Current knowledge about cranio-facial growth, the identification of different anatomic types by architectural cephalometric analysis, the new therapeutic methods and a multidisciplinary have changed the mode and the results of these treatments. However the key of success is: begin the treatment as soon as possible. The correction of skeletal anomalies and the normalization of all the oro-facial functions need a lot of time. It is advisable to be efficient at the good time with the good appliance. The quality of the result will be estimated at the end of the growth. In this way, a lot of orthognathic surgery can be avoided. So, certainly the results reward the efforts.