Due to the strong genetic component of dental development, research has shown that mineralization patterns of the human dentition are relatively buffered against environmental influences that normally affect bone growth and development. It is because of this resistance to environmental factors and the continuous growth of the permanent dentition throughout childhood and adolescence that the evaluation of dental development patterns has become the preferred method of age estimation in living and deceased children. Researchers (Harris and Mckee 1990; Tompkins 1996; Blankenship et al. 2007; Kasper et al. 2009) have suggested that the timing of dental development varies by ancestral descent and geographic populations. However, further evaluations of these perceived differences in the timing of dental development among populations are necessary as classical statistical methods result in age estimations that are biased toward the age structure of the reference population. However, the Bayesian approach is beneficial since it incorporates relevant prior knowledge into the analysis and formalizes the relationship between assumptions and conclusions (Buck et al. 1996). Therefore, the purpose of this research is to incorporate methods in Bayesian analysis to compare the timing of dental development between two contemporary populations of the Southeastern United States, as well as test the accuracy of dental development age parameters devised by Moorrees et al. (1963) on a contemporary Florida Population. For this study, 51 panoramic radiographs of individuals from a contemporary Florida population ranging in age from 7.7-20.4 years were reviewed. Statistical analyses incorporated a Bayesian approach to compare the timing of dental development for individuals comprising the contemporary Florida sample with the timing of dental development for a contemporary Middle Tennessee population by utilizing the age structure of the Middle Tennessee population as informed prior knowledge, otherwise referred to as an informed prior. Transition distributions for age, given stage of dental development, were also modeled for individuals comprising the contemporary Florida sample. The accurate observation and comparison of probability density distributions for age can serve as a noninvasive method for evaluating the probability of whether or not an unknown individual is a particular age, given the stage of dental development. Results of this research indicate that there is a consistent underestimation of age for individuals comprising the contemporary Florida population when the age structure of the Middle Tennessee population is utilized as an informed prior. Additionally, the results of this thesis indicate that there is a consistent underestimation of age when utilizing age parameters of Moorrees et al. (1963) for the estimation of age for individuals from a contemporary Florida population. By incorporating a Bayesian approach to compare two contemporary populations of the Southeastern United States, a comprehensive analysis of the relationship between age and stage of dental development can be achieved. Therefore, the results of this thesis support Bayesian analysis as an appropriate method of evaluating perceived differences in the timing of dental development between contemporary populations. Furthermore, the results of this research are beneficial to the field of forensic anthropology as the observation of advanced stages of molar development utilizing panoramic radiographs serves as a noninvasive method in estimating age for unknown juveniles and young adults, and can also assist courts within the United States in determining whether or not an individual is legally considered a minor or an adult.

The application of 3D laser scanning to the analysis of human skeletal remains provides the opportunity for new methodological approaches, including for the assessment of age at death. The focus of this new perspective revolves around the question of whether morphological development of skeletal features can be captured with quantitative measurements taken from 3D scanned representations of physical specimens, with the aims of adding an increased level of accuracy and precision over currently employed age estimations methods that focus on visual, and often subjective, assessments based comparisons with plaster casts and written descriptions. The current research was conducted to determine if specific morphological features of the pubic symphysis could be isolated and quantified