Irrompimento do primeiro molar permanente em crianças da zona urbana e rural do município de Santa Helena - Paraná / Irrompement of the first permanent molar in children from the urban and rural area of the city of Santa Helena - Paraná

O objetivo deste trabalho foi comparar a cronologia de erupção do primeiro molar permanente em crianças de ambos os sexos, residentes na zona urbana e rural do munícipio de Santa Helena - PR, Brasil. Foi realizado um estudo transversal com 154 crianças da zona rural e 300 crianças da área urbana de 04 a 07 anos (48 a 84 meses). Os primeiros molares avaliados foram considerados irrompidos quando qualquer porção de sua coroa estivesse clinicamente visível. A média de idade para erupção do primeiro molar permanente se mostrou de 72 a 83 meses. Destes, o grupo da zona rural apresentou uma média para idade de erupção mais precoce. Contudo, verificou-se um resultado considerável em crianças na faixa de 48 a 59 meses (4 anos), mostrando mais uma vez a erupção precoce nas crianças da zona rural. Este dente irrompeu primeiro na mandíbula, irrompendo primeiro nas meninas do que nos meninos, e o dente 46 foi o que mais se mostrou presente. A média de idade para erupção do primeiro molar permanente correspondeu àquela descrita pela literatura aos seis anos, mas não correspondeu ao atraso na erupção das crianças residentes em zona rural. Bem como este dente irrompeu primeiro na mandíbula... (AU)

The objective of this study was to compare the chronology of eruption of the first permanent molar in children of both sexes, living in the urban and rural areas of the city of Santa Helena-PR, Brazil. A cross-sectional study was carried out with 154 children from the rural area and 300 children from the urban area from 4 to 7 years old (48 to 84 months). The first molars evaluated were considered erupted when any portion of their crown was clinically visible. The average age for eruption of the first permanent molar was 72 to 83 months. Of these, the rural group had an earlier average age for eruption than the urban group. However, a considerable result was found in children 48-59 months showing once again the early eruption in rural children. This tooth erupted first in the jaw, erupting first in girls rather than boys, and tooth 46 was most present. The mean age of eruption of the first permanent molar corresponded to that described in the literature at age six, but did not correspond to the delayed eruption of children living in rural areas. Just like this tooth erupted in the jaw first... (AU)

Expression of Wnt and beta-catenin in mouse tooth germs and chick facial primordia: a comparison / Expresión de Wnt y beta-catenina en gérmenes de dientes de ratón y primordios faciales de polluelos: una comparación

In order to compare Wnt/ beta-catenin expression in mouse and chick facial primordia during development, we performed an immunohistochemical analysis of both protein expressions in E12 to E17 mouse embryos and in E3 and E10 chick embryos. During odontogenesis, from bud to bell stage, both proteins exhibit similar fixation patterns, with epithelial and mesenchymal immunoreactivity, consistant with literature data. Double labelling demonstrates that the same cells express both antigens, even in undifferentiated mesenchyme. The enamel knot, and the ameloblastic and odontoblastic layers are stained at the same manner. In the chick, Wnt and beta-catenin are diffusely present on craniofacial mesenchyme. In both species, premuscular blastemata express Wnt and b-catenin, but Wnt is specifically expressed on the perichondrium and ossification centers, suggesting a role independent from beta-catenin pathway.

Bioingeniería dental, ¿el futuro de la terapia odontológica? / Dental bioengineering: is this the future of dental treatment?

Desde las primeras épocas de la historia, el hombre ha intentado restituir la función de los órganos dentarios perdidos. El sueño de la odontología es sustituir los materiales que se usan hoy en día por otros de origen biológico, basados en células que tengan las mismas características o semejantes a las naturales para poder así regenerar o reparar los tejidos perdidos. Las publicaciones recientes enfatizan el uso de las células troncales inducidas a pluripotencia (iPSC por sus siglas en inglés), como la posible solución al controvertido uso de células madre y la obtención de ellas; ésta es sólo una de las muchas posibilidades que se plantean para las futuras investigaciones; sin embargo, debido a que es la más acertada, la aplicación de estas técnicas en el ámbito odontológico es la forma más cercana de poder llegar a restituir los tejidos perdidos. Es así como la bioingeniería dental se abre a nuevos horizontes, esperando obtener mejores alcances en beneficio de la salud de nuestra población.

