1-18. PREPARATION AND USAGE OF GLASS IONOMER CEMENT
a. Equipment. The equipment required for mixing glass ionomer cement
consists of a polymer paper pad or a glass mixing slab, a stainless steel spatula, and a
matched set of powder and liquid.
b. Powder and Liquid. The normal ratio is one level scoop of powder to two
drops of liquid. For cement bases, more powder may be added to the mix to achieve a
thicker consistency. For accurate proportioning, shake the powder bottle to fluff the
powder. Then, fill the scoop that comes with the bottle of powder without packing the
powder down. When removing the scoop from the bottle, slide it against the plastic lip
in the neck of the bottle to scrape off excess powder. Be sure to hold the bottle of liquid
vertically when dispensing drops of liquid so as to produce precise and uniform drops
(see figure 1-6).
c. Mixing. All powder is incorporated into the liquid in two or three large
increments. Each portion of the powder should be added to the liquid all at once. To
extend the working time, mix the powder and the liquid on a cold and dry glass slab. At
room temperature, the mix should be completed in about one minute (60 seconds).
d. Characteristics of a Completed Mix. The right consistency is obtained
when the material breaks away from the spatula when it is raised one-half inch from the
Figure 1-6. Dispensing uniform drops of glass ionomer liquid.