastname: Etikan
mesh_terms: D000465:Algorithms; D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002484:Cementation / Q000379:methods; D003116:Color; D020770:Compomers / Q000737:chemistry; D003801:Dental Veneers; D006801:Humans; D008027:Light; D008689:Methacrylates / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013223:Statistics as Topic; D013499:Surface Properties; D013997:Time Factors
chemical_list: D020770:Compomers; C088486:Dyract; C103503:EnForce-Sure Cure; D008689:Methacrylates; D019279:Resin Cements; D017640:Silicates; C086630:TwinLook cement; D017438:Bisphenol A-Glycidyl Methacrylate