title: A comparative evaluation of the dimensional stability of three different elastomeric impression materials after autoclaving - an invitro study.
abstract: OBJECTIVE
  The purpose of the study was to determine the effect of autoclaving on the dimensional stability of three different elastomeric impression materials at three different time intervals.
  
  
  METHODS
  Standardized stainless steel master die as per ADA specification number 19 was fabricated. The impression materials used for the study were condensation silicone (GP1), addition silicone (GP2) and polyether (GP3). A total of 45 samples of the stainless steel die were made (n = 45), that is 15 samples for each group. Impression materials were mixed according to the manufacturer's instructions and were loaded into the mold to make an impression of the die. Impressions were identified with the help of numerical coding system and measurements were made using stereomicroscope (MAGNUS MSZ-Bi) of 0.65x magnification with the help of image analysis software (IMACE PRO-INSIGHT VERSION.The results were subjected to statistical analysis using one way analysis of variance and student t-test for comparison between the groups.
  
  
  RESULTS
  Within the limitations of the study statistically significant dimensional changes were observed for all the three impression materials at three different time intervals but this change was not clinically significant.
  
  
  CONCLUSIONS
  It is well-known fact that all impressions should be disinfected to avoid possible transmission of infectious diseases either by direct contact or cross contamination. Immersion and spray disinfection as well as various disinfection solutions have been tested and proven to be effective for this purpose. But for elastomeric impression materials these methods have proven to be ineffective as they do not prevent cross contamination among the dental team. So autoclaving was one of the most effective sterilization procedure for condensation silicone and addition silicone. Since polyether is hydrophilic it is better to disinfect the impressions as recommended by the manufacturer or by immersion or spray atomization.
authors.affiliation: Reader, Department of Prosthodontics, Kamineni Institute of Dental Sciences, Sreepuram , Narketpally, Nalgonda, Telangana, India .
authors.forename: Kiran Kumar
authors.initials: KK
authors.lastname: Thota
authors.affiliation: Post Graduate Student, Department of Prosthodontics, Kamineni Institute of Dental Sciences, Sreepuram , Narketpally, Nalgonda, Telangana, India .
authors.forename: Sujana
authors.initials: S
authors.lastname: Jasthi
authors.affiliation: Reader, Department of Prosthodontics, Kamineni Institute of Dental Sciences, Sreepuram , Narketpally, Nalgonda, Telangana, India .
authors.forename: Rajyalakshmi
authors.initials: R
authors.lastname: Ravuri
authors.affiliation: Reader, Department of Prosthodontics, Kamineni Institute of Dental Sciences, Sreepuram , Narketpally, Nalgonda, TElangana, India .
authors.forename: Suchita
authors.initials: S
authors.lastname: Tella
keywords: Dimensional accuracy; Elastomeric impression materials; Infection control; Storage time