The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)


Secular changes in discrete dental traits on three continents

STEPHEN D. OUSLEY1 and HEATHER JH. EDGAR2.

1Department of Anthropology/Archaeology, Mercyhurst College, 2Department of Anthropology, University of New Mexico

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Secular changes in the dentition have been examined in terms of tooth loss, tooth size, and other features affecting mastication, but discrete dental traits rarely have been investigated to date (Edgar 2004, 2009).

The ASU dental traits were recorded from over 1800 Africans, Europeans, and Americans dating from the 9th to the 21st century, with a concentration of individuals after 1600. Samples originated in western Africa, western and central Europe, and diverse archaeological sites and collections in the US. Combinations of dental trait scores were analyzed as dichotomized and polychotomous variables using correlations, principal components, canonical variates analysis, and cluster analysis using R (R Development Core Team 2009) and Fordisc 3 (Jantz and Ousley 2005). All necessary statistical assumptions were tested for each method.

Numerous analyses were run using various time, trait, and sample divisions, and several results were consist in virtually all multivariate analyses: There are significant differences among all continental groups; the African and European groups changed the least over time, the African-Americans changed a bit more, but the Euro-Americans changed the most of all groups, and in one direction; all groups changed in different ways. Year of birth was significantly correlated with a smaller hypocone, metacone, protocone, and trigonid crest in Euro-American molars (adjusted p < 0.01); in African-Americans, only the hypocone became smaller, but the number of lingual cusps on the second mandibular premolar decreased, the mandibular first molar Y-groove pattern increased, and distal accessory ridges on mandibular and maxillary canines became more common.

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