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1.
J Clin Med ; 10(15)2021 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-34362130

RESUMEN

The dental pulp is a soft connective tissue of ectomesenchymal origin that harbors distinct cell populations, capable of interacting with each other to maintain the vitality of the tooth. After tooth injuries, a sequence of complex biological events takes place in the pulpal tissue to restore its homeostasis. The pulpal response begins with establishing an inflammatory reaction that leads to the formation of a matrix of reactionary or reparative dentin, according to the nature of the exogenous stimuli. Using several in vivo designs, antigen-presenting cells, including macrophages and dendritic cells (DCs), are identified in the pulpal tissue before tertiary dentin deposition under the afflicted area. However, the precise nature of this phenomenon and its relationship to inherent pulp cells are not yet clarified. This literature review aims to discuss the role of pulpal DCs and their relationship to progenitor/stem cells, odontoblasts or odontoblast-like cells, and other immunocompetent cells during physiological and pathological dentinogenesis. The concept of "dentin-pulp immunology" is proposed for understanding the crosstalk among these cell types after tooth injuries, and the possibility of immune-based therapies is introduced to accelerate pulpal healing after exogenous stimuli.

2.
Biochem Biophys Res Commun ; 567: 72-78, 2021 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-34144503

RESUMEN

Enhancer of zeste homolog 2 (EZH2) is the catalytic core of polycomb repressive complex 2 (PRC2), which primarily methylates lysine 27 on histone H3 (H2K27me3), generating transcriptionally suppressed heterochromatin. Since EZH2 suppresses expression of genes involved in dentin formation, we examined the role of EZH2 in tooth development. Intriguingly, microCT analysis of teeth from mice with conditional Ezh2 knockout in uncommitted mesenchymal cells showed hyper-mineralization of enamel, which is produced by the epithelial-lineage cells, ameloblasts. Scanning electron microscopy analysis and nano-indentation of the incisor enamel from knockout mice revealed smaller inter-rod spaces and higher hardness compared to wild type enamel, respectively. Interestingly, expression of the calcium channel subunit gene, Orai2, was decreased compared to its competitor, Orai1, both in knockout mouse incisors and the ex vivo culture of ameloblasts with the surrounding tissues under EZH2 inhibition. Moreover, histological analysis of incisor from knockout mice showed decreased ameloblastin and expedited KLK4 expression in the ameloblasts. These observations suggest that EZH2 depletion in dental mesenchymal cells reduces enamel matrix formation and increases enamel protease activity from ameloblasts, resulting in enamel hyper-mineralization. This study demonstrates the significant role of the suppressive H3K27me3 mark for heterochromatin on enamel formation.

4.
Dent Traumatol ; 37(5): 677-690, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-33861506

RESUMEN

BACKGROUND/AIM: Root length is a critical factor for dental pulp regeneration following tooth replantation. The aim of this study was to analyze the effects of reducing the root length by apicoectomy on the pulp healing process using a model for tooth replantation. MATERIAL AND METHODS: After extraction of the upper first molars (M1) of 3-week-old mice, the roots from the experimental group (EG) were shortened to half to two-thirds of their length before replantation, whereas in the control group (CG) the extracted teeth were immediately repositioned into their alveolar sockets. To determine the effects of root resection on the survival of inherent pulp cells, this study included tooth transplantation with root resection using wild-type (WT) and green fluorescent protein (GFP) transgenic mice. The M1 of GFP transgenic mice were transplanted into the alveolar socket of the M1 of WT mice. The roots of the right M1 were shortened (EG), whereas the left M1 remained untreated (CG). RESULTS: Apoptotic cells in the EG significantly decreased in number compared with the CG at day 3. Cell proliferative activity in the EG was significantly higher than that in the CG in the root pulp during days 3-5, and nestin-positive odontoblast-like cells began to arrange themselves along the pulp-dentin border in the cusp area at day 5 in the EG but not in the CG. At week 2, tertiary dentin had formed throughout the pulp in the EG, whereas the combined tissue of dentin and bone occupied the pulp space in 60% of the CG. Root resection also positively affected the survival of inherent pulp cells to differentiate into odontoblast-like cells as demonstrated by transplantation using GFP transgenic mice. CONCLUSIONS: Reducing the root length accelerated pulp regeneration following tooth replantation due to the better environment for revascularization.


