Anomalías dentales en personas con discapacidad / Dental Anomalies in People with Disabilities

RESUMEN Introducción: Durante la odontogénesis se pueden producir malformaciones congénitas que afectan la forma, el número, el tamaño, la estructura, la posición, el color y la erupción de los dientes. En las personas con discapacidades como parálisis cerebral, trastorno del desarrollo intelectual, síndrome de Down y trastorno del espectro autista, pueden presentarse variedad de anomalías dentales. Objetivo: Describir las anomalías dentales en las condiciones de discapacidad de parálisis cerebral, trastorno del desarrollo intelectual, síndrome de Down y trastorno del espectro autista. Métodos: Se realizó una búsqueda bibliográfica en las bases de datos Clinical Key, Medline, Dialnet y SciELO. Se aplicó la lista de comprobación PRISMA. Análisis e integración de la información: Posterior al proceso de lectura y análisis de la información, se recuperaron 800 artículos de las bases de datos, se eliminaron 590 por encontrarse repetidos. Luego de la discriminación, quedaron para revisar 210, a estos restantes se hizo la revisión de texto completo. Se eliminaron 193 no hacían referencia a anomalías dentales y/o a los trastornos o síndromes. De los 17 restantes, solo 15 cumplieron con los criterios de inclusión. Conclusiones: No se encontraron diferencias para afirmar que algunas de las anomalías y alteraciones presentadas correspondan de manera individual a cada tipo de discapacidad. Sin embargo, el síndrome de Down presenta anomalías dentales relacionadas al estado del paciente. La parálisis cerebral reporta otros hallazgos como bruxismo, debido al deficiente desarrollo muscular, lo que afecta la cavidad bucal y sus estructuras(AU)

ABSTRACT Introduction: During odontogenesis, congenital malformations can occur that affect teeth shape, number, size, structure, position, color and eruption. In people with disabilities such as cerebral palsy, intellectual development disorder, Down syndrome, and autism spectrum disorder, a variety of dental abnormalities can occur. Objective: To describe dental anomalies in such disability conditions as cerebral palsy, intellectual development disorder, Down syndrome and autism spectrum disorder. Methods: A bibliographic search was performed in the databases Clinical Key, Medline, Dialnet and SciELO. The PRISMA checklist was applied. Information analysis and integration: After reading and analyzing the information, 800 articles were retrieved from the databases, of which 590 were deleted because they were repeated. After the discrimination, 210 were pending to review; the remaining ones were reviewed full-text. 193 were deleted because they did not do any reference to dental anomalies and/or disorders or syndromes. Of the remaining 17, only 15 met the inclusion criteria. Conclusions: No differences were found to affirm that some of the anomalies and alterations presented correspond individually to each type of disability. However, Down syndrome has dental abnormalities related to patient condition. Cerebral palsy coincides with other findings such as bruxism, due to poor muscle development, which affects the oral cavity and its structures(AU)

Low birth weight and the delay on the eruption of deciduous teething in children / Baixo peso ao nascer e atraso na erupção de dentes decíduos em crianças

Abstract Objectives: To analyze the association between low birth weight (LBW) and the occurrence of the delay on the eruption of deciduous teething (DEDT) in children from 04 to 30 months, living in Salvador, Bahia. Methods: A cross-sectional study involved 520 children at four to thirty months of age, from public, private and philanthropic daycares from two districts in Salvador. A descriptive analysis and unconditional logistic regression were done to estimate the odds ratios (ORs), using the Confidence Interval of 95% as a criterion for accepting associations. Poisson regression was used as an analytical strategy to obtain the prevalence ratio. Results: the prevalence of the delay on the eruption was 10.29%. There was a positive association between LBW and occurrence of DEDT among children with less than 24 months, both in the unadjusted model (PR=2.07, 95%CI= 0.96 4.44) as in the adjusted (adjusted PR=2, 27, 95%CI= 1.02 5.07). Conclusions: the variables of development and nutritional at birth and during the early life may be important predictors of the chronology of eruption. Further investigations should be carried out towards the adequate evaluation of the LBW role in the occurrence of the delay on the eruption.

