O presente trabalho propõe-se a analisar as afinidades biológicas através da comparação estatística multivariada dos dados craniométricos dos Paleoíndios de Lagoa Santa com outras séries esqueletais representativas de diversas regiões do mundo, testando, de forma complementar, as relações biológicas primeiramente observadas por Neves & Pucciarelli (1989). De acordo com a proposta inicial de Neves e Pucciarelli (1989), que sugere que a ocupação do Novo Mundo se deu a partir da chegada de dois componentes biológicos à América, os Paleoíndios, representantes da primeira leva de colonizadores, apresentam morfologia craniana generalizada, semelhante à observada entre as populações australo-melanésicas e africanas atuais e diametralmente oposta à morfologia especializada, característica dos nativos americanos recentes, todos descendentes da segunda leva de colonizadores. Para a execução do trabalho proposto foi utilizado, como base de dados comparativa à série Paleoíndia de Lagoa Santa, uma base de dados alternativa ao banco Howells, classicamente utilizado nas investigações bioantropologicas. A base de dados alternativa, numericamente expressiva e contando com populações originárias de 19 grandes regiões geográficas, foi organizada pelo Prof. Tsunehiko Hanihara, do Departamento de Anatomia da Saga Medical School (Saga, Japão), e cedida ao Laboratório de Estudos Evolutivos Humanos para a execução deste trabalho. Os resultados gerados através das técnicas estatísticas multivariadas empregadas indicaram que a população Paleoíndia de Lagoa Santa, em escala intracontinental, não se associa com as populações indígenas nativas americanas tardias e atuais e, em escala extra-continental, apresentam, de maneira geral, uma morfologia craniana mais semelhante à apresentada por populações de morfologia craniana generalizada / The present work proposes the analysis of the biological affinities, through a multivariate statistics comparison, of the Lagoa Santa Paleoindians´ craniometric data and other skeletal series, representatives of other regions in the world, testing, in a complementary way, the biological relationships first observed by Neves & Pucciarelli (1989). In accordance with Neves and Pucciarelli initial proposal, which suggests that the New World settlement happened with the arrive of two biological components to the America, the Paleoindians, representatives of the first migration wave, who show the generalized cranial morphology, resembling the one observed among the australomelanesian and african current populations, and completely opposite to the specialized morphology of the current native americans, all descendents from the second migration wave. For the accomplishment of this work it was used, as comparative data base to the Lagoa Santa\'s Paleoindians series, an alternative data set from that produced by Howells, commonly utilized in physical anthropological studies. The alternative data base, numerically expressive and counting with populations derived from 19 great geographic regions, was organized by the Professor Tsunehiko Hanihara, from the Anatomy Department of Saga Medical School (Saga, Japan), and granted to the Laboratory of Human Evolution Studies (Laboratório de Estudos Evolutivos Humanos - LEEH), for the execution of this project. The results generated through the employee multivariate statistics technics pointed out that the Paleoindian population from Lagoa Santa, in a intra-continental scale, do not associate with the american indigenous populations, neither from the past nor the present and, from the extra-continental scale, they present, in a general manner, a cranial morphology that resembles more that one presented by the populations with the generalized cranial morphology.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第19265号 / 理博第4120号 / 新制||理||1593(附属図書館) / 32267 / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 濱田 穣, 准教授 平﨑 鋭矢, 教授 中村 克樹 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

A caracterização fenotípica representa uma temática clássica na biologia evolutiva e o modo como diferentes caracteres respondem aos processos evolutivos tem sido problemática frequente em estudos envolvendo as mais diversas espécies. O presente trabalho visou investigar justamente como determinado fenótipo se comporta mediante o fluxo gênico. Primeiramente, explorou-se a possibilidade de se identificar e distinguir a partir de análises de traços craniométricos indivíduos anteriormente separados quanto a cor em três grupos: brancos, negros e pardos. Em um segundo momento, testou-se se a morfologia craniana expressa por indivíduos classificados como pardos seria intermediária em comparação com a expressa por brancos e negros. As análises estatísticas uni e multivariadas empregadas sobre os diferentes bancos de dados (dados brutos, dados das parcelas masculina e feminina separadamente, dados corrigidos para tamanho e também corrigidos para normalidade) apontaram ser possível discriminar os indivíduos previamente classificados de acordo com a cor em brancos, negros e pardos. Estes últimos, por sua vez, apresentam morfologia intermediária entre os grupos considerados parentais. Tais resultados permitem inferir que traços craniométricos, além de bons marcadores para a