Estudo histomorfométrico do processo de cicatrização óssea em defeitos cirúrgicos de camanho crítico em calvárias de ratos preenchidos com polímero de mamona

Objectives: The aim of this study was to evaluate the behavior of the polymer histomorphometrically castor during the healing process of defects of critical size calvarial preparations in rats. Materials and Methods: Twenty animals underwent a surgical procedure that was to be held in the calvaria of each animal a critical defect of 8 mm in diameter with a drill trephine. The rats were divided into two groups according to the following procedures: group C received no treatment and the bone defect site was filled with blood clot, group M, the bone defect was filled with castor oil polymer particles. The animals were sacrificed 180 days after the surgical procedures. After routine laboratory procedures the specimens were subjected to analysis histomorphometric. Results: In groups C the newly formed bone tissue was well developed, with adjacent areas of osteoid matrix rich in osteoblasts, and restricted to the vicinity of the edges of the defect. In animals of group M was observed newly formed lamellar bone tissue restricted to the vicinity of the defect edges and particles of polymer Castor distributed throughout the defect. There was a higher percentage of newly formed bone area was statistically significant in group C compared to animals in group M. Conclusions: Within the limits of this study can conclude that the castor oil polymer is biocompatible and had kept the area during the healing of critical size defects in surgically prepared rat calvariae.

Estudo histomorfométrico do processo de cicatrização óssea em defeitos cirúrgicos de tamanho crítico em calvárias de ratos preenchidos com polímero de mamona

Objectives: The aim of this study was to evaluate the behavior of the polymer histomorphometrically castor during the healing process of defects of critical size calvarial preparations in rats. Materials and Methods: Twenty animals underwent a surgical procedure that was to be held in the calvaria of each animal a critical defect of 8 mm in diameter with a drill trephine. The rats were divided into two groups according to the following procedures: group C received no treatment and the bone defect site was filled with blood clot, group M, the bone defect was filled with castor oil polymer particles. The animals were sacrificed 180 days after the surgical procedures. After routine laboratory procedures the specimens were subjected to analysis histomorphometric. Results: In groups C the newly formed bone tissue was well developed, with adjacent areas of osteoid matrix rich in osteoblasts, and restricted to the vicinity of the edges of the defect. In animals of group M was observed newly formed lamellar bone tissue restricted to the vicinity of the defect edges and particles of polymer Castor distributed throughout the defect. There was a higher percentage of newly formed bone area was statistically significant in group C compared to animals in group M. Conclusions: Within the limits of this study can conclude that the castor oil polymer is biocompatible and had kept the area during the healing of critical size defects in surgically prepared rat calvariae

Regeneração óssea guiada com o uso de matriz óssea bovina desmineralizada em defeitos ósseos experimentais em cães

Background: The principles of tissue regeneration to repair alveolar bone defects are based on the fabrication of a biologic barrier with different biomaterials. Therefore, the present study aimed to investigate the guided bone regeneration (GBR) by using membrane of demineralized bovine bone matrix (DBBM) on experimental defects in tibia of dogs. Methods: Four dogs were used and after anesthesia, shaving and antisepsis, two standardized bone defects were created on the right tibia of each animal with trephine drill. In the Control Group, the defects were filled with blood coagulum, while in the Treated Group, a membrane of DBBM was used to cover the defects. After 90 days, animals were sacrificed. Results: In the Treated Group, 67.4% of new bone formation was observed and, in the Control Group, 32.6% of the bone tissue reabsorbed when compared with initial bone volume. The membrane remained intact and no inflammatory tissue was observed on membrane/ bone interface. Conclusion: It was concluded that the use of DBBM is an osteoconductive material, presents biocompatibility and may be promise option to repair bone defects.

Implantes curtos do tipo cone-Morse: proporção coroa-implante

The purpose of this study was to analyze the biomechanical interactions in bone tissue between short implants and implant-supported crowns with different heights. Two models were made using the programs InVesalius 3.0, Rhinoceros 4.0 and Solidworks 2010. The models were established from a bone block with the short implant (3.75 x 8.5 mm) with geometry Morse taper connection (MT). The height of the crown (cemented) was set at 10.0 mm and 15.00 mm. The models were processed by programs and 10 NEiNastran Femap 10.0. The force applied was 200N (vertical) and 100N (oblique). The results were plotted on maps Voltage Maximum Principal. Statistical analysis was performed using ANOVA. The results showed that the increase in crown height, increased stress concentration in the crown of 15 mm under oblique loading (p <0.001), the oblique loading has significantly expanded the area of stress concentration (p <0.001). Conclusion:the increase of the crown increased the stress concentration, being statistically significant for short implants Morse taper. The mesial and distal region had the highest concentration of stresses under oblique loading. The oblique loading was more harmful when compared with axial loading, being statistically significant.

