title: Color changes of restorative materials exposed in vitro to cola beverage.
abstract: OBJECTIVE
  The purpose of this in vitro study was to evaluate the color stability of restorative materials when exposed to a cola beverage.
  
  
  METHODS
  Color changes in restorative materials caused by exposure to a cola beverage were studied using a split-plot experimental design. Three restorative materials (composite, resin-modified glass ionomer cement, and compomer) and 3 shades of each material under 2 surface conditions (polished and unpolished) were studied. Using a chromameter, color changes were determined as the difference between color dimensions before and after cola exposure. Scanning electron microscopy was used to characterize the surface morphology of all materials before and after polishing.
  
  
  RESULTS
  72-hour cola exposure resulted in significant changes in color, including gray level and chromaticity, both as a function of materials and their shades. Clinically, these changes compromised both color stability and esthetics in the resin-modified glass ionomer cement in all shades and in composites and compomers in the darkest shade.
  
  
  CONCLUSIONS
  To avoid color degradation through cola, the lighter shades of composites and compomers should be favored over darker C shades to restore anterior and more visible lesions. Resin-modified glass ionomer cement is not recommended in esthetically critical areas due to its tendency to discolor due to cola exposure.
authors.affiliation: Department of Pediatric Dentistry, Dental School, University of Medicine and Dentistry of New Jersey, Newark, NJ, USA.
authors.forename: Madhu
authors.initials: M
authors.lastname: Mohan
authors.forename: Zia
authors.initials: Z
authors.lastname: Shey
authors.forename: Jayalakshmi
authors.initials: J
authors.lastname: Vaidyanathan
authors.forename: Tritala K
authors.initials: TK
authors.lastname: Vaidyanathan
authors.forename: Sivakumar
authors.initials: S
authors.lastname: Munisamy
authors.forename: Malvin
authors.initials: M
authors.lastname: Janal