Craniofacial Growth Studies and Craniofacial Growth

Abstract

Current understandings of human craniofacial growth are based on multiple historic longitudinal growth studies. The extent to which regional variation in growth patterns is present among the various growth studies even within the United States, however, is not well understood. The aim of this study is to compare growth patterns across six of the nation's largest growth studies.Lateral cephalographs were examined from the historical archives of the Denver Growth Study, Iowa Growth Study, and Oregon Growth Study (available via the AAOF Legacy Collection) as well as the Fels Longitudinal Study, the Michigan Growth Study, and the Bolton‐Brush Growth Study. A set of 44 two‐dimensional landmarks were collected on longitudinal series from participants 6–22 years old. A total of 5,622 cephalographs from 726 males and 5,514 cephalographs from 723 females were assessed. Fifth order polynomials were used to evaluate growth of 11 linear craniofacial measures for each growth study and by sex. Rates of growth and associated growth milestones were calculated from polynomial models and compared across study and by sex. In addition, geometric morphometric analyses were used to assess ontogenetic shape differences among studies using a regression of the shape variables on log centroid size, pooled by study, with subsequent evaluation of residual variation.Growth curves for the separate studies roughly parallel each other yet show differences in the timing of growth milestones and adult morphology. In general, for each linear trait participants in the Denver study are smaller and participants in the Iowa and Michigan studies are larger than participants in other studies at the same chronological age. Timing of onset and peak growth is similar in all 11 craniofacial measures, although trait values at those growth milestones differ by study. Preliminary results from the geometric morphometric analysis identify a common ontogenetic pattern shared across studies but demonstrate that, for a given size, individuals from the Denver study are more advanced along the common shape trajectory relative to other studies. Although ontogenetic trajectories are roughly similar, overall shape differences are present between study populations.Variations in growth and overall morphology among these six longitudinal growth study populations demonstrate regional differences in the rate and timing of growth that may be attributable to the ancestry and environmental conditions of study participants. Further study of the mechanisms for these differences in growth will improve the accuracy of craniofacial growth predictions, thereby improving the efficacy of growth modification interventions in pediatric craniofacial treatment.Support or Funding InformationFunding: NIH/NIDCR R03‐DE021435; NIH/NIDCR R01 DE024732This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.