Resumo Objetivos: analisar a associação entre o Baixo Peso ao Nascer (BPN) e a ocorrência de atraso na erupção da dentição decídua (AED) em crianças de 04 a 30 meses, residentes em Salvador-BA. Métodos: estudo transversal envolvendo 520 crianças que frequentavam creches públicas, privadas e filantrópicas de dois Distritos Sanitários de Salvador-Ba. Procedeu-se a análise descritiva e regressão logística não-condicional para estimação da oddsratios (ORs), empregando-se o Intervalo de Confiança a 95% como critério para aceitar as associações. A regressão de Poisson foi utilizada como estratégia analítica para obtenção da Razão de Prevalência. Resultados: a prevalência de atraso na erupção foi de 10,29%. Verificou-se uma associa-ção positiva entre BPN e ocorrência de AED entre as crianças com menos de 24 meses no modelo bruto (RP=2,07, IC95%= 0,96 4,44) e ajustado (RP ajustada=2,27, IC95%= 1,02 5,07). Conclusões: variáveis de desenvolvimento e nutricionais ao nascimento e durante a vida precoce podem ser importantes preditores do tempo de erupção, sendo necessárias outras investigações para uma adequada avaliação desta associação.

Dientes fuera de la cavidad oral, un hallazgo infrecuente / Teeth outside the oral cavity, an uncommon finding

Los dientes derivan de tres estructuras embriológicas importantes: las células de la cresta neural, el mesodermo y el ectodermo bucal. Asimismo, los teratomas son lesiones tumorales que se desarrollan a partir de las células germinales de las tres capas germinativas embrionarias y que pueden dar lugar a la formación de estructuras dentales, adiposas, pilosas, óseas, cartilaginosas en localizaciones anatómicas aberrantes pudiendo aparecer en los pulmones, los ovarios, los testículos, la región hipofisiaria y pineal. Se trata de lesiones generalmente asintomáticas y subclínicas que tienden a aparecer en las primeras tres décadas de la vida y son comúnmente diagnosticadas de forma accidental mediante estudios imagenológicos como la tomografía axial computarizada o la resonancia magnética. Se describe el caso de una paciente de 28 años a quien se le realizó la extirpación de una masa tumoral en el ovario con el diagnóstico presuntivo de teratoma, y al realizar su apertura se encontraron órganos dentarios en su interior. El objetivo principal de este artículo es explicar el proceso embrionario que da lugar a losdientes y las circunstancias patológicas que pueden ocasionar que esteproceso odontogénico se suscite en sitios anatómicos aberrantes yatípicos ajenos a la cavidad bucal.

Teeth are derived from three important embryological structures: the neural crest cells, oral mesoderm and ectoderm. Also, teratomas aretumoral lesions that are developed from the germ cells of the threeembryonic germinative layers and that can give rise to the formation of dental, adipose, hairy, bony, cartilaginous structures in aberrant anatomical locations that can appear in lungs, ovaries, testicles, pituitary and pineal region. These are usually asymptomatic and subclinical lesions that tend to appear in the first three decades of lifeand are commonly diagnosed accidentally by imaging studies such ascomputed tomograph or magnetic resonance imaging. We describe thecase of a 28-year-old patient who was removed from a tumor mass in theovary with a presumptive diagnosis of teratoma and when they openedit, dental organs were found inside. The main objective of this articleis to explain the embryonic process that gives rise to the teeth and thepathological circumstances that can cause this odontogenic process toarise in anatomical aberrant and atypical sites outside the oral cavity.

Medium modification with bone morphogenetic protein 2 addition for odontogenic differentiation

Abstract The aim of this study was to evaluate whether medium modification improves the odontogenic differentiation of human dental pulp stem cells (DPSC) in vitro and in vivo. DPSC isolated from human impacted third molar teeth were analysed for clusters of differentiation with flow cytometry. Odontogenic differentiation was stimulated by medium modification with the addition of bone morphogenetic protein 2 (BMP2). The expression of dentin sialophosphoprotein, dentin matrix protein 1, enamelysin/matrix metalloproteinase 20 and the phosphate-regulating gene with homologies to endopeptidases on the X chromosome of the cells were analysed with RT-PCR at 7, 14 and 21 days. Then, DPSC were transplanted on the back of immunocompromised mice via a hydroxyapatite tricalcium phosphate scaffold, and the structure of the formed tissue was investigated. The cells were identified as mesenchymal stem cells with a 98.3% CD73 and CD90 double-positive cell rate. The increase in mineralization capacity and expression of human enamel-dentin specific transcripts proportional to the culture period were determined after differentiation. Six weeks after transplantation, an osteo-dentin matrix was formed in the group in which odontogenic differentiation was stimulated, and the odontogenic characteristics of the matrix were confirmed by histological examination and RT-PCR analysis. Odontogenic differentiation of the isolated and characterized human DPSC was improved with medium modification by the addition of BMP2 in vitro and in vivo. The defined medium and applied technique have a potential use for forming reparative dentin in the future, but the effects of the method should be investigated in long-term studies.

