title: Effect of Storage Time and Temperature on Dimensional Stability of Impressions Made with Zinc Oxide Impression Paste.
abstract: OBJECTIVE
  This study aimed to assess the effect of storage time and temperature on dimensional stability of impressions made with Cavex Outline zinc oxide impression paste.
  
  
  METHODS
  A round stainless steel mold with five grooves (three horizontal and two vertical) was used in this in-vitro experimental study. Cavex Outline impression paste was prepared according to the manufacturer's instructions and applied to the mold. The mold was placed on a block and stored at 35°C and 100% humidity for setting. The impressions were poured with stone immediately and also after 30, 120, 240 and 420 minutes and 24 hours. The distance between the vertical lines on the casts was measured and compared with that in the immediately poured cast.
  
  
  RESULTS
  Storage in a refrigerator and at room temperature for zero to seven hours had no significant effect on dimensional stability of the impressions; however, 24 hours of storage in a refrigerator or at room temperature decreased the dimensional stability of Cavex Outline (P=0.001). Also, a significant association was found between dimensional changes following 24 hours of storage in a refrigerator (4°C) and at room temperature (23°C; P<0.01).
  
  
  CONCLUSIONS
  The optimal pouring time of Cavex Outline impressions with stone is between zero to seven hours, and 24 hours of storage significantly decreases the dimensional stability.
authors.affiliation: Assistant Professor, Department of Prosthodontics, School of Dentistry, International Campus, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Sareh
authors.initials: S
authors.lastname: Habibzadeh
authors.affiliation: Assistant Professor, Department of Prosthodontics, School of Dentistry, International Campus, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Shima
authors.initials: S
authors.lastname: Safaeian
authors.affiliation: Assistant Professor, Department of Dental Materials, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Marjan
authors.initials: M
authors.lastname: Behruzibakhsh
authors.affiliation: Under Graduate Student, International Campus, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Parisa
authors.initials: P
authors.lastname: Kaviyani
authors.affiliation: Statistical Advisor, Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohamadjavad
authors.initials: M
authors.lastname: Kharazifard
keywords: Cavex; Dental Impression Materials; Zinc Oxide