title: Color stability of visible light-cured, hard direct denture reliners: an in vitro investigation.
abstract: OBJECTIVE
  Previous studies have disclosed the unsatisfactory color stability of autopolymerizing, hard direct denture reliners (HDDR). The present study investigated the color stability of the newly introduced visible light-cured and dual-cured HDDRs.
  
  
  METHODS
  Five HDDRs were evaluated after 1 hour, 1 day, 7 days, and 30 days of immersion in coffee, tea, and water. Color measurements were obtained with a tristimulus colorimeter, and color differences (delta E*) were calculated.
  
  
  RESULTS
  After 30 days of immersion one visible light-cured material exhibited the highest delta E* value (17.8). The other materials showed acceptable color stability in water and coffee. However, tea strongly affected their color.
  
  
  CONCLUSIONS
  Reliners, staining solutions, and immersion time are significant factors that affect color stability. After 7 days of immersion, all of the materials showed perceptible color differences. Tea exhibited higher staining capacity than coffee.
authors.affiliation: Department of Prosthodontics, School of Dentistry, University of Athens, Greece. remprath@internet.gr
authors.forename: G L
authors.initials: GL
authors.lastname: Polyzois
authors.forename: S A
authors.initials: SA
authors.lastname: Yannikakis
authors.forename: A J
authors.initials: AJ
authors.lastname: Zissis
mesh_terms: D000704:Analysis of Variance; D003822:Denture Liners; D003823:Denture Rebasing; D005069:Evaluation Studies as Topic; D008027:Light; D008422:Materials Testing; D017797:Prosthesis Coloring; D012117:Resins, Synthetic / Q000737:chemistry*
chemical_list: D012117:Resins, Synthetic