During ontogeny there are a lot of changes in the entire human skeleton. This thesis deals with shape changes in the mandible, which are caused by genetic, hormonal, as well as mechanical factors. The most important mechanical factors influencing the shape of mandible are development of deciduous and permanent dentition and also development of masticatory muscles. 34 children mandibles of known age and 14 adult mandibles were analysed and compared for this thesis. Data were obtained by scanning coordinates of 36 landmarks using Microscribe G2X, and then were processed by software PAST and Morphologika2 using multivariate statistics (PCA, MANOVA). Geometric morphometrics is used for a detailed analysis of shape changes of the mandible. There is no difference between dental and chronological age. In conclusion, lower jaw narrows during growth, the body extends more in the region of third molars and the ramus grows mainly in the region of condylar process. Chin prominence also occurs during ontogeny. In the group of adult mandibles the variability is caused by coronoid process height and the body width. The hypothesis, that age groups are significantly different from each other, and therefore due to tooth mineralization there are marked shape changes, is confirmed.

Objetivo: Comparar los métodos de Demirjian, Nolla y Cameriere para la estimación de la edad según la edad cronológica en una población peruana. Materiales y métodos: El diseño del estudio es de tipo descriptivo, de corte transversal. Se seleccionaron 193 radiografías panorámicas aleatoriamente de niños de 6 a 14 años de edad. Se compararon la edad cronológica (EC) y la edad dental (ED) según los métodos de Nolla, Demirjian y Cameriere, utilizando las Pruebas de Rangos de Wilcoxon y Kruskall Wallis. Resultados: La media de la EC fue de 8.77±2.34 y 8.90±2.04 años para el género femenino y masculino, respectivamente. La diferencia de medias de la EC y ED de acuerdo con los métodos Nolla años, Demirjian y Cameriere años fue de -0.38, 0.96 y -0.29 años, respectivamente, para la muestra total de estudio. Conclusiones: Se encontró una correlación positiva para los tres métodos estudiados, sin embargo, el método de Demirjian mostró una diferencia estadísticamente significativa con una subestimación de -0.91 años en la muestra total. Asimismo, el método de Cameriere fue el que tuvo más cercanía a la edad cronológica. / Aim: The aim of this study is to compare Demirjian, Nolla and Cameriere methods for the estimation of dental age in peruvian population. Materials and Methods: This retrospective and cross-sectional study included 193 panoramic radiographs randomly selected from children aged between 6 and 14 years. Chronological age (CA) and dental age (DA) were compared using the Wilcoxon and Kruskall Wallis Range Tests. Results: The mean was 8.77 ± 2.34 and 8.90 ± 2.04 years of the CA for the female and male gender, respectively. The difference in means of the CA and DA according to the Nolla, Demirjian and Cameriere methods were -0.38, 0.96 and -0.21 years, respectively, for the total study sample. Conclusions: A positive correlation was found for the three methods studied, however, the Demirjian method showed a statistically significant difference with an underestimation of -0.91 years in the total sample. Also, the method of Cameriere was the closest to the chronological age. / Tesis

