호선 분석법에 의한 한국인 Angle씨 제Ⅲ급 부정교합자의 악안면 유형에 관한 두부방사선 계측학적 연구

A cephalometric study about maxillofacial patterns of angle s class Ⅲ malocclusions by archial analysis in koreans

Accurate appraisal of maxillofacial deformities in mandibular prognathism, commonly called Class Ⅲ malocclusion synonymously, is essential for their successful treatment by combined surgical-orthodontic technique. Maxillofacial deformities, caused by various horizontal and vertical growth imbalances, can be evaluated by means of roentgenocephalometric analysis. Considering the nature and balance of the individual maxillofacial components, it is more reasonable to measure the deformities by relative proportional values than by absolute quantitative ones. In order to study the maxillofacial patterns of Class Ⅲ malocclusions in Koreans, mainly using archial analysis, this research covered 667 samples of cephalometric radiographs consisting of 343 of puberties (101 of whom were normal occlusions with well-proportioned face and 242 of whom were Class Ⅲ malocclusions) and 324 of adults (121 of whom were normal occlusions with well-proportioned face and 203 of whom were Class Ⅱ malocclusions). The conclusions are as follows; 1. In Class Ⅲ malocclusions, the majority of maxillofacial deformities result from mandibular characteristics rather than maxillary ones. 2. In Class Ⅲ malocclusions, the components which exhibit severe discrepancies are O-B/O -A, A-Na-B, Md pl ∠ Ll, and O-Pog/O-Na. 3. With respect to the antero-posterior relationships of dental components, the posterior or normal position of maxillary teeth and the normal or anterior position of mandibular teeth are the dominant combinations in puberties, whereas the normal position of maxillary teeth and the normal or anterior position of mandibular teeth are those in adults. 4. With respect to the antero-posterior relationships of skeletal components, the patterns in puberties and those in adults generally exhibit similarities, and the normal or posterior position of maxillary bone and the anterior position of mandibular bone are dominant combinations in puberties and adults. 5. With respect to the antero-posterior and vertical relationships of skeletal components, the normal ratio of vertical component is the great prevalence in puberties, whereas the normal or increased one is that in adults, in addition to the dominant combinations of the anteroposterior relationships of skeletal components. 6. With respect to the antero-posterior and vertical relationships of skeletodental components, all of combinations exhibit various patterns, not a typical one. 7. The patterns in puberties and those in adults are generally similar, but adults have more mandibular characteristics than puberties have.