title: The effect of pouring time on the dimensional accuracy of casts made from different irreversible hydrocolloid impression materials.
abstract: OBJECTIVE
  To determine the time dependent accuracy of casts made from three different irreversible hydrocolloids.
  
  
  METHODS
  The effect of delayed pouring on the accuracy of three different irreversible hydrocolloid impression materials - Regular set CA 37(Cavex, The Netherlands), regular set chromatic (Jeltrate, Dentsply), and fast set (Hydrogum soft, Zhermack Clinical) was investigated. A brass master die that contained two identical posts simulating two complete crown-tapered abutment preparations with reference grooves served as a standardized master model. A total of 120 impressions were made using specially prepared stock-perforated brass tray with 40 impressions of each material. The impressions were further sub-grouped according to four different storage time intervals: 0 min (immediately), 12 min, 30 min, and 1 h. The impressions were stored at room temperature in a zip-lock plastic bag. Interabutment and intraabutment distances were measured in the recovered stone dies (Type IV, Kalrock) using a profile projector with an accuracy of 0.001 mm. The data so obtained was analyzed statistically.
  
  
  RESULTS
  Results of this study showed no statistically significant differences in the accuracy of casts obtained at different time intervals.
  
  
  CONCLUSIONS
  Because it is not always possible to pour the impression immediately in routine clinical practice, all irreversible hydrocolloid materials studied could be stored in a zip-lock plastic bag for upto 1 h without any significant distortion.
authors.affiliation: Department of Prosthodontics, Government Dental College and Hospital, Patiala, Punjab, India.
authors.forename: Supneet Singh
authors.initials: SS
authors.lastname: Wadhwa
authors.forename: Richa
authors.initials: R
authors.lastname: Mehta
authors.forename: Nidhi
authors.initials: N
authors.lastname: Duggal
authors.forename: Kamlesh
authors.initials: K
authors.lastname: Vasudeva
keywords: Accuracy; delayed pouring; dimensional stability; irreversible hydrocolloids; profile projector