Laboratory comparative study of wettability, dimensional changes, flexibility and tear resistance of two recent elastomeric impression materials

Abstract

Purpose: The purpose of this study was to assess and compare wettability, dimensional changes, flexibility and tear resistance of two recent elastomeric impression materials, vinyl polyether silicone (VPES) hybrid material and polyvinyl siloxane (PVS) containing nanofillers with conventional PVS and polyether (PE) impression materials. Materials and methods: The elastomeric impression materials are divided into four groups, two experimental: VPES (EXA'lence) and PVS containing nanofillers (Elite HD+) and two control groups: PVS (Imprint II) and PE (Impregum Soft). The properties that were investigated are wettability, dimensional changes%, flexibility and tear resistance. Ten specimens were made for each property of all groups. Results: The results indicated that VPES (EXA'lence) and PE (Impregum Soft) showed the highest wettability. PVS containing nanofillers (Elite HD+) showed the lowest dimensional changes%. The strain in compression % (flexibility) of PE, VPES and PVS were not significantly different from each other and they were significantly different from PVS containing nanofillers which showed the lowest strain in compression%. The tear resistance (N/mm) of PVS containing nanofillers (Elite HD+) and VPES (EXA'lence) were significantly higher than PE (Impregum Soft) and PVS (Imprint II) which were not significantly different from each other. Conclusion: All tested materials were hydrophilic specially VPES and PE which recorded the highest wettability. All tested mterials showed accepted dimensional changes according to ANSI/ADA No. 19 and PVS containing nanofillers showed the greatest dimensional stability. All materials recorded accepted flexibility according to ANSI/ADA No. 19. As related to flexibility; PE, VPES and PVS recorded higher flexibility than PVS containing nanofillers while PVS containing nanofillers and VPES showed the highest tear resistance.