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1.
Braz. j. oral sci ; 20: e211202, jan.-dez. 2021. ilus
Article in English | LILACS, BBO | ID: biblio-1254523

ABSTRACT

Aim: To evaluate the prevalence and predisposing factors for hypomineralization of second molars in children in primary dentition. Methods: A questionnaire was applied to parents to analyze predisposing factors and to assist in the diagnosis of hypomineralization in children between 2 and 6 years old, followed by an intraoral examination based on indices of non-fluorotic enamel defects in the primary dentition, according to the "Modified Index DDE" to determine demarcated opacity and HSPM presence / severity index to assess hypomineralization. Children from public and private schools were dived into two groups: if they presented HSPM-Group 1 (G1) and if they did not have HSPM-Control group (CG). Results: The most frequent predisposing factors associated with the child were Illness in the first year of life (X2= 6.49; p=0.01) and antibiotic use in the first year of life (X2= 41.82; p= 0.01). The factors associated with the mother were hypertension (X2= 9.36; p=0.01), infections during pregnancy (X2=14.80; p=0.01) and alcohol consumption during pregnancy (X2=97.33; p=0.01). There was a prevalence of 3.9% of HSPM in 14 children, with statistical difference regarding gender (X2 = 4.57; p <0.05), with boys presenting a higher frequency. In G1 hypomineralization was of the type with demarcated opacity, with more prevalent characteristics the yellowish spot, with moderate post-eruptive fracture and acceptable atypical restorations. All lesions were located in the labial region with 1/3 of extension. Conclusion: The prevalence of HSPM in children between 2 and 6 years old was 3.9%, with a predominance in males, with tooth 65 being the most affected. There was an association between HSPM and infection in the first year of life, as well as the use of antibiotics and sensitivity in the teeth affected by the lesion. There was an association between HSPM and hypertension, infection and mothers' alcohol use during pregnancy


Subject(s)
Humans , Male , Female , Child, Preschool , Tooth Demineralization , Dental Enamel , Dental Enamel Hypoplasia/epidemiology , Amelogenesis
2.
J. bras. nefrol ; 41(3): 433-435, July-Sept. 2019. graf
Article in English | LILACS | ID: biblio-1040252

ABSTRACT

ABSTRACT This report describes the oral manifestations of renal tubular acidosis (RTA) associated with secondary rickets and discusses the biological plausibility of these findings. The characteristic electrolyte changes during RTA or genetic mutations that trigger RTA may be responsible for impaired amelogenesis, dental malocclusion, impacted teeth, and absent lamina dura. This report reinforces the possibility of an association between RTA and the oral manifestations described.


RESUMO Este relato de caso descreve as manifestações bucais da acidose tubular renal (ATR) associada ao raquitismo secundário e discute a plausibilidade biológica desses achados. As alterações eletrolíticas características da ATR ou as mutações genéticas que a desencadeiam podem ser responsáveis pela amelogênese imperfeita, maloclusão dentária, dentes impactados e ausência de lâmina dura. Este relato reforça a possibilidade de uma associação entre ATR e as manifestações bucais descritas.


Subject(s)
Humans , Female , Adolescent , Rickets/complications , Rickets/etiology , Tooth, Impacted/etiology , Acidosis, Renal Tubular/pathology , Open Bite/etiology , Dental Enamel Hypoplasia/etiology , Acidosis, Renal Tubular/complications , Radiography, Panoramic , Amelogenesis
3.
Rev. Ciênc. Méd. Biol. (Impr.) ; 18(1): 32-37, jul 05, 2019. fig
Article in Portuguese | LILACS | ID: biblio-1280876

ABSTRACT

Introdução: a amelogênese compreende a formação do esmalte por células especializadas denominadas ameloblastos. Os ameloblastos secretam proteínas da matriz e são responsáveis pela criação de um ambiente extracelular que favorece a mineralização do esmalte. Contudo, diversos fatores, como o trauma dentário, podem interferir na amelogênese, contribuindo para a formação de um esmalte defeituoso. O trauma dentário tem sido responsável por muitos casos de hipoplasia que podem fragilizar o dente, além de trazer desconforto estético. Objetivo: examinar as alterações morfológicas sobre o epitélio odontogênico e a matriz de esmalte de incisivos de ratos, produzidas por um trauma dentário. Metodologia: incisivos de ratos foram extruídos e depois reposicionados em seus alvéolos originais. Decorridos 3, 7, 10, 20, 30 e 60 dias do procedimento cirúrgico, os dentes foram fixados em uma solução de formaldeído e glutaraldeído, processados histologicamente e corados com azul de toluidina. Resultados: a análise morfológica revelou a formação de uma matriz de esmalte bastante heterogênea, com espessura irregular, particularmente na porção mais apical dos incisivos. Algumas matrizes de esmalte expostas mostravam pequenas lacunas de reabsorção, muitas vezes com deposição de um material cementoide. Conclusão: o presente estudo mostrou que o trauma foi suficiente para produzir alterações hipoplásicas e de hipomineralização importantes no esmalte que se relacionaram com a fase funcional dos ameloblastos na região afetada.