Asunto(s)
Reimplante Dental , Diente , Animales , Apicectomía , Pulpa Dental , Ratones , Regeneración
8.
Int. j. odontostomatol. (Print) ; 12(4): 355-361, dic. 2018. tab, graf
Artículo en Español | LILACS | ID: biblio-975757

RESUMEN

RESUMEN: El objetivo del estudio fue determinar el efecto antibacteriano in vitro de la oleorresina de Copaifera reticulata (C. reticulata) "copaiba" y del aceite esencial de Oreganum majoricum (O. majoricum) "orégano" frente a Streptococcus mutans (S. mutans) y Enterococcus faecalis (E. faecalis). Se desarrollaron pruebas de sensibilidad activando primero las cepas bacterias a enfrentar. La oleorresina de copaiba fue diluida con dimetilsulfósido (DMSO), obteniéndose al final concentraciones a probar de 100 %, 50 %, 25 %, y 12,5 %. En relación al aceite esencial de orégano este se probó solamente al 100 %. Para la prueba de difusión en agar con discos, se tomaron inóculos 100 µL de cada cepa bacteriana a una turbidez de 0,5 de Mc Farlam, para ser sembrados por diseminación en placas de tripticasa soya agar, para luego colocar los discos de forma equidistante cargados con las diferentes concentraciones de los productos naturales, se utilizaron como control positivo a la clorhexidina al 0,12 % y al DMSO como control negativo. Se incubaron las placas por el método de la vela en extinción a 37 °C, por un periodo de 24 horas, pasado el tiempo se realizó la lectura de los halos de inhibición. Los resultados obtenidos por la copaiba, determinaron un efecto antibacteriano en sus cuatro concentraciones, siendo los mayores halos de inhibición a la concentración del 100 %, copaiba genero mayores halos promedios para S, mutans de 30,00 ± 0,00 mm y para E. faecalis de 8,3 ± 0,50 mm. Para el caso del orégano se producen halos a la concentración del 100 % con un promedio de 25,3 ± 0,96 mm para S. mutans y para E. faecalis de 9,5 ± 1,29 mm. Se concluye del estudio que tanto copaiba como el orégano presentan un efecto antibacteriano para ambas bacterias, siendo su mayor efecto antibacteriano para ambos productos naturales sobre S. mutans.


ABSTRACT: The objective of the study was to determine the in vitro antibacterial effect of the oleoresin of Copaifera reticulata (C. reticulata) "copaiba" and of the essential oil of Oreganum majoricum (O. majoricum) "oregano" against Streptococcus mutans (S. mutans) and Enterococcus faecalis (E. faecalis). Sensitivity tests were developed by first activating the bacteria strains to be confronted. The oleoresin of copaiba was diluted with dimethylsulphoside (DMSO), obtaining final concentrations to be tested of 100 %, 50 %, 25 %, and 12.5 %. In relation to the essential oil of oregano, it was only 100 % tested. For the disk agar diffusion test, 100 mL of each bacterial strain was taken at a turbidity of 0.5 of Mc Farlam, to be planted by dissecting trypticase soy agar plates, and then placing the disks equidistantly loaded with the different concentrations of natural products; 0.12 % chlorhexidine was used as a positive control and DMSO as negative control. The plates were incubated by the candle method in extinction at 37 °C, for a period of 24 hours, after which time the inhibition halos were read. The results obtained by the copaiba, determined an antibacterial effect in its four concentrations, being the biggest halos of inhibition at the concentration of 100 %, copaiba genus higher average halos for S. mutans of 30.00 ± 0.00 mm and for E. faecalis of 8.3 ± 0.50 mm. In the case of oregano, haloes are produced at a concentration of 100 % with an average of 25.3 ± 0.96 mm for S. mutans and for E. faecalis 9.5 ± 1.29 mm. It is concluded from the study that both copaiba and oregano present an antibacterial effect for both bacteria, being its greater antibacterial effect for both natural products on S. mutans.


Asunto(s)
Humanos , Streptococcus mutans/fisiología , Extractos Vegetales/farmacología , Infecciones por Bacterias Grampositivas/microbiología , Infecciones por Bacterias Grampositivas/patología , Enterococcus faecalis/patogenicidad , Origanum/química , Perú , Streptococcus mutans/inmunología , Técnicas In Vitro , Aceites Volátiles/análisis , Epidemiología Experimental , Antibacterianos
10.
Rev. cient. odontol ; 6(1): 7-8, ene.-jun. 2018.
Artículo en Inglés | LILACS | ID: biblio-998740

RESUMEN

Dental education comprises a variety of competences and fine motor skills that must be acquired by students not only in the classroom but also in preclinical laboratories and dental clinics. In Peru, the average duration of dental undergraduate programs is five years. While it is true that curriculums vary from one school to another, preclinical and clinical activities are usually initiated during the third and fifth semesters, respectively. While the curriculums of Peruvian dental school programs tend to emphasize the importance of know-how and clinical training, undergraduate students are also trained in complementary skills that enable them to deepen their understanding of the profession beyond the dental chair. (AU)


Asunto(s)
Educación en Salud Dental , Educación Basada en Competencias
11.
Histochem Cell Biol ; 149(4): 383-391, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29445893

