Ep-CAM (MOC-31) expression in tooth germ and ameloblastoma

Background: Ep-CAM, a transmembrane glycoprotein expressed in most epithelium in normal conditions, hasdiverse roles in these tissues, including in cell adhesion, proliferation, differentiation, cell cycle regu-lation, migration and intracellular signaling. It is also over-expressed in most malignant neoplasia, partic-ipating in theinitiation, progression, and metastatic dissemination of the tumor. The expression and roles of this protein in oralneoplasia, particularly in odontogenic tumors, remain unestablished. The objective of this study consisted in analyzing the expression of this protein in ameloblastoma and tooth germ.Material and Methods: Ep-CAM (MOC-31) expression was evaluated by immunohistochemistry in tooth germs(TG) (n = 16) ameloblastomas (AM) (n = 60) and 2 ameloblastic carcinomas. Sections were visualized in theirtotality with an optical microscope, and positivity observed in cell membrane and cytoplasm was graded according to the following semi-quantitative scale: Neg, "essentially unstained", for negative sections or staining <5% ofcells; + for staining of 5-50% of cells; ++ for staining >50% of cells.Results: Most tooth germs expressed MOC-31 (81.3%), strong staining was observed both in the inner epitheliumof the enamel organ and in the adjacent stellate reticulum. 16.7% of the AM cases showed MOC-31 expression,the immunoexpression expression was diffuse at the cytoplasmic and membrane level. The only two cases ofameloblastic carcinoma included were strong positive to MOC-31. No correlation was observed between proteinexpression and gender, age, clinical variants, or histological subtypes.Conclusions: Overexpression was found in TG and ameloblastic carcinoma compared to AM; further studies withdifferent experimental strategies are suggested to clarify the biological significance of this finding. (AU)

Evaluation of gubernacular tract with cone beam computed tomography in impacted supernumerary teeth

The gubernacular canal or gubernacular tract is filled by the gubernacular cord, which includes fibrous connective tissue containing peripheral nerves, blood and lymphatic ducts besides the epithelial cells from the fragmented dental laminae, including epithelial growth factor. The purpose of this study was to evaluate the gubernacular tract in unerupted supernumerary teeth by cone beam computed tomography. Sixty-four unerupted supernumerary teeth were selected from 44 patients (21 females, 23 males, 12-68 years). Gubernacular tract characteristics were evaluated in five different groups: No alteration, bending of gubernacular tract, contraction of gubernacular tract, obliterations of gubernacular tract, difference between erupted direction. Unerupted supernumerary teeth were classified according to their position. The presence and characteristics of the gubernacular tract in the supernumerary teeth were evaluated by cone beam computed tomography. In our study, the frequency of the gubernacular tract was found to be 31.7%. There was no significant difference between the presence of gubernacular tract and gender, age and gubernacular tract characteristics. It was found that gubernacular tract characteristics did not change according to gender, quadrant, age and unerupted positions. Cone beam computed tomography is an efficient method for the evaluation of the gubernacular tract in unerupted supernumerary teeth. Conducting these studies in larger populations will provide more detailed information about the prognosis of impacted supernumerary teeth

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Comparación de los métodos de Willems I y Willems II en la estimación forense de la edad en niños venezolanos / Comparison of the Willems I and Willems II methods for forensic age estimation in Venezuelan children

INTRODUCCIÓN: El presente trabajo tuvo como objetivo comparar los métodos de Willems et al. (WI y WII) en la estimación forense de la edad en niños venezolanos. MATERIAL Y MÉTODOS: Esta investigación fue de tipo retrospectiva y observacional. Se emplearon 516 ortopantomografías de individuos de ambos sexos (6-18 años), se asignaron los estadios de maduración dental descritos por Demirjian et al. en los 7 dientes inferiores izquierdos, para luego determinar la edad dental (ED) mediante WI y WII. Se calculó la diferencia de media entre la edad cronológica (EC) y la ED estimada mediante una prueba «t» de Student para muestras relacionadas. RESULTADOS: Para el total de la muestra se observó la subestimación de la edad por ambos métodos (0,17+/-1,75 años), siendo la diferencia EC-ED estadísticamente significativa (p = 0,04). Considerando todos los grupos de edad, WII mostró la menor diferencia EC-ED (0,05 años+/-1,40) en el sexo femenino, mientras que para el masculino se encontró menor diferencia para WI (0,04+/-0,54 años). En una submuestra hasta los 16 años se evidenció una subestimación de la edad en el sexo femenino para WI (0,03+/-1,23 años) y una sobreestimación para WII (-0,18+/-1,24 años), en el sexo masculino ambos métodos sobreestimaron la edad (W1=-0,21+/-1,17; WII=-0,06+/-1,20 años). CONCLUSIONES: La precisión de los métodos varió de acuerdo al sexo y grupo de edad, sin embargo, ambos resultaron aplicables a la muestra estudiada

