A method for monitoring the positioning of the teeth of a patient, said method comprising the following steps: a) less than 3 months after the end of an orthodontic treatment, production of a three-dimensional digital reference model of the arches of the patient, or "initial reference model" and, for each tooth, definition, from the initial reference model, of a three-dimensional digital reference model of said tooth, or "tooth model"; b) acquisition of at least one two-dimensional image of said arches, called "updated image", in actual acquisition conditions; c) analysis of each updated image and production, for each updated image, of an updated map relating to a discriminating piece of information; d) optionally, determination, for each updated image, of rough virtual acquisition conditions approximating said actual acquisition conditions; e) searching, for each updated image, for a final reference model corresponding to the positioning of the teeth during the acquisition of the updated image, the search being preferably performed by means of a metaheuristic method, preferably by simulated annealing, f) for each tooth model, comparison of the positionings of said tooth model in the initial reference model and in the reference model obtained at the end of the preceding steps, called "final reference model", in order to determine the movement of the teeth between the steps a) and b). method in which the step e) comprises - a first optimization operation making it possible to search for the virtual acquisition conditions best corresponding to the actual acquisition conditions in a reference model to be tested determined from the initial reference model, and - a second optimization operation making it possible to search, by testing a plurality of said reference models to be tested, for the reference model best corresponding to the positioning of the teeth of the patient during the acquisition of the updated image in the step b). a) less than 3 months after the end of an orthodontic treatment, production of a three-dimensional digital reference model of the arches of the patient, or "initial reference model" and, for each tooth, definition, from the initial reference model, of a three-dimensional digital reference model of said tooth, or "tooth model"; b) acquisition of at least one two-dimensional image of said arches, called "updated image", in actual acquisition conditions; c) analysis of each updated image and production, for each updated image, of an updated map relating to a discriminating piece of information; d) optionally, determination, for each updated image, of rough virtual acquisition conditions approximating said actual acquisition conditions; e) searching, for each updated image, for a final reference model corresponding to the positioning of the teeth during the acquisition of the updated image, the search being preferably performed by means of a metaheuristic method, preferably by simulated annealing, f) for each tooth model, comparison of the positionings of said tooth model in the initial reference model and in the reference model obtained at the end of the preceding steps, called "final reference model", in order to determine the movement of the teeth between the steps a) and b). method in which the step e) comprises - a first optimization operation making it possible to search for the virtual acquisition conditions best corresponding to the actual acquisition conditions in a reference model to be tested determined from the initial reference model, and - a second optimization operation making it possible to search, by testing a plurality of said reference models to be tested, for the reference model best corresponding to the positioning of the teeth of the patient during the acquisition of the updated image in the step b). - a first optimization operation making it possible to search for the virtual acquisition conditions best corresponding to the actual acquisition conditions in a reference model to be tested determined from the initial reference model, and - a second optimization operation making it possible to search, by testing a plurality of said reference models to be tested, for the reference model best corresponding to the positioning of the teeth of the patient during the acquisition of the updated image in the step b).