Figure 5-10. Instruments and materials for irreversible hydrocolloid impressions.
(a) When irreversible hydrocolloid is used, the dental specialist
prepares the impression material in strict accordance with the manufacturer's
instructions. During its manipulation, the assistant should prevent the entrapment of air
bubbles in the material by sifting the powder into the water, by using a stirring rather
than a whipping motion, and by spreading the mix around the walls of the mixing bowl
just before completion. Mixing should be done in the time specified by the
manufacturer. After the material is mixed, the impression tray is filled, the excess
material in the bowl is presented to the dental officer, and then the filled tray is passed
to the dental officer who will make the impression.