RESUMEN
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.
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Animales , Diente/química , Oncorhynchus mykiss , Mandíbula/química , Minerales/análisis , Espectrometría por Rayos X , Diente/ultraestructura , Microscopía Electrónica de Rastreo , Mandíbula/ultraestructuraRESUMEN
The present study aims to evaluate the effect of brushing with fluoride dentifrice on teeth severely affected by erosion due to respiratory medicaments. Enamel (n = 50) and dentin (n = 50) bovine specimens were prepared and treated with artificial saliva (S-control), acebrofilin hydrochloride (AC), ambroxol hydrochloride (AM), bromhexine hydrochloride (BR), and salbutamol sulfate (SS) and subjected to cycles of demineralization (immersing in 3 mL, 1 min, three times a day at intervals of 1 hr, for 5 days) followed by remineralization (saliva, 37°C, 1 hr). Simulated brushing with fluoridated toothpaste was performed using 810 strokes in a reciprocal-action brushing simulator. Scanning electron microscopy, micro energy dispersive X-ray fluorescence (µ-EDXRF) spectroscopy and attenuated total reflection Fourier transform infrared (ATR FTIR) spectroscopy were then performed. µ-EDXRF images showed extensive erosion after treatment with all medicaments. SEM images showed enamel erosion in order SS > BR > AC = AM > S after brushing and fluoridation. FTIR results were in agreement. In case of dentin, µ-EDXRF measurements showed significant difference in mineral content (percent weight of calcium and phosphate) in SS + brushing + fluoridation treated enamel compared to control, while µ-EDXRF images showed erosive effects in the order SS > AM>BR > AC = S post brushing + fluoridation. SEM images showed erosion in the order SS > AM = BR > AC > S post brushing + fluoridation. Again, FTIR multivariate results were in agreement. Overall, our study shows that proper oral care is critical when taking certain medication. The study also demonstrates the possible use of FTIR for rapid clinical monitoring of tooth erosion in clinics.
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Broncodilatadores/efectos adversos , Microscopía Electrónica de Rastreo , Espectrometría por Rayos X , Espectrofotometría Infrarroja , Desmineralización Dental/inducido químicamente , Diente/efectos de los fármacos , Animales , Bovinos , Esmalte Dental/química , Esmalte Dental/efectos de los fármacos , Esmalte Dental/ultraestructura , Dentina/química , Dentina/efectos de los fármacos , Dentina/ultraestructura , Diente/química , Diente/ultraestructuraRESUMEN
Most colubrid snake venoms have been poorly studied, despite the fact that they represent a great resource for biological, ecological, toxinological and pharmacological research. Herein, we explore the venom delivery system of the Aesculapian False Coral Snake Erythrolamprus aesculapii as well as some biochemical and toxicological properties of its venom. Its Duvernoy's venom gland is composed of serous secretory cells arranged in densely packed secretory tubules, and the most striking feature of its fang is their double-curved shape, exhibiting a beveled bladelike appearance near the tips. Although E. aesculapii resembles elapid snakes of the genus Micrurus in color pattern, this species produces a venom reminiscent of viperid venoms, containing mainly tissue-damaging toxins such as proteinases. Prominent hemorrhage developed both locally and systemically in mice injected with the venom, and the minimum hemorrhagic dose was found to be 18.8 µg/mouse; the lethal dose, determined in mice, was 9.5⯱â¯3.7⯵g/g body weight. This work has toxicological implications that bites to humans by E. aesculapii could result in moderately severe local (and perhaps systemic) hemorrhage and gives insight into future directions for research on the venom of this species.
