title: [Color stability of ceromer veneers/resin cements after accelerated ageing].
abstract: OBJECTIVE
  To investigate the color stability of ceromer veneers/resin cements after accelerated ageing, and to provide the reference for clinical application and choice.
  
  
  METHODS
  Fifteen groups of ceromer veneers/resin cements samples, five samples in each group, were prepared as experimental groups.In the fifteen groups, ceromer veneers in three thickness (1.00, 0.75, 0.50 mm) and resin cements of five shades(A1,A3, B 0.5, WO, TR), were matched through permutation and combination. Three groups of ceromer veneers with different thickness (1.00, 0.75, 0.50 mm) were used as control groups. All samples were put into xenon lamp ageing instrument to accelerate ageing.Spectrophotometer were used to measure the lightness(L(*)), red green color(a(*)) and blue yellow color(b(*)) of samples before and after accelerated ageing process, and the change of lightness (ΔL) , red green color (Δa) , blue yellow color (Δb) and color variation(ΔE) were calculated.We investigated the effect of thickness of ceromer veneer and color of resin cement on color variation by using analysis of variance.
  
  
  RESULTS
  The thickness factor and color factor showed significant effect on ΔE values, and they have interaction (P < 0.05). The ΔE values of all experimental groups were lower than 3.3. After accelerated ageing, all L(*) values of experimental groups decreased, and ΔL values were lower than 2.0.
  
  
  CONCLUSIONS
  The thickness of ceromer veneer and the color of resin cement could both affect the color stability of ceromer veneers/resin cements. The changes of lightness and color in ceromer veneers/resin cements were considered clinically acceptable after accelerated ageing.
authors.affiliation: Department of Stomatology, Boai Hospital, China Rehabilitation Research Center, Beijing 100068, China. Email: distancewlk@163.com.
authors.forename: Likai
authors.initials: L
authors.lastname: Wang
authors.forename: Yanan
authors.initials: Y
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Zheng
authors.forename: Pingping
authors.initials: P
authors.lastname: Li
authors.forename: Lianshui
authors.initials: L
authors.lastname: Shi
mesh_terms: D002516:Ceramics; D003116:Color; D003188:Composite Resins; D003776:Dental Porcelain; D003801:Dental Veneers; D006801:Humans; D008027:Light; D019279:Resin Cements
chemical_list: D003188:Composite Resins; D019279:Resin Cements; C111841:ceromer; D003776:Dental Porcelain