Glass Ionomer Cement sets because of what kind of reaction?

Glass Ionomer Cement sets through an acid-base reaction. This process involves the chemical interaction between the acidic component of the glass ionomer, typically polyacrylic acid, and the basic component, which is the glass particles (mainly fluoride-containing aluminosilicate). When mixed, the acid reacts with the glass powder, leading to the formation of a gel-like substance that eventually hardens.

During this setting process, the reaction releases ions such as calcium and fluoride, which can enhance the material's properties, including dental caries resistance. The acid-base reaction also results in the formation of cross-links between the material's components, contributing to its strength and stability once fully set.

This mechanism is distinct from addition polymerization reactions, which involve the joining of monomers to form polymers, and does not apply to glass ionomer cement. Similarly, the concepts of growth of glass crystals or slip plane locking are not relevant to the cement's setting process, making the acid-base reaction the defining characteristic of how glass ionomer cement achieves its final hardened state.