This thesis documents dental maturation in a mid C18, early C19 population where age at death is known (N=63, age range birth and 5.4 years). Emphasis is placed on the mineralization of individual deciduous and certain permanent teeth. In the first part of this thesis, the literature on dental maturation is reviewed with special reference to radiographic studies of populations, methodology and statistical analysis. Quantitative data on developing teeth, population differences and age estimation are also reviewed. In the second part of the thesis the Spitalfields material is described and used to investigate the accuracy of five types of age estimating methods that make use of the developing dentition. It emerges that the atlas method of Schour and Massler (1941) predicted age best. The third part of the thesis documents dental development in the Spitalfields Collection. New data for human deciduous anterior teeth and early stages of permanent anterior teeth are presented. In this study, few permanent anterior tooth crowns were complete before 5 years of age, contrary to published data from radiographic studies. Alveolar eruption of deciduous teeth and measurements of tooth length and weight are presented and discussed in context with published standards. The fourth part of this thesis is a preliminary investigation of cranial and postcranial development in this population. The fifth part is an appendix of data.

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Age estimation is a critical component of the biological profile in forensic and bioarchaeological contexts. The majority of age estimation methods are most accurate for individuals of younger age cohorts, typically those under 40 years of age. Skeletal degeneration can vary greatly between individuals, making age estimation less accurate for adult individuals. While there are some methods that attempt to age older individuals accurately and precisely, more research must be conducted to expand the range of methods available. Falys and Prangle (2014) developed a method for estimating age in individuals over the age of 40 using three degenerative characteristics of the sternal end of the clavicle: (1) surface topography, (2) porosity, and (3) osteophyte formation. In order to test their method, a sample of 1,510 individuals of known sex and age, ranging from 20 to 101 years of age (males: n = 1112, mean = 50.57, SD = 18.015; females: n = 398, mean = 53.065, SD = 20.358), were drawn from the McCormick Collection and the William M. Bass Donated Skeletal Collection at the University of Tennessee. Due to the paucity of remains of other ancestries, only individuals of reported White ancestry were used in this study. The two estimation methods proposed in Falys and Prangle (2014), regression equation and composite score, were tested to see how well they perform when applied to a different sample population than the populations used to develop the method. When applied to the collected data, the regression equation produced age estimations that fell within the 95% confidence interval in 47.6% of the male sample and 57.4% of the female sample. Composite scores were calculated and compared to the corresponding age ranges provided in Falys and Prangle (2014). The composite scores of the male sample estimated the age of an individual more accurately than the composite scores of the female sample (male = 65.9%; female = 58.8%). The lowest estimation accuracy for both males and females was between 70-79 years of age (male = 46.0%; female = 51.4%). From 80-89 years of age, the accuracy increased for males (76.4%) and females (69.4%). The sample also included individuals under the age of 40 in order to test whether the inclusion of clavicles with recent epiphyseal union would affect the applicability of the Falys and Prangle (2014) method. Multiple regression equations were generated: (1) individuals over 20 years of age, (2) individuals over 30 years of age, and (3) individuals over 40 years of age. The results from the multiple regression analyses show comparable Pearson’s coefficients for the above mentioned equations (r = 0.690, r = 0.632, and r = 0.611, respectively). Spearman’s rank correlation coefficients indicated a correlation significant at the 0.01 level for all three components individually, as well as the composite score. Of the three components, surface topography was most strongly correlated with age for both males (r = 0.643) and females (r = 0.590). Unlike the findings of Falys and Prangle (2014), porosity was found to be the least correlated with age for both males (r = 0.474) and females (r = 0.514). In addition, when broken down into ten year intervals (40-49, 50-59, etc.), the correlation coefficients increase with advancing age. This suggests that the method becomes more accurate as the age of an individual increases. The inter-observer and intra-observer agreement tests produced very low agreement values. The low observer agreement indicates that the current scoring method is not a reliable, repeatable technique. However, when examined further, the observed trait values that differed between the tests primarily differed by one score. These results suggest that condensing the scores in order to account for more variation would likely increase the observer agreement. However, condensing the scores would result in larger age intervals, which nullifies the purpose of this method. The findings in the present study indicate that the sternal end of the clavicle has potential for use in age estimation in older individuals. Although the present study produced lower correlation coefficients than proposed by the original study in 2014, the correlations and age-at-transition test results suggest that the sternal end of the clavicle deteriorates in a predictable manner that, with more observation and understanding, could be used to accurately age older individuals more precisely than the large age intervals currently in use. Despite the correlations between the degeneration of the sternal end of the clavicle and the age-at-death, the error rates suggest it is not a reliable alternative to the current methods used.

