Resorción intracoronal preeruptiva: una revisión de la literatura / Preeruptive intracoronal resorption: a review of the literature / Reabsorção intracoronária pré-eruptiva: uma revisão da literatura

RESUMEN La resorción intracoronal preeruptiva (RIPE) es un hallazgo radiográfico que consiste en la presencia de un área radiolúcida ubicada en la dentina coronal próxima a la unión amelodentinaria en el germen de una pieza dentaria; es usualmente singular y poco profunda (menor de 1/3 de la dentina cameral). La frecuencia reportada en la literatura varía entre 0,85 % y 27,3 %; no se ha encontrado asociación con el sexo; y afecta usualmente a las piezas posteriores. Su etiología no ha sido determinada, pero evidencias histológicas apuntan a que se trataría de secuelas de resorción dentinaria. Los defectos de la RIPE deben ser considerados como lesiones de caries una vez que la pieza erupcione en boca; y aunque no se han desarrollado esquemas de tratamiento o guías de práctica clínica, los tratamientos reportados dependen de la profundidad de los defectos y son frecuentemente conservadores. El objetivo de este trabajo fue revisar los estudios descriptivos y los reportes de casos publicados acerca de la RIPE para que estos defectos sean también considerados en la práctica clínica diaria.

ABSTRACT Preeruptive intracoronal resorption (PIRR) is a radiographic phenomenon characterized by the presence of a radiolucent area situated in the coronal dentin near the amelodentine junction within the tooth's germ. Typically, this radiolucent area is singular and shallow, encompassing less than one-third of the chambered dentin. The reported frequency in the literature varies between 0.85% and 27.3%. No association with gender has been identified, and it predominantly affects posterior teeth. While its precise etiology remains undetermined, histological evidence suggests that it results from a sequelae of dentin resorption. RIPE Defects as Caries Lesions: Once the tooth erupts into the oral cavity, RIPE defects should be regarded in a manner similar to caries lesions. Despite the absence of established treatment schemes or clinical practice guidelines, reported treatments are contingent upon the depth of the defects and frequently lean towards conservative approaches. The primary aim of this study was to comprehensively review descriptive studies and published case reports focusing on RIPE defects. This effort is directed towards integrating these defects into routine clinical practice considerations.

RESUMO A reabsorção intracoronária pré-eruptiva (RIPE) é um achado radiográfico que consiste na presença de uma área radiolúcida localizada na dentina coronária próxima à junção amelodentinária no germe de um dente. Geralmente, é singular e rasa, envolvendo menos de 1/3 da dentina da câmara. A frequência relatada na literatura varia entre 0,85% e 27,3%. Não foi encontrada associação significativa com o sexo, e a RIPE tende a afetar mais comumente os dentes posteriores. Sua etiologia ainda não foi totalmente determinada, mas evidências histológicas sugerem que pode ser consequência de reabsorção da dentina. Os defeitos de RIPE devem ser considerados como lesões de cárie quando o dente irrompe na cavidade bucal. Embora não tenham sido desenvolvidos esquemas de tratamento ou diretrizes de prática clínica específicas, os tratamentos relatados para RIPE são geralmente conservadores e baseiam-se na profundidade dos defeitos. Concluindo, a revisão dos estudos descritivos e dos relatos de casos de RIPE destaca a importância de considerar esses defeitos durante a prática clínica rotineira.

Spatial distribution of CD34 protein in primordial odontogenic tumour, ameloblastic fibroma and the tooth germ.

BACKGROUND: Primordial odontogenic tumour is a benign mixed neoplasm of recent description, which has histological similarities with other odontogenic tumours such as the ameloblastic fibroma. In this article, we investigate the architecture of the sub-epithelial layer of mesenchymal cells expressing the marker CD34 in primordial odontogenic tumour. OBJECTIVE: Analyse the spatial patterns of CD34 expression in primordial odontogenic tumour and compare them with those in ameloblastic fibroma and the normal tooth germ by means of objective imaging approaches, to better characterise these lesions. METHODS: Two cases of primordial odontogenic tumour, four cases of ameloblastic fibroma and two cases of tooth germ in cap and bell stages were used for morphological, structural and immunohistochemical analyses. RESULTS: CD34 expression was found in vascular endothelium of primordial odontogenic tumour, ameloblastic fibroma and tooth germ. In addition, a characteristic sub-epithelial expression was observed only in primordial odontogenic tumour, corresponding to 84%-86% of the sample boundaries. Moreover, the zone expressing CD34 corresponded with a higher cellularity, which was absent in ameloblastic fibroma and tooth germ. CONCLUSION: Image analysis of the primordial odontogenic tumour architecture revealed characteristics absent in other odontogenic tumours and tooth germs. This study provides additional information to support the idea that this neoplasm is a distinct entity from early stage AF or developing odontoma.

