Evaluación de la mineralización en mandíbula y diente de trucha arcoíris (Oncorhynchus mykiss) mediante microscopía electrónica de barrido de presión variable acoplada a detector de espectroscopía de rayos X de energía dispersiva / Evaluation of mineralization in jaw and teeth of rainbow trout (Oncorhynchus mykiss) using variable pressure scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy detector

RESUMEN: En salmonicultura se utilizan imágenes de rayos X, para evaluar la columna vertebral y las aletas, pero estas no permiten cuantificar los minerales que constituyen el hueso, para esto se utilizan otras técnicas que son destructivas. La Microscopía Electrónica de Barrido de presión variable (VP SEM) acoplada al detector espectroscopia de rayos X de energía dispersiva (EDX) acoplado, nos permite analizar la microestructura y a la vez determinar elementos químicos, porcentaje y distribución presentes en puntos específicos en una muestra. Se utilizaron 5 truchas control y 5 con deformidad mandibular, de agua dulce en etapa de smolt, se analizó la estructura y mineralización del hueso, se eligieron en promedio 6 puntos de cuantificación por región de interés y se analizaron mediante Microscopía Electrónica de Barrido (VP SEM-EDX). Los datos obtenidos muestran porcentaje en masa de Ca promedio en hueso articular de truchas fueron de 8.07 % y de 14.48 % en truchas con deformidad mandibular y control respectivamente y el porcentaje en masa promedio de P es de 4.07 % y 7.60 %, en truchas con deformidad mandibular y control respectivamente. Se identificó además otros elementos presentes en la muestra como Mg, Na, C, O, N, S, F, Zn, Al y Fe, con especial interés en el aumento de carbono en las muestras analizadas con deformidad mandibular y la presencia de aluminio en todas las muestras. La Técnica de VP SEM-EDX, permite evaluar de forma directa, sin destrucción de la muestra y con una preparación mínima de la muestra. En el hueso, la aplicación más frecuente de SEM-EDX es la medición del contenido de Ca y P y la relación que existe entre estos elementos Ca/P, en la muestra. Paralelamente la técnica nos permite la detección de otros microelementos provenientes del agua o de la alimentación y que eventualmente pueden provocar alteraciones en los peces, confirmando la hipótesis que el microanálisis elemental tiene utilidad para la salmonicultura.

SUMMARY: In salmon farming systems, X-ray images are used to evaluate the spine and fins, but these do not allow quantifying the minerals that make up the bone, for different techniques that are destructive are used. Variable Pressure Scanning Electron Microscopy (VP SEM) coupled to an Energy Dispersive X-ray spectroscopy detector (EDX), allows us to analyze the microstructure and at the same time determine chemical elements, percentages, and distribution present at specific points in a sample. Five control and five jaw deformity trout, from freshwater and in the smolt stage were used. The structure and mineralization of the bone were analyzed, an average six quantification points were chosen per region of interest (ROI) and then they were analyzed by Scanning Electron Microscopy (VP SEM-EDX). The data obtained have shown the average mass percentage of calcium in trout joint bone was 8.07 % and 14.48 % in jaw deformity and control trout, respectively; and the average mass percentage of phosphorus is 4.07 % and 7.60 %, in jaw deformity and control trout, respectively. Other elements present in the sample were also identified, such as magnesium, sodium, carbon, oxygen, nitrogen, sulphur, fluorine, zinc, aluminium, and iron, with special interest the increase of carbon in the analyzed samples with mandibular deformity and the presence of aluminum in all samples. The VP SEM-EDX Technique allows direct evaluation, without destruction of the sample and with minimal sample preparation. In bone, the most frequent application of SEM-EDX is the measurement of the content of calcium (Ca) and phosphorus (P) and the relationship that exists between these elements, calcium/phosphorus (Ca/P), in the sample. At the same time, the technique allows us to detect other microelements from water or food that can eventually cause alterations in fish, confirming the hypothesis that elemental microanalysis is useful for salmon farming.

Scanning electron microscopic observations of fibrous structure of cemento-dentinal junction in healthy teeth.

Introduction: The cemento‑dentinal junction (CDJ) is a structural and biologic link between cementum and dentin present in the roots of teeth. Conflicting reports about the origin, structure and composition of this layer are present in literature. The width of this junctional tissue is reported to be about 2‑4 µm with adhesion of cementum and dentin by proteoglycans and by collagen fiber intermingling. Aim and Objective: The objective of this study is to observe and report the fibrous architecture of the CDJ of healthy tooth roots. Materials and Methods: A total of 15 healthy teeth samples were collected, sectioned into halves, demineralized in 5% ethylenediaminetetraacetic acid, processed using NaOH maceration technique and observed under a scanning electron microscope. Results: The CDJ appeared to be a fibril poor groove with a width of 2-4 μm. Few areas of collagen fiber intermingling could be appreciated. A detailed observation of these tissues has been presented.

