Fig. 1

Automated measurement point selection by using curvature analysis on a representative cross-section. Digital model of maxillary left canine with a representative cross-section at the central buccal site in the direction of the long axis of the tooth (full black line) (a) and a corresponding close-up view (b). A side view of a cross-section (c) also depicting the view for manual measurement point selection. A “curvature comb”, i.e., a graph that displays the curvature values at a specific point on an actual cross-section, is shown at (d). Two cross-section segments of interest are marked with dashed grey lines, defined with two local extreme points with positive and negative curvature, i.e., maximum convexity (blue) and concavity (red), respectively. Both cemento-enamel junction (CEJ) and gingival margin (GM) points are defined as a local extreme point with maximum concavity (red) within the cross-section segments mentioned above