Accuracy of dental age estimation in Venezuelan children: comparison of Demirjian and Willems methods

La edad dental es un indicador de la maduración somática con importancia tanto para la odontología clínica como forense. Este estudio tiene como objetivo comparar la aplicabilidad de los métodos propuestos por Demirjian y por Willems para la estimación de la edad dental en un grupo de niños Venezolanos. Fueron evaluadas 238 radiografías panorámicas de niños venezolanos con edades de 5 a 13 años, para determinar la edad dental utilizando los métodos de Demirjan y de Willems. Fueron excluidos casos con radiografías defectuosas, agenesia dental y pérdida prematura de dientes primarios. Las medias de las diferencias entre la edad dental y la edad cronológica fueron estimadas, distribuyendo por género y por grupo de edad. Fueron utilizadas las pruebas estadísticas ANOVA y T de Student (p=0,05). Para el método de Demirjian, la media de la diferencia entre la edad dental y la edad cronológica fue 0,62 ± 0,93 siendo estadísticamente significativa. La media de la sobrestimación para el género femenino fue menor que para el género masculino (hembras 0,56 ± 0,96 años; varones 0,67 ± 0,93 años). Para el método de Willems la diferencia entre la edad dental y la edad cronológica fue 0,15± 0,97 sin significancia estadística. La precisión de este método presentó variación estadísticamente significativa entre géneros (hembras 0,01 ± 0,96 años, varones (varones 0,29 ±0,96 años). El método de estimación de edad dental de Willems presentó mayor precisión para esta muestra de niños Venezolanos...

In vitro evaluation of the odontogenic potential of mouse undifferentiated pulp cells

The aim of this study was to evaluate the odontogenic potential of undifferentiated pulp cells (OD-21 cell line) through chemical stimuli in vitro. Cells were divided into uninduced cells (OD-21), induced cells (OD-21 cultured in supplemented medium/OD-21+OM) and odontoblast-like cells (MDPC-23 cell line). After 3, 7, 10 and 14 days of culture, it was evaluated: proliferation and cell viability, alkaline phosphatase activity, total protein content, mineralization, immunolocalization of dentin matrix acidic phosphoprotein 1 (DMP1), alkaline phosphatase (ALP) and osteopontin (OPN) and quantification of genes ALP, OSTERIX (Osx), DMP1 and runt-related transcription factor 2 (RUNX2) through real-time polymerase chain reaction (PCR). Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests (p<0.05). There was a decrease in cell proliferation in OD-21 + OM, whereas cell viability was similar in all groups, except at 7 days. The amount of total protein was higher in group OD-21 + OM in all periods; the same occurred with ALP activity after 10 days when compared with OD-21, with no significant differences from the MDPC-23 group. Mineralization was higher in OD-21+OM when compared with the negative control. Immunolocalization demonstrated that DMP1 and ALP were highly expressed in MDPC-23 cells and OD-21 + OM cells, whereas OPN was high in all groups. Real-time PCR revealed that DMP1 and ALP expression was higher in MDPC-23 cell cultures, whereas RUNX2 was lower for these cells and higher for OD-21 negative control. Osx expression was lower for OD-21 + OM. These results suggest that OD-21 undifferentiated pulp cells have odontogenic potential and could be used in dental tissue engineering.