Intrauterine exposure to omeprazole increases the risk of teeth morphological anomalies in the offspring of a murine model.

Conditions experienced in early life have long-lasting effects on offspring health. Despite this, little is known about how maternal exposure to drugs during pregnancy affects offspring teeth morphogenesis. In humans, omeprazole is a common drug used to mitigate Gastroesophageal Reflux Disease. Importantly, omeprazole is a non-specific proton-pump inhibitor, which may inhibit the proton pumps expressed in the developing tooth germ. To date, however, the effects of intrauterine life exposure to omeprazole on offspring tooth development remain unknown. In this study, we addressed this gap in a murine model. Pregnant female Swiss mice were exposed to daily doses of 40 mg/kg of omeprazole from the 5th to the 17th day of pregnancy and the effects of such exposure on offspring odontogenesis parameters such as morphological abnormalities, disruptions in the ameloblast and odontoblast layers and the presence of dentin matrix were measured. Omeprazole exposure significantly increased the prevalence (control: 21.6%; treatment: 60%; p = 0.001) and the risk (posterior mean and 95% credible interval; control: 0.230 [0.129; 0.347]; treatment: 0.593 [0.449; 0.730]) of offspring teeth morphological abnormalities, although there were no statistically significant effects of omeprazole exposure on other parameters of tooth development. These findings suggest that there are potential side-effects to offspring oral health of omeprazole use during pregnancy.

Immunohistochemical localization of vascular factors in tooth germ of amphibian (Cynops pyrrhogaster) / Localización inmunohistoquímica de factores vasculares en germen dentario de anfibios (Cynops pyrrhogaster)

SUMMARY: Vascular endothelial growth factor (VEGF) and its receptor, VEGFR-2, are known to regulate blood vessel endothelium growth. They play important role in human and rodents teeth development. In newt jaws, there are sequential developmental teeth germs following behind the mature teeth. We examined the immunohistochemical localization of VEGF and its receptor and showed the specific expression pattern of VEGF and VEGF receptor in Cynops pyrrhogaster sequential tooth development. The intensity of immunoreactivity for VEGF in the inner enamel epithelium was weaker than that in the outer enamel epithelium in the dentine matrix formation and mineralization stages. Finally, at the enameloid maturation and enamel-like matrix formation stage, immunoreactivity for VEGF in inner enamel epithelium was stronger than in the outer enamel epithelium. The intensity of immunoreactivity for VEGFR-2 was positive for the outer enamel epithelium throughout tooth development. The crown sides of the odontoblasts were stained especially strongly for VEGF and VEGFR-2 during the dentine matrix formation and mineralization stage of the enameloid maturation and enamel- like matrix formation stage. We postulate that the expression of VEGF in the inner enamel epithelium and odontoblast widely effects tooth development in newts, as well as in human and rodents.

RESUMEN: Se sabe que el factor de crecimiento endotelial vascular (VEGF) y su receptor, VEGFR-2, regulan el crecimiento del endotelio de los vasos sanguíneos. Desempeñan un papel importante en el desarrollo de los dientes humanos y de los roedores. En las mandíbulas de tritón, hay gérmenes dentales de desarrollo secuenciales que siguen a los dientes maduros. Examinamos la localización inmunohistoquímica de VEGF y su receptor y mostramos el patrón de expresión específico de VEGF y receptor de VEGF en el desarrollo secuencial de dientes de Cynops pyrrhogaster. La intensidad de la inmunorreactividad para VEGF en el epitelio interno del esmalte era más débil que en el epitelio externo del esmalte en las etapas de formación y mineralización de la matriz de dentina. Finalmente, en la etapa de maduración del esmalte y de formación de la matriz similar al esmalte, la inmunorreactividad para VEGF en el epitelio interno del esmalte fue más fuerte que en el epitelio externo del esmalte. La intensidad de la inmunorreactividad para VEGFR- 2 fue positiva para el epitelio externo del esmalte durante el desarrollo del diente. Los márgenes de la corona de los odontoblastos se tiñeron especialmente para VEGF y VEGFR-2 durante la etapa de formación de la matriz de dentina y mineralización de la etapa de maduración del esmalte y la etapa de formación de la matriz similar al esmalte. Postulamos que la expresión de VEGF en el epitelio interno del esmalte y odontoblastos afecta ampliamente el desarrollo de los dientes en tritones, así como en humanos y roedores.

Methylphenidate effects on mice odontogenesis and connections with human odontogenesis.

