Research Focus: It’s all about TEETH!!

Research into modern human origins has largely centered on the question of continuity vs. discontinuity.  In Europe, testing hypotheses regarding continuity has focused on Neandertals and modern humans.  Investigations of contemporary Europeans have revealed a discontinuity with Neandertals, and it has largely been assumed that because of this, the most recent ancestors of these populations must be the earliest modern human inhabitants of Europe. Tests need to be conducted in order to understand where and from which populations these contemporary Europeans originated. There is a need for research that investigates whether early Europeans share morphological affinities with contemporary Europeans, and if not, with whom do they share affinities?  These questions directly impact our understanding of modern human origins, the origins and spread of agriculture in Europe, and the overall peopling of this region. My research focuses on testing hypotheses related to these questions using dental morphology.

Studying dental morphology is essentially examining the bumps and grooves on teeth.  There are numerous traits (specific bumps/and or grooves) that vary between individuals and populations.  Some of these traits have been shown to vary meaningfully between human populations.  For example, a well known morphological trait that is common in many populations (but perhaps most common among Europeans) is the Carabelli cusp.  Using this trait in conjunction with many others among a large sample can indicate important information about the ancestry of a population.

Nonmetric dental traits have been shown to be particularly useful in reconstructing patterns of population affiliations across wide geographical areas and long periods of time. Dental morphology is genetically controlled and only marginally influenced by environment. In addition, dental remains are the most common and often best-preserved remains from past populations.  For these reasons, studying dental morphology as a way to investigate questions about human origins is not only appealing, but is also a practical and effective way to understand biological relationships throughout the human lineage.

Previous Research: My past research has focused on dental development for forensic applications. The assessment of child development requires standards in order to compare an apparent physiologic age to an actual chronological age. In assessing chronological age of an individual, the use of multiple indicators is ideal and important in determining age at death. For individuals under the age of about 21 years, dental development is the most reliable indicator of age. My research aimed to understand the variation in tooth formation due to race and sex in order to help more accurately determine the age at death of remains of subadult individuals.

X-ray examples of different stages in molar development (Price, 2005)

Working with the Louisiana State University School of Dentistry as well as forensic odontologist Dr. Robert Barsley, I conducted research using panorex X-rays to assess group differences in the timing and pace of dental development.  Some sex differences could be found, but overall, little group difference could be seen with regard to ancestry.  Analyses did indicate, however, that variability within groups was exceptionally high, even more so than that between groups.  With such high variability, inter-group comparisons were difficult to examine.  One reason for this may have to do with the low socioeconomic status of participants, which would suggest that tooth development is more vulnerable to environmental influence than previously thought.  At least one future study will explore this finding further.

Publications:

Price, ST. 2005. A radiographic study of the impact of race and sex on 1st and 2nd

            molar development.  M.A. Thesis, Louisiana State University.

            Link to pdf:   http://etd.lsu.edu/docs/available/etd-05312005-190711/

Grants:

2004 Robert C. West / RJ Russell Field Research Grant