Patterns of Variation in the Permanent Maxillary Anterior Tooth Roots: A Different Approach to the Problem of Anterior Dental Reduction During the Transition from Archaic to Modern Homo Sapiens

Author

Steven P. Paquette, University of Tennessee, Knoxville

Date of Award

6-1985

Degree Type

Thesis

Degree Name

Master of Arts

Major

Anthropology

Major Professor

Fred H. Smith

Committee Members

Richard Jantz, William M. Bass

Abstract

The following investigation centers upon an attempt to examine the problem of anterior dental reduction during the bio-cultural transition from archaic (Neandertals) to fully modern human forms. By focusing on the nature of dental root variability in the permanent maxillary anterior teeth (I¹-C^-), an endeavor is made to explore the absolute and relative tooth size differences characterizing the comparative samples. The samples selected for study were a collection of individual anterior teeth from an Upper Pleistocene cave deposit (Krapina, Yugoslavia) and a Plains Indian Arikara population (Larson site, South Dakota).

The research objectives of this analysis are twofold: (1) To investigate the integration among the root and crown dimensions within individual anterior teeth in an effort to elucidate the differences that exist between the sample groups and generate meaningful comparisons aimed at understanding the factors contributing to the temporal patterns of dental variation; (2) To examine the relationship between the permanent maxillary anterior root dimensions (length, mesiodistal, buccolingual) and palato-facial measurements in the homogeneous population of Arikara Indians as a means of indirectly evaluating the proposition that expanded anterior dentition in Neandertals was a contributing factor toward the maintenance of vertical facial expansion and increased facial length.

Absolute tooth size differences between the archaic and modern groups were found to be statistically significant for all root and crown dimensions examined. Moreover, the results of the root-crown analyses indicate that both samples demonstrate relative concordance in the degree of association between corresponding tooth diameters (mesiodistal, buccolingual), but they exhibit marked divergence concerning the correlation between root length and corresponding root and crown diameters. These differences consist of greater buccolingual expansion associated with increased root length in the Arikara and a stronger association between the mesiodistal diameter of the root and root length in the Neandertals. The divergent patterns of variation were interpreted as reflecting the effects of intense selection maintaining a tooth morphology in the Neandertals highly efficient at dissipating greater levels of occlusal stress generated during the use of the anterior teeth in non-masticatory behaviors.

Based upon the results of the multivariate procedures employed to investigate the degree of integration between the anterior root dimensions and facial measurements, it is concluded that underlying effects are present which serve to associate these variables with one another. It is further concluded that expanded anterior tooth size in Neandertals was responsible for maintaining the extent of vertical facial displacement and subnasal prognathism characteristic of these archaic human groups. Finally, natural selection is considered the most likely evolutionary mechanism producing the directional pattern of variation observed in the modern comparative sample.

Recommended Citation

Paquette, Steven P., "Patterns of Variation in the Permanent Maxillary Anterior Tooth Roots: A Different Approach to the Problem of Anterior Dental Reduction During the Transition from Archaic to Modern Homo Sapiens. " Master's Thesis, University of Tennessee, 1985.
https://trace.tennessee.edu/utk_gradthes/4147