title: Effect of gypsum separating media on the appearance of stone cast surfaces.
abstract: BACKGROUND
  Several well-known parameters influence the appearance of the denture base surface, including proper isolation of the dental stone. There is lack of data describing the influence of this parameter on the appearance of the denture base surface.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the effectiveness of 2 dental stone separating media on the surface of the denture base.
  
  
  METHODS
  A conventional flasking technique for fabricating a denture base was used. Twenty casts were poured with Type III yellow dental stone to produce 20 identical denture bases. Each cast was sectioned into halves. One half of the cast was treated with Al-Cote (control group) and the other half with Iso-K separating material. Once the denture base was finished, a single examiner, blinded to the experiment, visually compared the 2 surfaces of each cast (right and left part of the cast) under natural light to determine which surface was glossier. The McNemar test (.05 significance level) was used to compare the discordant pairs (20 discordant pairs).
  
  
  RESULTS
  Two pairs (10%) were glossier than the Iso-K treatment, and 18 pairs (90%) within the Iso-K treatment were glossier than the treatment with Al-Cote. A statistically significant difference was found between the 2 treatments (P<.001). The odds ratio was 9.00, with a 95% confidence interval of 2.155 to 79.981.
  
  
  CONCLUSIONS
  When used according to the manufacturer's instructions, denture surfaces treated with Iso-K appeared glossier than when treated with Al-Cote separating material.
authors.affiliation: Assistant Professor of Clinical Dentistry, Division of Restorative Science, Chair of Removable Section, Ostrow School of Dentistry of USC, University of Southern California, Los Angeles, Calif. Electronic address: thk@usc.edu.
authors.forename: Tae Hyung
authors.initials: TH
authors.lastname: Kim
authors.affiliation: Assistant Professor of Clinical Dentistry, Division of Restorative Science, Ostrow School of Dentistry of USC, University of Southern California, Los Angeles, Calif.
authors.forename: Tae Jun
authors.initials: TJ
authors.lastname: Ahn
authors.affiliation: Assistant Professor of Clinical Dentistry, Division of Dental Public Health and Pediatric Dentistry, Ostrow School of Dentistry of USC, University of Southern California, Los Angeles, Calif.
authors.forename: Reyes
authors.initials: R
authors.lastname: Enciso
authors.affiliation: Clinical Assistant Professor, Division of Restorative Science, Ostrow School of Dentistry of USC, University of Southern California, Los Angeles, Zagreb, Croatia.
authors.forename: Alena
authors.initials: A
authors.lastname: Knezevic
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D002133:Calcium Sulfate / Q000737:chemistry*; D003734:Dental Casting Investment / Q000737:chemistry; D003735:Dental Casting Technique; D003764:Dental Materials / Q000737:chemistry*; D003819:Denture Bases; D003779:Denture Design; D006801:Humans; D008027:Light; D008422:Materials Testing; D003765:Models, Dental; D058105:Polymerization; D013499:Surface Properties
chemical_list: D000180:Acrylic Resins; D003734:Dental Casting Investment; D003764:Dental Materials; C040291:Lucitone; D002133:Calcium Sulfate