compreensão das relações histórico-biológicas populacionais, também seguiram o esperado como resposta ao fluxo gênico para um modelo de genética aditiva clássica segundo o qual a população híbrida apresenta frequências médias entre as populações parentais. Apesar de cor da pele e morfologia craniana representarem fenótipos com diferentes histórias evolutivas, observou-se correlação entre os dois caracteres para esta amostra, evidenciando-se que ambos representaram bons marcadores de mistura entre populações / Phenotypic characterization is a classic theme in evolutionary biology. The way different characters respond to evolutionary processes has been a frequent issue in studies involving a diverse number of species. This study aimed to investigate how a particular phenotype behaves by gene flow. First, it was explored the possibility to use analysis of craniometric traits to identify and distinguish individuals previously sorted by color into three groups: white, black and brown. Secondly, it was tested whether the cranial morphology expressed by individuals classified as brown would be intermediate compared to that expressed by whites and blacks. The univariate and multivariate statistical analysis used for the different databases (raw databases, data from male and female portions separately, data ajusted regarding size factor and normality) pointed out to be possible to discriminate individuals previously classified as white, black and brown, the latter being presented as an intermediate morphology between the considered parental groups. These results indicate that craniometric traits, besides being good markers for understanding the historical-biological population relationships, also followed as expected in response to gene flow for a classic additive genetic model, in which the hybrid population has medium frequencies between parental populations. Although skin color and cranial morphology represent phenotypes with different evolutionary histories, it was observed a correlation between the two characters for this sample, indicating that both represent good markers for mixture between populations

A caracterização fenotípica representa uma temática clássica na biologia evolutiva e o modo como diferentes caracteres respondem aos processos evolutivos tem sido problemática frequente em estudos envolvendo as mais diversas espécies. O presente trabalho visou investigar justamente como determinado fenótipo se comporta mediante o fluxo gênico. Primeiramente, explorou-se a possibilidade de se identificar e distinguir a partir de análises de traços craniométricos indivíduos anteriormente separados quanto a cor em três grupos: brancos, negros e pardos. Em um segundo momento, testou-se se a morfologia craniana expressa por indivíduos classificados como pardos seria intermediária em comparação com a expressa por brancos e negros. As análises estatísticas uni e multivariadas empregadas sobre os diferentes bancos de dados (dados brutos, dados das parcelas masculina e feminina separadamente, dados corrigidos para tamanho e também corrigidos para normalidade) apontaram ser possível discriminar os indivíduos previamente classificados de acordo com a cor em brancos, negros e pardos. Estes últimos, por sua vez, apresentam morfologia intermediária entre os grupos considerados parentais. Tais resultados permitem inferir que traços craniométricos, além de bons marcadores para a compreensão das relações histórico-biológicas populacionais, também seguiram o esperado como resposta ao fluxo gênico para um modelo de genética aditiva clássica segundo o qual a população híbrida apresenta frequências médias entre as populações parentais. Apesar de cor da pele e morfologia craniana representarem fenótipos com diferentes histórias evolutivas, observou-se correlação entre os dois caracteres para esta amostra, evidenciando-se que ambos representaram bons marcadores de mistura entre populações / Phenotypic characterization is a classic theme in evolutionary biology. The way different characters respond to evolutionary processes has been a frequent issue in studies involving a diverse number of species. This study aimed to investigate how a particular phenotype behaves by gene flow. First, it was explored the possibility to use analysis of craniometric traits to identify and distinguish individuals previously sorted by color into three groups: white, black and brown. Secondly, it was tested whether the cranial morphology expressed by individuals classified as brown would be intermediate compared to that expressed by whites and blacks. The univariate and multivariate statistical analysis used for the different databases (raw databases, data from male and female portions separately, data ajusted regarding size factor and normality) pointed out to be possible to discriminate individuals previously classified as white, black and brown, the latter being presented as an intermediate morphology between the considered parental groups. These results indicate that craniometric traits, besides being good markers for understanding the historical-biological population relationships, also followed as expected in response to gene flow for a classic additive genetic model, in which the hybrid population has medium frequencies between parental populations. Although skin color and cranial morphology represent phenotypes with different evolutionary histories, it was observed a correlation between the two characters for this sample, indicating that both represent good markers for mixture between populations

