Tensile elastic recovery of elastomeric impression materials

Academic Article

Abstract

  • Statement of problem: Currently, a standard protocol exists to measure the elastic recovery of impression materials from compressive strain; however, no protocol exists for the measurement of elastic recovery from tensile strain. Purpose: The purpose of this study was to compare elastic recovery from tensile strain test with the ISO elastic recovery test for 5 vinyl polysiloxane materials (Aquasil Ultra, Examix, Genie, Imprint 3, and StandOut) and 1 hybrid material (Senn). Material and methods: Specimens (n=5) were fabricated in a brass mold and loaded in tension with a crosshead speed of 300 mm/min to 50% or 100% strains. Two hours following specimen elongation, the change in length of the specimens was measured. Additional specimens (n=5) were tested in tension until failure at 200 mm/min. The maximum elongation at failure was recorded. Elastic recovery specimens (n=4) were prepared for each material following ISO standard 4823. The change in dimension of these specimens was measured following a 30% compressive strain. Group means were compared using 1-way ANOVA and Tukey-Kramer HSD test (α=.05). Correlation between different tests was evaluated using Pearson's correlation coefficient. Results: Vinyl polysiloxane materials of varying composition demonstrated significantly different elastic recovery, and the hybrid material demonstrated the least elastic recovery in both tests. All materials exceeded a 100% elongation before failure. Significant linear correlation was found between means of the ISO method and those of a 100% tensile strain (r2=0.69, P=.039), but not those of a 50% tensile strain (r2=0.56, P=.086). Conclusions: Elastic recovery from compressive strain can only partially predict elastic recovery from tensile strain, suggesting that elastic recovery from tensile strain is a relevant test. (J Prosthet Dent 2008;100:29-33). © 2008 The Editorial Council of the Journal of Prosthetic Dentistry.
  • Published In

    Digital Object Identifier (doi)

    Author List

  • Lawson NC; Burgess JO; Litaker MS
  • Start Page

  • 29
  • End Page

  • 33
  • Volume

  • 100
  • Issue

  • 1