Made available in DSpace on 2014-12-17T14:13:35Z (GMT). No. of bitstreams: 1 MariaCGM_DISSERT.pdf: 783345 bytes, checksum: 2bbd27cd96c8b3b35673be95266c5187 (MD5) Previous issue date: 2010-09-17 / Since Demirjian's system of estimating dental maturity was first described, many researchers from different countries have tested its accuracy among diverse populations. Some of these studies have pointed out a need to determine population-specific standards. In Brazil, the Northeast region is the one that most suffers the negative impact of exodus, specially related to the increase of abandoned children in the cities. The aim of this study was to test the accuracy of Demirjian's system for assessing the dental maturity of northeastern Brazilian children, so as to present a scale for maturity score conversion into dental age developed specifically for this population. This could be used for forensic, anthropological and legal matters, and also as a model for other countries attempting to formulate their own conversion scales. Panoramic radiographs of 1,491 children (821 females and 670 males), aged 7 to 13 years, from Cear? state, northeast Brazil, were assessed by a single observer to determine dental age (DA) according to Demirjian's system. The mean percentage of intra-observer agreement was 86.6%, with a mean Cohen's Kappa coefficient of 0.67 (substantial agreement). The DA was compared by paired t-test to subjects' chronological age (CA). The differences between CA and DA in all age groups were statistically significant (p<0.0001), demonstrating a great advancement in DA among Brazilians. Scatter plots were drawn for both genders, and the data were fitted to a growth curve, y = 100/ (1 + e-a(x b)). Graphs corresponding to the 50th percentile curves were produced. A table with new values for the conversion of maturity score into dental age for northeastern Brazilian children is presented. The great advancement in DA, as obtained by Demirjian's system in this population, justified the determination of specific scores for dental maturity assessment / A estimativa da maturidade dent?ria tem sido descrita na literatura basicamente atrav?s de dois m?todos, a observa??o direta do processo de erup??o do dente na cavidade oral ou por meio de radiografias. A radiografia panor?mica, obtida por t?cnica extra-oral de uso dos raios X, ? um elemento essencial para o diagn?stico por imagens em Radiologia odontol?gica. Este trabalho apresenta dois estudos quantitativos anal?tico-descritivos utilizando o m?todo de determina??o da idade dental atrav?s de radiografia panor?mica em crian?as brasileiras nordestinas. Um estudo piloto realizado com 325 crian?as (191 meninas e 134 meninos) de 7 a 16 anos, da cidade de Fortaleza, objetivando determinar as interrela??es entre as suas idades cronol?gica (data de nascimento), ?ssea (pelo m?todo de Grewlich & Pyle) e dental (segundo Demirjian et al.). Outro estudo, j? publicado, conduzido com 1.491 crian?as (821 meninas e 670 meninos) cearenses, de 7 a 13 anos, visando avaliar a aplicabilidade do m?todo de Demirjian na popula??o estudada. Em ambos os estudos, mostra-se que a estimativa de idade dental utilizando as tabelas de convers?o de maturidade dental propostas por Demirjian et al. n?o se ad?qua ? popula??o pesquisada. Assim, uma escala de valores de convers?o de maturidade dental em idade dental foi desenvolvida especificamente para crian?as nordestinas e ? agora apresentada, visando ? sua aplica??o n?o s? na cl?nica, mas em quest?es forenses, antropol?gicas, legais e/ou criminais. As pesquisas de car?ter interdisciplinar envolveram pesquisadores das ?reas de Odontologia (Odontopediatria, Ortodontia e Radiologia); Medicina (Endocrinologia e Metabologia); e F?sica, preenchendo os requisitos de multidisciplinaridade do Programa de P?s-Gradua??o em Ci?ncias da Sa?de

Age estimation is a common requirement in forensic, bioarcheological and biomedical practice. This master thesis deals with age estimation based on permanent tooth mineralization according to Demirjian et al. (1973). The research material consisted of orthopantomograms of 716 Czech and 743 French children aged between 4 and 15 years. The purpose of this study was to analyse the suitability of the original French-Canadian standards for age estimation (Demirjian a Goldstein, 1976) and the recent Belgian standards (Willems et al., 2001) in Czech and French population. Another aim of the study was to evaluate the accuracy of the neural network method that represents a completely new approach in data prediction. In order to express the accuracy of estimate we used mean and median of difference between chronological and dental age, and RMS error. Using logistic regression, differences in tooth mineralization between Czech and French population and between girls and boys were also evaluated. Our results indicate that the French-Canadian standards gave a consistent overestimation of dental age compared with chronological age. Mean difference was 0,33 years for Czech children and 0,45 and 0,46 years for French girls and boys, respectively. We found that Willem's method and neural network method were more...

