The purpose of this study was to investigate the tensile strength and flexibility of four automixing additional silicone rubber impression materials. To evaluate the tear resistance of impression material, the automixed impression material was
cured in
a 32℃ water bath with the necked specimen preparation mold for 5 minutes. Three minutes after the withdrawl from the specimens were tested for their maximum tensile strength with universal testing machine(Instron 4302, England). To evaluate the
flexibility of the impression materials, the cylindricla specimen was compress 10% of the original length, and the stress produced by the impression materials, the cylindricla specimen was evaluated. The flexibility of the cylindrical specimen
was
evaluated at 2 minutes-, 1 hour-, and 24 hours- after being withdrawn from the curing water bath by checking the stress at 10% compression.
@ES The results were as follows:
@EN 1. Examixfine showed the highest tensile strenght value at 18.11Kg/㎠ followed by Provil L C.D. at 16.77 Kg/㎠. The next was Express at 12.40 Kg/㎠ and Correct VPS showed a significantly low value at 9.62Kg/㎠ when compared with other
groups(P<0.01).
2. Under the 10% compression. Correct VPS showed significantly low stress at 1.511Kg/㎠ when compared with other groups(P<0.01). The other groups were Examinxfine at 1.897Kg/㎠. Provil at 2.025Kg/㎠, and Express showed significantly higher
stress
at
3.689Kg/㎠(P<0.01).
3. The order of stress from lowest to highest for the 10% compression at 1 hour- and 24 hours- after being withdrawn from the curing water bath was Correct VPS. Examixfine, Provil L C. D., and Express. In all experimental groups the stress for
dimensional shortening increased as the elapsed time increased.
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