Evaluación histológica de Straumann Bone Ceramic® en defectos óseos en tibias de conejo / Histological evaluation of Straumann Bone Ceramic® in bone defects in the rabbit tibia

Este estudio tiene como objetivo evaluar la utilización de Straumann® Bone Ceramic en el relleno de defectos óseos, pues es presentado como un sustituto óseo 100% sintético, con una óptima morfología para estimular la formación de hueso vital. Las excelentes propiedades humectantes facilitan su manipulación y aplicación y funciona como una estructura de soporte para la adhesión de hueso durante el proceso de osteogénesis. La estabilidad mecánica del volumen aumentado es mantenida gracias a la lenta reabsorción de la hidroxiapatita, que impide el exceso de reabsorción. Fueron utilizados para este trabajo seis conejos New Zeland, siendo utilizadas las tibias donde fueron elaborados defectos óseos con trefinas de 4 mm de diámetro. Transcurridos períodos de 30 y 60 días, los animales fueron sacrificados y se siguieron los trámites de laboratorio de rutina para el análisis histológico. Los resultados demostraron que la utilización de éste material para el relleno de defectos óseos, presenta un resultado significativamente superior a los sitios control, posibilitando una actividad celular mucho mas intensa. También se observó una gran facilidad de manipulación e instalación del material en el sitio. Se concluyó que Straumann® Bone Ceramic auxilió en el proceso regenerativo del defecto óseo creado experimentalmente, actuando como un agente ósteo-conductor, aumentando la proliferación celular para esas áreas.

This study aims to evaluate the use of Straumann Bone Ceramic® in filling bone defects, it is presented as a 100% synthetic bone substitute, with optimal morphology to stimulate new bone formation. The excellent wetting properties facilitate handling and application and functions as a structure for membership support bone during the process of osteogenesis. The increased volume mechanical stability is maintained due to the slow resorption of the hydroxyapatite, which prevents excessive resorption. Were used for this job six New Zealand rabbits, the tibiae being used where they were processed trephine bone defects 4 mm indiameter. After periods of 30 and 60 days, animals were sacrificed and followed the procedures for routine laboratories for histological analysis. The results showed that use of the material reviewed for the filling of bone defects presents a result significantly higher than the control sites, enabling a much more intense cellular activity. There is also a great ease of handling and installation of material on the site. It was concluded that Straumann Bone Ceramic® aid in the regenerative process experimentally created bone defect, acting as an agent osteoconductive, increasing cell proliferation for these areas.

Análise histológica e ultraestrutural da neoformação óssea em enxertos bovinos inorgânicos implantados em tíbias de coelho (Oryctolagus cunniculus) / Histological and ultrastrutural analysis of the new bone formation of inorganic bovine bone implanted in rabbit tibiae

A presente pesquisa consiste em uma avaliação da neoformação óssea em 24 implantes cilíndricos, em forma de bloco poroso, de osso bovino inorgânico, inseridos no terço proximal de ambas as tíbias de seis coelhos, observando o padrão celular e a qualidade do osso neoformado. Após um período de cicatrização de oito semanas, os animais foram sacrificados e a porção proximal das tíbias, com os enxertos, removidas e processadas para a microscopia de luz e eletrônica de varredura. Foi possível observar zonas de formação óssea no interior do enxerto, com a presença de processos ósseos, provenientes da lâmina cortical, seguindo em direção ao centro do material enxertado, invadindo e atravessando a cavidade medular, que normalmente apresenta tecido adiposo.

Three-dimensional characteristics of submandibular salivary gland of ageing rats: an HRSEM study.

The characteristics of the submandibular glands of ageing Wistar rats were studied using light and high-resolution scanning electron microscopy (HRSEM) methods. For light microscopy, the samples were fixed in Bouin solution and embedded in paraffin. Sections were stained with hematoxilin-eosin and Azo-Carmin. For conventional scanning electron microscopy, the tissues were fixed in modified Karnovsky solution, and treated with NaOH solution for 3-4 days. The O-D-O method was used for HRSEM. The samples were fixed in 2% osmium tetroxide, macerated in diluted osmium and dehydrated in an increasing series of ethanol. The samples were dried in a critical point dryer, coated with gold-palladium and examined in a Hitachi high-resolution scanning electron microscope, S-900. The results showed that submandibular glands with lobules are separated by connective tissue septum. The acinar formations and the ducts, revealing the serous and mucous cells were observed. After fracture in liquid nitrogen and treatment with NaOH solution to remove the cellular components, the original disposition of the collagen bundles fibers were revealed corresponding to the round, oval or irregular acinar and ductal structures. In the cytoplasm, organelles such as mitochondria, rough endoplasmic reticulum, Golgi apparatus and serous and mucous secretory granules were observed localized in the apical portion in three-dimensional HRSEM images. The serous secretory granules presented different sizes and shapes showing the modifications which occurred in the ageing rats. The striated duct cells revealed the presence of the secretory cells and mitochondria in parallel disposition. The mitochondrial cristae were noted in three-dimensional aspects. The lumen presented numerous cytoplasmic microprojections. The lumen of excretor ducts are covered by polygonal epithelial cells containing numerous microplicae.

