Influence of elastic recovery time on the Dimensional Stability of Polydimethylsiloxane (PDS)






The aim of this study was to determine the influence from the recovering time on the dimensional stability of polydimethylsiloxane (Speedex, Coltène/Whaledent Company, Altstätten, Switzerland) prior to type IV dental stone pouring. The double impression technique was utilized with uniform spacing of 1 mm for the wash paste, at 30 minutes, 24 hours and 72 hours after making the impression using an individual perforated metal tray. After the preparation of the impressions, six stone models were made by the standard procedure for all the impressions. The dimensional alterations (mm) of the models obtained were submitted to analysis of variance (ANOVA) and Tukey's test (α = 0.05). No statistically significant difference between the three groups (30 minutes, 24 hours and 72 hours) were recorded for either the height or diameter of the samples. However, upon comparing the results of the three groups with the metal standard model, there was a significant difference between group 1 (30 min) in relation to the diameter of the standard metal die (p = 0,047). The condensation silicone Speedex shows satisfactory dimensional stability, where dental stone models can be poured with assurance up to 72 hours after preparation of the impression.

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