The understanding of the masticatory apparatus including its functional and structural relationship with other components of the cranium increasingly requires an interdisciplinary approach. Recently, "traditional biological sciences" such as anatomy, comparative biology, anthropology and evolution have increasingly meshed with elements from other domains, such as mechanical engineering and material sciences, which has resulted in new and exciting paradigms to be explored. This is particularly true in the field of craniofacial biomechanics yet there are still many unexplored issues and numerous questions that remain unanswered. Numerical modelling in general and Finite Element Analysis (FEA) in particular, represent a numerical experimental procedure to generate such information. Originally derived from the field of structural engineering, FEA has steadily permeated its way into craniofacial biomechanics and has proven itself as a most useful scientific tool. The present study introduces an engineering-based workframe for applying FEA to craniofacial biomechanical research in a comprehensive manner to cover the entire analytical spectrum, from developing questions to providing their solutions. The study is composed of two major experimental parts addressing both the linear elastic and the non-linear behaviour of some biomaterials encountered in the craniofacial arena. In the first part I analysed mandibular biomechanics using linear elastic models while in the second part I used nonlinear discrete models to determine the optimal elastic properties of the cervical restorative materials. Modern humans have a number of anatomical features that set us apart from our ancestors. Amongst these perhaps the most striking is the emergence of a protruding chin, otherwise absent in other archaic humans and hominids. While it has been shown that the chin has its embryological origins in the postnatal remodelling of bone in the area around the mandibular symphysis which produces the midline keel in the form of an inverted �T� the functional significance of this novel evolutionary feature is still obscure. It is accepted that the mandible is optimally designed for resisting masticatory stress, whereby optimal is seen as maximual strength at the lowest biological cost. Here, I tested the currently most accepted theory, namely that the chin provides mechanical resistance to the mandible during mastication. In other words, I tested the hypothesis that a chinned mandible would be stiffer and hence experience lower strains when compared to a non-chinned counterpart under identical loadings. My functional analysis consisted firstly of three simple models which reproduce a simian shelf, a flat and a chinned symphysis, loaded using two unidirectional loadcases (torsion and wishboning) to represent a distortion similar to that which occurs in the mandible during mastication. Secondly, I developed complex geometrical models which incorporated the cortical bone, medullary bone and teeth. The models were then analysed using the same loadcases as those used for the first theoretical models. Additionally, I incorporated the coronal bending and also a coupled loadcase which simulated the complex deformation of the mandible during biting. The aim here was to test the hypothesis that the presence of a chin changed the strain pattern in the mastication-loaded mandible. The results were then interpreted using Frost�s mechanostat theory which relates in a more precise manner the mechanical loading environment to the adaptive response of the bone. My results showed that the calculated strain values for both the chinned and flat mandibles were within the normal bone maintenance levels of the mechanostat during molar biting. In other words, variation in bone strain magnitude across the mandible, which should differ between the chinned and the non-chinned mandibles if the hypothetical mechanical role of the chin is true, is similar in both forms. I concluded that the development of the human chin is thus unrelated to the functional demands placed upon it by mastication. I suggested a new functional demand associated with pronounced tongue activity during speech. I hypothesise that it is the resistance to stresses induced by strong, repetitive contractions of the tongue and perioral musculature during, phonation that shaped the modern human chin. I tested my hypothesis by loading the symphyseal region with two principal nonmasticatory, muscle systems; firstly, the tongue and secondly the peri-oral muscular curtain, anterior to the symphysis. My results suggested that the flat, non-chinned symphysis when subjected to speech-related genioglossal movements will undergo adaptive changes which would result in an optimised (chinned) shape, such as that found in the modern human symphysis. These results thus offer a new foundation to an old hypothesis and a solution to the longstanding controversy over the origin of the human chin. I conclude that forces generated by