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Colubridae/anatomía & histología , Venenos de Serpiente/química , Venenos de Serpiente/toxicidad , Animales , Antivenenos/inmunología , Glándulas Exocrinas/anatomía & histología , Femenino , Hemorragia/inducido químicamente , Humanos , Masculino , Maxilar/ultraestructura , Ratones , Microscopía Electrónica de Rastreo , Proteolisis , Mordeduras de Serpientes , Venenos de Serpiente/inmunología , Diente/ultraestructuraRESUMEN
This chapter describes laboratory protocols for TEM and SEM approaches allowing the examination of the dental hard tissues' constituents at the ultrastructural level. TEM has the highest resolution power to examine the cellular and extracellular matrix ultrastructure inside a given sample, detecting the presence, location, and quantification of organelles related to the metabolism of the cell type as well as membrane specializations. SEM allows the observation of the sample surface, for examining dimensional topography and distribution of exposed features.
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Microscopía Electrónica de Rastreo/métodos , Microscopía Electrónica de Transmisión/métodos , Diente/ultraestructura , Animales , Desecación/métodos , Humanos , Microtomía/métodos , Adhesión del Tejido/métodos , Fijación del Tejido/métodosRESUMEN
Dental enamel is formed by rod-like structures, the enamel prisms. Groups of prisms are packed together in successive horizontal layers of alternating directions, known as Hunter-Schreger bands (HSBs). HSBs are the major microstructural characteristic of mammalian enamel. The pattern of HSBs can vary among mammalian species and this variability may provide relevant information regarding the species life history and taxon identification. In human HSBs can be used as a biometric-based parameter for personal identification in automated systems. The analysis of HSBs has been hampered by technical difficulties. The low contrast between light and dark bands and variations in light intensity may hinder the observation of HSBs in digital images. This article describes a simple and efficient computational procedure that greatly enhances the contrast and minimizes the differences in the intensity of illumination in HSBs images. Its use can significantly increase the quality and the number of HSBs that can be recorded in intact teeth.
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Esmalte Dental/ultraestructura , Aumento de la Imagen/métodos , Diente/ultraestructura , Humanos , Procesamiento de Imagen Asistido por Computador/métodosRESUMEN
OBJECTIVES: To evaluate the influence of variations in the working angle of the piezoelectric ultrasonic scaler (PUS) on root surfaces. MATERIAL AND METHODS: Fifty-five uniradicular bovine teeth were used, of which 25 teeth were used for the analysis of the roughness and root wear, while the remaining 30 teeth were used for the analysis of morphology (MRS) and the attachment of blood components (ABC). The teeth were randomly divided into five groups according to the type of treatment (G1-G5: piezoelectric ultrasonic scaler; G6: manual curette) and to the PUS working angle applied (G1: 0°; G2: 30°; G3: 45°; G4: 60°; G5: 90°). For statistical analysis, the data describing the MRS and ABC were analysed by the Kruskal-Wallis and Dunn's tests, and the data describing the roughness and tooth wear were analysed by anova and Tukey's tests at the significance level of 5%. RESULTS: Manual curette (MC) promoted a smoother root surface than the application of the PUS. The PUS used at the angles of 30° and 45° resulted in a high level of ABC that was comparable to that obtained by MC. Additionally, the group in which the PUS was applied at an angle of 45° exhibited less tooth wear than the other groups. CONCLUSIONS: Changes in the working angle of the PUS influenced the characteristics of root surfaces after instrumentation.