Introduction: amelogenesis comprises of enamel formation by specialized cells called ameloblasts. Ameloblasts secrete matrix proteins and are responsible for the creation of an extracellular environment that favors the enamel mineralization. However, various factors, such as the dental trauma, can interfere with amelogenesis, contributing to the formation of a defective enamel. Dental trauma has been responsible for many cases of hypoplasia which can weaken the tooth, in addition to bringing aesthetic discomfort. Objective: examine the morphological changes on the odontogenic epithelium and the enamel matrix of rats incisors, produced by dental trauma. Methodology: rats incisors were extruded and then repositioned in their original alveoli. After 3, 7, 10, 20, 30 and 60 days of the surgical procedure, teeth were fixed in a solution of formaldehyde and glutaraldehyde, processed histologically and stained with toluidine blue. Results: the morphological analysis revealed the formation of enamel matrix extremely heterogeneous, with irregular thickness, particularly on the apical portion of the incisors. Some matrixes of exposed enamel showed small gaps of reabsorption, often with deposition of cementoid material. Conclusion: the present study showed that the trauma was enough to produce hypoplastic and hypomineralization changes important in the enamel that were related to the functional phase of the ameloblasts in the affected region


Subject(s)
Amelogenesis
4.
Article in English | WPRIM | ID: wpr-740086

ABSTRACT

The objective of this study was to examine the expression pattern of Kelch-like ECH-associated protein 1 (Keap1) in the maxillary 2(nd) molar germs of rats. We used the maxillary 2(nd) molar germs in rats' pup at postnatal day 3 (bell stage), 6 (crown formation stage) and 9 (root formation stage). The investigation on mRNA and protein levels were done using reverse transcription - polymerase chain reaction and western blot. Localization of Keap 1 in the maxillary 2(nd) molar germs were revealed through immunofluorescence staining. Keap1 from the maxillary 2nd molar germs were mostly manifested on postnatal day 3 and dramatically decreased on postnatal day 6 and 9 at mRNA and protein levels, while amelogenin and ameloblastin increased during the development of maxillary 2nd molar germs. During immunofluorescence analysis, the strong immunoreactivity against Keap1 was detected in the apical side of ameloblasts at the presecretory and secretory stages. However, Keap1 expression was hardly observed in the ameloblasts at the maturation stage. These results shows that Keap1 is strongly expressed in the presecretory and secretory ameloblasts of amelogenesis, and suggest that Keap1 may be a crucial molecule for the regulatory mechanisms tasked with the formation of enamel layer.


Subject(s)
Ameloblasts , Amelogenesis , Amelogenin , Animals , Blotting, Western , Dental Enamel , Fluorescent Antibody Technique , Molar , Polymerase Chain Reaction , Rats , Reverse Transcription , RNA, Messenger
5.
Rev. Fac. Odontol. Univ. Antioq ; 28(2): 408-421, Jan.-June 2017. graf
Article in English | LILACS | ID: biblio-957246

ABSTRACT

Abstract. The mechanisms involved in the development of dental fluorosis are still unknown. The development of in vivo and in vitro models using biologically relevant concentrations of fluoride for the emergence of fluorosis has allowed suggesting hypotheses that contribute to the understanding of the mechanisms that produce this defect in enamel development, with high prevalence in Colombia. This topic review presents an update on the normal mechanisms of the formation of enamel and how they are affected by exposure to high concentrations of fluoride. This is a thorough review of the deleterious effects of fluoride on the cells and the extracellular matrix, especially during the maturation stage, resulting in a delay of the removal of the protein matrix of amelogenins, as well as the appearance of mottled enamel-a characteristic of dental fluorosis. Finally, it shows the perspectives of the study of this defect in enamel development from biochemistry and cellular and molecular biology.