O objetivo foi avaliar o potencial odontogênico de células indiferenciadas da polpa (OD-21) por meio de indução química in vitro. As células foram divididas em grupos: controle (OD-21), induzido (OD-21 em meio suplementado/OD-21 + OM), e células odontoblastóides (MDPC-23). Após 3, 7, 10 e 14 dias, avaliou-se proliferação e viabilidade celular, proteína total e fosfatase alcalina (ALP), mineralização, imunolocalização da proteína da matriz dentinária 1 (DMP1), ALP e osteopontina (OPN), assim como a expressão dos genes ALP, OSTERIX (Osx), DMP1 e fator de transcrição RUNX2 por PCR em tempo real. Os dados foram avaliados pelo teste de Kruskal-Wallis seguido pelo teste de Mann-Whitney U (p<0.05). Houve diminuição na proliferação celular em OD-21 + OM, com viabilidade celular similar em todos os grupos, exceto aos sete dias. O conteúdo de proteína total foi maior no grupo OD-21 + OM em todos os períodos; o mesmo ocorreu com a atividade de ALP quando comparada com o grupo OD-21, além de apresentar resultados similares ao grupo MDPC-23. A mineralização foi maior em OD-21 + OM quando comparada com o controle negativo. A imunolocalização demonstrou expressão de DMP1 e ALP em MDPC-23 e OD-21 + OM, enquanto que todos os grupos foram positivos para OPN. A expressão gênica de DMP1 e ALP foi maior nas culturas de MDPC-23, enquanto que a de RUNX2 foi menor para estas células e maior no controle negativo. A expressão de OSTERIX foi menor em OD-21 + OM quando comparada aos outros grupos. Sugere-se que as células indiferenciadas da polpa da linhagem OD-21 apresentam potencial odontogênico e poderiam ser usadas para a engenharia tecidual.

El rol de los restos epiteliales de Malassez en el ligamento periodontal / The role of Malassez epithelial rests in the periodontal ligament

El periodonto de inserción es definido como aquellos tejidos que soportan y rodean a la raíz dentaria y está compuesto opr tres estructuras que constituyen una unidad topográfica y funcional: el cemento radicular, el ligamento periodontal y el hueso alveolar. Estas estructuras evolucionan interrelacionada y coordinadamente durante la vida del diente, adaptándose a las modificaciones que surgen en el medio bucal. El objetivo de este trabajo es transmitir los nuevos conceptos emergentes vinculados al periodonto de inserción, centrándonos fundamentalmente en la estructura y función de los restos epiteliales de Malassez (REM), células presentes en el ligamento periodontal. Si bien es conocida la participación de estas células en procesos patológicos, entre ellos, quistes inflamatorios y tumores odontogénicos, poco se sabe de los mismos. Por ello, para poder llevar a cabo esta actualización sobre los REM, se consideraron las últimas publicaciones al respecto que figuran en la base de datos de Pubmed. A través de esta búsqueda, se obtuvo información referida a su descubrimiento, origen embriológico, características histológicas, productos elaborados por los REM y posibles funciones por ellos desempeñadas. Se puede decir entonces, que los REM desempeñarían un papel importante dentro del ligamento periodontal normal y, posiblemente, durante las terapias periodontales regenerativas. Si bien se requieren más estudios al respecto, es posible por lo tanto, reivindicar a estas células en su función y considerarlas mucho más que simples vestigios de la odontogénesis, presentes en el ligamento periodontal.

Soluções estéticas para alterações da odontogênese

As alterações na Odontogênese podem manifestar-se clinicamente de diversas formas e, pela varideade de alterações, muitas vezes são de difícil diagnóstico. O trabalho tem como objetivo realizar uma revisão de literatura sobre três alterações que geralmente causam bastante confusão entre os profissionais, que são a Amelogênese Imperfeita e a Dentinogênese Imperfeita que tem caráter hereditário e acometem todos os dentes, em ambas as dentições. Além desssa, também aborda as Hipoplasias de esmalte, qie podem ocorrer por fatores locais ou sistêmicos e afetar um ou mais dentes...

Maturation of permanent teeth in different facial types: A comparative study.

Background: Accurate diagnosis of dental maturation help in diagnosis, treatment planning, and timing in orthodontics and dentofacial orthopedics. Aim and Objective: The present study is undertaken to compare and correlate chronological age and dental age of patients with average, vertical, and horizontal facial types, and to find out any sex difference in dental age in different growth patterns and to evaluated the reliability of Willem's method in Indian population. Materials and Methods: Subjects in the age group of 8-10 years were screened from Out Patients Department of Orthodontics and Dentofacial Orthopedics and from the various school of the City, were subjected to cephalometric radiography and orthopentomograms. Angular and linear measurements used included;-SN Go-Gn angle, J.R. (Jarabak ratio) and LAFH (lower anterior facial height), to group total sample of 150 children. Group 1 (average grower), Group 2 (vertical grower), and Group 3 (horizontal grower). Then dental age for each child in different group was calculated from OPG of each subject and compared with chronological age using Student t-test. Results: The results suggest a difference in dental age in subject with vertical and horizontal growers. Vertical grower showed earlier maturation compared to horizontal growth patterns. There was insignificant difference present when vertical grower and horizontal grower were compared with average growth pattern. Insignificant difference was found in dental age between males and females when compared to same growth pattern. Conclusion: Subjects with vertical growth pattern matured early than having the horizontal growth pattern in the same chronological age.