Reabilitação Oral: prótese livre de metal, Removível e implantes. Um caso de 12 anos de acompanhamento

The literature has suggested that the association of removable partial dentures with dental implants can improve the quality of life of patients. Thus, the purpose of this study was to present a case report. This case report describes the development of a removable partial denture associated with dental implants bilaterally been monitored for 12 years, and the efficacy of the proposed treatment. The radiographic controls demonstrated no changes on bone tissue. The maxillary arch was rehabilitated with metal-free crowns. The patient was fully satisfied with this technique providing stability, esthetics, and proper function. It was concluded that the technique of using removable partial dentures associated with dental implants is viable and show the advantages of improved function, aesthetics and cost reductions in rehabilitation treatment.

Influência do material oclusal na distribuição de tensões em próteses implantossuportadas unitárias

Objective: the aim of this study was to evaluate the influence of occlusal veneering material in single fixed implant-supported crowns through the 3-D finite element method. Material and methods: Four models were fabricated using the Rhinoceros 4.0, SolidWorks, and InVesalius softwares. Each model represented a block of mandibular bone with an external hexagon implant of 5 mm x 10 mm and different veneering materials including NiCr (1), porcelain (2), composite resin (3), and acrylic resin (4). An axial load of 200 N and an oblique load of 100 N were applied. Results: model (2) with porcelain veneering presented a lower stress concentration for the NiCr framework, followed by the composite resin and acrylic resin. The stress distribution to the implant and bone tissue was similar for all models. Conclusions: there is no difference of stress distribution to the implant and supporting structures by varying the veneering material of a single implant-supported prosthesis.

Influência do material oclusal na distribuição de tensões em próteses implantossuportadas unitárias

Objective: the aim of this study was to evaluate the influence of occlusal veneering material in single fixed implant-supported crowns through the 3-D finite element method. Material and methods: Four models were fabricated using the Rhinoceros 4.0, SolidWorks, and InVesalius softwares. Each model represented a block of mandibular bone with an external hexagon implant of 5 mm x 10 mm and different veneering materials including NiCr (1), porcelain (2), composite resin (3), and acrylic resin (4). An axial load of 200 N and an oblique load of 100 N were applied. Results: model (2) with porcelain veneering presented a lower stress concentration for the NiCr framework, followed by the composite resin and acrylic resin. The stress distribution to the implant and bone tissue was similar for all models. Conclusions: there is no difference of stress distribution to the implant and supporting structures by varying the veneering material of a single implant-supported prosthesis.

Wettability behavior of nanotubular TiO2 intended for biomedical applications

Nanotubes have been subject of studies with regard to their ability to promote differentiation of several cells lines. Nanotubes have been used to increase the roughness of the implant surfaces and to improve bone tissue integration on dental implant. In this study TiO2 nanotube layer prepared by anodic oxidation was evaluated. Nanotube formation was carried out using Glycerol-H2O DI(50-50 v/v)+NH4F(0,5 a 1,5% and 10-30V) for 1-3 hours at 37ºC. After nanostructure formation the topography of surface was observed using field-emission-scanning-microscope (FE-SEM). Contact angle was evaluated on the anodized and non-anodized surfaces using a water contact angle goniometer in sessile drop mode with 5 μL drops. In the case of nanotube formation and no treatment surface were presented 39,1° and 75,9°, respectively. The contact angle describing the wettability of the surface is enhanced, more hydrophilic, on the nanotube surfaces, which can be advantageous for enhancing protein adsorption and cell adhesion.

Efeito do ácido tranexâmico associado à cola de fibrina sobre o reparo ósseo: estudo histológico em ratos

The bone repair process is controlled by complex molecular mechanisms that involve systemic and local factors. Fibrin glue is derived from human plasma and mimics the final pathway of coagulation network. Tranexamic acid inhibits fibrinolysis and prevents or decreases the formation of degradation products of fibrin and fibrinogen. The purpose of this study was to evaluate histologically in rats the effect of tranexamic acid associated with the fibrin glue on bone healing. The experiment used 60 (n = 5) male rats in: GI: Control, GII: fibrin glue, GIII tranexamic acid and GIV /fibrin glue/tranexamic acid. Bone defect (2.5mm diameter) was created in right tibia. The animals were euthanized at 7,14 and 30 days postoperatively, and the pieces were processed with hematoxylin and eosin. The results showed at 7 days post-operative surgical cavity filled with dense connective tissue rich in fibroblasts, permeated by delicate neoformed bone trabeculae in percentage of 70-80% for GI, GII and GIII and GIV to 94.8%. At 14 days post-operative newly formed bone was found between 75-85% for GI, GII and GIII and percentage above 95% for GIV. At 30 days postoperative GI and GIV showed 95-100% of mature bone tissue; GII and GIII in percentage close to 80-90%. Based on the results and methodology is concluded that fibrin / tranexamic acid glue association has positive action on bone repair.