RESUMEN. Los mecanismos involucrados en el desarrollo de la fluorosis dental aún no se conocen a cabalidad. El desarrollo de modelos in vivo e in vitro que utilizan concentraciones de fluoruro biológicamente relevantes para la aparición de fluorosis ha permitido el planteamiento de hipótesis que aportan cada vez más al conocimiento de los mecanismos que generan este defecto del desarrollo del esmalte, de alta prevalencia en Colombia. Esta revisión presenta una actualización sobre los mecanismos normales de la formación del esmalte y cómo estos se ven afectados por la exposición a altas concentraciones de fluoruro. Se presenta una revisión en detalle de los efectos deletéreos del fluoruro sobre las células y sobre la matriz extracelular, especialmente durante la etapa de maduración, que tendrán como consecuencia el retraso de la remoción de la matriz proteica de amelogeninas y se traducirá en la apariencia de esmalte moteado, característica de la fluorosis dental. Por último, se muestran las perspectivas del estudio de este defecto del desarrollo del esmalte desde la bioquímica y la biología celular y molecular.


Subject(s)
Amelogenesis , Biochemistry , Dental Enamel , Fluorosis, Dental
6.
Int. j. morphol ; 35(2): 435-441, June 2017. ilus
Article in English | LILACS | ID: biblio-893000

ABSTRACT

Tooth enamel is the hardest tissue in the body. The organic matrix configuration is provided by the main proteins amelogenin, ameloblastin and enamelysin (MMP20), an enzyme that helps to shape the matrix. The aim of this study was to determine by histochemistry the expression of amelogenin and enamelysin through the rough endoplasmic reticulum in the late stages of amelogenesis, and its expression in the Complexus golgiensis (Golgi complex / Golgi apparatus) in the early stages in human fetuses. In early stages a colocalization of both proteins inside the Golgi apparatus was found, being more evident the relationship between Golgi and amelogenin (99.92 %). In the late stage, a colocalization of both proteins and rugged endoplasmic reticulum was found. With enamelysin being more evident in relation with rough endoplasmic reticulum (99.95 %). Our findings demonstrated the presence of amelogenin and enamelysin in odontoblast and ameloblast. However, the presence of these two proteins in odontoblast remains unknown.


El esmalte dental es el tejido más duro del cuerpo. La configuración de la matriz orgánica es proporcionada por las proteínas principales amelogenina, ameloblastina y enamelisina (MMP20), una enzima que ayuda a dar forma a la matriz. El objetivo de este estudio fue determinar mediante histoquímica la expresión de amelogenina y enamelisina a través del retículo endoplasmático rugoso en las últimas etapas de la amelogénesis , y su expresión en el Complexo golgiensis en las primeras etapas de formación en fetos humanos. En las primeras etapas se observó colocalización de ambas proteínas en el interior del Complexo golgiensis, siendo más evidente la relación entre Golgi y amelogenina (99,92 %). En la última etapa, se identificó una colocalización de ambas proteínas y retículo endoplásmico rugoso. Resulto más evidente la enamelisina en relación con el retículo endoplasmático rugoso (99,95 %). Nuestros resultados demostraron la presencia de amelogenina y enamelisina en odontoblastos y ameloblastos, sin embargo se desconoce la presencia de estas dos proteínas en odontoblastos.


Subject(s)
Humans , Amelogenin/metabolism , Dental Enamel Proteins , Endoplasmic Reticulum, Rough , Golgi Apparatus , Matrix Metalloproteinase 20/metabolism , Amelogenesis , Fluorescent Antibody Technique
7.
Int. j. morphol ; 35(1): 293-298, Mar. 2017. ilus
Article in Spanish | LILACS | ID: biblio-840968

ABSTRACT

La tuftelina es una proteína secretada en la matriz adamantina en desarrollo durante la formación del esmalte. Su función continúa sin esclarecerse, aunque se presume que juega un papel importante en la biomineralización de esmalte y dentina, así como en el desarrollo del órgano dental. Con el presente estudio se identificó su localización en las diferentes estructuras de gérmenes dentales de fetos humanos, conforme a los resultados se observó su expresión en el estadio pre-secretor observándose en el citoplasma de los ameloblastos, retículo estrellado, papila dental, así como en el estrato intermedio; en el secretor se identificó principalmente en la unión amelodentinaria, y en la superficie externa del esmalte, observando una marcada expresión de la proteína en la porción basal del proceso odontoblástico, pero no en la matriz extracelular de la dentina. De acuerdo a los resultados obtenidos se puede considerar que su expresión se presenta tanto en la amelogénesis, como en la odontogénesis en tejidos sin mineralizar.


The tuftelin is a secreted protein in the adamantine matrix in developing during the enamel formation. Its function continues unclarified, although it plays a role in the biomineralization of the dental organ. With the present studio the location was identified in the different structures of dental germs from human fetuses, according to the results it was observed the expression in the pre-secretor stage being observed in the cytoplasm of ameloblasts, stellate reticulum, dental papilla, also in the intermediate stratum; in the secretor it was mainly identified in the amelodentinal junction and in the outer surface of enamel, observing a marked expression of the protein in the basal portion of the odontoblastic process, but not in the extracellular matrix of the dentine. According to the results obtained it can be considered that its expression occurs in both amelogenesis and odontegenesis in unmineralized tissues.


