The holodent system, a new technique for measurement and storage of dental casts

A system for producing holograms and for three-dimensional measuring on holograms is described. The precision of the system was evaluated when three-dimensional measurements were made on (1) a holographic image superimposed on the corresponding object and (2) two superimposed holographic images of the same object. When a metal test object with sharp well-defined contours, easy to reorientate was used, the precision was 0.02 to 0.11 mm for x, y, and z coordinates (transverse, longitudinal, and vertical planes). When dental casts that have less distinct contours were used, precision was reduced to 0.03 to 0.43 mm. Precision was high for the x and y coordinates and satisfactory for the z coordinate. The system has a precision that is equal to that of previously reported methods and may be well-suited for studies of dental positional changes in longitudinal materials of study models. Holograms of dental casts may solve storage problems by replacing space consuming plaster models.