Placas em ponte para tratamento de falhas segmentadas em mandíbulas de cães: projetos e desenvolvimento

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Densitometria óssea em mandíbula de suínos submetidos a enxerto ósseo autógeno, homógeno e heterógeno

Pós-graduação em Odontologia - FOA

Membrana reabsorvível com enxerto ósseo autógeno ou BoneCeramic em rebordos atróficos em implante de titânio: estudo histométrico em cães

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cicatrização de enxertos de osso alógeno fresco congelado (OAFC) associados ou não ao plasma rico em plaquetas (PRP): estudo histológico e histométrico em mandíbulas de cães

Pós-graduação em Odontologia - FOA

Aspecto radiológico e macroscópico de matriz óssea mineralizada heteróloga fragmentada e polimetilmetacrilato autoclavados em falha óssea de tíbia de coelho

A segmental defect of 6mm diameter was performed in the medial metaphyseal region of the tibia of 12 rabbits. For the bone defect reconstruction there was implanted a combination of micro and macro fragments of heterologous fragmented cortical bone matrix preserved in glycerin (98%) and polymethylmethacrylate, both autoclaved. Radiological and macroscopic evaluation was performed at 30, 60, 90 and 120 days. Adhesion in relation to time of the micro and macro composites to the recipient bed was observed in 100% of the cases. This showed that this implant is biologically biocompatible, since it promoted bone defects repair, with no signs of infection, migration and/or rejection. In this way, this implant can be classified as one more option of substitute to fill large bone defects.

PLA/PGA copolymer as a bone substitute in maxillary sinus augmentation: histological, histometric and immunohistochemistry study in rabbits

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Scaffolds de polihidroxibutirato construídos por prototipagem rápida funcionalizados com hidroxiapatita e peptídeo osteogênico

Com a evolução da engenharia tecidual novos materiais estão sendo estudados visando o tratamento de defeitos ósseos. O objetivo deste projeto foi preparar e caracterizar scaffolds a base de polihidroxibutirato (PHB), apatita e peptídeo osteogênico, osteogenic growth peptide (OGP), para aplicação em reparação óssea. Além disso, avaliar a liberação prolongada do peptídeo incorporado aos scaffolds na forma livre ou incorporado a lipossomas. Os scaffolds de PHB foram confeccionados por prototipagem rápida (PR) empregando a tecnologia Selective Laser Sintering (SLS). Posteriormente, a apatita foi incorporada in situ por meio de ciclos alternados de imersão em soluções de CaCl2 e Na2HPO4, respectivamente. Neste estudo foram selecionadas 2 marcações para o OGP, uma com 5,6-carboxifluoresceína (CF) e outra com triptofano (W), para análise de liberação prolongada. Os peptídeos foram incorporados ao sistema de liberação no momento de seu preparo. A caracterização por espalhamento de luz dos sistemas de liberação desenvolvidos mostrou que os peptídeos marcados com CF foram os melhores desenvolvidos. Portanto estes peptídeos foram adsorvidos nos scaffolds de PHB-CaP. Estudos in vitro foram realizados para avaliar o perfil de liberação do peptídeo OGP-CF do sistema de liberação controlada. A incorporação da apatita às matrizes de PHB foi confirmada por análises de microscopia eletrônica de varredura/ espectroscopia de energia dispersiva (MEV/EDS), espectroscopia na região do infravermelho (FTIR), absorção atômica, a difratometria de raios-X (DRX). Estas análises sugeriram que a principal fase precipitada foi -TCP. O sistema de liberação lipossoma/OGP-CF foi caracterizado pelas análises de dicroísmo circular e espalhamento de luz, que confirmaram a presença do peptídeo nas amostras. Após a análise da liberação, observou-se que o sistema PHB-CaP/OGP-CF obteve ...

Caracterização radiográfica ex vivo de biomateriais utilizados para regeneração óssea em mandíbulas de porcos

Introduction: The radiographic characteristics of a biomaterial, such as its density, may influence the evaluation of the results obtained following its clinical use. Objective: The aim of this study was to evaluate the radiographic density of biomaterials used as bone substitutes, inserted into dental sockets and bone defects in created in the jaws of pigs. The influence of a soft tissue simulator on the results was also evaluated. Material and method: Two and three-millimeter-deep bone defects were created in the pigs mandible and the right first molar extraction socket were used. Commercial samples of five biomaterials were tested: Hydroxyapatite, Lyophilized Bovine Bone, 45S5 bioglass (generic), PerioGlass and β-Tri-Calcium Phosphate, and compared to a positive (mandibular bone) and negative (empty alveolar bone defects) controls. Radiographic images were acquired with and without a 10 mm thick soft-tissue simulator. Result: The results for the extraction sockets showed no differences between the biomaterials and the negative control. For the bone defects, the depth of the defect density influenced the density, both in the negative control (p < 0.01) and biomaterials (p < 0.05) groups. The soft- tissue simulator did not alter the results. Conclusion: The type of the evaluated defect can interfere in the radiographic features presented by each biomaterial, while the simulation of soft tissues was not statistically significant.