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Raspado Dental/instrumentación , Diseño de Equipo , Aplanamiento de la Raíz/instrumentación , Raíz del Diente/ultraestructura , Terapia por Ultrasonido/instrumentación , Animales , Bovinos , Cálculos Dentales/terapia , Raspado Dental/métodos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Aplanamiento de la Raíz/métodos , Propiedades de Superficie , Diente/ultraestructura , Desgaste de los Dientes/patología , AguaRESUMEN
This study aims to describe and analyze morphological and physical properties of deciduous teeth of Sus domesticus. Ultrastructural analysis, mineral composition and microhardness of enamel and dentine tissues were performed on 10 skulls of S. domesticus. External anatomic characteristics and the internal anatomy of the teeth were also described. Data regarding microhardness and ultrastructural analysis were subjected to statistical tests. For ultrastructural analysis, we used the analysis of variance (ANOVA) with Tukey's post hoc (p≤0.05) test. In the analysis of microhardness, the difference between the enamel and dentine tissues was analyzed by a Student's t test. Values were expressed as mean with standard error. The results of ultrastructural analysis showed the presence of an enamel prism pattern. A dentinal tubule pattern was also observed, with a larger diameter in the pulp chamber and the cervical third, in comparison to middle and apical thirds. We observed an average microhardness of 259.2kgf/mm(2) for enamel and 55.17kgf/mm(2) for dentine. In porcine enamel and dentine, the chemical elements Ca and P showed the highest concentration. The analysis of internal anatomy revealed the presence of a simple root canal system and the occurrence of main canals in the roots. The observed features are compatible with the functional demand of these animals, following a pattern very similar to that seen in other groups of mammals, which can encourage the development of research using dental elements from the pig as a substitute for human teeth in laboratory research.
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Esmalte Dental/anatomía & histología , Dentina/anatomía & histología , Diente/anatomía & histología , Animales , Calcio/análisis , Esmalte Dental/química , Esmalte Dental/ultraestructura , Pulpa Dental/anatomía & histología , Pulpa Dental/química , Pulpa Dental/ultraestructura , Cavidad Pulpar/anatomía & histología , Cavidad Pulpar/química , Cavidad Pulpar/ultraestructura , Dentina/química , Dentina/ultraestructura , Dureza , Masculino , Microscopía Electrónica de Rastreo , Fósforo/análisis , Sus scrofa , Diente/química , Diente/ultraestructuraRESUMEN
INTRODUCTION: The objective of this study was to evaluate the efficacy of passive ultrasonic irrigation (PUI) with 17% EDTA and 1% NaOCl solutions on smear layer removal. METHODS: Root canal preparations of 32 human teeth were performed with the ProTaper system. Next, they were longitudinally fractured to permit quantitation of smear layer creation from the cervical, middle, and apical thirds of the roots by using scanning electron microscopy. After reassembling the fractured tooth halves, they were divided into 4 groups according to different final irrigation protocols: group1, EDTA + NaOCl; group 2, EDTA with PUI + NaOCl; group 3, EDTA + NaOCl with PUI; and group 4, EDTA + NaOCl, both with PUI. After irrigation, the tooth halves were separated to permit imaging the same areas by scanning electron microscopy, and a percentage of opened dentinal tubules in irrigated areas as a percent of the total area was obtained. The results were submitted to Kruskal-Wallis, analysis of variance, and Bonferroni tests (α = 0.05). RESULTS: The cervical third of the samples from all groups showed higher percentage of smear layer removal and open dentinal tubule areas, followed by the middle and apical thirds. Among the irrigation groups, there were statistically significant differences in cervical third between group 2 and group 4 samples, with the highest and lowest percentage of smear layer removal, respectively. CONCLUSIONS: PUI by using 1% NaOCl and ultrasonic tip placed within 1 mm of the apical foramen did not show higher efficacy in smear layer removal compared with conventional irrigation.