RESUMEN

The Nestin gene encodes type VI intermediate filament and is known to be expressed in undifferentiated cells during neurogenesis and myogenesis. To regulate Nestin expression, the first or second intron enhancer is activated in a tissue-dependent manner, for example, the former in mesodermal cells and the latter in neural stem cells. Although Nestin has also been used as a differentiation marker for odontoblasts during tooth development, how Nestin expression is regulated in odontoblasts remains unclear. Therefore, this study aimed to compare the expression patterns of Nestin-GFP (green fluorescent protein) with that of endogenous Nestin in developing teeth of Nestin-EGFP (enhanced GFP) transgenic mice, in which the second intron enhancer is connected with the EGFP domain, at postnatal 7d, 3w, and 8w. Immunohistochemical and in situ hybridization analyses revealed that endogenous Nestin protein and Nestin mRNA were intensely expressed in differentiated odontoblasts, while GFP immunoreactivity, which reflects the activity of Nestin second intron enhancer-mediated transcription, was mainly observed in the subodontoblastic layer. These results indicate that the first intron enhancer may be activated in differentiated odontoblasts. Intriguingly, Nestin-GFP expression in the subodontoblastic layer was found to be restricted to the coronal pulp of molars, which is susceptible to tooth injuries. Because the subodontoblastic layer serves as a reservoir of newly differentiated odontoblast-like cells upon exogenous stimuli to dentin, our findings suggest that the original odontoblasts and regenerated odontoblast-like cells may differently regulate Nestin expression.


Asunto(s)
Nestina/biosíntesis , Odontoblastos/metabolismo , Animales , Diferenciación Celular , Proteínas Fluorescentes Verdes/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Nestina/genética , Odontoblastos/citología , ARN Mensajero/biosíntesis , ARN Mensajero/genética
12.
Sci Rep ; 7(1): 7129, 2017 08 02.
Artículo en Inglés | MEDLINE | ID: mdl-28769044

RESUMEN

Interferon Regulatory Factor 6 (IRF6) and TWIST1 are transcription factors necessary for craniofacial development. Human genetic studies showed that mutations in IRF6 lead to cleft lip and palate and mandibular abnormalities. In the mouse, we found that loss of Irf6 causes craniosynostosis and mandibular hypoplasia. Similarly, mutations in TWIST1 cause craniosynostosis, mandibular hypoplasia and cleft palate. Based on this phenotypic overlap, we asked if Irf6 and Twist1 interact genetically during craniofacial formation. While single heterozygous mice are normal, double heterozygous embryos (Irf6 +/- ; Twist1 +/- ) can have severe mandibular hypoplasia that leads to agnathia and cleft palate at birth. Analysis of spatiotemporal expression showed that Irf6 and Twist1 are found in different cell types. Consistent with the intercellular interaction, we found reduced expression of Endothelin1 (EDN1) in mandible and transcription factors that are critical for mandibular patterning including DLX5, DLX6 and HAND2, were also reduced in mesenchymal cells. Treatment of mandibular explants with exogenous EDN1 peptides partially rescued abnormalities in Meckel's cartilage. In addition, partial rescue was observed when double heterozygous embryos also carried a null allele of p53. Considering that variants in IRF6 and TWIST1 contribute to human craniofacial defects, this gene-gene interaction may have implications on craniofacial disorders.


Asunto(s)
Epistasis Genética , Huesos Faciales/embriología , Factores Reguladores del Interferón/genética , Proteínas Nucleares/genética , Organogénesis/genética , Cráneo/embriología , Proteína 1 Relacionada con Twist/genética , Alelos , Animales , Apoptosis/genética , Muerte Celular , Línea Celular , Proliferación Celular , Anomalías Craneofaciales/diagnóstico , Anomalías Craneofaciales/genética , Endotelina-1/genética , Endotelina-1/metabolismo , Elementos de Facilitación Genéticos , Femenino , Técnica del Anticuerpo Fluorescente , Dosificación de Gen , Regulación del Desarrollo de la Expresión Génica , Genotipo , Humanos , Factores Reguladores del Interferón/metabolismo , Masculino , Mandíbula/embriología , Ratones , Ratones Noqueados , Mutación , Proteínas Nucleares/metabolismo , Especificidad de Órganos , Fenotipo , Unión Proteica , Proteína 1 Relacionada con Twist/metabolismo
13.
J Endod ; 40(10): 1566-72, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25260727

