From the Mouths of Babes: Using Incremental Enamel Microstructures to Evaluate the Applicability of the Moorrees Method of Dental Formation to the Estimation of Age of Prehistoric Native American Children

This dissertation assesses 1) the appropriateness of applying traditional dental aging methods derived from a Euro-American population to prehistoric Native Americans from the Ohio Valley and 2) the utility of incremental microstructures of dental enamel. Enamel microstructures such as perikymata and cross striations have the potential to provide accurate, narrow, and population-specific age-at-death estimations based upon the circadian rhythm of enamel growth. Estimation of age is fundamental to both bioarchaeology and forensic anthropology when documenting unknown skeletons. Specific to bioarchaeology, chronological age is the baseline by which physiological age and delay in physiological growth due to environment-population interaction and genetic heterogeneity can be assessed. Accurate age estimation of children is therefore an essential part of the bioarchaeologists toolkit. The age-at-death of 38 juveniles with immature (developing) dentition from three archaeological sites in the Ohio Valley was estimated using the Moorrees et al. (1963a, b) method and compared to those obtained from dental histology. Cuspal and crown formation times of all tooth types were also measured and calculated from a combination of dental histology and nondestructive scanning electron microscopy of surface structures such as perikymata. The dental chronology, crown formation times, and crown formation sequences of the target population were determined and compared to several large dental histology collections from several modern and archaeological collections. Results indicate a high correlation between the ages derived from the Moorrees method with those from the enamel microstructures for children between one and ten years old. This suggests that despite the temporal and geographic disparities between the reference and target population, that the Moorrees method can provide appropriate age predictions for prehistoric Native American dental remains. Nevertheless, a closer look at the crown formation times and sequences of Native Americans as compared to several European and an African population indicate that variation in dental growth among populations is not negligible. In fact, this Native American sample displayed examples of slightly accelerated cuspal and imbricational formation and very advanced M2 and M3 formation. This provides some support for previous findings and hypotheses about the comparatively mature dentition of Native Americans at earlier dental formation stages than Europeans. This sample most closely resembled formation times recorded from the archaeological Cis-Baikal sample from Siberia. Since southern Siberia is the region cited as the origination point of Native American ancestors, this finding suggests that formation times may be a product of ancestry. It may appear that the results of this study are contradictory to each other (that is, that variation exists, yet does not inhibit age estimations). However, it seems likely that disparities in age estimations recorded in past studies of Native Americans are related to root development and eruption and that while the biological processes and timing behind enamel formation vary, enamel formation runs on a highly canalized schedule. And particular to this study, there is too much individual variation in crown formation sequences to conclude a pattern one way or another.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Anthropology

Grantor dc:publisher

The Ohio State University

Year dc:date

2013

Author dc:creator

• Blatt, Samantha Heidi

Contributors dc:contributor

• Sciulli, Paul

• Aging
• Archaeology
• Forensic Anthropology
• Histology
• Human Remains
• Native Americans
• Physical Anthropology
• dental anthropology
• perikymata
• enamel microstructures
• age-at-death
• Eastern Woodlands
• Moorrees method
• dental histology
• subadults

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=osu1365696693

OAI identifier oai:identifier

oai:etd.ohiolink.edu:osu1365696693