Abstract:

Objective:The aim of this study was to find the laws of angular changes of 5 cephalometric planes in children with mixed dentitions.Methods:Nineteen female children were annually examined with X-ray, and the cephalometric analysiswas performed in continuous 4 years. Of these children, 10 childrenwere investigated from the age of 7 years old, and the other9 children from 9 years old. The two groups were longitudinally studied. All of the children were observed almost at the same age (9~10 years old) in the two groups, and the resultswere analyzedwithmixed longitudinal methods. All datawere analyzedwithSPSS 8.0 soft- ware.Results:In the observation period, the angular relationship of FH to BaN remain constant among 5 cephalometric planes, and FHto SNwas almost in the same situation.Conclusion:In mixed dentition, the angular relationship of FH, BaN and SN barely change.

Key words: cephalometry, growthanddevelopment, mixeddentition, mixedlongitudinal, referenceplanes