Sex determination in mandibles in the first year of life by a quantitative approach / Determinación del sexo en mandíbulas en el primer año de vida mediante una aproximación cuantitativa

Numerous studies have shown that skeletal characteristics vary among different populations. Several authors suggest that it is possible to determine sex through the anatomical evaluation of children mandible, however there are few morphometrical studies conducted with such specimens. The purpose of this study was to analyze several mandibular dimensions and identify the ones that could be useful to perform sex differentiation in a sample of Brazilian young children. For this study we used 32 children dry mandibles of known sex, age ranging from 0 to 1 year old. The mandibles pertain to the collection of the Skull Museum of the Universidade Federal de Sao Paulo (UNIFESP). The parameters included bicondilar width, bigonial width, minimum width and height of the mandibular ramus, gonion-gnation length, height of the mandibular symphysis and transverse and anteroposterior condylar dimensions. The SPSS program was used to carry on the discriminant function analysis and the T test (p <0.05). There were no statistically significant differences that could allow identification of a specific parameter for sex determination. However, most of the dimensions were higher in male than in female, except for the minimum width of the mandibular ramus (0.2-0.16 mm) and transverse diameter of the right condyle (0.16mm). The values obtained for the anteroposterior diameter of the mandibular head were the most different between genders, although no statistically significance was found. Discriminant function analysis indicated that, despite differences, none of the evaluated parameters allow for sex classification with enough reliability. In conclusion, there is little sexual dimorphism in children's mandibles during the first year of life and anatomical analysis of this structure is not recommended as reliable quantitative approach for sex differentiation with forensic purposes.

Numerosos estudios han demostrado que las características esqueletales varían en las distintas poblaciones. Diversos autores indican que es posible la determinación del sexo en base a mandíbulas infantiles; sin embargo, existen escasos estudios morfométricos realizados en mandíbulas de niños brasileros. El propósito de este estudio fue analizar distintas dimensiones de mandíbulas y determinar aquellas de utilidad en el diagnóstico forense del sexo, en población infantil brasilera. Se utilizaron 32 mandíbulas de niños brasileros de entre 0 y 1 año de edad, de sexo conocido, pertenecientes a la colección de cráneos de la Universidade Federal de Sao Paulo (UNIFESP). Las mediciones mandibulares incluyeron ancho bicondilar, ancho bigonial, ancho mínimo y altura de la rama mandibular, longitud gonion- gnation, altura de la sínfisis mandibular y las dimensiones transversa y anteroposterior del cóndilo. Los datos obtenidos fueron sometidos al t test (p<0,05) y análisis de la función discriminante con SPSS. La mayoría de las dimensiones fueron superiores en hombres que en mujeres, con excepción del ancho mínimo de la rama mandibular (0,2-0,16 mm) y del diámetro transverso del cóndilo derecho (0,16 mm). El diámetro anteroposterior de la cabeza mandibular resultó la más dimórfica de las medidas analizadas, aunque ninguna diferencia resultó estadísticamente significativa. El análisis de la función discriminante indicó que a pesar de las diferencias, éstas no permiten clasificar de acuerdo al sexo, en base a las variables cuantitativas analizadas. En conclusión, la mandíbula de niño en el primer año de vida presenta escaso dimorfismo sexual y no se recomienda el abordaje cuantitativo para la determinación del sexo con fines forenses.

Dental maturity and chronological age in a sample of growth hormone deficient patients aged 4-16 years

In the past few decades, the availability of much improved endocrine assay techniques has focused attention upon hormones as major determinants of human growth and development. This cross-sectional study aimed to explore the direct effect of Growth Hormone Deficiency [GHD] on the rate of dental development that might indirectly affect the classical orthodontic treatment timing standards. Additionally, the magnitude of any possible differential effect of this endocrinopathy on the somatic and dental systems development has to be searched. The sample consisted of 87 patients suffering of isolated GHD aged 4-16 years with a comparable control group of normally growing Iraqi subjects. The results declared a highly significant retardation in the rate of dental development of the GHD patients, with a total mean delay of 1.5 years. The dental age delay of the youngest GHD children [4- 5 years] was minimal [tilde 0.6 years], meanwhile the maximal delay [tilde 1.8 years] was recorded about the pre-pubertal growth phase [9-12 years]. At the same time, there was an obvious differential effect of GHD on the height age and dental age, in which a greater retardation was always imposed on the somatic maturity indicator compared to the dental one, a finding that might be attributed to the different developmental patterns and embryonic origins of teeth and bones

Un error que no es de Darwin, sobre la formación de los dientes en la física de Aristóteles / A mistake, not a Darwin's one, about teeth formation in Aristoteles physics

Un párrafo traducido del griego y aislado de los anteriores y siguientes, hizo creer a Darwin que Aristóteles había incurrido en una falta de comprensión en la formación de los dientes de los seres vivos, pero señaló con acierto, al mismo tiempo, que la idea del filósofo sobre la finalidad que rige los cambios materiales era, como precedente de la "selección natural", una noción oscura