Answer is D
It must have an acid-base reaction (i.e. metal + acid= salt). You must mix materials
together to have a true glass ionomer. Calcium initially and the later aluminum replaces the hydrogen ions on the carboxyl groups resulting in the post set hardening stage.
Glass ionomers are materials consisting of ion-cross linked polymer matrices
surrounding glass-reinforcing filler particles. Fluoride is NOT an integral part of the matrix formation, therefore it is available for release without compromising the structural integrity of the restoration. Polyacrylic acid may be freeze dried and combined with aluminosilicate powder. The freeze dried form is called anhydrous, there also is a semi-hydrous form available. Water is a key ingredient for the setting reaction, it is critical for the reaction to occur. The water hydrates the salts and allows them to crosslink. Too much water results in an opaque weakened restoration, if water is lost during setting crazing will occur.
SOURCE: CAPT Cook’s lecture on Glass Ionomers, page 5,6.
SOURCE: STURDEVANTS ART AND SCIENCE OF OPERATIVE DENTISTRY 4TH EDITION. Page 207-211.
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