When human skeletal remains are found in prehistoric, historic, or forensic contexts, establishing age at death is an important step in reconstructing life histories, building demographic profiles, and identifying victims. Reliability for adult skeletal age estimations is generally lower than ideal, especially for individuals over the age of 40 years. A factor rarely considered in age estimation is that of body size; namely, how individuals of varying body sizes experience skeletal aging. This thesis explores the variables of BMI, stature, and body mass to quantify the influence of error from body size on adult skeletal age estimates. Eight age estimation methods were tested on 764 adult skeletons from the Hamann-Todd and William Bass Collections. These individuals were documented to have ranged in stature from 1.30m to 1.93m and body mass from 24.0kg to 99.8kg. Each age estimation method was evaluated separately. Analyses show that underweight individuals have the most error associated with their age estimations for all methods. All methods under-age underweight individuals by 5 to 15 years compared to average and obese individuals. The Kunos et al. method is the most reliable rib method, and the Lovejoy et al. and Suchey-Brooks methods are the most reliable pelvic methods. The İşcan et al. fourth rib method under-ages individuals by the highest degree compared to all other methods. The DiGangi et al. method is the most unreliable method with low accuracy (over twenty years) and high bias scores (under-aging individuals by almost 20 years). Body mass has a stronger influence on age estimation than stature. Studies have shown that body mass has a strong impact on bone resorption and remodelling rates, regardless of nutrition, and that tissue type (i.e. fat vs. muscle), physical activity, and mechanical loading influence bone remodelling. Skeletal remains of underweight individuals have fewer age markers while obese individuals show an increase in surface texture degeneration and osteophytic lipping. This is the first study to show that body size influences skeletal age estimation, and that age estimations are significantly different between weight-bearing and non-weight-bearing joints.

Magister Scientiae - MSc / Teeth are often used to assist in the identification of human bodies after death, especially in cases where the body is badly burned or decomposed, as teeth are usually preserved for a long period of time, even after most of the other tissues of the body have decomposed. Age estimation can play a significant role in order to help narrow down the spectrum of possible identities, for example from the missing person’s database. Gustafson created a method of age estimation, using 6 age-related changes of teeth that occur after the eruption of the dentition. He then compiled a regression line from which the age of a tooth donor could be determined by examining attrition, change of the level of the periodontal attachment, secondary dentine deposition in the pulp, resorption of the root, apposition of cementum and translucency of the root. Gustafson’s method of age estimation was based on Europeans from Sweden. This age estimation method has been used on unidentified individuals at the Salt River and the Tygerberg medicolegal laboratories, but the accuracy is questionable as to whether the method is applicable to the population of the Western Cape. The aim and objectives of this study were to test the accuracy of Gustafson’s method on a sample of adults of known chronological age, to determine the degree of accuracy of the method and to evaluate the consistency of the method. Extracted mandibular central and lateral incisors and maxillary central incisors were used in this study. Two examiners independently used Gustafson’s method of age estimation to estimate the ages of the donors of the teeth. This method was found to be inaccurate when applied to a sample of the adult population of the Western Cape.