speech rather than those generated by mastication, shaped the chin in anatomically modern humans. Prompted by an earlier observation I further investigated the apparent cross-over distribution of strains on the mandibular corpora during mastication. In doing so, I tested the hypothesis that this cross-over may be linked with another particular anatomical feature of the mandible that of the postcanine cortical asymmetry, which appears to be stereotypical among anthropoids. The results of my study hence suggest that strain patterns within the human mandible are more complex than previously thought. Not only do strains differ between lingual and buccal aspects of working and non-working sides, but they also differ within these areas (i.e. from alveolus to corpus, to lower border regions). I conclude that postcanine cortical asymmetry may be a retained evolutionary trait rather than the result of masticatory biomechanics. In the second section of the thesis I introduced a different analysis regime which allows the prediction of fracture initiation and propagation. In this part I analysed the mechanics underlying the failure of the restorations placed in non-carious cervical lesions and suggested changes in the material properties of the restorations used to treat them. Non-carious cervical lesions (NCCL) include those entities characterised by the cervical loss of hard dental tissue that occurs in the absence of any carious process. To distinguish between lesions that occur due to excessive occlusal load and other non-carious cervical lesion (i.e. erosion and abrasion) the clinical term "abfraction" has been adopted. Although a common clinical issue, failure of restoration placed in these lesions has not been subjected to a rigorous biomechanical analysis. To determine which of the material�s parameters should be changed and to what extent, I employed a combined numerical approach. Here I introduced a novel approach in simulating the cracking of restorative materials and tooth tissues which is based on a simpler material formulation and can be used in an advanced nonlinear numerical analysis. The material model I used allows automatic crack insertion and growth and also uniquely accounts for the microdamage which precedes the instalment of macroscopic cracks. The first step was to balance the factors that may affect failure employing a linear analysis with a stress-based approach to failure. Here, the aim was to investigate the influence of lesion shape and depth as well as the direction of occlusal loading on the mechanical response of the cervical glass-ionomer cements restoration in a lower first premolar. This analysis showed that the direction of loading was the major contributor to the failure of the restoration. The next step was to apply this fracture model to the restorations of the NCCL in order to verify if the material is able to accurately simulate the location and type of mechanical failure. The data for this problem, i.e. the geometry and the loadcase were derived from the conclusions of linear analysis, that is I chose the "worst case scenario" as the upper boundary of material endurance. My results showed that under the action of para-functional loadings the GIC failed on the cervical margin. I also showed that prior to fracture the restorative material undergoes strain softening, which in turn introduces damage and weakens the materials involved. After successfully testing the proposed model, the final step was to determine which material properties and restorative techniques would be most reliable under given biomechanical conditions. The present work relied on the hypothesis that a more flexible material would partially buffer the local stress concentration and hence reduce the likelihood of mechanical failure of the restoration. My study, a first of its kind, proposes a radical approach to address the problems of material improvement, namely: numerical-based material optimisation engineering. That is, I aimed to identify the "most favourable" selection of elastic modulus or E value for the restorative material, which will allow it to survive under the unfavourable occlusal loading conditions that may prevail. Two filling techniques were considered; firstly a single bulk material, namely glass-ionomer (GIC) and secondly a layered technique. The latter consisted of a layer of GIC supporting a composite bulk restorative. I chose two thicknesses for the GIC layer, 50 and 150 microns. My results showed that the restorative materials currently used in cervical non-carious lesions are largely unsuitable in terms of resistance to fracture of the restoration mostly because of their relative high stiffness irrespective of the filling technique. The best results are obtained for a bulk filling with a 1GPa elastic modulus material case in which the tensile stresses are about 50% of the failure limit. This approach in determining the mechanical properties of the restorative is novel and unique so far in the dental literature. The direct benefit of this study was the improvement of the restorative material, as it can be engineered to withstand the conditions identified as major cause of failure. This is consonant with the call for new materials better tailored for some specific needs.

