The longitudinal velocity of sound in a specific material depends, amongst others, on the material's density and elasticity (Young's Modulus). Ultrasound therefore may be used for indirect characterization of materials. In this paper a method is described which allows high resolution measurements on coplanar ground sections of human teeth. The results are presented in two-dimensional velocity profiles. There is evidence from the first images, that longitudinal sound velocity (LSV) in dentin varies depending on the location. The use of LSV may be another way to characterize hard dental tissues physically, and to monitor induced changes.