Angioarchitecture of the anterior and medium parts of the palatine mucosa of the gerbil, Meriones unguiculatus.

The aim of this study was to examine the microvasculature of the anterior and medium portions of the hard palatine mucosa in the adult gerbil (Meriones unguiculatus) using scanning electron microscopy. The vascular corrosion casts were obtained by injection of Mercox CL-2B synthetic resin and tissue corrosion was performed using sodium hydroxide solution. These casts revealed the presence of capillary loops in the palatine plicae and a smoother/flatter vascular network in the interplicae areas. The capillary loops consisted mainly of anteriorly oriented hair-pins and we also verified a differentiation in the shape of endothelial cell nuclei, which were elongated in arterial and circular in venous vessels.

Histological findings in titanium implants coated with calcium phosphate ceramics installed in rabbit's tibias.

Oral reconstruction using osteointegrated implants are widely indicated nowadays. The implant bone anchorage is very important for its functional stability. Thus, ceramic biomaterials are widely used as coatings of the implant surfaces to accelerate local osteogenesis. The purpose of this study is to assess the biocompatibility and the osteoconduction of two types of calcium phosphate ceramics used as titanium dental implant coatings. These implants were installed in rabbit tibia during an 8-week healing period. The light and fluorescent microscopy observations showed that the materials are biocompatible and that they have osteoconductive activities.

Bone remodeling analysis of various dental implant surfaces using polyfluorochrome sequential labeling in rabbit tibias.

The purpose of this study is to analyze the bone remodeling process after the placement of threaded implants with rough (RBM) and hydroxyapatite coated surfaces (HA) in rabbit tibias using polyfluorochrome sequential labeling. Histomorphometry was performed in order to quantify the amount of each label deposited during the healing period. This work demonstrates the possibility of periodic identification of apatite deposition during bone remodeling around titanium and ceramic implants. It has been concluded that the polyfluorochrome sequential labeling is an important tool for identification of bone remodeling after the insertion of titanium and ceramic implants inside rabbit tibias.

Sistema de centrifugação automatizada para a obtenção de plasma rico em plaquetas / Autoated centrifugation system for the platelet-rich plasma obtention

Fatores de crescimento contidos nas plaquetas podem ser aplicados em defeitos ósseos com o intuito de melhorar resultados clínicos pela aceleração do processo normal de reparo do organismo. O, assim chamado, plasma rico em plaquetas (PRP), obtido através de uma concentração de plaquetas autógenas, tem sido estudado nos reparos ósseo e tecidual, inclusive na osteointegração de implantes dentais. Um novo sistema de centrifugação automatizada, para a obtenção deste PRP é relatado. A orientação horizontal e vertical do recipiente é controlada automaticamente para obtenção do PRP em um único procedimento. Os métodos e a centrifugação apropriada do sangue são essenciais para assegurar resultados positivos na utilização do PRP

Fine structure of the 7 postnatal days Calomys callosus palatine salivary glands.

The aim of this study has been to determine the ultrastructural characteristics of the minor palatine salivary glands on the seventh day of development and to demonstrate wether their secretion is mucous, serous or seromucous by light, transmission and scanning electron microscopy. This study has shown that the palatine gland acinar cells are predominantly mucous with some serous units. These cells contain electron dense (serous) and low electron dense (mucous) granules in the apical portions. The cytoplasmatic organelles like mitochondria, Golgi apparatus and rough endoplasmic reticulum are localized in a supranuclear portion. We could also observe the flattened myoepithelial cells surrounding the basal part of the acini with myofilaments, Golgi apparatus and mitochondria. Desmosomal junctions and membrane interdigitations are present between the acinar and the myoepithelial cells. A basal lamina, divided in two layers, an electron dense and an electron lucent is present between the glandular stroma which is composed of dense connective tissue and the endpieces.

Histological findings of bone remodeling around smooth dental titanium implants inserted in rabbit's tibias.

Nowadays, there are many kinds of implants with different covering layers. The aim of these wide spectra is to discover the material that has the best possible biocompatibility. The presence of so many kinds of covering layers indicates that this aim has not been reached until now. The implant anchorage in the bone is very important for the stability of the element that has to support much pressure when under use. As it is known, the implant/bone interface does not present the ideal result expected by all professionals. In the laboratory there are possibilities of researching many kinds of implants--under different techniques of insertion. This will lead to the best methods and materials available. Titanium is the basic material used by many authors and needs no further discussion. So far it is the material with the best biocompatibility. The aim of this work is to observe and study the bone healing in the interface between a titanium implant and bone under light microscopic technique. Commercial pure titanium implants with a smooth surface were inserted in rabbit's tibias where they remained for eight weeks. The amount of bone inside the implant threads was quantified by the use of a stereologic method. The histological results indicated that an intense remodeling process of the cortical bone was found close to the implant surface and in the stereometry a higher amount of the new bone formation was also observed in the cortical tibia at the implant/bone interface.

