Method and system for determining tooth-gingiva segmentation contour

A method and system for determining an orthodontic treatment are provided. The method comprises: acquiring a 3D digital model representative of an arch form of the subject; generating a plurality of 3D curves on a surface of a given tooth; determining, for a given point of a given 3D curve, a curvature parameter; determining, based on the curvature parameter, a likelihood value of the given point being representative of a tooth-gingiva segmentation contour; generating, based on likelihood values associated with the points of the plurality of 3D cross-sectional curves, a graph whose nodes are representative of points of the plurality of 3D cross-sectional curves; determining, within the graph, a reference path including reference nodes such that a total likelihood value associated with the reference nodes is maximized; and determining the tooth-gingiva segmentation contour associated with the given tooth based on the reference path.