There is a growing recognition that there is a requirement for methods of age estimation of the living to be rigorously tested to ensure that they are accurate, reliable and valid for use in forensic and humanitarian age estimation. The necessity for accurate and reliable methods of age estimation are driven both by humanitarian, political and judicial need. Age estimation methods commonly in use today are based on the application of reference standards, known as atlases, which were developed using data collected from children who participated in longitudinal studies in the early to mid-1900s. The standards were originally developed to provide a baseline to which radiographs could be compared in order to assess the child’s stage of skeletal development in relation to their chronological age, a purpose for which they are still utilised in the medical community. These atlases provide a testable link between skeletal age and chronological age which has been recognised by forensic practitioners who have essentially hijacked this medical capability and applied it to their fields. This has resulted in an increased use of these standards as a method of predicting the chronological age from the skeletal age of a child when the former is unknown. This novel use of the atlases on populations who are distinct, ethnically, temporally and geographically, from those whose data was gathered and was used in the design of the standard leaves the forensic outcomes vulnerable to challenge in court. This study aims to examine the reliability and accuracy of these standards in relation to a modern population, providing a sound statistical base for the use of these standards for forensic purposes. Radiographs were collected from the local hospital from children who had been X-rayed for investigation during attendance at the local A&E department. Four body areas were selected for investigation; the hand-wrist, the elbow, the knee and the foot-ankle and tests were undertaken to assess the radiographs using six commonly uses methods of age estimation. Further images of the wrist and elbow were collected from children in New Delhi, India. These images were subject to age estimation utilising the methods described.

The estimation of age at time of death is often an important step in the identification of human remains. If this age can be accurately estimated, it will significantly narrow the field of possible identities that will have to be compared to the remains in order to establish a positive identification. Some of the more accurate methods of age estimation, in the juvenile and younger adult, have been based on the assessment of the degree of dental development as it relates to chronological age. The purpose of this current study was to test the applicability of one such system, the Demirjian system, to a Sydney sample population, and to develop and test age prediction models using a large sample of Sydney children (1624 girls, 1637 boys). The use of the Demirjian standards resulted in consistent overestimates of chronological age in children under the age of 14 years by as much as a mean of 0.97 years, and underestimates of chronological age in children over 14 years by as much as a mean of 2.18 years in 16 year-old females. Of the alternative predictive models derived from the Sydney sample, those that provided the most accurate age estimates are applicable for the age ranges 2-14 years, with a coefficient of determination value of R-square=0.94 and a 95% confidence interval of �1.8 years. The Sydney based standards provided significantly different and more accurate estimates of age for that sample when compared to the published standards of Demirjian.

The development of a child can be monitored by studying the changes in physical appearance or the development of capabilities e.g. walking and talking. But is it possible to find a quantitative measure for brain development? The aim of this thesis work is to investigate that possibility using quantitative magnetic resonance imaging (qMRI) images by answering the following questions: Can brain development be determined using qMRI? If so, what properties of the brain can be used? Can the age of a child be automatically detected with an algorithm? If so, how can this algorithm function? With what accuracy? Previous studies have shown that it is possible to detect properties in the brain changing with age, based on MRI images. These properties have e.g. been changes in T1 and T2 relaxation time, i.e. properties in water signal behavior that can be measured using multiple MR acquisitions. In the literature this was linked to a rapid myelination process that occurs after birth. Furthermore the organization and growth of the brain is a property that can be measured and monitored. This thesis have investigated several different properties in the brain based on qMRI images in order to identify those who have a strong correlation with age in the range 0-20 years. The properties that were found to have a high correlation were: Position of the first histogram peak in T1 weighted qMRI images, Fraction of white matter in the brain, Mean pixel value of PD weighted qMRI images, Volume of white matter in the brain, Curves on the form f(x) = ae^(-bx) +c are fitted to the data sets and confidence intervals are calculated to frame the statistical insecurity of the curve. The mean error in percent for the different properties can be seen in the list below: Property, Mean error [%] 0-20 years, Mean error [%] 0-3 years Peak position: 53.84, 98.17 Fraction of WM: 118.97, 71.67 Mean pixel value: 200.89, 126.28 Volume of WM: 241.72, 72.58 The conclusions drawn based on the presented results are that there are properties in the brain that correlates well to aging, but the error is too large for making a valid prediction of age over the entire range of 0-20 years. When decreasing the age range to 0-3 years the mean error becomes smaller, but it is still too large. More data is needed to evaluate and improve this result.

