Objective:The aim of this study is to evaluate the dimensional stability of 1 synthetic gypsum of V class and a polyurethan reinforced by silica. Materials and Methods:According to ISO 4823 standardisation, 12 metallic specimens were prepared using the micrometric system, with diameters of 7±0,01mm, and heights of 3±0,01mm. 15 imprints of the metallic specimens were made (bifase tecnic) using a vinyl polysiloxan (Express STD, 3M). After ward the imprints were casted with to synthetic gypsum of V class (Perio Tuff Rock Formula 44, Periodent), and a polyurethan reinforced by silica (Quartz Die, Zhermack). The imprints were casted after 2 hours, and gypsum were mixed at a vacuum level following the time and the dose indicated by the manufactures. The imprints casted with the polyurethan reinforced by silica were pre-treated with a spray isolator (QD Separator, Zhermack), to reduced the surface tension of the imprints materials. The measurements were effected trough a computerised system that include the imprint scannerization, and the results were deemed significant based on the student statistical t-test (p<0,05).Results: Express STD (3M) -0,3% Perio Tuff Rock Formula 44 (Periodent) +0,18% Quartz Die (Zhermack) +0,1% Conclusion:From the date it emerged that the materials underwent contraction that remained within the specific n.°19 of the ADA and the polyurethan reinforced by silica, underwent low dimensional expansion comparison to gypsum of V class tested.

Back to the Dental Materials: VIII - Others-Non-metallic Program
Back to the IADR/AADR/CADR 80th General Session (March 6-9, 2002)

Top Level Search