Our group pioneered in applying nondestructive tests of acoustic microscopy for determining mechanical properties and microstructure of cements used in stomatology. We compare states of hardened cements for various portions of powder and water in mixtures. The values of elastic parameters obtained numerically based on acoustic characteristics are compared with results of conventional mechanical tests. It is established that the rise in a portion of water of a mixture leads to the increase of acoustic impedance of the material after hardening as well as to the increase in the rate of propagation of a longitudinal ultra-sonic wave and a transversal one. In addition, it is shown that the elastic parameters and the strength of material under compression obtained both experimentally and theoretically decrease. Variation in acoustic and mechanical characteristics may be explained by specific peculiarities of microstructure of materials that are disclosed in acoustic pictures of high resolution obtained by using a scanning acoustic microscope.