Subject(s)
Humans , Amelogenesis , Dental Enamel Proteins/metabolism , Dental Enamel Proteins/analysis , Immunohistochemistry
8.
Article in Korean | WPRIM | ID: wpr-91592

ABSTRACT

Amelogenesis imperfecta characterized as abnormally formed enamel is caused by a defect of unique group of genes. Patients affected by this disease might have difficulties in social and psychological aspects due to non-esthetic teeth as well as functional problems caused by enamel detachment and tooth wear from their early ages. Adult patients with amelogenesis imperfecta can be treated with full-mouth restorations, which make functional and esthetic rehabilitations of severely worn tooth. However, the anterior open bite and lack of occlusal clearance for posterior teeth restorations due to compensatory extrusion are the intervening factors in the prosthetic treatment. Therefore, the determination of anterior tooth lengths, vertical dimension, and anterior guidance should be set carefully. Recently, computer-aided design and computer-aided manufacturing (CAD/CAM) techniques help systematic approaches and enable dentists to reduce time-consuming procedures in the diagnosis and treatment of full-mouth rehabilitation. This case report demonstrates the successful full mouth rehabilitation using a CAD/CAM system in a young adult patient with amelogenesis imperfecta and anterior open bite.


Subject(s)
Adult , Amelogenesis Imperfecta , Amelogenesis , Computer-Aided Design , Dental Enamel , Dentists , Diagnosis , Humans , Mouth Rehabilitation , Open Bite , Rehabilitation , Tooth , Tooth Wear , Vertical Dimension , Young Adult
9.
Rev. Fac. Odontol. Univ. Antioq ; 27(1): 154-176, July-Dec. 2015. tab
Article in English | LILACS | ID: biblio-957208

ABSTRACT

ABSTRACT. Introduction: ameloblasts are cells responsible for the production and mineralization of the organic matrix of enamel through several stages: pre-secretory, secretory, transition, and maturation. The organic matrix components are produced in the secretory phase. In the maturation phase, the organic component is removed and the mineralization process starts. This process requires the involvement of matrix metalloproteinase 20 (MMP-20), also called enamelysin. Several studies have shown the presence of MMP-20 in tooth development and its relationship to alterations in enamel formation. The objective was: to classify the different studies and laboratory techniques used to demonstrate the involvement of enamelysin in tooth development and its relation to pathologies during enamel formation. Methods: a systematic review was conducted with the following bibliographic databases: PubMed, Science-Direct, Hinari, and SciELO, in order to classify the different studies related to the involvement of MMP-20 in tooth development and the methods to detect its expression, between the years of 2009 and 2014. Results and conclusions: 11 in vitro models show that MMP-20 has specific cleavage sites for enamel matrix proteins. This process is altered by chemical composition, ions, and the presence of hydroxyapatite. Enamel morphology is altered in the knockout models. In human studies, MMP-20 has been associated with increased susceptibility to dental caries, enamel thickness, and dental agenesis.


RESUMEN. Introducción: el ameloblasto es la célula encargada de la producción y mineralización de la matriz orgánica del esmalte. Atraviesa varias etapas: la fase pre-secretora, secretora, de transición y maduración. En la fase secretora se producen los componentes de la matriz orgánica. En la fase de maduración se elimina el componente orgánico y se inicia el proceso de mineralización. Este proceso requiere de la participación de la metaloproteinasa de matriz 20 (MMP-20) o también llamada enamelisina. Diversos estudios demuestran la presencia de MMP-20 en el desarrollo dentario y su relación con alteraciones en la formación del esmalte. El objeto fue clasificar los diferentes estudios y técnicas de laboratorio empleadas que demuestren la participación de enamelisina en el desarrollo dentario y su relación con patologías en la formación del esmalte. Métodos: se realizó una revisión sistemática de la literatura con las siguientes bases bibliográficas: PubMed, Science-Direct, Hinari y SciELO, con el fin de clasificar los diferentes estudios relacionados con la participación de MMP-20 en el desarrollo dental y los métodos utilizados para detectar su expresión, entre los años de 2009 a 2014. Resultados y conclusiones: los modelos in vitro evidencian que MMP-20 tiene sitios específicos de escisión para las proteínas de matriz de esmalte. Este proceso se ve alterado por la composición química, iones, y la presencia de hidroxiapatita. En los modelos knockout la morfología del esmalte está alterada. En los estudios en humanos, se ha relacionado la MMP-20 con una mayor susceptibilidad de caries dental, el grosor completo de esmalte y agenesias dentales.


