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


Enamel thickness and dental tissue proportions in Neanderthal and modern human upper deciduous molars

CINZIA FORNAI1, STEFANO BENAZZI1, PRISCILLA BAYLE2, ILDIKÓ PAP3, JIŘÍ SVOBODA4,5, KATERINA HARVATI6 and GERHARD W. WEBER1.

1Department of Anthropology, University of Vienna, 2UMR 5199 PACEA, Université Bordeaux 1, 3Department of Anthropology, Hungarian Natural History Museum, 4Institute of Archaeology, Academy of Sciences of the Czech Republic, 5Department of Anthropology, Masaryk University, 6Paleoanthropology, Senckenberg Center for Human Evolution and Paleoecology, Eberhard Karls Universität Tübingen

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Enamel thickness and dental tissue proportions have been suggested as quantitative measurements useful to distinguish between Neanderthal and modern human permanent teeth. It seems obvious to apply the same to deciduous dentition. However, the intra-specific range of variability for these parameters in milk teeth is mostly unknown.

In this contribution we explore the variability of the 2D enamel thickness and dental tissue proportions in Neanderthal and modern human upper first and second deciduous molars.

The Neanderthal (dm1= 8; dm2= 8) and modern human (dm1= 24; dm2= 25) samples were scanned by means of µCT (isotropic voxel size: 15-45 µm). Firstly, the best-fit plane of the cervical line was determined. Secondly, the µCT image stack was realigned so that this best-fit plane was parallel to the xy-plane of the Cartesian coordinate system. Finally, the enamel and dentine areas and the EDJ length were collected on each section perpendicular to the cervical plane of the tooth and passing through two of the dentine horn tips (i.e., dm1's paracone and protocone, and dm2's paracone and metacone dentine horn tips).

Our results show that Neanderthal dm1 and dm2 relative enamel thickness indexes (dm1's RET= 7.17 ± 0.54; dm2's RET= 10.89 ± 0.84) are significantly lower (p < 0.001; permutation test on group mean and variance differences) than those of modern humans (dm1's RET= 9.43 ± 0.87; dm2's RET= 13.84 ± 1.53). Accordingly, the RET index can be confirmed as an effective parameter distinguishing between modern human and Neanderthal upper deciduous molars.

Supported by A.E.R.S. Dental Medicine Organisations GmbH, National Science Foundation Physical Anthropology HOMINID Grant 2007 (01-120), and the Deutsche Forschungsgemeinschaft grant DFG INST 37/706-1.

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