on 3D models, and whether these measurements captured the general age related trends of symphyseal development. Using CAD software, each symphyseal face was divided into half and quadrant specific sections in an attempt to better capture the development of symphyseal morphology. A sample of left male pubic symphyses (n = 40) scanned from a well-documented collection of known-age individuals (Coimbra Identified Skeletal Collection) was selected for this study. Seven symphyseal features were identified from the Suchey-Brooks method unisex age phase descriptions. Eight measurements were generated to quantify these features. The data for each feature was subjected to linear regression analyses to test for statistical correspondence to known chronological age at death. Rim completeness, billowing height and area, and depth of symphyseal face depression demonstrated the strongest relationships with chronological age, while curvature of the ventral rampart and the angle of the dorsal aspect, showed significant but weak relationships with known age. Degree of dorsal lipping and dorsal rampart curvature showed no relationship with age. The results of the study suggest that quantitative assessments of morphological changes at the pubic symphysis are possible and therefore can potentially add further insights into age at death estimations based on the pubic symphysis, as measurements taken within CAD software are far more precise than traditional measuring implements. This study illustrates the potential for 3D imaging to improve the methods of osteological analyses applied particularly in the fields of bioarchaeology and forensic anthropology. / Graduate

The Suchey-Brooks (1990) method for estimating adult age-at-death from the pubic symphysis is widely used and popular among forensic anthropologists. While this technique is quite accurate, it yields wide age interval estimates and is imprecise for individuals aged over fifty years at death. Berg (2008) and Hartnett (2010a) each altered Brooks and Suchey's phase descriptions and added a seventh phase with the goal of increasing precision while maintaining accuracy, especially for older individuals. The hypothesis for this validation study states that the new methods improve the existing Suchey-Brooks method. A total of 384 White Americans (n=213 males and 171 females) aged 26-97 years at death were analyzed at the William M. Bass Donated Skeletal Collection at the University of Tennessee, Knoxville using all three methods. Descriptive statistics, percentages of "correct" age estimates, inaccuracy and bias scores, and rates of inter- and intra-observer agreement were calculated and compared across the three methods. The Hartnett and Suchey-Brooks methods yielded similar percentages of correct estimates for males (85.0% and 84.5% correct, respectively, using ±2 standard deviations from the phase means), although the Hartnett method was significantly less inaccurate (p<0.001) and biased (p<0.001). The Suchey-Brooks method yielded the highest percentage of "correct" estimates for females aged less than sixty years (100.0% using ±2 standard deviations or 83.1% using ±1 standard deviation) and was significantly less inaccurate (p<0.001) and biased (p<0.001) than the Hartnett and Berg methods. The Hartnett and Berg methods were both significantly (p<0.001) less inaccurate and biased than the Suchey-Brooks method for females aged over sixty years, but Hartnett's and Berg's scores were not significantly different from each other (p=0.496 inaccuracy, p=0.066 bias). The Berg method yielded the highest percentage of "correct" estimates for females aged greater than sixty years (90.2% using ±2 standard deviations or 54.5% using ±1 standard deviation). The results of the present study were similar to those obtained by Merritt's (2014) validation study of Hartnett (2010a, b), although Merritt's rates of intra-observer agreement were substantially higher than those calculated for the present study. The hypothesis for the present study was supported.