Tooth regeneration: Current status.

Regeneration of a functional tooth has the potential to be a promising therapeutic strategy. Experiments have shown that with the use of principles of bioengineering along with adult stem cells, scaffold material, and signaling molecules, tooth regeneration is possible. Research work is in progress on creating a viable bioroot with all its support. A new culture needs to be created that can possibly provide all the nutrients to the stem cells. With the ongoing research, tissue engineering is likely to revolutionize dental health and well-being of people by regenerating teeth over the next decade.

Dentin matrix protein 1 (DMP1) expression in developing human teeth

Dentin matrix protein 1 (DMP1) is an acidic phosphoprotein that plays an important role in mineralized tissue formation by initiation of nucleation and modulation of mineral phase morphology. The purpose of the present study was to examine the immunoexpression of DMP1 in tooth germs of 7 human fetuses at different gestational ages (14, 16, 19, 20, 21, 23 and 24 weeks) comparing with completed tooth formation erupted teeth. The results showed the presence of DMP1 in the dental lamina, as well as in the cells of the external epithelium, stellate reticulum and stratum intermedium of the enamel organ. However, in the internal dental epithelium, cervical loop region and dental papilla some cells have not labeled for DMP1. In the crown stage, DMP1 was expressed in the ameloblast and odontoblast layer, as well as in the dentinal tubules of coronal dentin near the odontoblast area. Erupted teeth with complete tooth formation exhibited immunolabeling for DMP1 only in the dentinal tubules mainly close to the dental pulp. No staining was observed in the enamel, predentin or dental pulp matrix. DMP1 is present in all developing dental structures (dental lamina, enamel organ, dental papilla) presenting few immunoexpression variations, with no staining in mineralized enamel and dentin.

A proteína da matriz dentinária 1 (DMP1) é uma fosfoproteína ácida que tem sido relacionada diretamente ao processo de mineralização dos tecidos em formação sendo iniciadora do processo de nucleação e modulação da fase mineral. O objetivo desse trabalho foi avaliar a imunoexpressão da DMP1 em germes dentários em diferentes fases da odontogênese, obtidos de 7 fetos humanos em diversos estágios gestacionais (14, 16, 19, 20, 21, 23 e 24 semanas), comparando-se com dentes com rizogênese completa. Os resultados mostraram que a DMP1 esteve expressa na lâmina dentária, bem como, nas células do epitélio externo, retículo estrelado e estrato intermediário do órgão do esmalte. Diferentemente, no epitélio interno do órgão do esmalte, alça cervical e papila dentária algumas células não apresentaram a DMP1. Nas fases de coroa, os ameloblastos e odontoblastos apresentaram marcação positiva para a DMP1, bem como os túbulos dentinários da dentina coronária próximos à região odontoblástica. Os dentes com rizogênese completa exibiram marcação para a DMP1 apenas nos túbulos dentinários principalmente próximos à polpa dentária. Nenhuma marcação foi observada na matriz de esmalte ou pré-dentina, nem na polpa dentária. Concluímos que a DMP1 está presente em todas as fases da odontogênese, tanto na lâmina dentária, órgão do esmalte, bem como na papila dentária, com pequenas variações de nuances de expressão, estando ausente na dentina e esmalte mineralizados.

