title: Color stability over time of three resin-based restorative materials stored dry and in artificial saliva.
abstract: OBJECTIVE
  To evaluate the color match of different composite resins relative to Vitapan Classical shade guide tab and their respective manufacturers' shade guide tabs as a function of time and storage.
  
  
  METHODS
  Three enamel shade A2 composite resins were used to fabricate 36 disk-shaped polymerized specimens (12 each), allocated into 2 groups of 6 and stored dry (GD) and in artificial saliva (GS). CIELAB coordinates from shade tabs and resin specimens immediately after polymerization (t0), and 24 hours (t1), 7 (t7), 14 (t14) and 21 (t21) days after polymerization were captured using a colorimeter. Color difference (ΔE00 ) between composite specimens and the reference tabs was calculated using the CIEDE2000 formula. The results were analyzed with repeated measures ANOVA, Tukey's HDS post-hoc test, and Student t test (p ≤ 0.05).
  
  
  RESULTS
  Color of the three tested composites relative to Vita and their respective tabs significantly changed as a function of time until t14; however, between t14 and t21, no significant differences were found. No differences in color were found relative to storage at t14 and t21. ΔE00 values of specimens at t14 were significantly higher relative to their respective tabs than to Vitapan tab.
  
  
  CONCLUSIONS
  For all brands color changed up to day 14, when it stabilized, regardless of whether composite specimens had been stored in artificial saliva or simply in a box. Vitapan tab presented a better color match than the manufacturers' tabs.
  
  
  CONCLUSIONS
  The results found in this study demonstrated that the Vitapan Classical shade guide tab A2 provided a better color match than the respective shade guide tabs A2 supplied by the composite manufacturers. If custom shade tabs are to be made, however, they could be kept in a box and used as shade references from 14 days after being fabricated, when color stabilizes.
authors: Department of Dentistry, State University of Maringá, Maringá, Paraná, Brazil.
authors: Joana Yumi Teruya
authors: JY
authors: Uchimura
authors: Francielle
authors: F
authors: Sato
authors: Giselly
authors: G
authors: Bianchi
authors: Mauro Luciano
authors: ML
authors: Baesso
authors: Rosângela Geritana
authors: RG
authors: Santana
authors: Renata Corrêa
authors: RC
authors: Pascotto
mesh_terms: D003116:Color; D003124:Colorimetry / Q000295:instrumentation / Q000379:methods; D003188:Composite Resins; D003793:Dental Restoration, Permanent; D012463:Saliva
chemical_list: D003188:Composite Resins