A CEPHALOMETRIC STUDY ON SUB-GROUPINGS IN KOREAN CHILDREN WITH CLASS I MALOCCLUSIONS : A COUNTERPART ANALYSIS

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Journal of the Korean Academy of Pediatric Dentistry 1999;26(1):172-184.
Published online February 28, 1999.

A CEPHALOMETRIC STUDY ON SUB-GROUPINGS IN KOREAN CHILDREN WITH CLASS I MALOCCLUSIONS : A COUNTERPART ANALYSIS

Angle 1급 부정교합 아동의 안면두개골 형태의 유형적 특징에 관한 연구

이정옥, 최영철

경희대학교 치과대학 소아치과학교실

Abstract

The present study was performed to identify morphologic sub-groupings in Korean children with Class I malocclusions, and to find out anatomic differences between the sub-groups. Standardized lateral cephalometric radiographs of 152 Korean children, aged between 6 and 12 years, with Class I malocclusions were analyzed by the Counterpart Analysis. A statistical method, Ward's Minimum Variance Cluster Analysis, was employed to divide the sample into sub-groups those with similar morphologic characteristics. The results were as follows; 1. There appeared two facial types, Type I and Type II, in Korean children with Class I malocclusions, 48.7% and 51.3%, respectively. 2. In both sub-groups, there existed strong Class III skeletal patterns due to a counterclockwise rotation of the Middle Cranial Fossa alignment, and strong Class II skeletal patterns due to the long Posterior Maxillary vertical dimension and a clockwise rotation of the Ramus alignment. 3. There were no significant differences in Upper Anterior Facial Height between Type I and Type II, 52.6±2.92mm and 52.8±3.23mm, respectively. 4. The Lower Anterior Facial Height in Type II was longer (66.0±4.03mm) due to the long Posterior Maxillary vertical dimension, the clockwise rotation of the Ramus alignment, and a clockwise rotation of the Mandibular plane alignment than that of Type I (64.2±4.15mm).

Key Words: Class I malocclusion, Counterpart analysis, Craniofacial skeleton