A CROSS-SECTIONAL LONGITUDINAL CEPHALOMETRIC STUDY ON CRANIOFACIAL SKELETAL CHARACTERISTICS IN KOREAN CHILDREN AGED 6 TO 14 WITH CLASS III MALOCCLUSIONS

III급 부정교합을 지닌 $6\sim14$세 아동의 중두개저각에 따른 안면두개골의 형태적 특징: 측두방사선규격사진을 이용한 횡단누년적 연구

It is well known that there are different craniofacial skeletal groups in the same malocclusion types. The present study was performed to determine morphologic sub-groups in Korean children with Class III malocclusions, and to find out morphological differences between subgroups by means of a cross-sectional longitudinal cephalometric study. In this study, 135 children aged 6 to 14 year-old with untreated Class III malocclusions were selected. The samples were divided into two groups depending on the angulation of middle cranial fossa (MCF). That is, when the MCF of an individual was measured smaller than 40.3, he/she was tossed into mandibular protrusive-effect group(MREG), while when an individual was measured larger than 40.3, he/she was tossed into mandibular retrusive-effect group(MREG). Thereafter, the grouped samples were divided into 4 age groups(7, 9, 11 and 13 year-old). Thirty four linear and angular measurements on the tracings of lateral cephaloradiographs were measured, and the morphological characteristics and differences were compared and analysed by means of Wilcoxon test. It was found that Korean children with Class III malocclusions were divided into two groups, in which 39.3% were belonged in the MREG and 60.7% were in the MREG. In the MREG, anterior-posterior length of cranial base, nasomaxillary complex, maxilla and mandible were larger than the MREG. And although there was no difference in the total length of mandible (Co-Gn), mandibular body length (Go-Gn) was larger in the MREG during the majority of the observed periods. These results would suggest that a majority of the samples, 60.7%, demonstrated many of configurations of craniofacial skeletal relationships that can be found in the leptoprosopic faceform.

부정교합의 분류가 치아의 위치적 관계에 의해 구분되면, 동일한 집단에 속하더라도 이들의 안면두개골은 서로 다른 구조적 관계를 지니고 있어 이들을 동일시 할 수 없으며 안면두개골의 형태적 특징에 의한 분류가 필요하다. 저자는 $6\sim14$세 사이의 III급 부정교합 아동 135명의 측두방사선규격사진을 7, 9, 11, 13세의 연령으로 구분한 후, 중두개저각 $40.3^{\circ}$를 기준으로 이보다 작은 집단(하악전돌효과군)과 큰 집단(하악후퇴효과군)으로 분류하여 각 집단의 안면두개골의 형태적 특징을 횡단 누년적으로 비교 평가하였다. 모집단의 39.3%가 하악전돌효과군으로, 60.7%가 하악후퇴효과군으로 나타났으며, 두 개저, 비상악복합체 상악골 및 하악골의 전후방적 길이 그리고 전안면높이와 후안면높이 등의 수직적 길이가 하악후퇴효과군에서 크게 나타난 것으로 미루어 III급 부정교합 아동의 많은 수가 좁고 긴 얼굴형 (leptoprosopic faceform)에서 찾아볼 수 있는 형태적 특징을 많이 지니고 있으며, 두 군간에는 형태적, 구조적인 차이와 함께 시기적으로도 각기 다른 성장양태를 보이는 것으로 가늠된다.