title: Comparison of color stability of a composite resin in different color media.
abstract: BACKGROUND
  Color change of composite restorations in different color media during the time is a common problem in esthetic dentistry, causing the need to replace the restoration, and spending a great deal of cost and time to patients. The aim of this study is to investigate the effects of different common drinks consumed by patients on one of the widely used composites in dentistry.
  
  
  METHODS
  Sixty-five disk-shaped specimens were prepared with a light-cured composite (Z100-shade A2) and divided into five groups of 13 specimens. Samples of each group were immersed in staining solutions (tea, coffee, lemonade, and cola) and distilled water (as control). Color values (L*, a*, b*) were measured relative to the standard illuminant D65 over a white background, using the CIE L*a*b* system. Color change values were calculated before and after 1, 7, and 14 days of immersion. Repeated measures and one-way analysis of variance (ANOVA) and paired t tests were applied for statistical analysis.
  
  
  RESULTS
  Tea and coffee produced the most discoloration, whereas, water exhibited the least color change after immersion for 14 days in Z100 (P < 0.05). After one day of immersion, coffee caused the lowest discoloration in the test composite, compared to tea, cola, distilled water, and lemonade (P < 0.05).
  
  
  CONCLUSIONS
  Staining solutions and immersion time are significant factors that affect color stability of composite resins.
authors.affiliation: Department of Operative Dentistry, Faculty of Dentistry, Azad University, Khorasgan (Isfahan Branch), Isfahan, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Malekipour
authors.forename: Ala
authors.initials: A
authors.lastname: Sharafi
authors.forename: Shantia
authors.initials: S
authors.lastname: Kazemi
authors.forename: Saber
authors.initials: S
authors.lastname: Khazaei
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Shirani