IADR Abstract Archives
Viscoelastic Properties of Normal and Fast Set Alginate Impression Materials
Objectives: Investigation of viscoelastic properties of a normal and fast set alginate impression material in terms of time and degree of undercut compression.
Methods: Normal and fast set alginate material (n = 15)(Aroma Fine Plus, GC Cooperation, Japan) cylinders (20mm x Ø10mm) were subjected to 25% and 40% compression. The materials were held in compression for 1 second to simulate the “Snap” technique and 2 seconds for a slow removal technique prior to soaking in a chlorine solution (Haz-tab, Guest Medical Ltd, UK) for 5 minutes to simulate cross-infection control protocols. The cylinder heights were measured pre and post compression using an electronic dial gauge (Mitutoyo IDC-1012E, Mitutoyo Corp, Japan). Cryo-scanning electron microscopy analysis (n = 1) was carried out to visualise the polysaccharide polymer chains before and after compression.
Results: There was no statistically significant difference (P > 0.05) between the fast and slow speed compression times. There was a statistically significant difference (P < 0.05) between the 25% and 40% compression in terms of elastic recovery. Neither group showed full elastic recovery with a mean recovery of the 25% compression - 98.19% and the 40% compression -92.09%. The Cryo-SEM analysis showed ruptured polymer chains in the 40% compression groups.
Conclusions: The degree of tooth undercut in relation to the spacer provided by the impression tray design is a significant factor in the elastic recovery of both fast and slow set alginate impression materials. The speed of removal from the mouth does not appear to affect the elastic recovery of both fast and slow set alginate impression materials.
Methods: Normal and fast set alginate material (n = 15)(Aroma Fine Plus, GC Cooperation, Japan) cylinders (20mm x Ø10mm) were subjected to 25% and 40% compression. The materials were held in compression for 1 second to simulate the “Snap” technique and 2 seconds for a slow removal technique prior to soaking in a chlorine solution (Haz-tab, Guest Medical Ltd, UK) for 5 minutes to simulate cross-infection control protocols. The cylinder heights were measured pre and post compression using an electronic dial gauge (Mitutoyo IDC-1012E, Mitutoyo Corp, Japan). Cryo-scanning electron microscopy analysis (n = 1) was carried out to visualise the polysaccharide polymer chains before and after compression.
Results: There was no statistically significant difference (P > 0.05) between the fast and slow speed compression times. There was a statistically significant difference (P < 0.05) between the 25% and 40% compression in terms of elastic recovery. Neither group showed full elastic recovery with a mean recovery of the 25% compression - 98.19% and the 40% compression -92.09%. The Cryo-SEM analysis showed ruptured polymer chains in the 40% compression groups.
Conclusions: The degree of tooth undercut in relation to the spacer provided by the impression tray design is a significant factor in the elastic recovery of both fast and slow set alginate impression materials. The speed of removal from the mouth does not appear to affect the elastic recovery of both fast and slow set alginate impression materials.