A method for true coordinate three-dimensional measurement of casts using a measuring microscope

Exact 3-dimensional measurements are more useful for researchers and clinicians than are relative distance measurements. Through the use of a measuring microscope and a personal computer, the technique presented in this article provides meaningful and accurate (0.005 mm) 3-dimensional measurements of casts in true coordinates (x, y, z). By fabricating the master cast with reference landmarks, leveling the casts before measurement, removing the cast between repeat measures, and mathematically rotating the data points, this technique places all the landmarks in a standardized reference plane that allows for the comparison of dimensional changes between different casts. (J Prosthet Dent 1998;80:506-10.)