Reabilitação total da maxila com enxerto intraoral: relato de caso

The early tooth loss and periodontal disease often leave inadequate bone volume for installation of osseointegrated implants. The autogenous bone graft is considered the gold standard for reconstruction of residual bone defects. Some surgical techniques can be performed, including extra or intraoral donor sites depending on the degree of bone loss, depending on surgical-prosthetic planning and general condition of the patient. The intraoral bone grafts offer a safe option to rebuilt bone volume in smaller rehabilitations, with low morbidity and minimal postoperative discomfort. Among the possible donor sites, the mandibular ramus and body, which offer predominantly cortical bone, and the chin area, which offers corticomedullary bone tissue, can be harvested. The graft will be suitable both in quantity and quality, preserving the capacity of osteogenesis, osteoinduction and osteoconduction, which differentiate autogenous grafts from other biomaterials. The aim of this study was to report a clinical case in which the mandibular ramus graft was used for total reconstruction of an edentulous maxilla, showing that even large areas can be reconstructed with grafts from intraoral origin. All the steps that allowed the complete reconstruction of the maxilla done by an intraoral donor area are listed in the text, culminating in an extremely satisfactory clinical result.

O uso do beta-tricálcio fosfato como substituto ósseo em odontologia

The correction of bone defects is the restoration of lost structures which can be replaced by alloplastic implants or bone grafts. Due to the known disadvantages of removal of autogenous grafts, most researches in dentistry aim to develop alloplastic or non-alloplastic materials able to replace bone without these limitations. Beta-Tricalcium Phosphate (β-TCP) is a synthetic granular bone substitute, biocompatible, osteoconductive, which can be used in the alveolar reconstruction. In this work, we perform a literature review on the β-TCP characteristics and discuss its application in dentistry.

Avaliação do efeito osteoindutivo do PDGF-BB associado a diferentes carreadores na regeneração óssea em cavidades cirurgicamente criadas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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.

Osseointegração de implantes instalados sem estabilidade primária: o papel dos materiais à base de fibrina e fosfato de cálcio

When implants are installed immediately after tooth extraction may occur anchoring primary decreased, delay or failure of osseointegration process. This occurs because of the large interface between the surrounding walls of the socket and the surface of the implant. For reconstruction, replacement or filling of bone defects the solution can be obtained with the use of autogenous, heterogenous or allogeneic bone grafts. However, these grafts suffer certain drawbacks, particularly a high rate of donor site morbidity, limited amounts of available bone, and the additional operative time required for harvest. For these reasons, intensive efforts have been directed toward developing alternative substances for to either augment or substitute. In this paper, we will examine some of the commonly used materials : fibrin and calcium phosphate.

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.

Estudo comparativo do desempenho de diferentes membranas oclusivas de Látex Natural no reparo ósseo

Introduction: In dentistry, alveolar bone resorption is a limiting factor in the well being of individuals directly interfering in the stomatognathic system, causing problems in the context of overall health. Aiming to promote biological methods that can stimulate bone regeneration, several biomimetic strategies have been developed by the use of diverse materials possible to the bone matrix, culminating in the development of techniques that promote such repair. Objective: This work is a comparative study of the performance of films made with latex as occlusive membrane for Guided Bone Regeneration (GBR) procedure in three preparations: Latex preserved in ammonia, produced by Latex rubber clones IAN873 and PR255 polymerized immediately after collection and without use ammonia as a preservative. Methods: Sixty Wistar rats were randomly divided into 4 groups of 15 animals in which bone defects of critical size (8mm diameter) were made surgically in the skull. Group A was treated by GBR through the membrane latex preserved with ammonia, Group B received the membrane made of latex from IAN873, Group C, the membrane clone PR255 and group D was not treated by GBR. After a period of 7, 15 and 50 days, 5 animals from each group were euthanized, and specimens containing bone defect collected for microscopic examination (descriptive histology and histomorphometry). Results: The results showed that after 50 days there was bone formation in higher proportions in group D (p <0.05, ANOVA followed by Tukey), suggesting that further experiments should be conducted to conclude about the presence of ammonia and the influence of kind of rubber. Conclusion: GOR is a procedure proven effective in the treatment of bone defects. Therefore, further experiments should be conducted to reach a conclusion regarding the presence of ammonia in the latex composition for the manufacture of membranes, as well as the difference induced by the species of rubber.