Tratamento de superfície de implantes dentários: SBF

Various surface treatments of dental implants have been developed in order to ensure anchorage to bone tissue, optimization of the determinants of electronic structure, crystallinity, composition and properties. Coating techniques have been proposed in order tocreate unionbiochemicalable to accelerate the early stages ofbone tissue, combining the positive properties of titanium and its alloys bioactivity of ceramic materials. This paper discusses protocol for handling the SBF coating of titanium alloys. The apatite phase nucleation occurs by immersing the substrate in synthetic solution simulating blood plasma (Simulated Body Fluid). The protocol allows manipulation of the SBF solution to establish guidelines regarding the usestreamlinedand organized to make practical application.

Avaliação da incorporação de enxerto osseo homogeno fresco congelado em humanos: análise histologica e imuno-histoquímica

Allogeneic, fresh-frozen bone has been used in order to replace bone autografts. However, its osteoinduction and osteoconduction properties are not well-defined in the scientific literature. This work aimed to evaluate samples of homogenous bone grafts in humans by qualitative histological and immunohistochemical analysis. For this, ten pre-selected patients underwent surgical augmentation of bone defects. The homogenous fresh frozen block bone graft was stabilized and fixed by bicortical screws. After six months, the reopening procedure was performed for installation of osseointegrated implants. At this time surgical bone graft samples were removed by means of drill trephine. The samples were fixed in 10% formalin, processed with decalcified paraffin, and stained with hematoxylin and eosin. Immunohistochemistry was performed for the expression of Caspase 3 enzyme. The slides were brought to light microscopy for qualitative histology and immunohistochemistry. The results showed non-vital bone tissue, with few areas of deposition of new bone formation on the amorphous matrix, presence of chronic inflammatory infiltrate with areas of osteomyelitis, and expressive immunolabeling of Caspase 3. Given the methods employed and the results it was concluded that the allograft fresh-frozen block is not incorporated into the recipient bed after a healing period of six months.

Enxerto ósseo em odontologia: revisão de literatura

Bone is a specialized connective tissue, vascular and dynamic changes over the life of the organism. When injured, has a unique ability to regenerate and repair without the presence of scars, but in some situations due to the size of the defect, the bone tissue does not regenerate so completely, it is necessary to carry out bone grafting procedures. Considering there are various types of grafts and various donor sites. Thus, the aim of this study was to review the literature to some type of graft most commonly used in dentistry. Given the importance of bone reconstruction in oral and maxillofacial surgery, it is necessary to know the viability and influence of biomaterials, or not associated with autogenous grafts in bone repair. Even this, with many qualities, but further studies should be done to achieve each day, a synthetic material compatible with bone tissue lost in adequate amounts without requiring extra-oral surgeries that are considered to be devoted to higher morbidity.

Reabilitação de maxila atrófica com tecido ósseo homógeno e prótese fixa implantossuportada

The techniques of bone reconstruction for atrophic maxillae have been improved in order to promote bone tissue growth in both height and thickness. The grafts performed with use of autogenous bone is considered the gold standard by most researchers, for demonstrating osteogenic capacity and not to promote antigenic response. However, this type of grafting is not possible to get bone tissue in large quantity for extensive renovations. In recent years, alternatives have been researched to overcome the limitations of autogenous bone. Several alternatives have been investigated to supply the disadvantages of autogenous bone grafts. In such studies, allogeneic bone grafts which are obtained from individuals with different genetic load, but from the same species have been extensively used. They can be indicated in cases of arthrosplasty, surgical knee reconstruction, and large bone defects as well as in oral and maxillofacial reconstruction. Besides showing great applicability and biocompatibility, this type of bone is available in unlimited quantities. To rehabilitate atrophic maxillae an option that has been performed with high success rate is the reconstruction with bone graft followed by osseointegrated dental implants to rehabilitate the patient aesthetics and functionally. This paper aims to show the feasibility of allogenic bone as material for reconstruction of atrophic maxilla, and subsequent rehabilitation with metal ceramic fixed prosthesis implant and dental restoration with accompanying three years through literature review and clinical case report.

Efeitos do desuso e da deficiência de estrógeno sobre a microarquitetura óssea e suas propriedades biomecânicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo comparativo de imunomarcações (OC, VEGF, TRAP) em humanos, nas cirurgia de levantamento do assoalho de seio maxilar utilizando osso autógeno e heterógeno

Pós-graduação em Odontologia - FOA