A utilização de Células-tronco e técnicas da Engenharia Tecidual representa um grande avanço tecnológico e beneficiará muitos pacientes com suas conquistas. A descoberta de germes dentários como uma fonte confiável de células-tronco possibilitou diversas pesquisas nesta área. Duailibi et al. (2011) sugeriram uma nova classificação de desenvolvimento dentário baseada pela quantidade de material biológico coletado indicando a necessidade de métodos de diagnóstico por imagem para esta nova classificação. Na literatura diversos trabalhos indicam métodos de classificação dentária e métodos para estimar a idade fisiológica de indivíduos. O presente estudo tem o objetivo de adaptar alguns destes métodos para estimar o estágio de desenvolvimento proposto por Duailibi et al. (2011) consequentemente indicando a quantidade de células-tronco esperadas nas amostras. Para tanto, submeteu-se uma coleção de 67 dentes previamente classificados por Duailibi et al. (2011) à técnica rpcl e à tcfc para a obtenção de imagens e a aplicação de técnicas de estimativas por proporções lineares e volumétricas. Os resultados por análises lineares indicaram valores de R2 para o método de proporção de comprimento CDCP de 0,14050; CCCP de 0,65369; CCCR de 0,5408; CDCR de 0,54074; o método de proporção de área APAD de 0,23925; e método de proporção de volume VPVD de 0,08553, com valor de p menor ou igual à 0,05. Concluindo este estudo indica-se o método de rpcl utilizando a análise do comprimento entre coroa e polpa como o mais indicado para estimar o estágio de desenvolvimento. / The usage of human dental stem cells and tissue engineering technics represents a huge tecnological development and it may benefits many patients in a promissing future. The discovery of suitable source of human dental stem cells were made using tooth buds. Duailibi et al. 2011 indicated a new tooth classification on a stem cell harvesting based research, sugesting new methods for diagnosis these stages. Several method were developed for dental age assesement. The presente study aims to evaluate some of these dental age technics and make adaptations for estimating Duailibi et al. 2011 tooth stages. A 67 tooth sample previoulsy classificated by Duailbi et al. 2011 were submited through periapical parallel long cone X-rays and CBCT analysis. Age estimation ratio methods were applied by measuring tooth/root lenth, crown/root lenth, tooth/pulp lenth, crown/pulp lenth, tooth/poulp área and tooth/pulp volume. Results indicated by linear regression analisys a R2 value of tooth/pulp lenth 0,14050; crown/pulp lenth 0,65369; crown/root lenth 0,5408; tooth/root lenth 0,54074; pulp/tooth volume 0,23925; e tooth/pulp volume de 0,08553, with p value of 0,005. In conclusion , the best method for estimating Duailibi et al. 2011 tooth classification techinic is made by using periapical long cone X-rays using crown/pulp lenth ratio.

A utilização de Células-tronco e técnicas da Engenharia Tecidual representa um grande avanço tecnológico e beneficiará muitos pacientes com suas conquistas. A descoberta de germes dentários como uma fonte confiável de células-tronco possibilitou diversas pesquisas nesta área. Duailibi et al. (2011) sugeriram uma nova classificação de desenvolvimento dentário baseada pela quantidade de material biológico coletado indicando a necessidade de métodos de diagnóstico por imagem para esta nova classificação. Na literatura diversos trabalhos indicam métodos de classificação dentária e métodos para estimar a idade fisiológica de indivíduos. O presente estudo tem o objetivo de adaptar alguns destes métodos para estimar o estágio de desenvolvimento proposto por Duailibi et al. (2011) consequentemente indicando a quantidade de células-tronco esperadas nas amostras. Para tanto, submeteu-se uma coleção de 67 dentes previamente classificados por Duailibi et al. (2011) à técnica rpcl e à tcfc para a obtenção de imagens e a aplicação de técnicas de estimativas por proporções lineares e volumétricas. Os resultados por análises lineares indicaram valores de R2 para o método de proporção de comprimento CDCP de 0,14050; CCCP de 0,65369; CCCR de 0,5408; CDCR de 0,54074; o método de proporção de área APAD de 0,23925; e método de proporção de volume VPVD de 0,08553, com valor de p menor ou igual à 0,05. Concluindo este estudo indica-se o método de rpcl utilizando a análise do comprimento entre coroa e polpa como o mais indicado para estimar o estágio de desenvolvimento. / The usage of human dental stem cells and tissue engineering technics represents a huge tecnological development and it may benefits many patients in a promissing future. The discovery of suitable source of human dental stem cells were made using tooth buds. Duailibi et al. 2011 indicated a new tooth classification on a stem cell harvesting based research, sugesting new methods for diagnosis these stages. Several method were developed for dental age assesement. The presente study aims to evaluate some of these dental age technics and make adaptations for estimating Duailibi et al. 2011 tooth stages. A 67 tooth sample previoulsy classificated by Duailbi et al. 2011 were submited through periapical parallel long cone X-rays and CBCT analysis. Age estimation ratio methods were applied by measuring tooth/root lenth, crown/root lenth, tooth/pulp lenth, crown/pulp lenth, tooth/poulp área and tooth/pulp volume. Results indicated by linear regression analisys a R2 value of tooth/pulp lenth 0,14050; crown/pulp lenth 0,65369; crown/root lenth 0,5408; tooth/root lenth 0,54074; pulp/tooth volume 0,23925; e tooth/pulp volume de 0,08553, with p value of 0,005. In conclusion , the best method for estimating Duailibi et al. 2011 tooth classification techinic is made by using periapical long cone X-rays using crown/pulp lenth ratio.