INTRODUCTION: The purpose of this study was to compare the methods of Willems et al., (WI and WII) in estimating the forensic age in Venezuelan children. MATERIAL AND METHODS: A retrospective and observational study was performed on 516 orthopantomographs of individuals of both genders (6-18 years) in order to evaluate the stages of dental maturation described by Demirjian et al. Using the dental age (DA) in the seven left inferior teeth, DA was calculated using the WI and WII methods. The mean difference between the chronological age (CA) and DA was calculated using a paired-sample t-Test. RESULTS: The under-estimation of age by both methods (0.17+/-1.75 years) was observed, with the CA-DA difference being statistically significant (P=.04). Considering all age groups, WII showed the smallest difference between CA-DA (0.05+/-1.40 years) in girls, while a smaller difference was found for WI (0.04+/-0.54 years)for boys. In a subsample up to the age of 16, there was an under-estimation of age in females for WI (0.03+/-1.23 years) and an over-estimation for WII (-0.18+/-1.24 years). In the males both methods over-estimated the age (W1=-0.21+/-1.17 years, WII=-0.06+/-1.20 years). CONCLUSIONS: The accuracy of the methods varied according to gender and age group: however, both were applicable to the studied sample

¿Cuál es su diagnóstico? / What is your diagnosis?

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Expression of hMLH1 and hMSH2 proteins in ameloblastomas and tooth germs

Background: Mismatch repair proteins (MMRPs) are a group of nuclear enzymes that participate in the repair of base mismatches that occur during DNA replication in all proliferating cells. The most studied MMRPs are hMSH2 and hMLH1, which are known to be highly expressed in normal tissues. A loss of MMRPs leads to the accumulation of DNA replication errors in proliferating cells. Ki-67 is a biomarker regarded to be the gold-standard tool for determining cell proliferation by immunohistochemical methods. The aim of this study was to investigate the immunohistochemical expression of hMLH1, hMSH2 and Ki-67 proteins in ameloblastomas and tooth germs, to contribute to the understanding of the development of this odontogenic neoplasm. Material and Methods: Immunohistochemical assays to determine the presence of proteins hMSH2, hMLH1 and Ki-67 were performed in 80 ameloblastomas (40 solid and 40 unicystic) and five tooth germs. Results: Unicystic ameloblastomas showed higher MMRP expression (hMLH1: 62.5 ± 43.4; hMSH2: 83.3 ± 47.8) than did solid ameloblastomas (hMLH1: 59.4 ± 13.5; hMSH2: 75.8 ± 40.2). Additionally, the cell proliferation index assessed by Ki-67 was inversely proportional to the expression of MMRP. Comparison between tooth germs and ameloblastoma revealed significantly higher expression of hMLH1, hMSH2 and Ki-67 in tooth germs (p=0.02). Conclusions: The differences of MMRP and Ki-67 immunoexpression between ameloblastomas and tooth germ suggest that alterations in the MMRP mechanisms could participate in the biological behavior of ameloblastomas (AU)

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Morbilidad de la extracción de los terceros molares en pacientes entre los 12 y 18 años de edad / Morbidity of third molar extraction in patients between 12 and 18 years of age

Objetivo: El propósito de este estudio fue analizar la incidenciade complicaciones después de la extracción quirúrgica de losterceros molares en pacientes de 12 a 18 años de edad.Pacientes y método: Se realizó un estudio retrospectivo de390 extracciones quirúgicas de terceros molares superiores einferiores en 173 pacientes en edades comprendidas entre los12 y 18 años de edad, intervenidos bajo anestesia locorregionalen el año 2000 en el Máster de Cirugía Bucal e ImplantologíaBucofacial de la Universidad de Barcelona.Los pacientes fueron divididos en tres grupos (A: 12-14 años,B:15-16 años, C: 17-18 años). Se registró la edad y el sexo delpaciente, el motivo de la extracción, el grado de desarrollo dentario,la posición, la angulación y la inclusión del tercer molar.Finalmente se valoró la asociación entre dichas variables y laaparición de complicaciones postoperatorias.Resultados: La mayoría de los pacientes intervenidos fuerondel sexo femenino (66,9%), y el grupo de edad en la que serealizó el mayor número de extracciones (62,8%) fue en elgrupo C (17-18 años). El principal motivo de extracción fuela indicación por parte del ortodoncista (40,5%), seguido porla indicación profiláctica (39,5%). La presencia de clínica fueel motivo de extracción en un 20% de los casos. Se observóuna incidencia del 15,6% de complicaciones postoperatoriastras la extracción de 390 terceros molares. En el grupo A elriesgo de complicaciones fue de 17,4%, en el grupo B de 19% y en el grupo C de 13,7%. Todas las complicaciones fueronreversibles y de corta duración como el dolor y la inflamaciónpersistente, la infección, el trismo y la equimosis. Se presentóun caso de parestesia del nervio dentario inferior y un caso deparestesia del nervio lingual que remitieron a los 2 meses y almes respectivamente.Conclusiones: este estudio demuestra que no hay diferenciassignificativas en las complicaciones observadas entre los tresgrupos de edad, y por lo general, éstas son leves y reversibles. Seobservó una mayor tendencia de complicaciones en las mujeresy el porcentaje de complicaciones aumenta cuanto menor es elespacio disponible para la erupción