Sequential expressions of Notch1, Jagged2 and Math1 in molar tooth germ of mouse

The Notch signaling pathway is an evolutionary conserved mechanism that plays an important role in cell-cell communication and cell fate in a wide range of tissues. The mammalian family of Notch receptors consists of 4 members: Notch1/2/3/4. The Notch ligand family consists of 5 members: Delta1/3/4 and Jagged1/2. Math1 encodes a murine Basic helix-loop-helix (bHLH) transcription factor that acts as positive regulator of cell differentiation. Recently, links between Notch and Math1 pathways were demonstrated in various tissues. Expression of Notch1, Jagged2 and Math1 were analyzed in the mouse molar tooth germ during embryonic stage (E) 13 and E15 and during postnatal stage (PN) 1, PN3, PN5, PN10 and PN14 by using in situ hybridization. Positive Notch1 expression was found at the tooth bud during embryonic stages, but its expression was absent from the basal cells in contact with the dental mesenchyme. Jagged2 and Math1 were strongly expressed in differentiated ameloblasts and odontoblasts and Math1 strong expression was even maintained until PN14 stage. Math1 showed the strongest expression. Our results suggest that the Notch1 signaling pathway through Jagged2 could be importantly related to Math1, directing the process of odontogenesis toward cell differentiation.

Immunology of root resorption: a literature review.

Root resorption seems to be related to a complex combination of mechanical factors and biological activity, which comprehends the role of immunologic structures including specialized cells. The aim of this research was to explain the development of the process--from mineralization to the destruction of hard tissues--and the possible relationship between root resorption and immunology, along with discussing current concepts described in the literature.

Alteraciones estructurales del esmalte: hipoplasias y opacidades del primer molar permanente / Enamel structural alterations: hypoplasia and hypomineralization of the first permanent molars

Las últimas décadas la odontología ha conseguido importantes avances para entender cabalmente la etiopatogenia y los mecanismos aptos para la prevención y tratamiento de una de sus enfermedades más prevalentes: la caries dental. Esto ha permitido especialmente a la odontopediatría, dirigir la atención a otras patologías que hoy se incrementan como las erosiones y las anomalías estructurales del diente. Dentro de estas últimas las hipoplasias dentales de origen genético van encontrando nuevas respuestas con el enfoque molecular merced al desarrollo de la biología molecular y la genética. El efecto nocivo que producen por vía sistémica las tetraciclinas o los fluoruros también han sido especialmente estudiados, así como el efecto deletéreo de factores locales como la infección y el trauma de las piezas primarias sobre la estructura dentaria de las piezas permanentes de reemplazo. Sin embargo la clínica muestra con una frecuencia cada vez mayor opacidades e hipoplasias de los primeros molares permanentes, con una severidad que varía desde aquellos que tienen los cuatro primeros molares afectados, donde se podría suponer que al desarrollarse simultáneamente obedecen a una causa sistémica, hasta otros que muestran una distribución azarosa afectando solo a uno, dos o tres molares. En esta materia queda aun mucho por resolver ya que plantea un esencial desconocimiento etiológico que impide el desarrollo de medidas preventivas y eficaces procedimientos terapéuticos.

Localization of Bmp-4, Shh and Wnt-5a transcripts during early mice tooth development by in situ hybridization

A comparative nonisotopic in situ hybridization (ISH) analysis was carried out for the detection of Bmp-4, Shh and Wnt-5a transcripts during mice odontogenesis from initiation to cap stage. Bmp-4 was expressed early in the epithelium and then in the underlying mesenchyme. Shh expression was seen in the odontogenic epithelial lining thickening, being stronger in the enamel knot area, during the cap stage. Wnt-5a transcripts were expressed only in the mesenchyme during the initiation, bud and cap stages, with strong expression in the dental mesenchyme during the bud stage. The present results showed that Bmp-4, Shh and Wnt-5a are expressed since the very early stages of tooth development, and they suggest that the Wnt-5a gene is expressed in different cell populations than Bmp-4 and Shh.

No presente trabalho, realizou-se uma análise comparativa não isotópica por hibridização in situ a fim de se detectar a presença de transcritos de Bmp-4, Shh e Wnt-5a durante as fases iniciais da odontogênese em camundongos, desde a iniciação até o estágio de capuz. No estágio de iniciação, observou-se expressão precoce de Bmp-4 no epitélio e no mesênquima subjacente, enquanto que a expressão de Shh ocorreu durante o estágio de capuz, na região de espessamento do revestimento epitelial odontogênico, tornando-se mais intensa na área de nó do esmalte. Os transcritos de Wnt-5a foram expressos somente no mesênquima durante os estágios de iniciação, botão e capuz, com intenso sinal na região no mesênquima na fase de botão. Estes resultados mostraram que Bmp-4, Shh e Wnt-5a são expressos desde os estágios mais precoces do desenvolvimento dentário, sugerindo que o gene Wnt-5a seja expresso em populações celulares distintas daquelas que expressam Bmp-4 e Shh.

