Fig. (1) The acoustic modes of visualization for the material "VITA Enamic":a) Oscillogram (A-scan) 1 - the signal reflected from the sample surface, 2 - the signals from the elements of the internal structure, 3 - the signal from the lower limit of the sample;b) Vertical cut of the sample (B-scan); 1 - the surface of the sample; 2 - focus of acoustic lens;c) Two-dimensional acoustic image (C-scan), the structure of the image corresponds to a layer in the sample, its position and thickness are shown in A and B-scans.