Análise tomográfica, histológica, histométrica e imunoistoquímica do beta tricálcio fosfato com osso autógeno em aumento do soalho de seio maxilar

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo comparativo do processo de reparo utilizando osso autógeno e beta-tricálcio fosfato em levantamento do assoalho do seio maxilar em humanos: análise tomográfica, histológica, histométrica e imunoistoquímica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Kinome profiling of osteoblasts on hydroxyapatite opens new avenues on biomaterial cell signaling

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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.

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)

Regeneração óssea guiada com o uso de membrana de copolímero PLA/PGA em levantamento da membrana do seio maxilar: estudo experimental com análises histomorfométrica e imunoistoquímica

Pós-graduação em Odontologia - FOA

Avaliação comparativa do potencial osteocondutor de quatro diferentes substitutos ósseos em defeitos críticos em calvárias de coelhos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação in vivo do efeitos do osso bovino desproteinizado revestido com estrôncio sobre o reparo ósseo

Pós-graduação em Ciências Odontológicas - FOAR

Avaliação in vivo do efeitos do osso bovino desproteinizado revestido com estrôncio sobre o reparo ósseo

Pós-graduação em Ciências Odontológicas - FOAR

Rehabilitative treatment of cleft lip and palate: experience of the Hospital for Rehabilitation of Craniofacial Anomalies - USP (HRAC-USP) - Part 3: Oral and Maxillofacial Surgery

This paper presents the treatment protocol of maxillofacial surgery in the rehabilitation process of cleft lip and palate patients adopted at HRAC-USP. Maxillofacial surgeons are responsible for the accomplishment of two main procedures, alveolar bone graft surgery and orthognathic surgery. The primary objective of alveolar bone graft is to provide bone tissue for the cleft site and then allow orthodontic movements for the establishment of an an adequate occlusion. When performed before the eruption of the maxillary permanent canine, it presents high rates of success. Orthognathic surgery aims at correcting maxillomandibular discrepancies, especially anteroposterior maxillary deficiencies, commonly observed in cleft lip and palate patients, for the achievement of a functional occlusion combined with a balanced face.

Biomimetica per l'ingegneria tissutale dell'osso

Reconstruction of bone is needed for high bone loss due to congenital deformities, trauma or neoplastic diseases. Commonly, orthopaedic surgical treatments are autologus or allogenic bone implant or prosthetic implant. A choice to the traditional approaches could be represented by tissue engineering that use cells (and/or their products) and innovative biomaterials to perform bone substitutes biologically active as an alternative to artificial devices. In the last years, there was a wide improvement in biology on stem cells potential research and in biomedical engineering through development of new biomaterials designed to resemble the physiological tissues. Tissue engineering strategies and smart materials aim together to stimulate in vivo bone regeneration. This approaches drive at restore not only structure integrity and/or function of the original tissue, but also to induce new tissue deposition in situ. An intelligent bone substitute is now designed like not only a scaffold but also as carrier of regeneration biomolecular signals. Biomimetics has helped to project new tissue engineered devices to simulate the physiological substrates architecture, such extracellular matrix (ECM), and molecular signals that drive the integration at the interface between pre-existing tissue and scaffold. Biomimetic strategies want to increase the material surface biological activity with physical modifications (topography) o chemical ones (adhesive peptides), to improve cell adhesion to material surface and possibly scaffold colonization. This study evaluated the effects of biomimetic modifications of surgical materials surface, as poly-caprolattone (PCL) and titanium on bone stem cells behaviour in a marrow experimental model in vitro. Two biomimetic strategies were analyzed; ione beam irradiation, that changes the surface roughness at the nanoscale, and surface functionalization with specific adhesive peptides or Self Assembled Monolayers (SAMs). These new concept could be a mean to improve the early (cell adhesion, spreading..) and late phases (osteoblast differentiation) of cell/substrate interactions.

