Bruno König Júnior

A study of different calcification areas in newly formed bone 8 weeks after insertion of dental implants in rabbit tibias

In orofacial implantology there are many types of implants for the different systems. Among these is the implant surface type, e.g., a screw type, cylindrical and laminar. Furthermore, the implants are different in their dimensions, their metal composition, their surface condition, such as smooth, grit or layered surfaces and in their methods of application. Two different self-tapping implants, one smooth and the other grit-blasted, are screwed into the bone, and another one with a plasma of titanium coating, which is also in a screw form but with greater spaces between the screw threads are compared. The greatest amount of bone deposition in the bone/implant interface was encountered in the latter one, the smooth surfaced implant being in second place. All of these systems can alter the implant healing process and to demonstrate this, we injected bone markers in the rabbits over different periods of time so as to observe the different areas of bone deposition in the tibias where the implants had been inserted. The bone tracers used were Alizarin, Calcein and Xylenol-orange. The amount of deposition was calculated by using the method of surface morphometry.

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 rabbits 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.

Summary 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 rabbits tibias at different periods of time.

Three-dimensional angioarchitecture of tongue corrosion casts from normal young rats

The three-dimensional architecture of the vascular network of the rats 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.

Scanning electron microscopy study of the interface epithelium-connective tissue surface of the lingual mucosa in Calomys callosus

The characteristics of the interface epithelium-connective tissue of the lingual mucosa of Calomys callosus was studied by employing scanning electron microscopy after removal of the epithelial cells. In the anterior part, the connective tissue papillae of filiform papillae are distributed at random in their original configuration, and the round-shaped fungiform papillae are scattered among the filiform papillae. In the middle part, the filiform papillae present several rod-shaped projections. In the posterior part, the vallate papilla are oval in shape, and the connective tissue reveals a large ridge separated by deep lateral grooves. The posterior adjacent area is a flat surface and shows several openings of salivary gland ducts. The foliate papillae are formed by several small ridges separated by grooves. In the areas adjacent to the foliate papilla, small pointed and laminar papillae were observed.

Biocompatibility of the polyurethane resin of the castor bean inserted into the alveolar bone of the dog

The biocompability of the polyurethane resin of the castor bean (Ricinus vulgaris) was studied following its insertion into the alveolar bone of dogs, after extraction of their premolar teeth. The resin was left to polymerise in the dental alveolus. Excess of material due to polymerisation was removed and polishing was employed to smooth and adapt the occlusal surface to the margins of the alveolar bone. This allowed a perfect suture of the mucosa together with the periosteum. The resin remained in the dental alveolus for 90 days. It was observed that the polyurethane was replaced by osteoid and bone tissues and no immune or inflammatory reactions were detected. There has been work on and discussion about the use of the polyurethane in grafts, prostheses and orthoses. Attention was paid to all the surgical steps, in particular the preservation of the periosteal integrity. Further research is being followed in our Department in order to test the biocompatibility of the material presented in this paper when used together with metallic or ceramic implants.

Corrosion casts of young rabbit palatine mucosa angioarchitecture.

The microvascular system arrangement of the palatine mucosa in young rabbits was studied using vascular corrosion casts. Specimens were obtained by injecting low viscosity resin. Superficial microvessels were observed mainly by scanning electron microscopy (SEM). The blood microvessels showed differing features in the areas considered palatine rugae, inter-rugal areas and posterior region of the palatine raphe. Larger vessels were noted in deeper layers. Several capillary loops were distributed all over the palatine rugal surface. In spite of being a young animal, the rabbits palatine mucosa demonstrated a complex angioarchitecture.

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.

ANGIOARCHITECTURAL ARRANGEMENTS IN CORROSION CAST OF THE NASAL SEPTUM OF THE MONGOLIAN GERBIL

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.

Ultrastructure of the parotid and submandibular glands of the Old World Marten (Carnivora; Mustelidae).

The morphology of the parotid and submandibular glands in the marten, a carnivore, were studied and analyzed under a transmission electron microscope. The nature of the granules in both glands, as well as in the acini and in the secretory tubules, is rather mucous. The structure of the secretory tubules is very characteristic, especially the striated ones. The myoepithelial cells are close to the acini and tubules and covered by the basement membrane separating them from the connective tissue, which enhances its epithelial origin. The cytoplasm of the basal parts of the acinar and tubular cells is abundant and separates the nucleus from the secretion granules. Although the morphology of the salivary glands of many carnivores is known, those of the parotid gland of the marten present peculiar characteristics, since they produce a rather mucous saliva and the granules, when forming, are far from the base as well as from the apex of the secretory cells. The submandibular gland contains granules of different densities, an aspect that in general resembles that of other animals.