Dimensional accuracy and stability of a claimed to be stable alginate

ABSTRACT

Dimensional changes of three brands of irreversible hydrocolloid impression materials were evaluated immediately and after eight different periods of storage up to 96 hours at 100% relative humidity. The manufacturer of one of these brands [Kromopan] claims that the model can be cast within 100 hours with very good results if the impression is kept in a plastic envelope without any other addition. Stone casts were obtained after storage of the impressions for the different periods of time, then horizontal and vertical changes were measured by means of a micrometer. The results showed that the best dimensional accuracy and, the least dimensional change occurred at immediate pour followed by impressions stored for 1/2 hour. While 96-hour-storage time produced the highest dimensional change in all the impressions