Résumé
Spatial change of craniofacial structures from growth or orthopedic force is usually evaluated by cephalometric superimpositions at different points in time.As the evaluation can be changed according to cephalometric superimposition method,selection for correct superimposition method is very important. Double registration of nineteen pairs of female lateral head films,their growth period is average 3.7 years and age is average 10.7 years, were performed by two observers. Comparisions was made between two methods and the results revealed the following; 1. NS line and ACE superimpositions are not markedly different in reliability due to almost same registration error of them. 2. The investigation was undertaken to examine interobserver difference. In NS line method, there is no significance in all measurements. In ACE method, significant difference was revealed in 4 measurements of 7 measurements was 3. In the investigation of intermethod difference, there is no significance between NS line and ACB superimpositions