Abstract
Dimensional changes of 23 brands of conventional and dustless alginate impression materials in various environments were directly measured by restraining the deformation induced by measuring load on materials soon after the initial setting.A wide range of contraction due to syneresis of the material itself was observed in 100% relative humidity.The expansion due to imbibition in water was greatly influenced by syneresis.An additive for dustlessness seemed to be less of an influence on the dimensional stability of the alginate, but an alternation of filler contributed to reduce the contraction in 100% relative humidity and in air.