Bone remodeling analysis after placement of dental implants using polyfluorochrome sequential labeling.

Nowadays there is a general consensus related to the stability of dental implants during bone repair. The implant anchorage in the bone is very important for the stability of the element that has to support much pressure when under use. This stability is attained by bone modeling and remodeling processes. As it is known, the implant/bone interface does not present the ideal result expected by every professional. The possibility of stimulation of the bone formation at the interface and around titanium implants is based on the reaction of the bone to trauma due to the surgical procedure. This bone reaction leads to bone repair during healing. The purpose of this study is to analyze the efficiency of bone tissue labeling through polyfluorochrome sequential labeling during remodeling or neo-formation processes after the placement of smooth threaded implants used in dentistry. This work demonstrates the possibility of periodic deposition of bone identification around titanium osseointegrated implants. It was concluded that the polyfluorochrome sequential labeling is an important tool to identify bone modeling and remodeling after the insertion of titanium implants inside rabbit's tibias at different periods of time.

Obtençäo de matriz mineral de osso bovino e a comprovaçäo de sua biocompatibilidade / A process to obtain bovine bone inorganic components and submitted to biocompatibility tests

A estrutura óssea bovina, tanto na condiçäo de tecido cortical como medular, viabiliza através de processo termo-químico a obtençäo de material mineral rico em cálcio e fósforo com características funcionais plenamente adequadas para a sua aplicaçäo como enxerto reabsorvível e condutor para reparaçöes de defeitos ósseos. A implantaçäo de cilindros deste material em tíbia de coelho com posterior análise histológica por microscopia de luz, eletrônica e fluorescência, comprovam a integraçäo biocompatível com a matriz óssea original e o estímulo condutor na neoformaçäo tecidual rico em atividade celular para a reparaçäo óssea do leito receptor

Avaliaçäo da ocorrência de canais acessórios na furca e no terço cervical radicular de molares humanos: estudo dos forames em microscópio eletrônico de varredura / Evaluation of the occurrence of accessory canals in the furcae and in the cervical third of human molars: a foramina study under scanning electron microscope

Foram examinados no presente trabalho forames acessórios nas furcas de 62 molares permanentes superiores e inferiores recém-extraídos, na superfície cervical radicular externa e no terço cervical do canal radicular, empregando a microscopia eletrônica de varredura. Constataram-se, no grupo I, 65,99 por cento de forames na furca e 87,77 por cento de forames na superfície radicular externa (Grupo II). No interior dos canais radiculares (Grupo III), na sua porçäo cervical, foram encontrados 66,66 por cento. Conclui-se que a freqüência de canais acessórios comunicando o periodonto cervical com a polpa do dente é de 2/3 em molares

Surface of interface epithelium-connective tissue of gingival mucosa of the calomys callosus: a scanning electron microscopic study

Las características del tejido conectivo epitelial interfásico de la mucosa gingival del Calomys callosus fue estudiada usando microscopía electrónica de barrido. Diez animales fueron fijados y perfundidos con solución modificada de Karnovsky. Las gingivas fueron cuidadosamente removidas y fijadas durante la noche a 4C. Los ejemplares se trataron con solución de NaOH, lavados en agua destilada, postfijados en una solución al 1 por ciento de OsO4 y deshidratados en una serie de etanol. Las muestras secas en un punto crítico, revestidas con iones de oro y examinadas en un microscopio de barrido Jeol JSM-5-300. Los resultados revelaron que la superficie de la mucosa gingival está cubierta por un epitelio estratificado escamoso queratinizado y el tejido conectivo epitelial interfásico presenta formaciones numerosas de papilas, que se muestran con un aspecto tridimensional. Hay papilas irregulares del tejido conectivo dispuestas en direcciones variables. Entre las papilas, se destacan depresiones que corresponden a las criptas epiteliales. En una gran ampliación, la superficie de cada papila muestra nudos gruesos de fibras colágenas

Histometric study of periodontal trauma in dental germs to be transplanted - scanning electron microscopy

Dental transplants are of great interest in modern dentistry. Research has been directed toward the study of different techniques and observations of the results. Scientific basis is also to be observed and the aim of this paper is to associate technical with scientific data. Dental germs in different stages of development were carefully removed from their alveolar cavities together with the dental sac. Trauma was observed in some areas resulting from the movements of extraction or of the removal of the dental sac by dissection. It should be noticed that by the trauma produced by removal of the dental sac is very uncommon, since the operation is performed at a mesoscopic level. The material showed that the periodontal collagen net is complex in form and the meshes are wider in the surface. Smaller meshes could be seen closer to the cementum surface. Measures could be taken in order to have a basis of the distribution of collagen material around the dental root in different levels. The results showed that extraction should be performed in a most conservative manner and the movements for extraction should be applied to the crown of the dental germ. The maintenance of the periodontal integrity is very important in order to preserve the vascular barrier created by the dental cementum