Subject(s)
Tooth Abnormalities , Dental Enamel , Matrix Metalloproteinase 20 , Amelogenesis , Amelogenesis Imperfecta
10.
Article in English | WPRIM | ID: wpr-71151

ABSTRACT

Numerous cases of enamel renal syndrome have been previously reported. Various terms, such as enamel renal syndrome, amelogenesis imperfecta and gingival fibromatosis syndrome, and enamel-renal-gingival syndrome, have been used for patients presenting with the dental phenotype characteristic of this condition, nephrocalcinosis or nephrolithiasis, and gingival findings. This report describes a case of amelogenesis imperfecta of the enamel agenesis variety with nephrolithiasis in a 21-year-old male patient who complained of small teeth. The imaging modalities employed were conventional radiography, cone-beam computed tomography, and renal sonography. Such cases are first encountered by dentists, as other organ or metabolic diseases are generally hidden. Hence, cases of amelogenesis imperfecta should be subjected to advanced diagnostic modalities, incorporating both dental and medical criteria, in order to facilitate comprehensive long-term management.


Subject(s)
Amelogenesis Imperfecta , Amelogenesis , Cone-Beam Computed Tomography , Dental Enamel Hypoplasia , Dental Enamel , Dentists , Fibromatosis, Gingival , Humans , Kidney Diseases , Male , Metabolic Diseases , Nephrocalcinosis , Nephrolithiasis , Phenotype , Radiography , Tooth , Young Adult
12.
Pakistan Oral and Dental Journal. 2014; 34 (1): 122-125
in English | IMEMR | ID: emr-157679

ABSTRACT

Developmental defects of the enamel are the result of alterations during amelogenesis due to hereditary, systemic or environmental factors. The present study was done to determine the frequency of developmental defects of enamel in primary teeth at Children Hospital PIMS, Islamabad from February 2011 to January 2012. The study was cross sectional and sample comprised of 300 children, which included 182 [60.7%] males and 118 [39.3%] females. The mean age of the studied population was 3.63 +/- 1.05 years. Enamel defects were present in 115 [38.3%] children. Out of 182 males 69 [37.9%] males and out of 118 females,46 [38.9%] females had enamel defect; thus frequency of enamel defect was not significantly different between the two genders [p=0.852]. The mean age of the children with enamel defect was 3.74 +/- 1.00 and mean age of children without enamel defect was 3.55 +/- 1.06 years respectively. This difference was not statistically significant [p=0.124]. Frequency of enamel defect was significantly higher among families with higher income categories [p=0.020].Out of 300 children, 185 [61.7%] had normal enamel, 5 [1%] had only demarcated opacity, 9 [3%] had only diffuse opacity, 80 [26.7%] had only hypoplasia, 3 [1%] had demarcatead diffuse opacity, 3 [1%] had demarcated opacity with hypoplasia, 13 [4.3%] had diffuse opacity with hypoplasia and 2 [0.7%] had all three defects. Present study concluded that more than one third of the children had developmental defects of enamel in primary teeth and most frequent lesion was enamel hypoplasia


Subject(s)
Humans , Male , Female , Tooth, Deciduous/abnormalities , Amelogenesis , Cross-Sectional Studies , Child
13.
Araraquara; s.n; 2013. 100 p. ilus, tab.
Thesis in Portuguese | LILACS, BBO | ID: biblio-867783

ABSTRACT

Distúrbios genéticos durante o desenvolvimento dentário influenciam na variação do número e formada dentição. Este é o primeiro estudo a avaliar se a variação genética nos genes da formação do esmalte dentário está associada com a Hipomineralização Molar-Incisivo (HMI), levando também em consideração, a experiência de cárie. Amostras de DNA de 71 casos (com HMI) e 89 controles (não afetados) de Araraquara/SP (Brasil) foram analisadas. Onze marcadores em cinco genes [ameloblastina (AMBN), amelogenina (AMELX), enamelina (ENAM), tuftelina (TUFT1), e proteína 11 interagindo com tuftelina (TFIP11)] foram genotipados pelo método TaqMan. O teste Qui-quadrado foi utilizado para comparar as frequências alélicas e genotípicas entre os grupos caso e controle. A experiência de cárie no grupo HMI também foi avaliada para a associação com a variação genética nos genes da formação do esmalte. Os marcadores rs3796704 (ENAM), rs4694075 (AMBN); rs5997096/rs134136 (TFIP11), foram associados com a HMI (p<0.05). Associações dos marcadores rs5997096/rs134136(TFIP11), rs12640848/rs3796704 (ENAM) e rs17878486 (AMELX) (p<0.05) com a cárie dentária foram observadas. O presente estudo sugere possibilidade de associação entre o esmalte hipomineralizado e variação genética nos genes da formação do esmalte dentário


