Modified zinc phosphate cements

The zinc phosphate cement dates back to at least 1879, when Rollins reported a formulation based on syrupy orthophosphoric acid [13]. The first really satisfactory cement of this type was reported by Fleck in 1902 [14], His report described a paper based on zinc oxide that had been deactivated by heating, together with a solution of phosphoric acid modified by the inclusion of aluminium and zinc. These two approaches to moderating the reaction led to a setting process that took place at a sufficiently slow speed that a smooth paste could be prepared from the components, and there was time to apply it before hardening took place. 

These cements are based on the reaction product of phosphoric acid with other materials, such as sodium silicate, metal oxides and hydroxides, and the salts of the basic elements. Zinc phosphate is the most important phosphate cement and is widely used as permanent dental cement. It is also modified with silicones to produce dental-filling materials. Compressive strengths of up to 200 MPa are typical of these materials, which are formulated to have good resistance to water. Copper phosphates are used for similar applications, but they have a shorter useful life and are used primarily for their antiseptic qualities. Magnesium, aluminum, chromium, and zirconium phosphates are also used. ... 

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