RESUMEN
The first condition required for carrying out a successful orthodontic treatment involves patient cooperation. Yet, for a long time, orthodontic research has minimized the importance of nontechnical factors: until a recent period practitioners had to content themselves with mere impressions, feelings and other beliefs, rather than a qualitative control of knowledge and behaviors. Thanks to data processing, testing one's choices, decisions and therapeutic strategies has been made possible to obtain a better cooperation. At the beginning of this third millennium, this new concept of the orthodontist's role is moreover in keeping with a general trend in medical and dental therapeutics: any biotechnological innovation is nowadays presented with a concern for the patient's information, education and relation, taking into account his/her social and cultural background.