RESUMO
RESUMEN El objetivo de este artículo es analizar la relación entre la hipomineralización incisivo molar (HIM) y los factores asociados a su etiología publicados en la literatura. Material y métodos: El estudio se basó en una búsqueda de estudios epidemiológicos de casos y controles de HIM que describieron un factor etiológico asociado para obtener las odds ratio (OR) necesarias para analizar la prevalencia del factor afectado y su posible papel en la etiología de la condición. Resultados: Ocho artículos cumplieron los criterios para el análisis. La población total analizada consistió en una muestra de 7,901 sujetos, de los cuales 992 tenían HIM. En estos sujetos fueron reportados como factor asociado (FA) para HIM: asma (OR = 4.4954), uso de antibióticos (OR = 5.5348), fiebre (OR = 4.0545) y neumonía. Conclusión: Los resultados del presente estudio sugieren que un FA común a todos los casos de HIM estudiados es un proceso inflamatorio que conduce a una mayor concentración de agentes en el microambiente en el que se desarrollan las células formadoras del esmalte, lo que aumenta la presencia de proteínas en la matriz del esmalte o interfieren con su hidrólisis y eliminación y produce como resultado una deficiente mineralización.
ABSTRACT Hypomineralization enamel of the first permanent molars is the most common developmental abnormalities observed in the teeth. The aetiology of MIH remains unclear and may have a multifactor aetiology. The aim of this paper is to analyze the relationship between MIH and associated factors published in the literature. Material and methods: The study was based on a search for epidemiological case-control studies of MIH that described an associated etiological factor, in order to obtain the odds ratios needed to analyze the prevalence of the factor concerned and its possible role in the etiology of the condition. Results: The initial search produced 50 articles, eight of which met the criteria for the analysis. The total population analyzed consisted of a sample of 7,901 subjects, 992 of whom had MIH (i.e., a prevalence of 12.55%). Asthma was reported as an etiological factor in five papers, which included 474 subjects with MIH with an OR of 4.4954 (p < 0.0001). Antibiotic use was reported as an etiological factor in three papers, which reported on a population of 231 subjects with MIH and OR of 5.5348 (p < 0.0001). Fever was reported as an etiological factor in two papers, involving a population of 176 subjects with MIH and an OR of 4.0545 (p < 0.0001). Pneumonia was reported as an etiological factor in two papers, which dealt with a population of 454 cases of MIH and produced an OR of 2.285 (p < 0.0001). Conclusion: The results of the present study suggest that one etiological factor common to all of the MIH cases studied is an infl ammatory process, in which the presence of agents that cause alterations in ameloblasts can lead to higher concentrations of these agents in the microenvironment in which enamel forming cells develop, thus increasing the presence of proteins in the enamel matrix or interfering with their hydrolysis and removal, producing defects in enamel mineralization.
RESUMO
Resumen: El ligamento periodontal es un tejido conectivo fibroso, de origen ectomesenquimal que contiene una población de células troncales postnatales multipotenciales, con capacidad clonogénica y alto índice de proliferación. Se ha conseguido cultivar células troncales postnatales multipotenciales a través de diferentes métodos de extracción, con algunos problemas técnicos. Por esta razón, se compararon seis diferentes métodos a fin de mejorar el aislamiento de células primarias del ligamento periodontal. Se aislaron células troncales postnatales multipotenciales a partir de 36 premolares sanos, que se cultivaron en medio de Eagle modificado por Dulbecco (BioWest) completo (adicionado con L-glutamina, 10% de suero fetal bovino y 1% de antibiótico) y en condiciones estándares de cultivo. Se realizaron los ensayos para proliferación celular mediante la técnica de 3-(4,5-dimetiltiazol-2-il)-2,5difeniltetrazolio, migración celular a través de la prueba de lesión del cultivo, y se evaluó su diferenciación osteogénica. Los cultivos realizados por triplicado con cada una de las técnicas publicadas, nos condujo a obtener una población mínima de células que fueron susceptibles a contaminarse. Se realizó con el «método simplificado¼: por digestión enzimática y cultivo de explantos, con las células troncales postnatales multipotenciales obtenidas se observó una proliferación durante 14 días en condiciones estándares de cultivo ascendente, en las pruebas de migración las células troncales postnatales multipotenciales cubrieron totalmente la superficie lesionada a las 72 horas, se observó expresión positiva de CD90 en más del 80% de las células; expresión positiva a CD73 en un 70%, CD105 en un 60% y vimentina en un 90% de la población, así como un marcaje negativo a CD11b y CD45. Se observó una diferenciación osteogénica positiva a los 14 días mediante la expresión positiva a RUNX2 en al menos el 15% de las células y a osteocalcina en un 90%, así como las pruebas positivas a rojo de alizarina. Con los resultados obtenidos, podemos afirmar que el método simplificado permite aislar una población de células mesenquimales, que se pueden obtener a partir de premolares sanos extraídos.
Abstract: Periodontal ligament is a fibrous connective tissue of ectomesenchymal origin which contains a multipotent postnatal stem cells population with clonogenic capacity and high proliferation index. Multipotent postnatal stem cells population culture has been achieved through several extraction methods, nevertheless some technical problems have been encountered. For this reason, in the present study, 6 different methods were compared so as to improve isolation of primary periodontal ligament cells. Multipotent postnatal stem cells population were isolated from 36 healthy premolars, which were then cultured in complete Dulbecco m odified Eagle medium (BioWest) (added with L-glutamine, 10% fetal bovine serum and 1% antibiotic), in standard culture conditions. Assays for cell proliferation were conducted with 3-(4,5 dimethylthiazol-2-yl)-2,5 diphenyltetrazolium technique as well as cell migration through crop injury test, after which osteogenic differentiation was assessed. Cultures were performed in triplicate with each of the published techniques; thus we were able to obtain a minimum population of cells susceptible to contamination. The «simplifled method¼ was conducted through explant enzymatic digestion and culture: with obtained multipotent postnatal stem cells population, a 14 day proliferation was observed in standard conditions of ascendant culture; in migration tests, multipotent postnatal stem cells population totally covered injured surfaces after 72 hours. CD90 positive expression was observed in over 80% of all cells; CD73 positive expression was found in 70% of cells, CD105 in 60% and vimentin in 90% of the population, as well as negative marking to CD11b and CD45. Positive osteogenic differentiation was observed after 14 days, through positive expression to RUNX2 in at least 15% of cells, and to osteocalcin in 90% as well as positive test to alizarin red. Based on obtained results we were able to affirm that the simplified method allows to isolate a population of mesenchymal cells, which might be obtained from extracted healthy premolars.