A Study of Biological Sex Estimation Across Populations Using Measurements of the Cementoenamel Junction and Dental Arcade

• Main Author: Chapman, Erin Nicole
• Language: EN
• Published: State University of New York at Buffalo 2017
• Subjects: Evolution & development
• Online Access: http://pqdtopen.proquest.com/#viewpdf?dispub=10284576

<p> Biological sex estimation has been a central tenant in physical anthropology and bioarchaeology since the foundation of the fields. Traditionally, sex estimation techniques have centered on pelvic morphology but features of the pelvis are often poorly preserved in forensic and archaeological contexts. However, teeth have very high preservation potential. Because the crown is susceptible to ante- and postmortem damage, the cementoenamel junction (CEJ) provides a more often preserved portion of the tooth. Several studies have shown the potential use of measurements of the CEJ in biological sex estimation; however, these studies have been limited in their scope, samples sizes, and materials utilized. Additionally, the role of biological affinity in the estimation of biological sex from measurements of the CEJ have not been fully explored. Three main goals of the present study are: 1) to assess the ability to estimate biological sex from measurements of the cementoenamel junction across populations; 2) to assess the role of biological affinity in sex estimation based on the measurements of the cementoenamel junction across populations; and 3) to examine the relationship between dental arcade size and biological sex within and between populations. </p><p> A total of 737 dentitions (7,369 teeth) from American and South African Whites and Blacks were measured based on buccal-lingual and mesial-distal CEJ measurements defined by Hillson and colleagues (2005). Percent dimorphism was calculated for buccal-lingual, mesial-distal and geometric mean measurements for each tooth. Percent dimorphism was highest in the canines for all groups. Discriminant function and logistic regression analyses were run to assess the ability of the measurements to correctly classify biological sex within and between populations and groups. Correct classification ranged from 84.1% to 90.7%. Within group comparisons (i.e., American females, South African males, etc.) highlighted that molars, premolars, and incisors have the greatest weight in the discriminant function in classifying differences between ancestral groups.</p><p> Finally, a total of 162 dental arcades (maxillary and mandibular) were measured from photographs using <i>ImageJ</i> software to assess differences in dental arcade size and to assess the relationship between mesial-distal measurements of the CEJ and the length of the dental arcade. Statistically significant differences in mean arcade size were found for all groups except South African Whites and South African Blacks (mandible only). Pearson&rsquo;s correlation coefficient tests were used to test if a correlation existed between the sum of the mesial-distal CEJ measurements and the total arc length. A significant correlation was found in all groups except American Whites, South African Whites, and All Whites combined (mandible only). In summary, the buccal-lingual and mesial-distal measurements of the CEJ can be used to estimate biological sex with a high degree of correct classification. Canines, specifically the lower canine, shows the highest percent of sexual size dimorphism for all groups. Lower overall sexual size dimorphism is noted in the South African groups, especially South African Whites, when compared with their American contemporaries. Results indicate that the size (and possibly the shape) of molars, premolars and incisors have the most influence on differences seen between ancestral groups.</p><p>