The purpose of this study is to evaluate the effects of Methylphenidate exposure on mice odontogenesis and connect them by bioinformatics with human odontogenesis. Thirty-two pregnant Swiss mice were divided into treated group and control group, which received, respectively, 5 mg/kg of Methylphenidate and saline solution from the 5th to the 17th day of pregnancy. The mouse embryos tooth germs were analyzed through optical microscopy, and the data collected were analyzed statistically by Fisher's exact test. The presence and similarity of Methylphenidate-associated genes (Pharmgkb database) in both organisms and their interaction with dental development genes (AmiGO2 database) were verified on STRING database. Rates of tooth germ malformations were higher in treated than in control group (Control: 18; Treated: 27; p = 0.035). Mouse embryo malformations were connected with 238 interactions between 69 dental development genes with 35 Methylphenidate genes. Fourteen interactions for four Methylphenidate genes with four dental development genes, with human experimental data, were connected with mouse phenotype data. By homology, the interactions and conservation of proteins/genes may indicate similar outcomes for both organisms. The exposure to Methylphenidate during pregnancy affected odontogenesis in mouse embryos and may affect human odontogenesis. The study of malformations in mice, with a bioinformatics approach, could contribute to understanding of the Methylphenidate effect on embryo development. These results may provide novel hypotheses for further testing and reinforce the FDA protocol: as Methylphenidate is included in category C, its use during pregnancy should be considered if the benefits outweigh the risks.

Prognóstico entre eixo de erupção dos caninos permanentes superiores e espaço para erupção dos segundos molares inferiores / Prognosis between superior permanent canines teeth eruption axis and second lower molars space for eruption

Resumo O objetivo deste estudo foi verificar a associação entre a má posição do germe dos segundos molares inferiores com o eixo de erupção dos caninos permanentes superiores na dentadura mista. A amostra foi composta por 506 radiografias panorâmicas digitais, no período intertransitório da fase de dentadura mista, na faixa etária de 7 a 12 anos, de ambos os sexos. Os caninos foram avaliados utilizando-se a divisão da porção anterior do hemiarco em cinco setores sendo o setor 1 a melhor posição para eixo de erupção correto e 5 para a pior. Para a localização do germe dos segundos molares inferiores foi utilizada a distância horizontal entre a face distal dos primeiros molares inferiores e a borda anterior do ramo da mandíbula. Os dados foram analisados por tabelas de distribuição de frequências e regressão logística, com estimação dos Odds Ratio brutos e os respectivos intervalos de confiança. Não houve associação significativa entre o sexo e o eixo de erupção de caninos permanentes superiores (p>0,05). Houve associação entre a má posição de segundos molares inferiores e o eixo de erupção de caninos. Participantes com má posição de segundos molares inferiores apresentaram 3,40 (IC 95%, 2,12-5,47) vezes mais chance de ter o eixo de erupção de caninos permanentes superiores mal posicionados. Conclui-se que houve associação entre a má posição de segundos molares inferiores e o eixo de erupção de caninos.(AU)

Abstract This study aimed to associate malposition of lower second molar germ with the upper permanent canine teeth eruption axis in the mixed dentition. The sample included 506 digital panoramic radiographies taken in the mixed dentition inter-transitional period in the age group of 7 to 10 years of both sexes. The canines were assessed by dividing the anterior portion of the hemiarch into five sectors, in which sector 1 was the best position for the correct eruption axis and 5 was the worst. For locating the lower second molar germ, a horizontal distance was used between the distal aspect of the lower first molars and the anterior margin of the mandibular ramus. The data was analyzed with frequency distribution and logistic regression tables, estimating crude Odds Ratio and respective confidence intervals. There was no significant association between sex and upper permanent canines eruption axis (p>0.05). There was association between the lower second molars malposition and canines eruption axis. Participants with malposition of lower second molars presented 3.40 (95% CI, 2.12-5.47) times more likely to present upper permanent canines eruption axis malpositioned. It was concluded that there was association between the malposition of lower second molars and the canine eruption axis. (AU)

Dental trauma on primary teeth at different root resorption stages-A dynamic finite element impact analysis of the effect on the permanent tooth germ.