The understanding of the masticatory apparatus including its functional and structural relationship with other components of the cranium increasingly requires an interdisciplinary approach. Recently, "traditional biological sciences" such as anatomy, comparative biology, anthropology and evolution have increasingly meshed with elements from other domains, such as mechanical engineering and material sciences, which has resulted in new and exciting paradigms to be explored. This is particularly true in the field of craniofacial biomechanics yet there are still many unexplored issues and numerous questions that remain unanswered. Numerical modelling in general and Finite Element Analysis (FEA) in particular, represent a numerical experimental procedure to generate such information. Originally derived from the field of structural engineering, FEA has steadily permeated its way into craniofacial biomechanics and has proven itself as a most useful scientific tool. The present study introduces an engineering-based workframe for applying FEA to craniofacial biomechanical research in a comprehensive manner to cover the entire analytical spectrum, from developing questions to providing their solutions. The study is composed of two major experimental parts addressing both the linear elastic and the non-linear behaviour of some biomaterials encountered in the craniofacial arena. In the first part I analysed mandibular biomechanics using linear elastic models while in the second part I used nonlinear discrete models to determine the optimal elastic properties of the cervical restorative materials. Modern humans have a number of anatomical features that set us apart from our ancestors. Amongst these perhaps the most striking is the emergence of a protruding chin, otherwise absent in other archaic humans and hominids. While it has been shown that the chin has its embryological origins in the postnatal remodelling of bone in the area around the mandibular symphysis which produces the midline keel in the form of an inverted �T� the functional significance of this novel evolutionary feature is still obscure. It is accepted that the mandible is optimally designed for resisting masticatory stress, whereby optimal is seen as maximual strength at the lowest biological cost. Here, I tested the currently most accepted theory, namely that the chin provides mechanical resistance to the mandible during mastication. In other words, I tested the hypothesis that a chinned mandible would be stiffer and hence experience lower strains when compared to a non-chinned counterpart under identical loadings. My functional analysis consisted firstly of three simple models which reproduce a simian shelf, a flat and a chinned symphysis, loaded using two unidirectional loadcases (torsion and wishboning) to represent a distortion similar to that which occurs in the mandible during mastication. Secondly, I developed complex geometrical models which incorporated the cortical bone, medullary bone and teeth. The models were then analysed using the same loadcases as those used for the first theoretical models. Additionally, I incorporated the coronal bending and also a coupled loadcase which simulated the complex deformation of the mandible during biting. The aim here was to test the hypothesis that the presence of a chin changed the strain pattern in the mastication-loaded mandible. The results were then interpreted using Frost�s mechanostat theory which relates in a more precise manner the mechanical loading environment to the adaptive response of the bone. My results showed that the calculated strain values for both the chinned and flat mandibles were within the normal bone maintenance levels of the mechanostat during molar biting. In other words, variation in bone strain magnitude across the mandible, which should differ between the chinned and the non-chinned mandibles if the hypothetical mechanical role of the chin is true, is similar in both forms. I concluded that the development of the human chin is thus unrelated to the functional demands placed upon it by mastication. I suggested a new functional demand associated with pronounced tongue activity during speech. I hypothesise that it is the resistance to stresses induced by strong, repetitive contractions of the tongue and perioral musculature during, phonation that shaped the modern human chin. I tested my hypothesis by loading the symphyseal region with two principal nonmasticatory, muscle systems; firstly, the tongue and secondly the peri-oral muscular curtain, anterior to the symphysis. My results suggested that the flat, non-chinned symphysis when subjected to speech-related genioglossal movements will undergo adaptive changes which would result in an optimised (chinned) shape, such as that found in the modern human symphysis. These results thus offer a new foundation to an old hypothesis and a solution to the longstanding controversy over the origin of the human chin. I conclude that forces generated by speech rather than those generated by mastication, shaped the chin in anatomically modern humans. Prompted by an earlier observation I further investigated the apparent cross-over distribution of strains on the mandibular corpora during mastication. In doing so, I tested the hypothesis that this cross-over may be linked with another particular anatomical feature of the mandible that of the postcanine cortical asymmetry, which appears to be stereotypical among anthropoids. The results of my study hence suggest that strain patterns within the human mandible are more complex than previously thought. Not