Curing contraction of some elastomeric impression materials

ABSTRACT

The curing contraction in% [%] of seven elastomeric impressionmaterials, available on the Egyptian market, was measured by means of amercury bath technique. Measurements were done at different time intervalsafter mixing for 15 min, 60 min and 24 hr. Four of the elastomeric impressionmaterials tested in the present study [Coltex, Impregum, Brovil and Reproisl]showed a curing contraction of 0.08% after 24 hr. Although the presenttechnique is a simple test compared to ADA No. 19 for measuring thedimensional changes of elastic impression materials, yet the effectivecontraction determined as the accuracy of stone dies produced by dentalimpressions perhaps is more realistic than the free contraction of theimpression by either mercury bath technique or by the ADA No. 19