Western University Scholarship@Western Electronic Thesis and Dissertation Repository 8-23-2019 1:00 PM Getting Better All The Time: Re-evaluating Macroscopic Dental Age Estimation Standards In Egypt Casey Kirkpatrick The University of Western Ontario Supervisor Molto, Joseph E. The University of Western Ontario Graduate Program in Anthropology A thesis submitted in partial fulfillment of the equirr ements for the degree in Doctor of Philosophy © Casey Kirkpatrick 2019 Follow this and additional works at: https://ir.lib.uwo.ca/etd Part of the Biological and Physical Anthropology Commons Recommended Citation Kirkpatrick, Casey, "Getting Better All The Time: Re-evaluating Macroscopic Dental Age Estimation Standards In Egypt" (2019). Electronic Thesis and Dissertation Repository. 6472. https://ir.lib.uwo.ca/etd/6472 This Dissertation/Thesis is brought to you for free and open access by Scholarship@Western. It has been accepted for inclusion in Electronic Thesis and Dissertation Repository by an authorized administrator of Scholarship@Western. For more information, please contact [email protected]. Abstract This dissertation investigates the use of dental anthropological methods for estimating chronological age-at-death in ancient Egypt, and determines whether these methods can be improved. Tooth calcification, emergence and eruption standards are time honoured in their ability to accurately age subadults though they are compromised by the fact that populations and the sexes vary in their developmental timing. Determining sex in subadults, particularly in the infant and child cohorts, in all populations is not possible, though advances in ancient DNA methods hold promise. This dissertation provides a feasible and ethical model for developing a sex-and region-specific standard for age estimation of subadults for use on ancient Egyptian samples.This method rectifies methodological errors affecting the accuracy of pre-existing standards; and thus, demonstrates that macroscopic subadult dental age estimation methods can be improved. Moreover, using a photographic sample of occlusal dentition from the Kellis 2 cemetery population in Roman Period Egypt, a new method for adult dental age estimation is designed and tested. To this end, the percentages of exposed occlusal dentine in first and second molars were calculated through photogrammetry, in a technique shown to have little intra- and inter-observer error. These data showed a strong linear correlation with skeletal age estimates, and varied significantly from the popular Brothwell (1963a) standard for age estimation based on dental wear. Dental caries and antemortem tooth loss were similarly tested for correlation with skeletal age, with only antemortem tooth loss showing a strong correlation. As a result, linear regression models were designed and tested for quantified first and second molar wear as well as antemortem tooth loss. Multiple regression models for all combinations of these dental indicators of age were also designed and tested. Although it is also recommended that these models are revised with expanded reference samples, these standards improve the ability to estimate age in individuals from the Kellis 2 cemetery population. It is recommended that these standards are tested and modified for use on geographically- and temporally-diverse populations to determine the boundaries of its application beyond a single population sample. In summary, this study rejects the null hypothesis (Ho): ‘Current dental age estimation standards cannot be improved’. Consequently, this dissertation serves to encourage the creation of more accurate and precise subadult and adult macroscopic dental age estimation standards. Keywords Age estimation, senescence, dental age estimation, dental development, dental attrition, dental wear, primary and permanent teeth, subadult, adult, public oral health, Egypt, North Africa, Middle East, physical anthropology, forensics, archaeology, dentistry, orthodontics, population studies. ii Lay Abstract This dissertation investigates the use of dental anthropological methods for estimating age-at- death in subadult and adult ancient Egyptians, and their potential for improvement. Dental developmental standards are time honoured in their ability to accurately age subadults. Unfortunately, they are compromised by the fact that developmental timing can vary among populations and between the sexes. This dissertation presents an improved method for developing a region- and sex-specific standard for age estimation of subadult Egyptians. This feasible and ethical method rectifies methodological errors affecting the accuracy of pre- existing subadult dental aging standards. This demonstrates potential for improved age estimation in subadults. Using a