Abstract
Objectives: To assess the potential of predicting adult facial types at different stages of mandibular development. Setting and Sample Population: A total of 941 participants from the Bolton-Brush, Denver, Fels, Iowa, Michigan and Oregon growth studies with longitudinal lateral cephalograms (total of 7166) between ages 6-21 years. Material and Methods: Each participant was placed into one of three facial types based on mandibular plane angle (MPA) from cephalograms taken closest to 18 years of age (range of 15-21 years): hypo-divergent (MPA < 28°), normo-divergent (28°≤ MPA ≤ 39°) and hyper-divergent (MPA > 39°). Cephalograms were categorized into 13 age groups 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 and 18-21. Twenty-three two-dimensional anatomical landmarks were digitized on the mandible and superimposed using generalized Procrustes analysis, which projects landmarks into a common shape space. Data were analysed within age categories using stepwise discriminant analysis to identify landmarks that distinguish adult facial types and by jackknife cross-validation to test how well young individuals can be reclassified into their adult facial types. Results: Although each category has multiple best discriminating landmarks among adult types, three landmarks were common across nearly all age categories: menton, gonion and articulare. Individuals were correctly classified better than chance, even among the youngest age category. Cross-validation rates improved with age, and hyper- and hypo-divergent groups have better reclassification rates than the normo-divergent group. Conclusions: The discovery of important indicators of adult facial type in the developing mandible helps improve our capacity to predict adult facial types at a younger age.
Original language | English (US) |
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Pages (from-to) | 154-162 |
Number of pages | 9 |
Journal | Orthodontics and Craniofacial Research |
Volume | 22 |
Issue number | S1 |
DOIs | |
State | Published - May 2019 |
Bibliographical note
Publisher Copyright:© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Keywords
- facial type
- geometric morphometrics
- longitudinal growth
- mandibular shape
PubMed: MeSH publication types
- Journal Article