RESUMEN
Orthodontic treatments aim at improving the positions of teeth, the form of dental arches and their reports relations. Determining the age to perform these treatments consists in defining the ideal moment to achieve them in the shortest time possible and with the best stability success. To know when to address the child or the teenager to the orthodontist, it is necessary for the pediatrician to observe the patient, his/her positions, orofacial functions (phonation, swallowing, aeration), his/her face and profile, oral cavity, particularly the way his/her teeth articulate in the three spatial directions. This orthodontic check-up allows the detection of abnormalities, for which two kinds of treatments exist. Firstly, early treatments which start in temporary dentition stage, in order to prevent or intercept abnormalities and, secondly, late treatments performed on permanent dentition, when well-developed bony and alveolar growths make it possible to correct these abnormalities.