Craniofacial heterogeneity of prepubertal Korean and European-American subjects with Class III malocclusions: procrustes, EDMA, and cephalometric analyses.

The purpose of this study is to determine whether there is a difference in craniofacial morphology in subjects of diverse ethnic origin with untreated Class III malocclusions, and thus to examine the validity of using similar therapeutic protocols in their orthodontic management. Lateral cephalographs of 142 Korean and European-American children aged 5 to 11 years were traced, and homologous cranial, midfacial, and mandibular landmarks were digitized. Procrustes analysis and Euclidean Distance Matrix Analysis (EDMA) were performed to identify size-corrected differences of the three craniofacial configurations, and bivariate analysis to determine statistical differences between 42 cephalometric parameters. Procrustes analysis indicated statistical significance for each configuration of landmarks; these results were confirmed by EDMA and cephalometry. Korean children appear to develop Class III malocclusions because of smaller anterior cranial base and midfacial dimensions, exacerbated by a large and less favorable mandibular morphology. Therefore, morphologic diversity of craniofacial components, presumably due to heterochrony during development, contributes to distinctive facial profiles associated with Class III malocclusions. Ethnic heterogeneity may need to be taken into account in the orthodontic management of Class III malocclusions.