The estimation of age at time of death is often an important step in the identification of human remains. If this age can be accurately estimated, it will significantly narrow the field of possible identities that will have to be compared to the remains in order to establish a positive identification. Some of the more accurate methods of age estimation, in the juvenile and younger adult, have been based on the assessment of the degree of dental development as it relates to chronological age. The purpose of this current study was to test the applicability of one such system, the Demirjian system, to a Sydney sample population, and to develop and test age prediction models using a large sample of Sydney children (1624 girls, 1637 boys). The use of the Demirjian standards resulted in consistent overestimates of chronological age in children under the age of 14 years by as much as a mean of 0.97 years, and underestimates of chronological age in children over 14 years by as much as a mean of 2.18 years in 16 year-old females. Of the alternative predictive models derived from the Sydney sample, those that provided the most accurate age estimates are applicable for the age ranges 2-14 years, with a coefficient of determination value of R-square=0.94 and a 95% confidence interval of �1.8 years. The Sydney based standards provided significantly different and more accurate estimates of age for that sample when compared to the published standards of Demirjian.

Although the pubic symphysis remains the most commonly utilized osteological feature to ascertain age-at-death estimations by forensic anthropologists (Garvin and Passalacqua, 2012), these aging methods do not accurately age elderly individuals. Through the re-examination of a Balkan sample, Berg (2008) noted a morphological variant, which may be correlated to osteoporosis expression by the increasing presence of macroporosity, present on female individuals that had previously been unexplained. This morphological variant can assist in the application of the Suchey-Brooks method to age elderly female individuals with the inclusion of a seventh phase (Berg, 2008). Hartnett (2010) also re-examined the pubic symphysis to better estimate age for modern populations and noted morphological variants similar to those described by Berg (2008). Hartnett (2010) attributed this variant to a decrease in bone quality associated with age-related morphological change. The present study examined the 330 female skeletons housed at Lisbon Collection, with the specific aim to provide a comparison of pubic symphysis age estimation methods, including Suchey-Brooks (1990), Berg (2008), Hartnett (2010), and Boldsen et al. (2002), on a known modern skeletal collection geographically dissimilar from the collections originally examined by Berg (2008) and Hartnett (2010). This dissimilar population was important because Berg's original study noted regional differences in the appearance and applicability of the seventh phase. The morphological variants present in female elderly individuals in the Lisbon Skeletal Collection support the introduction of a seventh phase to the standard Suchey-Brooks pubic symphysis method. Using the seventh phase, the Berg (2008) and Hartnett (2010) method improved their accuracy rates for aging older individuals. However, when the entire female population sample is considered the established age-at-death estimation methods do not perform well. The relationship between bone quality, aging method estimation assessment, and known age are discussed with considerations made for the influencing factors on bone preservation. A major difficulty in this analysis was parsing out information regarding bone density loss that occurred as natural degeneration and had a relationship to age-related change. The most significant confounding factor for the analysis of bone density loss and its importance to age-related change is the influence of bone preservation. While it is clear that the seventh phase provides more valuable information for the age estimation of the elderly, the poor correlation of bone quality suggests that this feature is not particularly important for the assessment of elderly phases in this population. This research supports the induction of a seventh phase to help provide more accurate age estimations for elderly populations, as it has been found in various populations, including the Portuguese population.