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Irrigantes del Conducto Radicular/uso terapéutico , Preparación del Conducto Radicular/métodos , Capa de Barro Dentinario/terapia , Terapia por Ultrasonido/métodos , Análisis de Varianza , Ácido Edético/uso terapéutico , Humanos , Microscopía Electrónica de Rastreo , Distribución Aleatoria , Hipoclorito de Sodio/uso terapéutico , Diente/efectos de los fármacos , Diente/ultraestructuraRESUMEN
The aim of this study was to evaluate the effects of different power parameters of an Erbium, Cromium: Yttrium, Scandium, Gallium, Garnet laser (Er,Cr:YSGG laser) on the morphology, attachment of blood components (ABC), roughness, and wear on irradiated root surfaces. Sixty-five incisive bovine teeth were used in this study, 35 of which were used for the analysis of root surface morphology and ABC. The remaining 30 teeth were used for roughness and root wear analysis. The samples were randomly allocated into seven groups: G1: Er,Cr:YSGG laser, 0.5 W; G2: Er,Cr:YSGG laser, 1.0 W; G3: Er,Cr:YSGG laser, 1.5 W; G4: Er,Cr:YSGG laser, 2.0 W; G5: Er,Cr:YSGG laser, 2.5 W; G6: Er,Cr:YSGG laser, 3.0 W; G7: scaling and root planning (SRP) with manual curettes. The root surfaces irradiated by Er,Cr:YSGG at 1.0 W and scaling with manual curettes presented the highest degrees of ABC. The samples irradiated by the Er,Cr:YSGG laser were rougher than the samples treated by the manual curette, and increasing the laser power parameters caused more root wear and greater roughness on the root surface. The Er,Cr:YSGG laser is safe to use for periodontal treatment, but it is not appropriate to use irradiation greater than 1.0 W for this purpose.
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Raspado Dental/métodos , Láseres de Estado Sólido/uso terapéutico , Raíz del Diente/efectos de la radiación , Diente/efectos de la radiación , Animales , Bovinos , Microscopía Electrónica de Rastreo , Diente/ultraestructura , Raíz del Diente/ultraestructuraRESUMEN
The transition from terrestrial ancestry to a fully pelagic life profoundly altered the body systems of cetaceans, with extreme morphological changes in the skull and feeding apparatus. The Oligocene Epoch was a crucial time in the evolution of cetaceans when the ancestors of modern whales and dolphins (Neoceti) underwent major diversification, but details of dental structure and evolution are poorly known for the archaeocete-neocete transition. We report the morphology of teeth and ultrastructure of enamel in archaeocetes, and fossil platanistoids and delphinoids, ranging from late Oligocene (Waitaki Valley, New Zealand) to Pliocene (Caldera, Chile). Teeth were embedded in epoxy resin, sectioned in cross and longitudinal planes, polished, etched, and coated with gold palladium for scanning electron microscopy (SEM) observation. SEM images showed that in archaeocetes, squalodontids and Prosqualodon (taxa with heterodont and nonpolydont/limited polydont teeth), the inner enamel was organized in Hunter-Schreger bands (HSB) with an outer layer of radial enamel. This is a common pattern in most large-bodied mammals and it is regarded as a biomechanical adaptation related to food processing and crack resistance. Fossil Otekaikea sp. and delphinoids, which were polydont and homodont, showed a simpler structure, with inner radial and outer prismless enamel. Radial enamel is regarded as more wear-resistant and has been retained in several mammalian taxa in which opposing tooth surfaces slide over each other. These observations suggest that the transition from a heterodont and nonpolydont/limited polydont dentition in archaeocetes and early odontocetes, to homodont and polydont teeth in crownward odontocetes, was also linked to a marked simplification in the enamel Schmelzmuster. These patterns probably reflect functional shifts in food processing from shear-and-mastication in archaeocetes and early odontocetes, to pierce-and-grasp occlusion in crownward odontocetes, with the implication of less demanding feeding biomechanics as seen in most extant odontocetes.
