Method for monitoring positioning of patient's teeth including the following steps: a) less than three months after the end of an orthodontic treatment, producing an initial reference model of the patient's arches, and, each tooth, defining, from the initial reference model, tooth model; b) acquiring at least one updated image of the arches, under actual acquisition conditions; c) analyzing each updated image and producing, for each updated image, an updated map relative to a piece of discriminating information; d) optionally determining, for each updated image, rough virtual acquisition conditions that approximate actual acquisition conditions; e) searching each updated image for a final reference model corresponding to the teeth positioning during acquisition of the updated image, and; f) for each tooth model, comparing tooth model positions in the initial reference model and in reference model obtained at the end of the preceding steps, in order to determine the movement of the teeth between steps a) and b).