Zinc phosphate cements (ZPCs) are used in dentistry. Cement formulation (liquid+solid) is largely empirical because of lack of information on the exact chemical nature of the amorphous product and on factors affecting ZPC microstructure. Characterization of the detected generic ‘bound’ and ‘unbound’ water populations, evolving in time, is absent, but its of great importance for understanding the development of the ZPC microstructure, and, consequently, the mechanical performance when in the mouth, the capacity to release/uptake fluoride, and dissolution rate. Our previous results showed that porosity develops because of segregation of the liquid component and that some gel-like material likely forms in time in the pores. With Quasi-elastic neutron scattering we want to characterize the evolution of the water populations dynamics in ZPC at two times, to help the design of more durable ZPC