BACKGROUND/AIM: Dental trauma is a common emergency in children with primary teeth. The aim of this study was to determine stress propagation to the permanent tooth germ and surrounding bone and soft tissues during dental trauma to primary central incisors with three levels of physiological root resorption. MATERIAL AND METHODS: Stresses were determined using finite element analysis (FEA). Cross-sectional models were created using cone-beam computed tomography images of 3.5, 5, and 6 years olds, representing three different physiological root resorption stages of a maxillary primary central incisor. The models included periodontal ligament, bone, and soft tissues. An impact with an asphalt block moving at 1 m/s,was simulated for two impact two directions, frontal on the labial tooth surface, and on the incisal edge. Stresses and strains were recorded during impact. RESULTS: The impact caused stress concentrations in the surrounding bone and soft tissues and permanent tooth germ, regardless of the direction of impact and the primary tooth resorption stage. Impact stresses in dental follicles and surrounding bone increased in models with more physiological root resorption of the primary tooth. Incisal impact generated higher stress concentrations in surrounding bone and soft tissues and permanent tooth germ regardless of physiological root resorption stage. The primary incisor with no physiological root resorption showed high stress concentrations at its root apex. CONCLUSION: During impact to a primary incisor, stresses most significant for potential damage to the formation of permanent enamel and dentin were at the dental follicle and surrounding bone tissue with the three levels of physiological root resorption.

Primordial odontogenic tumor: Subepithelial expression of Syndecan-1 and Ki-67 suggests origin during early odontogenesis.

Primordial odontogenic tumor (POT) is composed of variably cellular myxoid connective tissue, surrounded by cuboidal to columnar odontogenic epithelium resembling the inner epithelium of the enamel organ, which often invaginates into the underlying connective tissue. The tumor is delimited at least partially by a thin fibrous capsule. It derives from the early stages of tooth development. Syndecan-1 is a heparan sulfate proteoglycan that has a physiological role in several cellular functions, including maintenance of the epithelial architecture, cell-to-cell adhesion and interaction of cells with extracellular matrix, and with diverse growth factors, stimulating cell proliferation. Ki-67 is considered the gold standard as a cell proliferation marker. The aim of this study was to examine the expression of Syndecan-1 and Ki-67 proliferation index in POT and normal tooth germs to better understand the biological behavior of this tumor. Results showed that Syndecan-1 was more intensely expressed in subepithelial mesenchymal areas of POT, in a pattern that resembles the early stages of tooth development. The cell proliferation index (4.1%) suggests that POT is a slow growing tumor. Syndecan-1 expression in tooth germs in late cap and early bell stages was similar to POT, showing immunopositivity in subepithelial mesenchymal condensed areas. The immunohistochemical findings showed a pattern in which the population of subepithelial mesenchymal cells exhibited greater proliferative activity than the central portion of the dental papilla.

Analisis inmunohistoquimico de CK14 y CK19 en germen dentario y ameloblastoma / Immunohistochemical analysis of ck14 and ck19 in tooth germs and ameloblastoma

La odontogénesis es el proceso de formación de los órganos dentarios, en el cual se expresan diversas moléculas, dentro de las cuales encontramos las citoqueratinas 14 y 19 (CK14, CK19). Una vez concluido el proceso de formación del diente quedan restos del epitelio odontogénico, el cual se ha sugerido se encuentra implicado en el desarrollo del ameloblastoma, uno de los tumores odontogénicos más frecuentes. Se ha sugerido que las CK14 y CK19 tienen utilidad como marcadores de diferenciación ameloblástica, y podrían tener implicación dentro del comportamiento tumoral de los ameloblastomas. El objetivo del presente estudio fue describir los patrones de expresión inmunohistoquímica de estas dos citoqueratinas en gérmenes dentarios y ameloblastomas. Materiales y métodos. Se incluyeron 6 ameloblastomas sólidos multiquísticos y 5 gérmenes dentarios a los cuales se les realizó técnica de inmunohistoquímica para CK14 y CK19. Resultados. Este estudio permitió visualizar la inmunoexpresión de CK14 y CK19 en el epitelio y la negatividad en el ectomesénquima, tanto en los gérmenes dentarios como en ameloblastomas. También permitió concluir que CK19 puede ser considerada como un eficiente marcador de diferenciación ameloblástica, mientras que CK14 es gradualmente remplazada por CK19 en el epitelio interno del órgano del esmalte, evidenciándose marcada inmunoexpresión de esta última en ameloblastos secretores...

Introduction. Odontogenesis is the process by which teeth form, and where different molecules are expressed, among them some cytokeratins (CK) like CK14 and CK19. Remnants of odontogenic epithelium may persist once the development process is complete, which has been suggested to be involved in the development of ameloblastoma, one of the most common benign odontogenic tumours. It has been suggested that CK14 and CK19 are useful markers of ameloblast differentiation and that they could have implications for tumour behaviour. The aim of this study is to describe the patterns of immunohistochemical expression of these cytokeratins in tooth germs and ameloblastomas. Materials and methods. We worked with 6 solid multicystic ameloblastomas and 5 tooth germs. The immunohistochemistry technique was used to visualise CK14 and CK19. Results. We detected CK14 and CK19 immunoexpression in the epithelium and no expression in the ectomesenchyme in both tooth germs and ameloblastomas. It was concluded that CK19 can be considered an efficient marker of ameloblast differentiation, whereas CK14 is gradually replaced by CK19 in the inner epithelium of the enamel organ, showing strong immunoexpression in secretory ameloblasts...

