A method and associated system. Such is for orthodontic treatment or for assessing shape of an aligner. Within an example, there is participation in communication of an assessment of the suitability of an aligner as a function of the value of: a tooth attribute of an analysis tooth zone of an analysis image, the tooth attribute relating to a separation between the tooth represented by the analysis tooth zone and the aligner represented on the analysis image, or an image attribute of an analysis image, the image attribute relating to a separation between at least one tooth represented on the analysis image and the aligner represented on the analysis image. The analysis image is an image of an aligner in a service position in which it is worn by the patient acquired by a cellphone more than 1 week, and is a photograph, or an image extracted from a film.