RESUMO
This study verified the effect of unilateral teeth extraction on the periodontal ligament in gerbils (Meriones unguiculatus). Ten adult male gerbils weighing about 50 g had induced occlusal alterations by upper left molar extractions while the other ten animals, only submitted to surgical stress, were considered as controls. The periodontal ligament was characterized by qualitative and quantitative analysis, histological description and histomorphometric quantification. Significant alterations were observed on the left side of the experimental group (P < 0.05), the hypofunctional region, when it was compared with the contralateral side and the corresponding region of the control group. Two months after occlusal alterations induced by unilateral teeth extraction, atrophic histological alterations and a decrease in the periodontal space on the ipsilateral side characterized the periodontal ligament. In this study it was possible to conclude that the gerbil can be used in experimental models attempting to correlate the periodontium's biological response to various mechanical stresses, as the periodontal ligament was shown to be highly sensitive to occlusal alterations.
Assuntos
Análise do Estresse Dentário/veterinária , Gerbillinae , Ligamento Periodontal/patologia , Extração Dentária/veterinária , Animais , Modelos Animais de Doenças , Masculino , Distribuição Aleatória , Extração Dentária/efeitos adversosRESUMO
The angioarchitecture of young rabbits' palatine gingiva was studied by using the corrosion resin cast method. The vascular corrosion casts were obtained using low viscosity resin (Mercox CL-2B) and were observed with scanning electron microscopy (SEM). The palatine gingiva had areas with various arrangements. The capillaries of the palatine gingiva and interdental papillae had numerous projections, but in the gingival sulcus, the blood vessels were arranged in a flattened network from their capillary extremities. The blood vessels supplying the alveolar bone were also clearly seen.
Assuntos
Gengiva/irrigação sanguínea , Mucosa Bucal/irrigação sanguínea , Processo Alveolar/irrigação sanguínea , Processo Alveolar/ultraestrutura , Animais , Molde por Corrosão , Feminino , Gengiva/ultraestrutura , Masculino , Microcirculação/ultraestrutura , Microscopia Eletrônica de Varredura , Mucosa Bucal/ultraestrutura , Palato Duro , CoelhosRESUMO
Histological and scanning electron microscopy (SEM) characteristics of the microvasculature of muscle fibers in the anterior third of the adult rat tongue are described. For light microscopy, the specimens were embedded in paraffin and frontal sections were stained with Picro-Sirius. Thick sections were obtained from Spurr embedded samples and stained with toluidine blue solution. For SEM, specimens were obtained by the corrosion cast method and fractured specimens in dimethyl sulfoxide were observed with high-resolution SEM (HRSEM). The blood vessels, enveloped with a thin layer of connective tissue, had fibers running parallel to the muscular fibers. Capillary arterioles were noted following the endomysium, but their lateral branches often ran at right angles to the fibers. The capillary beds were clearly revealed in transverse sections where the individual capillaries appeared ring-like or elliptical in shape. The nuclei of endothelial cell cores could be seen on the vessel surfaces. Collagen fibers type I and III were noted in the connective tissue and in the fibrous layer of vessels.
Assuntos
Fibras Musculares Esqueléticas/ultraestrutura , Língua/irrigação sanguínea , Animais , Arteríolas/ultraestrutura , Compostos Azo , Capilares/ultraestrutura , Núcleo Celular/ultraestrutura , Colágeno Tipo I/ultraestrutura , Colágeno Tipo III/ultraestrutura , Corantes , Tecido Conjuntivo/ultraestrutura , Molde por Corrosão , Crioprotetores , Dimetil Sulfóxido , Endotélio Vascular/ultraestrutura , Técnica de Fratura por Congelamento , Microcirculação/ultraestrutura , Microscopia Eletrônica de Varredura , Miofibrilas/ultraestrutura , Fibras Nervosas/ultraestrutura , Inclusão em Parafina , Poliésteres , Ratos , Ratos Wistar , Resinas Sintéticas , Cloreto de Tolônio , Língua/inervação , Língua/ultraestruturaRESUMO
The characteristics of trabecular bone in human fetuses at seven to nine months of intra-uterine life were studied in the vestibular surface of the mental and body portions of the mandible. In the mental portion, many circular trabeculae joined by "bridges" were observed in the alveolar region (AR). In the 8-month old fetus are trabeculae with tortuous disposition in the medium region (MR). Oblique trabeculae with superior and inferior dispositions defining a triangular area (future mental fossae) are verified in 9-month old fetuses. Trabeculae circularly disposed and vascular foramina are present close to the apex of this area. In the basilar region (BR) some trabeculae obliquely oriented are observed disposed near to the mandibular symphysis. The longitudinal bundles of collagen fibers assume an antero-posterior direction. At 9-month age the vascular foramina range from 6 to 20 microns and the osteocyte lacunae ranging from 1 to 4 microns diameter, are present in mandibles from all ages examined. In the body portion the presence of circular trabeculae joined by "bridges" is the main characteristic of the AR. In the MR most of the trabeculae are circular and the longitudinal trabeculae of this region assume an antero-posterior direction. The laminar, antero-posterior and juxtaposed trabeculae lying parallel to mandible base are a characteristic of the BR. The bundles of collagen fibers exhibit the same pattern of the trabeculae. The vascular foramina of the BR are smaller than that of the precedent regions. In the body portion of the mandible from all ages examined the osteocyte lacunae range from 1 to 4 microns in diameter.
