ABSTRACT A system for producing holograms and for three dimensional measurement of dental casts is described. Measurements were performed on a metal testpiece with sharp well-defined contours and on a dental cast. Measurement of the testpiece gave a precision of0.02 0.11 mm for x, y and z coordinates. Corresponding figures for the dental cast were 0.03 0.43 mm. Precision was higher for the testpiece than for the dental cast, highestfor the x and y coordinates and satisfactory for the z coordinates. No difference wasfound if the hologram was superimposed on the object or two holograms were supe- rimposed on each other. Holograms of dental casts solve storage problems by replacingspace consuming models.1. INTRODUCTION Many different devices have been used for measuring tooth position on dental casts,e.g. rulers, callipers, dividers, symmetrographs and clear plastic arch form overlayswith millimeter scales.1-3 Computers have facilitated recording of an increasing num-ber of reference planes and points. In some studies measurements have been made