Objective: An analysis is made of the incidence of complicationsfollowing third molar surgical extraction in patients between 12and 18 years of age.Patients and method: A retrospective study was conducted of390 surgical extractions of upper and lower third molars in 173patients operated upon under locoregional anesthesia during theyear 2000 in the Master in Oral Surgery and Implantology ofBarcelona University Dental School (Spain).The patients were divided into three age groups (A: 12-14 years,B: 15-16 years, C: 17-18 years). The reason for extraction, thedegree of dental development, and third molar position, angleand impaction were recorded. Finally, the association of thesevariables to the appearance of postoperative complications wasanalyzed.Results: Most patients were females (66,9%), and the age groupin which most extractions were carried out (62,8%) correspondedto Group C (17-18 years). The main reason for extraction wasorthodontist indication (40,5%), closely followed by prophylaxis(39,5%). The existence of clinical manifestations was an indicationfor extraction in 20% of cases. The postoperative complicationsrate after the extraction of the global 390 molars was15,6%. In Groups A, B and C the complication risks were 17,4%,19% and 13,7%, respectively. All complications were reversibleand of short duration. One case each of inferior alveolar nerveparesthesia and lingual nerve paresthesia was recorded, which subsided after one and two months, respectively.Conclusions: There were no significant differences in complicationsbetween the three age groups. An increased tendencytowards complications was observed in females, and the percentageof postoperative problems increased

Evolución del germen dental trasplantado heterotópicamente en la dermis. Un estudio histológico en la rata / Development of tooth germ heterotopically grafted within the ear skin. An histological study in the rat

En este estudio hemos analizado la potencialidad de desarrollo del germen dental en fase de corona. Para ello, los gérmenes dentales de rata recién nacida fueron trasplantados en las bolsas dérmicas de la oreja de ratas isogénicas. Siete y catorce días después del trasplante, se desarrollaron las estructuras morfológicas dentales típicas, con ameloblastos y odontoblastos bien diferenciados. Ulteriormente, los procesos de reacción inflamatoria del tejido huésped con infiltración celular abocaron a la desaparición de los tejidos dentales. Desde el primer momento de nuestro análisis, los trasplantes desarrollaron una dentina anómala u osteoide cuyo tamaño fue paulatinamente incrementando con el tiempo, llegando a sustituir al resto de los tejidos dentales. Esta dentina osteoide, fruto tanto de la transformación de los odontoblastos del trasplante en células de alta actividad secretora como de la inducción que el germen dental ejerce en el tejido huésped circundante; y a diferencia de la observada en estudios previos, mostró diversos grados de polimerización fibrilar, lo que nos induce a sugerir que nuestro modelo puede ser un buen medio de estudiar los mecanismos de reacción en la formación de tejidos reactivos a la lesión dental (AU)

The main goal of this study was the analysis of the developmental potentiality of tooth germ from late bell stage on, after its heterotopic placement within the skin. Teeth germs of newborn rats were grafted within a skin pouch of the ear of adult rats. Seven to fourteen days after grafting, dental germs developed normal dental structures in which ameloblasts and odontoblasts were well differentiated. Twenty to forty-one days after graft, the inflammatory host reaction destroyed the dental developed tissues by cell infiltration. The dentin of the grafts was of osteoid characteristics, and its size increased dependinng on grafting time until the complete substitution of all dental tissues. This atypical dentin showed several degrees of polymerisation from collagen fibres smooth dentin devoid near the graft a to fibres rich dentin far from the dental germ. Present results suggest that this type of dental graft could be a valuable model to study the self-development of dental tissues and the reactive mechanisms taking place after dental injuries (AU)