Coating of surfaces of composite materials with enzymatically formed biosilica

Die Bildung kieselsäurehaltiger Spicula in marinen Schwämmen ist nur möglich durch die enzymatische Aktivität des Silicatein- in Verbindung mit der stöchiometrischen Selbstassemblierung des Enzyms mit anderen Schwammproteinen. Die vorliegende Arbeit basiert auf einem biomimetischen Ansatz mit dem Ziel, unterschiedliche Oberflächen für biotechnologische und biomedizinische Anwendungen mit Biosilica und Biotitania zu beschichten und zu funktionalisieren. Für biotechnologische Anwendungen ist dabei das Drucken von Cystein-getaggtem Silicatein auf Gold-Oberflächen von Bedeutung, denn es ermöglichte die Bildung definierter Biotitania-Strukturen (Anatas), welche als Photokatalysator den Abbau eines organischen Farbstoffs bewirkten. Des Weiteren zeigte sich die bio-inspirierte Modifikation von Tyrosin-Resten an rekombinantem Silicatein-(via Tyrosinase) als vielversprechendes Werkzeug zur Beschleunigung der Selbstassemblierung des Enzyms zu mesoskaligen Filamenten. Durch eine solche Modifikation konnte Silicatein auch auf der Oberfläche von anorganischen Partikeln immobilisiert werden, welches die Assemblierung von anorganisch-organischen Verbundwerkstoffen in wäßriger Umgebung förderte. Die resultierenden supramolekularen Strukturen könnten dabei in bio-inspirierten und biotechnologischen Anwendungen genutzt werden. Weiterhin wurde in der vorliegenden Arbeit die Sekundärstruktur von rekombinantem Silicatein- (Monomer und Oligomer) durch Raman Spektroskopie analysiert, nachdem das Protein gemäß einer neu etablierten Methode rückgefaltet worden war. Diese Spektraldaten zeigten insbesondere Änderungen der Proteinkonformation durch Solubilisierung und Oligomerisierung des Enzyms. Außerdem wurden die osteoinduzierenden und osteogenen Eigenschaften unterschiedlicher organischer Polymere, die herkömmlich als Knochenersatzmaterial genutzt werden, durch Oberflächenmodifikation mit Silicatein/Biosilica verbessert: Die bei der Kultivierung knochenbildender Zellen auf derart oberflächenbehandelten Materialien beobachtete verstärkte Biomineralisierung, Aktivierung der Alkalischen Phosphatase, und Ausbildung eines typischen zellulären Phänotyps verdeutlichen das Potential von Silicatein/Biosilica für der Herstellung neuartiger Implantat- und Knochenersatzmaterialien.

Wear particles and surface topographies are modulators of osteoclastogenesis in vitro

Prosthetic and osteosynthetic implants from metal alloys will be indispensable in orthopedic surgery, as long as tissue engineering and biodegradable bone substitutes do not lead to products that will be applied in clinical routine for the repair of bone, cartilage, and joint defects. Therefore, the elucidation of the interactions between the periprosthetic tissues and the implant remains of clinical relevance and several factors are known to affect the longevity of implants. Within this study, the effects of metal particles and surface topography on the recruitment of osteoclasts was investigated in vitro in a coculture of osteoblasts and bone marrow cells. The cells were grown in the presence of particles of different sizes and chemical composition or on metal discs with polished or sandblasted surfaces, respectively. At the end of the culture, newly formed osteoclasts were counted. Osteoclastogenesis was reduced when particles were added directly to the coculture. The effect depended on the size of the particles, small particles exerting stronger effects than larger ones. The chemical composition of the particles, however, did not affect the development of osteoclasts. In cocultures grown on sandblasted surfaces, osteoclasts developed at higher rates than they did in cultures on polished surfaces. The data demonstrate that wear particles and implant surfaces affect osteoclastogenesis and thus may be involved in the induction of local bone resorption and the formation of osteolytic lesions, leading eventually to the loosening of orthopedic implants.

Absorbable collagen membranes for periodontal regeneration: a systematic review

Guided tissue regeneration (GTR) with bioabsorbable collagen membranes (CM) is commonly used for the treatment of periodontal defects. The objective of this systematic review of randomized clinical trials was to assess the clinical efficacy of GTR procedures with CM, with or without bone substitutes, in periodontal infrabony defects compared with that of open flap debridement (OFD) alone. Primary outcomes were tooth loss and gain in clinical attachment level (CAL). Screening of records, data extraction, and risk-of-bias assessments were performed by two reviewers. Weighted mean differences were estimated by random effects meta-analysis. We included 21 reports on 17 trials. Risk of bias was generally high. No data were available for the primary outcome tooth loss. The summary treatment effect for change in CAL for GTR with CM compared with OFD was 1.58 mm (95% CI, 1.27 to 1.88). Despite large between-trial heterogeneity (I2 = 75%, p < .001), all trials favored GTR over OFD. No differences in treatment effects were detected between trials of GTR with CM alone and trials of GTR with CM in combination with bone substitutes (p for interaction, .31). GTR with CM, with or without substitutes, may result in improved clinical outcomes compared with those achieved with OFD alone. Our findings support GTR with CM for the treatment of infrabony periodontal defects.