Morfologia radicular da dentição permanente de Sapajus apella: morfometria, anatomia macroscópica, ultraestrutura e propriedades físicas / Root morphology of the permanent dentition Sapajus apella: morphometry, gross anatomy, ultrastructure and physical properties

O objetivo desse trabalho foi contribuir com o estudo anatômico, morfométrico, ultraestrutural e propriedades físicas dos dentes permanentes do primata Sapajus apella. Para tal, foram utilizados 10 animais adultos e machos. Os dentes foram avaliados quanto ao seu comprimento e quanto à anatomia radicular externa e interna considerando número de raízes e canais, forma e direção radicular e forma do canal, assim como análise da densidade e diâmetro tubular do canal radicular, composição e microdureza dentinária. A anatomia radicular desse primata apresentou especificidades, como o número de raízes do segundo pré-molar superior e a presença do terceiro pré-molar. Quanto à densidade e o diâmetro dos túbulos dentinários, observou-se uma diminuição do número e diâmetro de túbulos ao longo do canal radicular, havendo diferença estatisticamente significante ao se comparar o terço apical com as regiões cervical e média, padrão de densidade e tamanho semelhantes a dentes humanos. Semelhanças também foram encontradas com dentes humanos quando comparados os valores de microdureza e proporção de elementos químicos encontrados na dentina radicular...

This paper aimed the anatomical study including morphometric, ultrastructural and physical properties of permanent teeth of Sapajus apella primate. Ten adult male monkeys were studied. The teeth were evaluated for their length, root anatomy (external and internal considering the number of roots and canals), direction and shape of the root canal, density and diameter of the tubular root canal, dentin microhardness, and composition. The root anatomy showed specificity regarding the number of roots of the second premolar and the presence of the third premolar. We observed a decrease in the number and diameter of dentinal tubules along the root canal, a statistically significant difference when compared with the apical and cervical regions. Similarities with human teeth were found in regard to microhardness values and proportion of chemical elements in the root dentin...

Evaluation of the remineralization potential of amorphous calcium phosphate and fluoride containing pit and fissure sealants using scanning electron microscopy.

Aim: To evaluate the remineralization potential of Amorphous Calcium Phosphate (ACP) and Fluoride containing pit and Fissure Sealants using Scanning Electron Microscopy. Materials and Methods: Thirty maxillary first premolars were divided into three groups of ten each and were randomly selected for ACP containing (Aegis- Opaque White, Bosworth Co. Ltd.), Fluoride containing (Teethmate F1 Natural Clear, Kuraray Co. Ltd.), resin based (Concise- Opaque White, 3M ESPE Co. Ltd.) pit and fissure sealant applications. The Concise group served as a control. The teeth weresubjected to the pH-cycling regimen for a period of two weeks. After two weeks, the teeth were sectioned bucco-lingually into 4mm sections and were observed under Scanning Electron Microscope at 50X, 250X, 500X, 1000X and 1500X magnifications. The qualitative changes at the tooth surface and sealant interface were examined and presence of white zone at the interface was considered positive for remineralization. Results: Both ACP containing (Aegis) and Fluoride containing (Teethmate F1) group showed white zone at the tooth surface-sealant interface. The resin based group (Concise) showed regular interface between the sealant and the tooth structure, but no clear cut white zone was observed. Conclusion: Both, Aegis and Teethmate F1 have the potential to remineralize. Release of Amorphous Calcium Phosphate molecules in Aegis group and formation of Fluoroapetite in Teethmate F1 group, were probably responsible for the remineralization.

Radular ultrastructure of South American Ampullariidae (Gastropoda: Prosobranchia)

The radula of five species of South American Ampullariidae was analysed by Scanning Electron Microscope (SEM) with the purpose of enlarging new studies on the systematic of this family. The studied species were Pomacea -canaliculata (Lamarck, 1822), Pomacea scalaris (d'Orbigny, 1835), Pomella (P.) megastoma (Gray, 1847), Asolene (A.) platae (Maton, 1809) and Felipponea neritiniformis (Dall, 1919). The central tooth shows different attributes which provide the means for generic determination; the analysis of the central tooth, the lateral and marginal ones by SEM adds further information for species differentiation.