Assuntos
Mandíbula/embriologia , Mandíbula/ultraestrutura , Microscopia Eletrônica de Varredura , Feminino , Idade Gestacional , Humanos , MasculinoRESUMO
The three-dimensional architecture of the vascular network of the nasal septum of the gerbil rat was studied using the corrosive resin cast technique. The angioarchitecture of the nasal septum observed with scanning electron microscopy (SEM) showed that a vascular network is disposed in the lamina propria. The capillaries, arterioles, venules and arteries were closely observed in different areas of the nasal septum mucosa.
Assuntos
Capilares/ultraestrutura , Gerbillinae/anatomia & histologia , Microcirculação/ultraestrutura , Mucosa Nasal/irrigação sanguínea , Septo Nasal/irrigação sanguínea , Animais , Artérias/ultraestrutura , Arteríolas/ultraestrutura , Molde por Corrosão , Feminino , Masculino , Microscopia Eletrônica de Varredura , Vênulas/ultraestruturaRESUMO
PURPOSE: To evaluate with the scanning electron microscope (SEM) the effects of a pulsed Nd: YAG laser on the occlusal surface of human premolars in vitro. MATERIALS AND METHODS: Twenty normal premolars extracted for orthodontic reasons were used and separated in two groups. Group 1 received the irradiation at 2.0 watts, repetition rate of 20 Hz and 124.3 J/cm2 of energy density during 3 minutes, on the occlusal fissure. Group 2 received the laser irradiation in only half of the fissure. RESULTS: The SEM analysis revealed that in the case of shallow fissures the sealing was total but in narrow and deep fissure the sealing was partial or was in complete.
Assuntos
Esmalte Dentário/efeitos da radiação , Fissuras Dentárias/radioterapia , Lasers , Dente Pré-Molar , Humanos , Terapia a Laser , Microscopia Eletrônica de Varredura , NeodímioRESUMO
The three-dimensional architecture of the vascular network of the rat's lingual papillae has been studied employing the corrosive resin cast technique. The casts of the microvasculature of these types of papillae (the small conical filiform, true filiform, fungiform and vallate papillae) have been observed under scanning electron microscopy (SEM). The microvascular arrangements of the filiform papillae consist of well-defined simple or twisted capillary loops. The fungiform papillae have a cylindrical form with a central hole, and the capillary network gives shape to the whole papilla. Finally, the capillary bed of the oval-shaped vallate papilla with its characteristic network and small hairpin-like loops was also examined.
Assuntos
Capilares/ultraestrutura , Ratos Wistar/anatomia & histologia , Língua/irrigação sanguínea , Animais , Feminino , Masculino , Microcirculação/ultraestrutura , Microscopia Eletrônica de Varredura , Modelos Estruturais , Ratos , Língua/ultraestruturaRESUMO
The three-dimensional structure of the lamina propria of the hard and soft palatine mucosa of the nine-banded armadillo was observed by scanning electron microscopy. Sodium hydroxide cell maceration method was applied to demonstrate the architecture of the connective tissue papillae. The palatine mucosa of the armadillo had a triangular shape and measured appr. 6.5 cm length. The hard palate showed 9 transverse palatine plicae while the soft palate was smooth. In the 10% NaOH treated specimens, the lamina propria of the hard palatine mucosa showed numerous connective tissue papillae with a general finger-like shape. These structures were composed by a meshwork of collagen fibers arranged in several directions. On the other hand, the connective tissue papillae of the soft palate mucosa were scattered and small. Numerous openings of glandular ducts with circular or elliptical shape were located in the interplicae area and in the soft palate.
Assuntos
Tatus/anatomia & histologia , Mucosa Bucal/ultraestrutura , Palato/ultraestrutura , Animais , Colágeno/análise , Feminino , Masculino , Microscopia Eletrônica de Varredura , Palato Mole/ultraestrutura , Glândulas Salivares/ultraestruturaRESUMO
The lingual nerves from ten mice were examined so that normal axonal populations could be determined. After perfusion fixation, they were removed and processed, and sections were taken from nerves for transmission electron microscopy. The fiber-diameter spectrum of unmyelinated fibers for the mouse lingual nerve is characterized by a unimodal curve with the more pronounced peak in the medium-diameter fiber range (0.28 micron). The spectrum from the myelinated fibers also shows a population of axons of the lingual nerve (0.22-3.2 microns) that reflects different functional specializations. These data establish some baseline values for morphological evaluation of the effects of experimental lingual nerve damage.
Assuntos
Axônios , Nervo Lingual/anatomia & histologia , Animais , CamundongosRESUMO
Natal and neonatal teeth may occur in patients up to 30-days after birth. The presence of two neonatal teeth in cleft lip and palate patients is reported in this study describing the structural aspects of the enamel and the dentin, using scanning electron microscopy.