A classification and characterization of skeletal class III malocclusion on etio-pathogenic basis

Skeletal Class III malocclusion has been classified by the position of the maxilla, the mandible, the maxillary alveolus, the mandibular alveolus and vertical development. This morphologic approach is simple and useful for clinical use, but it is insufficient to permit understanding of the pathophysiology of dysmorphoses. The authors hypothesized that there were different patterns of mutual relation of the skeletal components contributed to pathologic equilibrium of skeletal Class III malocclusion. The purpose of this study is 3-fold; (1) to classify skeletal Class III malocclusion in subgroups that can show the architectural characteristics of the deformity, (2) to analyze the craniofacial architecture of each subgroup on etio-pathogenic basis, and (3) to characterize and visualize the pattern as a prototype. Materials used in this study were lateral cephalograms of 106 untreated skeletal Class III malocclusion adults, which were analyzed with modified Delaire's analysis. Linear and angular measurements of each subject were obtained and cluster analysis was used for grouping. In the results, seven groups were identified and presented as prototypes, which could show the etio-pathology of the skeletal architecture. The classification and description presented in this study is thought to be biologic and helpful in the understanding of skeletal Class III malocclusion and treatment planning.