title: Influence of Custom Trays, Dual-Arch Passive, Flexed Trays and Viscosities of Elastomeric Impression Materials on Working Dies.
abstract: BACKGROUND
  Dual arch impression technique signifies an essential improvement in fixed prosthodontics and has numerous benefits over conventional impression techniques. The accuracy of working dies fabricated from dual arch impression technique remains in question because there is little information available in the literature.
  
  
  OBJECTIVE
  This study was conducted to compare the accuracy of working dies fabricated from impressions made from two different viscosities of impression materials using metal, plastic dual arch trays and custom made acrylic trays.
  
  
  METHODS
  The study samples were grouped into two groups based on the viscosity of impression material used i.e. Group I (monophase), whereas Group II consisted of Dual Mix technique using a combination of light and heavy body material. These were further divided into three subgroups A, B and C depending on the type of impression tray used (metal dual arch tray, plastic dual arch tray and custom made tray). Measurements of the master cast were made using profile projector. Descriptive statistics like mean, Standard Deviation (SD) were calculated for all the groups. One way analysis of variance (ANOVA) was used for multiple group comparisons. A p-value of 0.05 or less was considered statistically significant.
  
  
  RESULTS
  The gypsum dies obtained with the three types of impression trays using two groups of impression materials were smaller than the master models in dimensions.
  
  
  CONCLUSIONS
  The plastic dual arch trays produced dies which were the least accurate of the three groups. There was no significant difference in the die dimensions obtained using the two viscosities of impression materials.
authors.affiliation: Private Practioner (Prosthodontics), New Delhi, India .
authors.forename: Mansi
authors.initials: M
authors.lastname: Arora
authors.affiliation: Senior Lecturer, Department of Prosthodontics, MAHSA University , Kuala Lumpur, Malaysia .
authors.forename: Shivani
authors.initials: S
authors.lastname: Kohli
authors.affiliation: Reader, Department of Periodontics, Shree Bankey Bihari Dental College , Ghaziabad, U.P, India .
authors.forename: Rupali
authors.initials: R
authors.lastname: Kalsi
keywords: Crown and bridge; Impression; Profile projector; Quadrant; Technique