Morphological analysis of the enamel organ in rats treated with fluoxetine.

PURPOSE: Previous studies have evaluated the presence of serotonin in the dental epithelia and mesenchyme during odontogenesis, suggesting its participation in tooth development. MATERIALS AND METHODS: Here, we used fluoxetine, a selective serotonin re-uptake inhibitor, at a dose of 10 mg/kg, administered for 20 days during pregnancy in 12 Wistar rats to examine the influence of this drug on the development of the enamel organ of the upper first molars of rat fetuses at 17 days of intra-uterine life (i.u.l.), and at one, five and ten days postpartum. The pregnant rats were anesthetized with xylazine at 10 mg/kg and ketamine at 25 mg/kg. The fetuses were removed and beheaded; their jaws were removed, and the upper jaws were exposed. The tissues were fixed in Bouin's fixative, decalcified in 5% nitric acid for 4 - 12 h, conventionally processed for microscopy, and embedded in paraffin. Serial sections of approximately 5 mum were obtained and stained with hematoxylin and eosin, as well as periodic acid-Schiff. RESULTS AND CONCLUSION: Morphological analysis showed no structural changes in the experimental group compared to the controls, suggesting that, at the dose used, fluoxetine does not interfere with serotonin-mediated development of the enamel organ or the process of amelogenesis.

Morphological analysis of the enamel organ in rats treated with fluoxetine

Purpose: Previous studies have evaluated the presence of serotonin in the dental epithelia and mesenchyme during odontogenesis, suggesting its participation in tooth development. Materials and methods: Here, we used fluoxetine, a selective serotonin re-uptake inhibitor, at a dose of 10 mg/kg, administered for 20 days during pregnancy in 12 Wistar rats to examine the influence of this drug on the development of the enamel organ of the upper first molars of rat fetuses at 17 days of intra-uterine life (i.u.l.), and at one, five and ten days postpartum. The pregnant rats were anesthetized with xylazine at 10 mg/kg and ketamine at 25 mg/kg. The fetuses were removed and beheaded; their jaws were removed, and the upper jaws were exposed. The tissues were fixed in Bouin's fixative, decalcified in 5 percent nitric acid for 4 - 12 h, conventionally processed for microscopy, and embedded in paraffin. Serial sections of approximately 5 mm were obtained and stained with hematoxylin and eosin, as well as periodic acid-Schiff. Results and conclusion: Morphological analysis showed no structural changes in the experimental group compared to the controls, suggesting that, at the dose used, fluoxetine does not interfere with serotonin-mediated development of the enamel organ or the process of amelogenesis.

Desenvolvimento dentário em humanos nos primeiros meses de vida intra-uterina. Avaliação histológica / Tooth development in the first five months of intra uterine life. Histological study

Neste estudo, investigamos os complicados processos do desenvolvimento dentário em 14 embriões ou fetos humanos no período compreendido entre a 6a e a 21a semana de vida intra-uterina. Após exame ultra-sonofráfico bidimensional e o estabelecimento da idade gestacional, procedemos a análise morfológica de todos os embriões e fetos, cujas arcadas foram submetidas aos procedimentos de rotina para o fornecimento dos cortes histológicos os quais evidenciaram que o início da odontogênese ocorre com a formação da lâmina dentária no período gestacional de 11 semanas e meia de vida intra-uterina, sendo os molares decíduos os primeiros germes dentários a se formarem, tanto na maxila quanto na mandíbula. Numa mesma idade gestacional o desenvolvimento de germes dentários homólogos contralaterais não ocorre de maneira absolutamente igual, podendo mostrar diferenças quando comparados os de um lado com os do outro

The aim of this study was to investigate the process of human developing teeth from the 6th to the 21th gestational week by. Using bidimensional ultra-sonography examination, after determination of the gestational age, it was made the morphologic analysis of fourteen embryos and fetuses, whose dental arches were prepared for histological evaluation. The histological sections showed the odontogenesis beginning with dental lamina formation at the gestational period of 11,5 weeks. The first tooth germ present were the maxilar or mandibular deciduous molars. The homolog contralateral tooth germs did not show an equal level of development but differences could be found when compared then evolution at both right nd left sides