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Made available in DSpace on 2014-10-09T12:43:08Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:52Z (GMT). No. of bitstreams: 0 / Eletrólitos sólidos cerâmicos de ZrO2:8% mol Y2O3 foram preparados com pós de três origens: pó comercial fabricado pela Nissan (Japão), pó obtido por coprecipitação dos hidróxidos no IPEN e pó obtido por mistura de óxidos (utilizando-se ZrO2 produzido na Usina de Zircônio do IPEN e Y2O3 (USA) de pureza superior a 99,9%). Esses materiais de partida foram analisados pelas seguintes técnicas: fluorescência de raios X para a determinação dos teores de ítrio, difração de raios X para a determinação das fases, sedimentação para a determinação da distribuição do tamanho de partículas, adsorsão gasosa (BET) para a determinação da área de superfície específica e microscopia eletrônica de transmissão para a determinação do tamanho médio de partícula. Amostras compactadas foram analisadas por dilatometria para avaliar os estágios de sinterização. As amostras sinterizadas foram caracterizadas por difração de raios X para análise de fases e microscopia eletrônica de varredura para análise da morfologia dos grãos. Análises por espectroscopia de impedância foram feitas para acompanhar o envelhecimento térmico dos eletrólitos sólidos de zircônia-ítria a 600 ºC, temperatura de trabalho do sensor permanente de oxigênio, e para estudar a sua cinética de sinterização. Os principais resultados mostram que o envelhecimento térmico a 600 ºC diminui a resposta (fem) do sensor nas primeiras 100 h até um valor estável. Além disso, os estudos de sinterização por espectroscopia de impedância permitiram encontrar correlações entre parâmetros elétricos, a cinética de sinterização e os mecanismos de crescimento de grão. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

O objetivo deste estudo foi estimar a idade dentária e compará-la com a idade cronológica de crianças HIV+ com finalidade odontolegal, utilizando o método de estimativa da idade, baseado no estudo dos estágios de desenvolvimento dos elementos dentários da dentição permanente. Além disso, verificamos a relação entre a infecção pelo HIV e os efeitos da terapia anti-retroviral na cronologia de mineralização dentária destas crianças. Foram analisados, retrospectivamente, prontuários odontológicos e radiografias panorâmicas de 50 pacientes pediátricos infectados pelo HIV, 25 do sexo feminino e 25 do sexo masculino, entre 37 a 168 meses de idade. Através dessas radiografias, a idade dentária foi estimada com o auxílio do software Cronologia de Mineralização, que utiliza o método de Nicodemo, Moraes e Médici Filho (1974) e, em seguida, comparada com a Idade Real (IE). A média da Idade Estimada (IE) foi significativamente menor do que a média da IR para o total da amostra (p<0,01), ocorrendo uma subestimativa. Houve diferença estatística entre as crianças que recebiam drogas anti-retrovirais e as que não faziam uso de qualquer droga (p=0,02), ou seja, os indivíduos não tratados apresentaram diferença entre IR e IE de praticamente zero, enquanto os tratados apresentaram uma diferença de 10,67 meses. Na amostra observada, concluímos que a IE das crianças infectadas apresentou-se atrasada em relação à IR para o amostra total e que houve uma relação entre o uso da terapia anti-retroviral com um atraso na cronologia da mineralização dentária nas crianças HIV+. / The purpose of this study was to estimate the dental age and compare it to the chronological age of the HIV+ children for legal issues, using a method of age determination based on a study of the stage of development of the permanent teeth. In addiction we studied the relationship of HIV and the side effects of the antiretroviral therapy on the chronology of tooth formation of these children. Dental records, along with their panoramic radiographies of 50 pediatric patients infected with the HIV were analyzed, 25 males and 25 females, with ages between 37 months to 168 months. With these radiographies, the dental age was estimated with the aid of software Mineralization Chronology, witch used the method of Nicodemo, Moraes and Médici Filho (1974), and than compared with the Real Age (RA) of the patient. The mean Estimated Age (EA) was significantly lower than the mean RA in the entire studied sample (p<0.01), leading to an underestimated age prediction. There was a statistical difference between children who received antiretroviral drugs and those who used no drugs (p=0.02), i.e., the non treated individuals presented practically no difference between RA and EA, while the treated patients showed a difference of 10.67 months. From these results, we conclude that there is an underestimated age prediction for patients infected with HIV, or that the (EA) was delayed compared to the (RA) for the total sample, and there was a positive association between the use of antiretroviral therapy and a delay in the chronology of dental mineralization in the sample.