A rádula de cinco espécies sul-americanas de Ampullariidae é analisada ao microscópio eletrônico de varredura com objetivo de fornecer novos subsídios à sistemática desta família. As espécies estudadas são Pomacea canaliculata (Lamarck, 1822), Pomacea scalaris (d'Orbigny, 1835), Pomella (P.) megastoma (Gray, 1847), Asolene (A.) platae (Maton, 1809) e Felipponea neritiniformis (Dall, 1919). O dente central apresenta novos subsídios à determinação genérica, o estudo ao microscópio eletrônico os dentes central, laterais e marginais acrescentam novos subsídios na determinação das espécies.

The development and evolution of mammalian enamel: structural and functional aspects

Dental enamel is the most highly mineralized tissue of vertebrates and consists mainly of submicroscopic crystals of hydroxyapatite. Comparative analysis of enamel structure has revealed a marked structural diversity among vertebrates. In most cases, the enamel of amphibians and reptiles is aprismatic, since the crystallites are roughly parallel to each other and perpendicular to the enamel surface. The enamel of mammals is formed by prismatic structures, the diversity of which may be used to infer phylogenetic relationships and to identify mammalian taxa in higher orders. The complexity of enamel has been also related to feeding habits, since the patterns observed have usually evolved as functional adaptations in response to biomechanical stress imposed on teeth. In this article we review and discuss the modifications in enamel structure that occurred during mammalian evolution, as well as the functional and cellular aspects related to these changes.

Diente de bovino, una alternativa a los dientes humanos como sustrato en investigación: revisión bibliográfica / Bovine teeth, an alternative to the human teeth in research: bibliographic review

Como consecuencia del auge de la Odontología preventiva y conservadora es que cada vez se cuenta con menos dientes humanos extraidos para los estudios odontológicos. Surge la necesidad de buscar dientes que sean homologables a los dientes humanos. Según numerosas investigaciones los dientes de bovino serían los de primera selección por ser de fácil obtención y por tener muy pocas o ninguna diferencia tanto a nivel macro como microscópico con respecto a los dientes humanos. Esta publicación pretende analizar las características que justifican el uso de dientes de bovino en investigación, como también evidenciar similitudes y/o diferencias que existen entre el esmalte y dentina humano y de bovino, tanto a nivel químico como de sus estructuras macro y microscópica, en investigaciones realizadas a nivel nacional como internacional. Como conclusión, podemos decir que tanto al MEB como la microscopía óptica, el esmalte y dentina humano y bovino presentan las mismas estructuras. En relación a la adhesión de la resina compuesta a esmalte humano y bovino, no existen diferencias estadísticamente significativas, observándose un ligero aumento en la adhesión a esmalte de bovino que a esmalte humano. Esto último es contrario a resultados obtenidos por otros investigadores. A pesar de esto, ambos tipos de esmaltes serían esencialmente comparables en lo referente a la adhesión. Al análisis químico comparativo del esmalte humano y bovino grabado y no grabado, existen diferencias que pueden justificar la mayor adhesión de las resinas compuestas al esmalte bovino. Se observa una disminución importante en el porcentaje de algunos elementos cuando se somete el esmalte a la técnica de grabado ácido, especialmente del ion calcio. Las mayores diferencias en el análisis comparativo del esmalte humano y bovino sin grabado ácido se observa en el ion zinc. El tiempo de grabado ácido de 30 seg. en diente bovino demostró ser el más efectivo ya que presentó los mejores valores en cuanto a la resistencia a la fuerza de cizallamiento en comparación con los tiempos de 15, 60 y 0 seg. respectivamente

Estudio anatomohistológico de tejido dentario por descalcificación / An anatomohistological study of dental tissue by decalcification

Con la finalidad de estudiar las estructuras normales del tejido dentinario y pulpar en dientes permanentes incluidos, se procedió a realizar la técnica de descalcificación del diente por un método químico. Para realizar las observaciones, se realizaron cortes de 5 micras, se tiñeron con hematoxilina-eosina y posterioremente se realizaron las observaciones en microscopio de luz, así como la toma de microfotografía

Periodontal implications of Class II restorations. Clinical and SEM evaluation.

30 subjects with class II silver amalgam restorations were studied to evaluate the influence of these restorations on periodontal health of the adjacent region. The incidence of overhangings were noted. The periodontal changes were recorded with the help of indices. The surface of the restoration and the interface between the restoration and the cavity margin were observed on extracted teeth under SEM. The gingival and periodontal status at the site of the restoration were affected by the restoration and the restoration showed a rough surface as compared to the enamel on SEM examination.