RESUMEN

INTRODUCTION: This study analyzed the detailed biological events underlying pulpal dynamics evoked by 3Mix (the mixture of ciprofloxacin, metronidazole, and minocycline) solution after intentionally delayed tooth replantation because 3Mix improves pulpal healing after tooth injuries. METHODS: The maxillary first molars of 3-week-old mice were extracted and immersed in 3Mix solution for 30 minutes in comparison with phosphate buffered saline (PBS) alone. Cell proliferation, apoptosis, and differentiation were assessed in extracted/replanted teeth during days 0-14 using immunohistochemistry, apoptosis assay, and reverse-transcriptase polymerase chain reaction. RESULTS: 3Mix solution accelerated odontoblast differentiation in the coronal pulp on day 7 and tertiary dentin formation on day 14, whereas the regenerative process was delayed in the PBS group. Cell proliferation and apoptosis occurred in the pulp of the 3Mix group during days 5-7 and subsequently decreased from days 7-14. On day 5, dentin sialophosphoprotein and nestin were first recovered in the 3Mix group, whereas expression levels for alkaline phosphatase, osteopontin, and osteocalcin increased in the PBS group. The expression levels for octamer-binding factor 3/4A and 3/4B reached the maximum level on day 1 and were sharply decreased on day 3 in both groups. High expression levels of Cd11c were first observed in the 3Mix group on day 1 and later at days 5 and 7. CONCLUSIONS: The results suggest that the application of 3Mix may suppress osteoblast differentiation by the migration of dendritic cells to the injury site and via the activation of stem/progenitor cells, resulting in the acceleration of odontoblastlike cell differentiation.


Asunto(s)
Antibacterianos/uso terapéutico , Pulpa Dental/efectos de los fármacos , Soluciones Preservantes de Órganos/uso terapéutico , Reimplante Dental/métodos , Fosfatasa Alcalina/efectos de los fármacos , Animales , Apoptosis/efectos de los fármacos , Tampones (Química) , Antígenos CD11/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Ciprofloxacina/uso terapéutico , Pulpa Dental/citología , Dentina Secundaria/efectos de los fármacos , Combinación de Medicamentos , Proteínas de la Matriz Extracelular/efectos de los fármacos , Metronidazol/uso terapéutico , Ratones , Minociclina/uso terapéutico , Nestina/efectos de los fármacos , Factor 3 de Transcripción de Unión a Octámeros/efectos de los fármacos , Odontoblastos/efectos de los fármacos , Osteocalcina/efectos de los fármacos , Osteopontina/efectos de los fármacos , Fosfatos , Fosfoproteínas/efectos de los fármacos , Sialoglicoproteínas/efectos de los fármacos , Cloruro de Sodio , Factores de Tiempo
14.
Biomed Res ; 33(2): 119-32, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22572386

RESUMEN

Differentiated odontoblasts could not be identified by one unique phenotypic marker, but the combination of expression of dentin phosphoprotein (Dpp), dentin sialoprotein (Dsp), dentin matrix protein 1 (Dmp1), and nestin may be valuable for the assessment of these cells. However, the findings using these proteins remain controversial. This study aimed to compare two odontoblast differentiation markers: nestin and Dsp in the process of dentinogenesis in mice. We performed immunohistochemistry and/or in situ hybridization technique for nestin and Dsp using 3-week-old incisors as well as postnatal 1-day- to 8-week-old molars. Preodontoblasts began to express nestin and Dsp proteins and Dsp mRNA, which increased in their intensity according to the progress of odontoblast differentiation in both incisors and developing molars. Nestin was consistently expressed in the differentiated odontoblasts even after the completion of dentin matrix deposition. The expression of Dsp mRNA coincided with the odontoblast secretory activity for dentin matrix deposition. In contrast, other pulpal cells, predentin matrix and dentinal tubules also showed a positive reaction for Dsp protein in addition to differentiated odontoblasts. In conclusion, nestin is valuable as a differentiation marker for odontoblasts, whereas Dsp mRNA is a functional marker for their secretory activity.


Asunto(s)
Dentinogénesis , Proteínas de la Matriz Extracelular/metabolismo , Proteínas de Filamentos Intermediarios/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Fosfoproteínas/metabolismo , Sialoglicoproteínas/metabolismo , Animales , Antígenos de Diferenciación/genética , Antígenos de Diferenciación/metabolismo , Diferenciación Celular , Proteínas de la Matriz Extracelular/genética , Regulación del Desarrollo de la Expresión Génica , Incisivo/citología , Incisivo/crecimiento & desarrollo , Incisivo/metabolismo , Proteínas de Filamentos Intermediarios/genética , Ratones , Ratones Endogámicos ICR , Diente Molar/citología , Diente Molar/crecimiento & desarrollo , Diente Molar/metabolismo , Proteínas del Tejido Nervioso/genética , Nestina , Odontoblastos/metabolismo , Fosfoproteínas/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Sialoglicoproteínas/genética , Transcripción Genética
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