Subject(s)
Amelogenesis , Dental Caries , Dental Enamel , Polymorphism, Genetic
14.
Araraquara; s.n; 2013. 109 p. ilus, tab.
Thesis in Portuguese | LILACS, BBO | ID: biblio-867818

ABSTRACT

O uso da amoxicilina durante a primeira infância tem sido relacionado ao desenvolvimento de defeitos de esmalte denominados Hipomineralização Molar-Incisivo (HMI). Ademais, há relatos de possível potencialização dos efeitos do fluoreto no esmalte pela amoxicilina. Objetivo: A proposta do presente estudo foi avaliar o efeito da amoxicilina, e da associação amoxicilina com fluoreto no desenvolvimento do esmalte dentário de ratos. Metodologia: O experimento foi dividido em três capítulos. Capítulo 1 - Quinze ratas prenhas (Rattus norvegicus, albinus, Holtzman) foram aleatoriamente distribuídas em três grupos que receberam, a cada 24 h, dose intragástrica de amoxicilina 100 mg/kg/dia (grupo GA100), amoxicilina 500 mg/kg/dia (grupo GA500) ou soro fisiológico (grupo GS), a partir do 130 dia de prenhez. Após o nascimento, doze filhotes de cada grupo receberam o mesmo tratamento das respectivas mães durante os períodos de 7 dias (n=6) e 12 dias (n=6) de vida. Após a eutanásia, as cabeças dos ratos foram removidas, fixadas e processadas para inclusão em parafina. Os cortes frontais da cabeça exibindo os primeiros molares superiores foram em parte corados com H&E e em parte submetidos à reação imuno-histoquímica para detecção de amelogenina e metaloproteinases da matriz-20 (MMP-20). Os cortes corados com H&E foram utilizados para análise morfológica e mensuração da espessura da camada de esmalte. A imunoexpressão para amelogenina e MMP-20 foram avaliados por análise semiquantitativa (H-score). Os dados foram analisados estatisticamente pelo teste Tukey com nível de significância de 5%. Capítulo 2 - Quinze ratas prenhas (Rattus norvegicus, albinus, Holtzman) foram aleatoriamente distribuídas em três grupos, que receberam, amoxicilina 100 mg/kg/dia (grupo GA100), amoxicilina 500 mg/kg/dia (grupo GA500) ou soro fisiológico (grupo GS), conforme descrito no capítulo 1. Após o na...


Subject(s)
Amelogenesis , Amoxicillin , Dental Enamel , Dental Enamel Hypoplasia , Rats , Sodium Fluoride
15.
Article in English | WPRIM | ID: wpr-358198

ABSTRACT

This study aimed to compare epithelial cells derived from human embryonic stem cells (hESCs) to human ameloblast-lineage cells (ALCs), as a way to determine their potential use as a cell source for ameloblast regeneration. Induced by various concentrations of bone morphogenetic protein 4 (BMP4), retinoic acid (RA) and lithium chloride (LiCl) for 7 days, hESCs adopted cobble-stone epithelial phenotype (hESC-derived epithelial cells (ES-ECs)) and expressed cytokeratin 14. Compared with ALCs and oral epithelial cells (OE), ES-ECs expressed amelogenesis-associated genes similar to ALCs. ES-ECs were compared with human fetal skin epithelium, human fetal oral buccal mucosal epithelial cells and human ALCs for their expression pattern of cytokeratins as well. ALCs had relatively high expression levels of cytokeratin 76, which was also found to be upregulated in ES-ECs. Based on the present study, with the similarity of gene expression with ALCs, ES-ECs are a promising potential cell source for regeneration, which are not available in erupted human teeth for regeneration of enamel.


Subject(s)
Ameloblasts , Physiology , Amelogenesis , Genetics , Amelogenin , Bone Morphogenetic Protein 4 , Pharmacology , Cell Culture Techniques , Cell Differentiation , Cell Line , Cell Lineage , Embryonic Stem Cells , Physiology , Epithelial Cells , Physiology , Fibroblast Growth Factor 8 , Hedgehog Proteins , Homeodomain Proteins , Humans , Keratins , Classification , Lithium Chloride , Pharmacology , MSX1 Transcription Factor , Mouth Mucosa , Cell Biology , Phenotype , Regeneration , Physiology , Skin , Cell Biology , Transcription Factors , Tretinoin , Pharmacology
16.
Article in English | WPRIM | ID: wpr-358182

