New, fast, and accurate procedure to calibrate a 2-dimensional digital measurement method.

Traditionally, dental casts have been measured by hand, with conventional calipers. Today, several digital methods are available for automatically measuring tooth size, but their accuracy depends on proper calibration. The purpose of this article is to introduce a fast and accurate procedure to calibrate a previously introduced 2-dimensional computerized system of measuring mesiodistal tooth size and calculating overall and anterior Bolton ratios. In this calibration method, the cast is digitized while sitting on a sheet of graph paper. The magnification of the paper in 2 axes can be easily calculated and hence the magnification of the dental cast digital image.