only do strains differ between lingual and buccal aspects of working and non-working sides, but they also differ within these areas (i.e. from alveolus to corpus, to lower border regions). I conclude that postcanine cortical asymmetry may be a retained evolutionary trait rather than the result of masticatory biomechanics. In the second section of the thesis I introduced a different analysis regime which allows the prediction of fracture initiation and propagation. In this part I analysed the mechanics underlying the failure of the restorations placed in non-carious cervical lesions and suggested changes in the material properties of the restorations used to treat them. Non-carious cervical lesions (NCCL) include those entities characterised by the cervical loss of hard dental tissue that occurs in the absence of any carious process. To distinguish between lesions that occur due to excessive occlusal load and other non-carious cervical lesion (i.e. erosion and abrasion) the clinical term "abfraction" has been adopted. Although a common clinical issue, failure of restoration placed in these lesions has not been subjected to a rigorous biomechanical analysis. To determine which of the material�s parameters should be changed and to what extent, I employed a combined numerical approach. Here I introduced a novel approach in simulating the cracking of restorative materials and tooth tissues which is based on a simpler material formulation and can be used in an advanced nonlinear numerical analysis. The material model I used allows automatic crack insertion and growth and also uniquely accounts for the microdamage which precedes the instalment of macroscopic cracks. The first step was to balance the factors that may affect failure employing a linear analysis with a stress-based approach to failure. Here, the aim was to investigate the influence of lesion shape and depth as well as the direction of occlusal loading on the mechanical response of the cervical glass-ionomer cements restoration in a lower first premolar. This analysis showed that the direction of loading was the major contributor to the failure of the restoration. The next step was to apply this fracture model to the restorations of the NCCL in order to verify if the material is able to accurately simulate the location and type of mechanical failure. The data for this problem, i.e. the geometry and the loadcase were derived from the conclusions of linear analysis, that is I chose the "worst case scenario" as the upper boundary of material endurance. My results showed that under the action of para-functional loadings the GIC failed on the cervical margin. I also showed that prior to fracture the restorative material undergoes strain softening, which in turn introduces damage and weakens the materials involved. After successfully testing the proposed model, the final step was to determine which material properties and restorative techniques would be most reliable under given biomechanical conditions. The present work relied on the hypothesis that a more flexible material would partially buffer the local stress concentration and hence reduce the likelihood of mechanical failure of the restoration. My study, a first of its kind, proposes a radical approach to address the problems of material improvement, namely: numerical-based material optimisation engineering. That is, I aimed to identify the "most favourable" selection of elastic modulus or E value for the restorative material, which will allow it to survive under the unfavourable occlusal loading conditions that may prevail. Two filling techniques were considered; firstly a single bulk material, namely glass-ionomer (GIC) and secondly a layered technique. The latter consisted of a layer of GIC supporting a composite bulk restorative. I chose two thicknesses for the GIC layer, 50 and 150 microns. My results showed that the restorative materials currently used in cervical non-carious lesions are largely unsuitable in terms of resistance to fracture of the restoration mostly because of their relative high stiffness irrespective of the filling technique. The best results are obtained for a bulk filling with a 1GPa elastic modulus material case in which the tensile stresses are about 50% of the failure limit. This approach in determining the mechanical properties of the restorative is novel and unique so far in the dental literature. The direct benefit of this study was the improvement of the restorative material, as it can be engineered to withstand the conditions identified as major cause of failure. This is consonant with the call for new materials better tailored for some specific needs.

Doktoravhandling--Copenhagen. / Bibliography: p. 97-[100].

Doktoravhandling--Copenhagen. / Bibliography: p. 97-[100].

Thesis (Ph.D.)--University of Alberta, 2009. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Medical Sciences - Orthodontics. Title from pdf file main screen (viewed on August 16, 2009). Includes bibliographical references.

Craniometrical evaluation skull roebuck common was realised on show trophy in term sof territorial administrative unit Kaplice in the years 2007 and 2008. In the first year of research there were measured 114 roebuck skulls o show trophy . In the second year of research there were measured 78 roebuck skulls o show trophy Twenty three craniometrical values were measured on each skulls. There were made photos of each measured skulls. Craniometric data were statistically evaluated. Statistical analysis were not confirmed with hypothesis, that all craniometrical data depend on the age.