Accuracy of three polyvinyl siloxane putty-wash impression techniques

J Prosthet Dent. 2000 Feb;83(2):161-5. doi: 10.1016/s0022-3913(00)80007-4.


Statement of problem: There is much discussion in the dental literature concerning the effect of the impression technique on the accuracy of cast restorations.

Purpose: This study assessed the accuracy of 3 putty-wash impression techniques using the same impression material (polyvinyl siloxane) in a laboratory model.

Material and methods: The 3 putty-wash impression techniques used were (1) 1-step (putty and wash impression materials used simultaneously); (2) 2-step with 2-mm relief (putty first as a preliminary impression to create 2-mm wash space with prefabricated copings. In the second step, the wash stage was carried out); and (3) 2-step technique with a polyethylene spacer (plastic spacer used with the putty impression first and then the wash stage). For each technique, 15 impressions were made of a stainless steel master model that contained 3 complete crown abutment preparations, which were used as the positive control. Accuracy was assessed by measuring 6 dimensions (intraabutment and interabutment) on stone dies poured from impressions of the master model.

Results: One-way analysis of variance showed statistically significant differences among the 3 putty-wash impression techniques, for all intraabutment and interabutment measurements (P <.001). Overall discrepancies of the 2-step technique with 2-mm relief putty-wash impression technique were significantly smaller than that in the 1-step and polyethylene putty-wash impression techniques.

Conclusion: The polyvinyl siloxane 2-step, 2-mm, relief putty-wash impression technique was the most accurate for fabricating stone dies.

MeSH terms

  • Analysis of Variance
  • Dental Abutments
  • Dental Impression Materials*
  • Dental Impression Technique*
  • Denture, Partial, Fixed
  • Materials Testing
  • Models, Dental*
  • Polyvinyls*
  • Reproducibility of Results
  • Siloxanes*


  • Dental Impression Materials
  • Polyvinyls
  • Siloxanes
  • vinyl polysiloxane