Abstract
A lateral cephalogram analysis system has been developed allowing an extended application of the Ricketts analysis to primary dentition. Using this system, we first examined the growth of facial patterns from the BA-NA ratio profilograms. As samples, we used records of children with normal occlusions stored at Nihon University School of Dentistry Department of Pedodontics. We then used the Fuzzy theory to change Vert's formula and obtained facial types. Lastly, we obtained compositional ratios of facial types within each age group. The results were as follows:
1) Facial patterns tended to show three divisions according to three age groups; from 3 to 5-year olds, from 6 to 7-year olds and from 8 to 10-year olds.
2) The Vert's values of the BA-NA ratio profilograms in each age group based on the data of 9-year olds tended to decrease as age increased. The change was mostly restricted to the range of Mesiofacial type.
3) As for the compositional ratio of facial types in each age group, a nearly normal distribution was observed mainly with the Mesiofacial type.
4) From the lateral cephalogram analysis system which has been developed and the profilograms of the average values for each age group which have been obtained by this system, we obtained the standard values for future evaluation of facial patterns of children with malocclusions.