ABSTRACT

Formation of the periodontium begins following onset of tooth-root formation in a coordinated manner after birth. Dental follicle progenitor cells are thought to form the cementum, alveolar bone and Sharpey's fibers of the periodontal ligament (PDL). However, little is known about the regulatory morphogens that control differentiation and function of these progenitor cells, as well as the progenitor cells involved in crown and root formation. We investigated the role of bone morphogenetic protein-2 (Bmp2) in these processes by the conditional removal of the Bmp2 gene using the Sp7-Cre-EGFP mouse model. Sp7-Cre-EGFP first becomes active at E18 in the first molar, with robust Cre activity at postnatal day 0 (P0), followed by Cre activity in the second molar, which occurs after P0. There is robust Cre activity in the periodontium and third molars by 2 weeks of age. When the Bmp2 gene is removed from Sp7(+) (Osterix(+)) cells, major defects are noted in root, cellular cementum and periodontium formation. First, there are major cell autonomous defects in root-odontoblast terminal differentiation. Second, there are major alterations in formation of the PDLs and cellular cementum, correlated with decreased nuclear factor IC (Nfic), periostin and α-SMA(+) cells. Third, there is a failure to produce vascular endothelial growth factor A (VEGF-A) in the periodontium and the pulp leading to decreased formation of the microvascular and associated candidate stem cells in the Bmp2-cKO(Sp7-Cre-EGFP). Fourth, ameloblast function and enamel formation are indirectly altered in the Bmp2-cKO(Sp7-Cre-EGFP). These data demonstrate that the Bmp2 gene has complex roles in postnatal tooth development and periodontium formation.


Subject(s)
Actins , Activating Transcription Factor 2 , Genetics , Age Factors , Ameloblasts , Pathology , Amelogenesis , Genetics , Animals , Bone Morphogenetic Protein 2 , Genetics , Cell Adhesion Molecules , Cell Differentiation , Genetics , Cementogenesis , Genetics , Dental Cementum , Pathology , Dental Pulp , Fluorescent Dyes , Green Fluorescent Proteins , Male , Mice , Mice, Knockout , Microvessels , Pathology , Molar , Molar, Third , NFI Transcription Factors , Odontoblasts , Pathology , Odontogenesis , Genetics , Periodontal Ligament , Sp7 Transcription Factor , Stem Cells , Physiology , Tooth Root , Transcription Factors , Genetics , Vascular Endothelial Growth Factor A , Zinc Fingers , Genetics
17.
Article in Korean | WPRIM | ID: wpr-27857

ABSTRACT

Some patients with generalized attrition and teeth discoloration may want their anterior teeth to be treated just for esthetic improvement. Ameologenesis imperfecta, however, should be considered for such patients prior to any treatment with thorough clinical and radiographic examination. If a patient is diagnosed with amelogenesis imperfecta, the treatment on anterior teeth just for esthetic purpose is not advisable. In this case, a young man with amelogenesis imperfecta was treated with metal-ceramic restorations. The patient had generalized attrition, teeth discoloration, crown fracture, and cross-bite on the left teeth. The ultimate objective of this treatment was to enhance esthetics and masticatory function. The cross-bite on the left anterior teeth was treated with restorations, whereas the reverse horizontal overlap was maintained on the posterior. The patient was satisfied with the result esthetically and functionally, and the third month recall examination revealed no pathologic changes associated with the treatment.


Subject(s)
Amelogenesis , Amelogenesis Imperfecta , Crowns , Esthetics , Humans , Tooth , Young Adult
18.
Article in English | WPRIM | ID: wpr-358214

ABSTRACT

Enamel crystals are unique in shape, orientation and organization. They are hundreds of thousands times longer than they are wide, run parallel to each other, are oriented with respect to the ameloblast membrane at the mineralization front and are organized into rod or interrod enamel. The classical theory of amelogenesis postulates that extracellular matrix proteins shape crystallites by specifically inhibiting ion deposition on the crystal sides, orient them by binding multiple crystallites and establish higher levels of crystal organization. Elements of the classical theory are supported in principle by in vitro studies; however, the classical theory does not explain how enamel forms in vivo. In this review, we describe how amelogenesis is highly integrated with ameloblast cell activities and how the shape, orientation and organization of enamel mineral ribbons are established by a mineralization front apparatus along the secretory surface of the ameloblast cell membrane.


