title: Color stability of restorative materials in response to Arabic coffee, Turkish coffee and Nescafe.
abstract: OBJECTIVE
  To evaluate the effect of Arabic coffee, Turkish coffee and Nescafe on the color stability of four different composite resins after a period of aging time 1, 7 and 30 days.
  
  
  METHODS
  Twenty specimens from each type of tested composite resin material were prepared. Five specimens from each tested material (Z350 XT, Artist, GC and Z250) was evaluated after storage in Arabic coffee, Turkish coffee, Nescafe and distil water (control) at 37°C in a dark container for 1, 7 and 30 days. Color measurement was done using colorimeter based on the CIE L* a* b* color scale. Color differences ΔE*ab, Δb* and Δa* among specimens immersed in distil water and staining coffee beverages were evaluated overtime. Mean values were statistically analyzed with one-way analysis of variance (ANOVA), followed by Tukey test with p < 0.05 as significance level.
  
  
  RESULTS
  All tested composite resins showed increase color change after a period of 1, 7 and 30 days. The color change ΔE*ab , Δb* and Δa* exhibited by Arabic coffee, in Turkish coffee and Nescafe except Δa*. The highest total color difference ΔE*ab after 30 days was in group A Arabic coffee (ΔE > 1.5 perceivable) and not perceivable in group B Turkish coffee and group C Nescafe. For Δb* all materials discolored toward yellowness after 30 days except Arabic coffee group which shifted from yellowness toward blueness (Δb*> 1.5 perceivable).
  
  
  CONCLUSIONS
  The effect of staining beverages on the resin composite materials increases with time of aging toward yellowness and not perceivable in all groups except with Arabic coffee which had highest effect after 30 days and the discoloration shifted from yellowness to blueness perceivable.
authors.affiliation: Assistant Professor and Consultant, Department of Restorative Dental Science, College of Dentistry, Taibah University, Al Madinah Al Munawwarah-43353, Saudi Arabia, e-mail: kalsamadani@yahoo.com.
authors.forename: Khalid H
authors.initials: KH
authors.lastname: Al-Samadani
mesh_terms: D003069:Coffee / Q000145:classification*; D003116:Color; D003124:Colorimetry; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry*; D019279:Resin Cements / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D003069:Coffee; D003188:Composite Resins; D003764:Dental Materials; C444701:Filtek Z250; D005899:Glass Ionomer Cements; D019279:Resin Cements; C533204:filtek Z350; D014867:Water