Dental development of Didelphis albiventris (Marsupialia): I - incisors and canines

Estudou-se o desenvolvimento dos dentes incisivos e caninos em 76 amostras de Didelphis albiventris com idade entre 0 e 100 dias. Cortes transversais, seriados de 6 µm de espessura foram obtidos da região da maxila, corados com Hematoxilina e Eosina e analisados ao microscópio de luz. Verificou-se que o período estudado abrange todo o desenvolvimento dental, desde a fase de iniciação da interação epitélio/mesenquima até a completa formação e erupção dos incisivos e caninos. O espessamento do epitélio oral dá origem aos incisivos e caninos funcionais, enquanto o epitélio dental externo do órgão dental origina uma lâmina dental secundária, a qual sofre degeneração, quando o dente alcança o estágio de botão. Não há vestígios de dentição decídua. Sugere-se que a lâmina dental secundária é remanescente de uma condição primitiva na qual ocorria dentição secundária.

Collagen analysis in human tooth germ papillae

The extracellular matrix (ECM) performs a very important role in growth regulation and tissue differentiation and organization. In view of this, the purpose of this study was to analyze the collagen, the major organic component of dental pulp ECM, in papillae of human tooth germs in different developmental phases. The maxillas and mandibles of 9 human fetuses ranging from 10 to 22 weeks of intrauterine life were removed and 16 tooth germs (1 in the cap stage, 8 in the early bell stage and 7 in the late bell stage) were obtained. The pieces were processed for histological analysis and stained with hematoxylin-eosin, Masson's Trichrome and picrosirius staining technique. Both types of collagen in the dental papilla were only detected by the picrosirius staining technique under polarized light microscopy. Type III collagen was detected in all specimens. Type I collagen was present in focal areas of the dental papilla only in some specimens. In conclusion, the findings of this study showed that type III collagen is a regular component of the papillae of human tooth germs whereas type I collagen is present in a significantly lesser amount.

A matriz extracelular (MEC) tem um papel importante na regulação do crescimento e na diferenciação e organização dos tecidos. Com base nestes aspectos o objetivo do deste estudo foi analisar o colágeno, maior componente orgânico da MEC da polpa dentária, na papila de germes dentários humanos, em diferentes fases do desenvolvimento. Foram obtidos fragmentos de maxilas e mandíbulas de 9 fetos humanos com 10 a 22 semanas de vida intra-uterina, dos quais foram analisados 16 germes dentários (1 em estágio de capuz, 8 em estágio de campânula precoce e 7 em estágio de campânula tardia). Secções histológicas seriadas foram coradas com hematoxilina e eosina, tricrômico de Masson e técnica de coloração do picrosirius. Ambos os tipos de colágeno na papila dentária foram somente detectados pela técnica de coloração do picrosirius usando microscopia de luz polarizada. Colágeno tipo III foi detectado em todas as amostras. Colágeno tipo I estava presente em áreas focais da papila dental em algumas amostras. Concluiu-se que o colágeno tipo III mostrou-se um componente regular da papila de germes dentários humanos, enquanto o colágeno tipo I esteve presente em quantidade significativamente menor.

Lactate dehydrogenase isoenzymes in dental pulp of rats according to stage of root development

The objective of this study was to present a classification of the root development stage of female rat molar teeth and to evaluate the variation in the lactate dehydrogenase (LDH) activity and electrophoretic isoenzyme profile according to the stage of root development of the molar teeth. We also studied the LDH activity and isoenzymes of the pulp of incisor teeth. The stage of development of the rat first molar at the age of 15 days and that of the second molar at the age of 18 days was classified as the beginning of root formation. At the age of 15 days, the electrophoretic profile of the isoenzymes for the first molar showed a prevalence of LDH-1 followed by LDH-2. However, for the maxillary second molar there was a prevalence of LDH-4 followed by LDH-1, while for the mandibular second molar LDH-1 predominated followed by LDH-2 and LDH-4. From 18 days of age, the prevalence was always of LDH-1. The electrophoretic profile of LDH isoenzymes from the pulp of the incisor teeth at the ages studied (25 and 60 days) showed the following order of prevalence: LDH-1 > LDH-2 > LDH-3 > LDH-4 > LDH-5. These results suggest that there are variations in the prevalence of the various forms of LDH isoenzymes in the dental pulp of rats according to the developmental stage of the root