Subject(s)
Ameloblasts , Chemistry , Cell Biology , Amelogenesis , Physiology , Basement Membrane , Chemistry , Crystallization , Dental Enamel , Chemistry , Dental Enamel Proteins , Bodily Secretions , Humans , Tooth Calcification
19.
Article in English | WPRIM | ID: wpr-358208

ABSTRACT

Deletion or mutation of dentin matrix protein 1 (DMP1) leads to hypophosphatemic rickets and defects within the dentin. However, it is largely unknown if this pathological change is a direct role of DMP1 or an indirect role of phosphate (Pi) or both. It has also been previously shown that Klotho-deficient mice, which displayed a high Pi level due to a failure of Pi excretion, causes mild defects in the dentinal structure. This study was to address the distinct roles of DMP1 and Pi homeostasis in cell differentiation, apoptosis and mineralization of dentin and enamel. Our working hypothesis was that a stable Pi homeostasis is critical for postnatal tooth formation, and that DMP1 has an antiapoptotic role in both amelogenesis and dentinogenesis. To test this hypothesis, Dmp1-null (Dmp1(-/-)), Klotho-deficient (kl/kl), Dmp1/Klotho-double-deficient (Dmp1(-/-)/kl/kl) and wild-type (WT) mice were killed at the age of 6 weeks. Combinations of X-ray, microcomputed tomography (μCT), scanning electron microscopy (SEM), histology, apoptosis and immunohistochemical methods were used for characterization of dentin, enamel and pulp structures in these mutant mice. Our results showed that Dmp1(-/-) (a low Pi level) or kl/kl (a high Pi level) mice displayed mild dentin defects such as thin dentin and a reduction of dentin tubules. Neither deficient mouse line exhibited any apparent changes in enamel or pulp structure. However, the double-deficient mice (a high Pi level) displayed severe defects in dentin and enamel structures, including loss of dentinal tubules and enamel prisms, as well as unexpected ectopic ossification within the pulp root canal. TUNEL assay showed a sharp increase in apoptotic cells in ameloblasts and odontoblasts. Based on the above findings, we conclude that DMP1 has a protective role for odontoblasts and ameloblasts in a pro-apoptotic environment (a high Pi level).


Subject(s)
Ameloblasts , Pathology , Amelogenesis , Physiology , Animals , Apoptosis , Physiology , Cell Differentiation , Physiology , Dental Enamel , Pathology , Dental Pulp , Pathology , Physiology , Dental Pulp Cavity , Pathology , Dentin , Congenital Abnormalities , Pathology , Dentinogenesis , Physiology , Extracellular Matrix Proteins , Genetics , Physiology , Glucuronidase , Genetics , Homeostasis , Physiology , Hyperphosphatemia , Immunohistochemistry , Mice , Mice, Knockout , Microscopy, Electron, Scanning , Odontoblasts , Pathology , Odontogenesis , Physiology , Ossification, Heterotopic , Genetics , Pathology , Phosphates , Physiology , Tooth Calcification , Physiology , X-Ray Microtomography
20.
Chinese Journal of Stomatology ; (12): 173-176, 2012.
Article in Chinese | WPRIM | ID: wpr-281637

ABSTRACT

<p><b>OBJECTIVE</b>To invesitgate the expression patterns of amelogenin and enamelin in the developing tooth germs.</p><p><b>METHODS</b>Mandible sections of postnatal day 1, 3, 7 and 14 mouse were prepared, immunohistochemical analysis and reverse transcriptase polymerase chain reaction (RT-PCR) were performed to detect the expression patterns of amelogenin and enamelin in mandibular first molars.</p><p><b>RESULTS</b>Amelogenin was observed in the cytoplasm of secretory ameloblasts and the whole enamel matrix layer. It was also transiently expressed in the odontoblasts of postnatal day 1 molars. Enamelin proteins were observed in the enamel layer deposited by secretory ameloblasts, especially intense beneath the ameloblast process and dentino-enamel junction. The mRNA levels of both amelogenin and enamelin were highest on postnatal day 7 (the ratio to glyceraldehyde phosphate dehydrogenase of amelogenin and enamelin: 0.813 ± 0.085 and 0.799 ± 0.064, respectively, P < 0.05).</p><p><b>CONCLUSIONS</b>Amelogenin and enamelin were enamel matrix proteins predominately expressed by secretory ameloblasts. The temporal-spatial expression patterns of amelogenin and enamelin indicate the important roles they played in amelogenesis and biomineralization.</p>


Subject(s)
Ameloblasts , Metabolism , Amelogenesis , Amelogenin , Genetics , Metabolism , Animals , Dental Enamel , Metabolism , Dental Enamel Proteins , Genetics , Metabolism , Mice , Mice, Inbred ICR , Molar , Metabolism , Odontoblasts , Metabolism , RNA, Messenger , Metabolism , Time Factors , Tooth Germ , Metabolism
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