Journal of Dental Research, Vol 59, 1152-1155, Copyright © 1980 by International & American Associations for Dental Research Online Journals
Linear dimensional changes in elastic impression materials
C. F. Marcinak, F. A. Young, R. A. Draughn and W. R. Flemming
Four classes of elastomeric impression materials (polysulfide, polyether,
silicone, and agar-agar) were evaluated on the basis of linear dimensional
stability as a function of time between taking and pouring an impression of
mounted teeth. Four polysulfide materials produced dies which were larger
than the teeth and generally increased in size with impression storage
time. One silicone material produced dies slightly smaller than the teeth,
and the dies from another silicone were dramatically smaller with
increasing storage times. A polyether material produced slightly smaller
dies for up to four hours' storage time, then increasingly larger dies up
to 24 h. The dies from a reversible hydrocolloid were larger than the teeth
for storage times up to 30 min, and then decreased rapidly at longer times.
