title: Dimensional accuracy of improved dental stone and epoxy resin die materials. Part I: Single die.
abstract: BACKGROUND
  Improved dental stone has been widely used for producing dies for the fabrication of restorations with the lost-wax technique. Improved dental stone is used for several reasons, but it is selected most often because of its reasonable cost, ease of use, and ability to produce consistent results.
  
  
  OBJECTIVE
  This study evaluated the ability of an epoxy resin die material and a type IV dental stone to dimensionally reproduce a custom-fabricated metal die.
  
  
  METHODS
  Dies were fabricated and measurements were made from three reference lines. Measurements were repeated three times for the master die and for the specimen dies. A mean measurement and percent relative change for each dimension was calculated.
  
  
  RESULTS
  A significant difference in the relative change for die height was found between the groups studied (p < 0.003).
  
  
  CONCLUSIONS
  This epoxy die system will provide a degree of dimensional accuracy comparable to gypsum when used with addition silicone impression material.
authors.affiliation: Department of Adult Restorative Dentistry, University of Nebraska Medical Center College of Dentistry, Lincoln, USA.
authors.forename: N R
authors.initials: NR
authors.lastname: Chaffee
authors.forename: J H
authors.initials: JH
authors.lastname: Bailey
authors.forename: D J
authors.initials: DJ
authors.lastname: Sherrard
mesh_terms: D000704:Analysis of Variance; D002133:Calcium Sulfate; D003760:Dental Impression Materials; D003761:Dental Impression Technique / Q000295:instrumentation; D004853:Epoxy Resins; D005069:Evaluation Studies as Topic; D003765:Models, Dental / Q000592:standards; D015203:Reproducibility of Results; D012828:Silicones; D013674:Technology, Dental / Q000592:standards
chemical_list: D003760:Dental Impression Materials; D004853:Epoxy Resins; D012828:Silicones; D002133:Calcium Sulfate