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Cetáceos/anatomía & histología , Esmalte Dental/ultraestructura , Fósiles , Diente/ultraestructura , Animales , Evolución Biológica , Chile , Microscopía Electrónica de Rastreo , Nueva ZelandaRESUMEN
Micro energy-dispersive X-ray fluorescence spectrometry (µ-EDXRF) and scanning electron microscopy (SEM) were used to evaluate dentin treated with an etch and rinse adhesive (ER) and a self-etch adhesive (SE). Ten human molars (H) and ten bovine anterior teeth (B) were prepared (exposure of dentin and divided in the middle) and allocated into two different adhesion strategy groups per substrate (n=40). µ-EDXRF data and SEM images were obtained before and after treatment. Untreated dentin of both substrates did not differ in terms of Ca (p<0.1503), P (p<0.2986) or Ca/P ratio (p<0.1400). H-SE and B-SE specimens showed reduced P content (p<0.0001; p<0.0002), while H-ER and B-ER specimens showed reduced Ca and P content (p<0.0001; p<0.0001) when compared with untreated specimens. The Ca/P ratio was significantly higher in H-ER and B-ER specimens than in H-SE and B-SE specimens (p<0.0001; p<0.0080). Untreated dentin showed a homogeneous elemental distribution. However, after adhesive treatments, the surface of the dentin showed an irregular demineralization pattern. The resin tags and adhesive layer were shorter in bovine specimens than in human specimens due to morphological differences.
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Adhesivos/química , Dentina/anatomía & histología , Animales , Bovinos , Dentina/ultraestructura , Recubrimientos Dentinarios/química , Humanos , Microscopía Electrónica de Rastreo , Cementos de Resina/química , Espectrometría por Rayos X , Diente/anatomía & histología , Diente/ultraestructuraRESUMEN
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...
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Animales , Cebus/anatomía & histología , Dentición Permanente , Diente/anatomía & histología , Diente/ultraestructura , BiometríaRESUMEN
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.(AU)
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.(AU)
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Animales , Cebus/anatomía & histología , Diente/anatomía & histología , Diente/ultraestructura , Dentición Permanente , BiometríaRESUMEN
The aim of this work was to evaluate, by means of scanning electron microscopy (SEM) and electron dispersive spectroscopy (EDS), the different irrigation protocols concerning the formation of chemical smear layer (CSL). Fifty-five teeth were instrumented by using distilled water (DW) as irrigant. Next, the teeth were submitted to a protocol for removal of the mechanical smear layer produced. The teeth were divided into 11 groups, according to irrigation regimen. Then, the teeth were prepared and analyzed with SEM and EDS. Only in Group 1 [1 mL sodium hypochlorite (NaOCl) + 10 mL DW + 1 mL chlorhexidine (CHX) solution], Group 2 [1 mL NaOCl + 10 mL DW + 1 mL ethylenediaminetetraacetic acid (EDTA) + 10 mL DW + 1 mL CHX solution], and Group 3 [1 mL NaOCl + 10 mL DW + 1 mL citric acid (CA) + 10 mL DW + 1 mL CHX solution], the formation of CSL was observed. In the groups where CHX gel was used alone or in association with EDTA, CA, phosphoric acid (PA), and CHX solution, no formation of CSL was observed. According to the results found in the cases in which one wants to associate NaOCl with CHX, the protocol using PA (1 mL NaOCl + 10 mL DW + 1 mL PA + 10 mL DW + 1 mL CHX solution) did not induce formation of CSL.
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Desinfectantes/química , Irrigantes del Conducto Radicular/química , Capa de Barro Dentinario , Diente/efectos de los fármacos , Diente/ultraestructura , Humanos , Microscopía Electrónica de Rastreo , Análisis EspectralRESUMEN
We describe two isolated molariforms recovered from early-middle Eocene (early Lutetian) levels of northwestern Patagonia, Argentina. Comparisons with major lineages of therian and non-therian mammals lead us to refer them to a new genus and species of Gondwanatheria (Allotheria). There is a single root supporting each tooth that is very short, wide, rounded, and covered by cementum; the steep sidewalls, lack of a neck between the crown and root, and the heavily worn stage in both molariforms suggest that they were of a protohypsodont type. Both teeth are strongly worn at their centers, all along their length, with the labial edge less worn than the lingual; they show strong transverse crests that alternate with lingual grooves. The protohypsodont aspect of the teeth, as well as the strong, transverse crests, are suggestive of sudamericid affinities; on the other hand, the thin enamel layer and the occlusal pattern formed by the crests and grooves shows more similarities to molariform teeth of the Ferugliotheriidae. The new taxon adds evidence regarding the (1) extensive radiation of the Gondwanatheria throughout the Southern Hemisphere, (2) persistence of several lineages well after the Cretaceous/Paleogene boundary, and (3) early evolution of hypsodont types among South American herbivorous mammals.
