Morphometric analysis of nasal profile in patients with Cl II skeletal malocclusion

Introduction: The nasal projection should be considered in Cl II patients treatment planning. This study aimed to investigate the morphometric characteristics of the nasal profile in skeletal Cl II patients in a sample of Iranian population.Materials and Methods: In this random analytical/cross-sectional study cephalometric radiographs of 123 Cl II patient were evaluated using morphometric analysis. The radiographs were superimposed by Procrust superimposition technique and principal component analysis was carried out on 8 nasal soft tissue landmarks and 15 hard tissue landmarks to describe the existing natural tendencies. Multiple linear regression analysis was used to determine the relationship between morphometric characteristics of hard tissue and soft tissue nasal profile. Principal component analysis was carried out using Viewbox 4 orthodontic software and regression analysis was carried out by SPSS 15 software (α = 0.05).Results: Variations of the soft tissue profile of the nose were described by 22 principal components (PCs). The first 7 PCs accounted for approximately 88.5% of the total shape variance. Correlation coefficient of the skeletal and soft tissue components was 35.5%.Conclusion: All Cl II patients have varied nasal forms and there is no significant relationship between skeletal pattern of Cl II patients and their nasal form. Key words: Cephalometry, Malocclusion, Nose, Principal component analysis