photographic sample of occlusal dentition from the Roman Period Kellis 2 cemetery in Egypt, a new method for adult dental age estimation is also designed and tested. To this end, dental wear is quantified through photogrammetry in first and second molars. These data were used to create linear regression models that can be used to predict age based on dental wear. These models vary significantly from the popular Brothwell (1963a) standard for age estimation based on dental wear. Dental caries and antemortem tooth loss were similarly tested for correlation with skeletal age, with only antemortem tooth loss showing a strong correlation. Consequently, linear regression models were also designed and tested for antemortem tooth loss. Multiple regression models were also created to incorporate all combinations of these dental indicators of age in an effort to increase accuracy. Unfortunately, in some cases, the small sample sizes applicable to multiple regression models indicate that these models should be revised with expanded reference samples. Nevertheless, these standards improve the ability to age adults from Kellis 2 cemetery population. In future, it is recommended that these standards are tested and modified for use on geographically- and temporally-diverse populations to test its applicability beyond a single cemetery population. In summary, this dissertation rejects the null hypothesis (Ho): ‘Current dental age estimation standards cannot be improved’. Consequently, this dissertation serves to encourage the creation of more accurate and precise user-friendly subadult and adult macroscopic dental age estimation standards. iii Epigraph “While we agree that the current status of age estimation in paleodemography is largely that of an “art,” we see no apparent reason why we should not strive to make it a science.” ~ Lyle Konigsberg and Susan Frankenberg (1992: 253) ~ iv Dedication For those who give me strength. v Acknowledgments I would like to thank Dr. El Molto for his continuous support and excellent supervision during my time as a doctoral student. If it weren’t for his inspirational undergraduate lectures, I would not have found my passion in bioarchaeology. Thanks also go to Mary Denvir for wonderful editing skills. I am also grateful to the Egyptian dentists, radiologist, and school superintendent, as well as my dear friends and colleagues (Mohamed Hakim, Ahmed Mokhtar, Hassan Demrdash, Ali Hassan, and Tayyib Hassan), who helped me with various practical aspects of the dental development project. I am also indebted to Dr. Scott Haddow for the photographs on which my dental wear study is based. My sincere thanks also go to several institutions: the Egyptian Ministry for State of Antiquities, the Egyptian Ministry of Health, the Dakhleh Oasis Project, BYU’s Egypt Excavation Project, the Ontario Graduate Scholarship, and the University of Western Ontario’s Department of Anthropology. In particular, I would like to thank UWO’s Dr. Andrew Nelson, Dr. Ian Colquhoun, Dr. Alexis Dolphin (now at UW), Dr. Matt Teeter, Dr. Karyn Olsen, Dr. Kim Clark, Diane Belleville, and Christine Wall for their help throughout this journey. Although I have had the pleasure of learning from some of the greatest minds at UWO, I would also like to thank the many brilliant people from outside of UWO who have mentored me and/or provided some amazing opportunities along the way (in chronological order); Dr. Henry Choi, Dr. Kasia Szpakowska, Dr. Daniel Antoine, Dr. Hourig Sourouzian, Dr. Janice Kamrin, Dr. Don Ryan, Dr. Joel Irish, Dr. Greg Nelson, Dr. G. Richard Scott, Dr. Loren Lease, Dr. Kerry Muhlestein, Dr. Peter Sheldrick, Dr. Jessica Kaiser, Dr. Jane Buikstra, Dr. Bruce Ragsdale, Dr. Suzanne Onstine, Dr. Sabine Huebner, and Dr. Spyros Retsas. I have been truly privileged by knowing all of you. I am also grateful to Dr. Brenda Baker, Dr. Jerome Rose and Dr. Lyle Konigsberg - thank you for your thoughtful suggestions and for enduring methodological discussions of my dissertation. Special thanks are also due to Dr. Larry Sawchuk and Dr. Dan Shrubsole for their thoughtful questions and suggestions while serving on my dissertation defense committee. I would be remiss if I didn’t mention my inspiring colleagues in the Paleo-oncology Research Organization, Dr. Rose Campbell, Kathryn Hunt, and Khrystyne Tschinkel, who inspire me to keep going and enjoy geeking out at conferences just as much as I do. As an honorary member of PRO, Amr Shahat has also been invaluable for his support and enthusiasm. Given that a few years of this degree were significantly affected by health troubles, I am also indebted to Kate and Matt Vlemmix for always having an open door so that I didn’t have to risk falling asleep at the wheel driving to and from London. My