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Fósiles , Mamíferos/anatomía & histología , Mamíferos/clasificación , Diente/anatomía & histología , Animales , Argentina , Diente/ultraestructura , Raíz del Diente/anatomía & histologíaRESUMEN
Amelogenesis imperfecta (AI) is a group of hereditary disorders that affect the quality and/or quantity of dental enamel. This paper describes the clinicopathological features of a patient who was born of consanguineous parents and who presented with oral alterations, including yellow and misshapen teeth, intrapulpal calcifications, delayed tooth eruption, and gum enlargement. Scanning electron microscopy of the teeth revealed hypoplastic enamel, and a renal ultrasound detected bilateral nephrocalcinosis, leading to a diagnosis of AI and nephrocalcinosis syndrome. Since nephrocalcinosis is often asymptomatic and can be associated with impaired renal function, dentists who see children with generalized and thin hypoplastic AI should consider a renal ultrasound scan and referral to a nephrologist, if appropriate. Children with nephrocalcinosis should also be considered for a dental check.
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Anomalías Múltiples/diagnóstico , Amelogénesis Imperfecta/diagnóstico , Nefrocalcinosis/diagnóstico , Diente/patología , Anomalías Múltiples/genética , Niño , Consanguinidad , Femenino , Humanos , Microscopía Electrónica de Rastreo , Nefrocalcinosis/diagnóstico por imagen , Síndrome , Diente/ultraestructura , UltrasonografíaRESUMEN
PURPOSE: This study evaluated and compared in vitro the microstructure and mineral composition of permanent and deciduous teeth's dental enamel. METHODS: Sound third molars (n = 12) and second primary molars (n = 12) were selected and randomly assigned to the following groups, according to the analysis method performed (n = 4): Scanning electron microscopy (SEM), X-Ray diffraction (XRD) and Energy dispersive X-ray spectrometer (EDS). Qualitative and quantitative comparisons of the dental enamel were done. The microscopic findings were analyzed statistically by a nonparametric test (Kruskal-Wallis). The measurements of the prisms number and thickness were done in SEM photomicrographs. The relative amounts of calcium (Ca) and phosphorus (P) were determined by EDS investigation. Chemical phases present in both types of teeth were observed by the XRD analysis. RESULTS: The mean thickness measurements observed in the deciduous teeth enamel was 1.14 mm and in the permanent teeth enamel was 2.58 mm. The mean rod head diameter in deciduous teeth was statistically similar to that of permanent teeth enamel, and a slightly decrease from the outer enamel surface to the region next to the enamel-dentine junction was assessed. The numerical density of enamel rods was higher in the deciduous teeth, mainly near EDJ, that showed statistically significant difference. The percentage of Ca and P was higher in the permanent teeth enamel. CONCLUSIONS: The primary enamel structure showed a lower level of Ca and P, thinner thickness and higher numerical density of rods.
