Secular trends in the facial skull from the 19th century to the present, analyzed with geometric morphometrics.
BACKGROUND
Over the last 100 years, Austrian facial form has changed for various reasons, including changes in growth pattern, changes in shape pattern, or a combination of these. In this study, we explored and contrasted these 2 explanations.


METHODS
We compared cephalograms from 54 recruits in the present-day Austrian Federal Army to those from 49 dry skulls of soldiers from the Imperial Hapsburg army. Body height was measured or acquired from military records. Forty-three landmarks were located on each lateral cephalogram. Secular change and growth allometry were analyzed with standard Procrustes methods.


RESULTS
Body height correlated only weakly with size of the facial skull in these samples, and secular change in facial size (4.5% over a century) was proportionately less than that in height. Growth allometry was nearly unchanged over the century, emphasizing the typical changes of vertical to horizontal proportions and bimaxillary prognathism. Secular changes over the century took the form of far more localized remodeling around the coronoid process and the anterior maxilla. The large-scale differences, in contrast, were opposite to those one would expect from the size change.


CONCLUSIONS
The observed trends shed considerable light on secular changes in the range of dysmorphologies for clinical orthodontic correction. At the same time, the dissociation between within-century and between-century allometry is an important possibility that was hitherto typically observed only at far greater time scales than the 150 years spanned by these data.
Jonke
Erwin
E
Vienna University Clinic of Dentistry, Department of Orthodontics, Medical University of Vienna, Vienna, Austria.
Prossinger
Hermann
H
Bookstein
Fred L
FL
Schaefer
Katrin
K
Bernhard
Markus
M
Freudenthaler
Josef W
JW
D000885:Anthropology, Physical; D001317:Austria; D001827:Body Height; D002508:Cephalometry / Q000639:trends*; D005147:Facial Bones / Q000033:anatomy & histology / Q000254:growth & development*; D049672:History, 19th Century; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D008297:Male; D008445:Maxillofacial Development; D012044:Regression Analysis