Figure 5. Variations of orientation of enamel occlusal surface.

Each profile corresponds to the relative proportion of area expression (in percentage) of the eight orientation intervals. Since orientation is coded on 360°, the relative contribution of the orientation intervals is given in polar coordinates. The schematic drawing (lower right) indicates the direction of orientation for the considered surface according to the tooth orientation. Thus, for instance, polygons for which normal vector is in the 90–135° intervals correspond to a mesially oriented surface. Ms1, Ms2, mesial quadrants; Ds1, Ds2, distal quadrants; MB, DB, mesio- and distobuccal quadrants; ML, DL, mesio- and distolingual quadrants.