Asunto(s)
Esmalte Dental/química , Esmalte Dental/ultraestructura , Diente/química , Diente/ultraestructura , Humanos , Microscopía Electrónica de Rastreo , Minerales/análisis , Espectrometría por Rayos X , Difracción de Rayos XRESUMEN
PURPOSE: Regional odontodysplasia (RO) is a rare developmental odontogenic defect. The affected teeth are described as "ghost teeth," due to malformation of dentin, enamel, and cementum. The purpose of this study was to describe the ultrastructural characteristics of the affected teeth as well as the immunohistochemical features of the soft tissue associated with 2 cases of regional odontodysplasia. METHODS: Two cases diagnosed as RO were included on the study. After diagnosis, affected teeth and associated soft tissue were surgically removed from both patients and processed for light and scanning electron microscopy (SEM) analysis. For light microscopy, the specimens were decalcified in 5% nitric acid for 10 to 16 days and stained with hematoxylin and eosin. For SEM studies, specimens were cleaned with diamond paste and, after polishing, treated with 37% phosphoric acid for 5 minutes and covered by a thin layer of metallic gold. Soft tissues covering and surrounding the extracted teeth were routinely processed, and submitted to immunohistochemical reactions against pan-cytokeratins, cytokeratin 19, vimentin, laminin and collagen IV. RESULTS: Both enamel and dentin showed gross alterations, including hypomineralization and discoloration, being more prominent on the coronal structures than the radicular structures. Ultrastructural features included alterations on the prismatic enamel surface, dentinal grooves, interglobular dentin, and hypoplastic and hypocalcified dental hard tissues. The soft gingival and alveolar tissue surrounding and covering the affected teeth showed calcifications and odontogenic remnants, positive for cytokeratin 19, laminin, and collagen IV. CONCLUSIONS: Enamel and dentin are grossly altered in regional odontodysplasia, while cementum is less affected, and soft-tissue calcifications are associated with odontogenic cytokeratin-positive epithelial remnants, in addition to mesenchymal components.
Asunto(s)
Odontodisplasia/patología , Diente/patología , Adulto , Calcinosis/patología , Niño , Colágeno Tipo IV/análisis , Colorantes , Tejido Conectivo/patología , Cemento Dental/patología , Cemento Dental/ultraestructura , Esmalte Dental/patología , Esmalte Dental/ultraestructura , Dentina/patología , Dentina/ultraestructura , Femenino , Colorantes Fluorescentes , Encía/patología , Encía/ultraestructura , Humanos , Inmunohistoquímica , Queratina-19/análisis , Queratinas/análisis , Laminina/análisis , Masculino , Microscopía Electrónica de Rastreo , Mucosa Bucal/patología , Mucosa Bucal/ultraestructura , Diente/ultraestructura , Decoloración de Dientes/patología , Vimentina/análisisRESUMEN
The preservation of teeth that have been exposed to a heat source is a key factor in order to keep their value as evidence. This research paper presents some methods under development for the analysis of dental evidence after exposure to high temperatures; it also establishes age related alterations of young and aged teeth which have been exposed to direct heat. A total of thirty permanent healthy teeth (young=15 and old=15) were submitted to direct heat (n=14) and to a controlled raise of temperature (n=16); they were embedded in polymethylmetacrilate. For the macroscopic study, blocks were cut in half, polished and their surfaces were digitalized. Subsequently, blocks were put in slides, worn away and observed through a photomicroscope. The study of the colorimetric pattern was done by Corel Photo Paint 12.0 and Image J. software. All teeth submitted to the gradual raise of temperature presented a degree of structural damage lower than those exposed to direct heat. The internal surface of young teeth exposed to direct heat showed lines of fracture oblique to the long axis of the tooth; in contrast, a reticular pattern was observed on aged teeth. All teeth exposed to direct heat showed some matte-black coloration areas, while those submitted to a gradual increment of temperature showed a greyish colour in the enamel and a chalky-white in the cementum. By using both thermal treatments in young teeth, the amelodentinal junction was lost, thus preserving the integrity of each tissue. In aged teeth, the separation of this junction was produced because of the breakdown of the dentine. Microscopically, in teeth exposed to direct heat, it was neither possible to differentiate the dentin from the cementum, nor to distinguish the incremental lines of the latter; while in those submitted to a controlled increment of temperature, the corresponding morphology in the tissues was observed. A significant statistical difference was obtained for black colour among young and aged teeth exposed to direct heat, as well as among the means of all colours obtained from the teeth exposed to both treatments. The structural changes observed allow locating a tooth in the studied age groups. Our results show the viability of the applied method for the processing of samples, allowing their preservation as evidence during an indefinite time.