Abstract
In the present study, the authors concerned themselves with the application of a 3-grade contour line plotter (commercially known as the M-3 plotting device) for analyses of the morpholgies of the teeth and palates as well as antagonistic relationships of the upper and lower teeth in terms of stereoscopic photographs. In basic considerations of the plotting device, particular attention was here given to its accuracy. By way of material, three threecornered columns with angles of 60°, 90° and 120° were manufactured of yellow hard plaster. These specimens were stereoscopically phothgraphed at three different distances of (i) 350mm, (ii) 400mm and (iii) 450mm.
Tow stereoscopic photographs taken under each condition were then subjected to the plotting of contour lines by the use of the M-3 plotting device.
Measurements consisted of the length of vertical and horizontal arcs of the column base, the product of basal area and sectional area at a height of 5 mm from the base, and the angles. The actual measurements of the plaster specimens were compared with those of contour line plottings so as to compute differences between the two sets of values.
As a result, it was established that differences between the two were reasonably small within the inevitable bounds of the plotting device. For this reason, this plotting device can be used for future analyses with a tolerable degree of accuracy.