The identification of victims involved in mass fatality incidents, as well as the identification of unknown individuals in criminal cases has become an increasingly important issue nowadays. Sex assessment represents a key point in forensic evaluations due to its significance in providing biological identity. Even though the availability of documented skeletal remains to forensic practitioners is a common practice in many countries, in Turkey, contemporary documented skeletal remains are not available for this purpose. For this reason, studies have been focused on living populations. Previous research has shown that modern technologies such as CT scanning present very promising potential in establishing new standards for contemporary populations. Therefore, the main aim of this project was to examine the application of the measurements taken from 3D CT images of the femur in order to assess sex, and to contribute to the establishment of discriminant function equations for the Turkish population for forensic applications. The accuracy and reproducibility of imaging methods in the assessment of the measurements taken from femora are essential when estimating sex. This research also concentrated on determining the accuracy and repeatability of CT measurements, using the femur. Prior to primary data collection, a preliminary study was performed in an effort to test the reliability of the femur measurements. The results of reliability analysis indicated no significant difference between the three observations of each measurement. Thus, the methodology employed in the current study appears reliable and reproducible. In addition, a validation study was conducted to determine the linear measurement accuracy of the 3D volume rendering models derived from a medical CT scanner and the influence of different reconstruction parameters. The differences between measurements obtained from dry bones and their 3D volume rendered models were also evaluated. The results from this study indicated that there were no statistically significant differences between measurements taken from different reconstruction parameters and measurements obtained from CT images and drybones. Using the CT data, volume-rendering function (VR), 3D Curved Multiplanar reconstruction (MPR), and Scout View on OsiriX were employed in order to compare the accuracy and reliability of each rendering method and to determine which technique is optimal for linear measurements. Overall, the measurements taken from the 3D Volume Rendering images had the highest intra-observer reliability when compared to the other two rendering methods. This research study produced data and interpretations that will inform on and improve population specific standards of sex assessment from three-dimensional postcranial osteometric landmarks. Additionally, this research is believed to provide value for a developing discipline of forensic anthropology, and integrate within the existing systems of criminal investigation and disaster victim identification practices in Turkey. A Turkish sample population, consisting of 300 adult hospital patients was examined via the interpretation of CT reconstructed images using the OsiriX software. The 3D reconstructions were then created using the volume-rendering function in OsiriX (v.5.6.). Following the 3D reconstruction, an image of each femur was segmented from the surrounding bones to ensure the correct usage of landmarks as accurately as possible. Thirteen measurements were acquired using a 3D viewer after being located and marked on each CT reconstructed femora. These thirteen anthropometric parameters were measured and analysed by basic descriptive statistics and discriminant analysis methods using the SPSS 21.0 software package. The intra-observer variation was assessed by obtaining the intraclass correlation coefficient in order to evaluate the accuracy of the linear measurements taken. Asymmetry was also tested. The results indicated that an accuracy of 92.3% was acquired from a combination of six of the measurements, and the Femur Vertical Diameter of Neck (FVDN) measurement was found to be the most dimorphic with 88.0% accuracy.

Philosophiae Doctor - PhD / Age estimation of the skeletal remains of children can be accomplished by examination of the ossification centres and the fusion of the epiphyseal plates of long bones. Dental age estimation is done by examining the eruption of the deciduous and permanent teeth. Both these methods are inaccurate and are subject to the nutritional status of the individual. A more accurate method of age estimation is by the examination of radiographic images of the developmental stages of the tooth crown and root formation. Two methods of dental age estimation used are those of Moorrees, Fanning and Hunt (1963) (MFH) and that of Demirjian, Goldstein and Tanner (1973) (DGT). These methods were tested on a sample of 913 Tygerberg dental patients; a random mixture of Caucasoid and Khoisanoid children. The MFH method under-estimated the ages of the sample by an average of 0.91 years and the DGT method over-estimated the ages by an average of 0.89 years. Samples of Indian and Negroid children from Kwa-Zulu Natal were tested in a similar manner and the results showed similar under and over-estimation of the ages by these methods. The Negroid children were labelled the Zulu sample. Correction factors were derived for the MFH and DGT methods of dental age estimation when used on Tygerberg, Indian and Zulu children. These correction factors were tested on the samples and found to improve the accuracy of the age estimation methods of MFH and DGT significantly.A second sample group of Tygerberg, Indian and Zulu children were then tested firstly using the standard method of MFH and DGT and the using the correction factors. The results showed that the correction factors improved the age estimation on these samples except in the case of the DGT method on Zulu children. A sample of Xhosa speaking children were added to the two Zulu samples and made an Nguni sample. The Tygerberg samples were combined as were the Indian samples to form data bases for the construction of dental age related tables for Tygerberg, Indian and Nguni children. These tables show that there are distinct differences in the ages at which the teeth develop in the different sample groups and that dental age related tables are necessary for children of different population origins. Statistical analysis of the age related tables from this study (Phillips Tables) show these tables are more accurate in the age estimation of South African children.