title: Comparative analysis of dimensional precision of different silicone impression materials.
abstract: OBJECTIVE
  To investigate the accuracy of four commercial types of additional silicone impression materials (AFFINIS®, Virtual®, Relay 2002 CD® and Silagum®).
  
  
  METHODS
  The accuracy of impression material was measured indirectly by measuring three dimensions on stone cast poured from impressions of a stainless steel master model. The three dimensions on stone cast were measured at 1 hour, 2 days, 1 and 2 weeks after making the impression. Two impression techniques were used in the current study. The two-step impression technique was used for AFFINIS® and Virtual®, while single-step technique was used for Relay 2002 CD® and Silagum® materials. Twenty impressions were made of the master cast at four different periods for each of the tested four materials with a total of 320 impressions. Two vertical dimensions and one horizontal dimension were measured on master cast using optical microscope. Statistical analysis was run to compare the mean measurements for tested casts from each impression and time interval with the master cast.
  
  
  RESULTS
  No statistical significant differences were found (p > 0.05) in the accuracy of tested materials. There was no significant difference of master cast and impression cast means over time. Additionally, impression technique could be correlated with accuracy.
  
  
  CONCLUSIONS
  The tested additional silicones showed accuracy over time and they could be delayed up to 4 weeks duration without any significant changes in its dimensional stability. Silagum® impression material was the most accurate followed by Relay 2002 CD®, Virtual® and AFFINIS®.
  
  
  CONCLUSIONS
  Silagum® impression material is most accurate followed by Relay 2002 CD®, Virtual® and AFFINIS®.
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry Al Jouf University, Al Jouf, Saudi Arabia.
authors.forename: Bader K
authors.initials: BK
authors.lastname: Al-Zarea
authors.forename: Mohamed G
authors.initials: MG
authors.lastname: Sughaireen
mesh_terms: D000704:Analysis of Variance; D003760:Dental Impression Materials; D003761:Dental Impression Technique; D008422:Materials Testing; D003765:Models, Dental; D011145:Polyvinyls; D015203:Reproducibility of Results; D012833:Siloxanes; D013997:Time Factors
chemical_list: D003760:Dental Impression Materials; D011145:Polyvinyls; D012833:Siloxanes; C034183:vinyl polysiloxane