title: Change of optical properties of contemporary resin composites after one week and one month water ageing.
abstract: OBJECTIVE
  To compare color and translucency changes after water ageing for one-week and one-month in light and dark shades of contemporary polychromatic resin composites.
  
  
  METHODS
  Enamel (e) and dentine (d), light and dark (A1 and A4 or equivalents) shades were selected from the composites Enamel-Plus HRi/Micerium, Miris-2/Coltene, IPS Empress-Direct/Ivoclar and Filtek-Supreme/3M ESPE and light and dark shades from the TPH-Spectum/Densply monochromatic composite. Five disks (d = 10mm, h = 1mm) per material, enamel/dentine and light/dark shade were prepared. A colorimetric evaluation, over white and black background, according to the CIELab system was performed just after preparation and after one-week and one-month dark water-storage at 37°C. Color (ΔEab) and translucency (ΔTP) differences were calculated. Results were analysed by ANOVA and Scheffe's test, paired t-test and linear regression analysis (a = 0.05).
  
  
  RESULTS
  One-week water ageing provided a wide range of ΔEab values (0.79 Filtek(e)/D2 to 5.19 Filtek(d)/A1) and ΔTP values (-2.74 Hri/UD1 to 1.03 TPH/A1). After one-month water ageing ΔEab ranged from 1.09 Filtek(e)/D2 to 7.94 Filtek(d)/A1 and ΔTP values from -2.71Hri/UD1 to 1.07 Filtek(d)/A4. Significant changes in ΔEab between one-week and one-month water ageing were noted for Filtek and Miris dentine and Miris light enamel shades. As for ΔTP, significant difference was recorded only for IPS(e)/A4. ΔEab was significantly correlated with ΔL, Δα, Δb and ΔTP after one-week and with ΔL and Δα after one-month ageing.
  
  
  CONCLUSIONS
  Water ageing caused remarkable color changes, which were material and shade depended. Thirteen out of eighteen of the tested composites exhibited clinically perceptible (ΔEab>2.6) color changes even after short water ageing period.
authors.affiliation: Department of Operative Dentistry, Dental School, University of Athens, Greece. Electronic address: sophia.diamantopoulou@gmail.com.
authors.forename: Sofia
authors.initials: S
authors.lastname: Diamantopoulou
authors.forename: Efstratios
authors.initials: E
authors.lastname: Papazoglou
authors.forename: Vasileios
authors.initials: V
authors.lastname: Margaritis
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Lynch
authors.forename: Afrodite
authors.initials: A
authors.lastname: Kakaboura
mesh_terms: D003116:Color; D003124:Colorimetry / Q000379:methods; D003188:Composite Resins / Q000737:chemistry*; D003624:Darkness; D003764:Dental Materials / Q000737:chemistry*; D006801:Humans; D008027:Light; D008422:Materials Testing; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry*
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C474035:Filtek Supreme; C467914:TPH spectrum; D014867:Water
keywords: Color; Composites; Translucency; Water ageing