Biomateriais a base de quitosana na correção de defeitos ósseos críticos criados em calvaria de ratos: avaliação radiográfica

OBJETIVO: Este estudo avaliou através de imagens radiográficas digitais, a ação de biomateriais de quitosana e de cloridrato de quitosana, com baixo e alto peso molecular, utilizados na correção de defeitos ósseos de tamanho crítico (DOTC)em calvária de ratos. MATERIAL E MÉTODO: DOTCs com 8 mm de diâmetro foram criados cirurgicamente na calvária de 50 ratos Holtzman. Em 10 animais o defeito foi preenchido foram preenchidos com coágulo sanguíneo (controle negativo). Os 40 animais restantes foram divididos de acordo com o biomaterial utilizado no preenchimento do defeito (quitosana de baixo peso e de alto peso molecular, e cloridrato de quitosana de baixo e de alto peso molecular), e foram avaliados em dois períodos experimentais (15 e 60 dias), totalizando 5 animais/biomaterial/período de avaliação. RESULTADO: A avaliação radiográfica foi feita utilizando duas radiografias digitais do crânio do animal: uma tomada logo após o defeito ósseo ser criado e a outra no momento do sacrifício. Nessas imagens, foi avaliada a densidade óssea radiográfica inicial e a final na área do defeito, que foram comparadas. As análises na densidade óssea radiográfica indicaram aumento da densidade óssea radiográfica dos DOTCs tratados para todos os biomateriais testados, em ambos os períodos. Resultados semelhantes foram encontrados no grupo controle. CONCLUSÃO: Conclui-se que os biomateriais de quitosana testados não foram capazes de aumentar a densidade radiográfica em DOTC realizados em calvária de ratos

GUIAS EMPILHÁVEIS (STACKABLE GUIDES) PARA REABILITAÇÃO DE ARCOS TOTAIS EM UM FLUXO DIGITAL: RELATO DE CASO CLÍNICO

The objective of this article is to describe a digital flow developed to test the use of software from the company Nemotec (Madrid, Spain) for the rehabilitation of a case of total maxillary and partial mandibular edentulism with a high degree of complexity, resulting in implant-supported prostheses milled in PMMA, installed at immediate load. The planning, guided installation of the implants and transsurgical adaptation of the prosthesis prototype were tested, using stackable guides. The previous prosthetic preparation consisted of the manufacture of a device made of dense silicone, based on condensation, which established the correct lip recomposition, the relationship of tooth length with the upper lip at rest and in the smile, the vertical dimension of occlusion and the recording of the position of the centric occlusion relationship. The previous design of the prostheses was used to check the design and thus the final CAD was obtained, allowing the milling of the temporary prostheses in polymethylmethacrylate, with immediate loading protocol. The analysis of the obtained result allowed us to observe that the technique is predictable, since the use of stackable guides facilitated the stages of treatment, considerably reducing the surgical time and also the time for installation of the prostheses. Based on the clinical case performed, it is possible to conclude that the digital workflow was effective for the double rehabilitation of the patient's total arches.El objetivo de este artículo es describir un flujo digital desarrollado para probar el uso de software de la empresa Nemotec (Madrid, España) para la rehabilitación de un caso de edentulismo mandibular total maxilar y parcial con un alto grado de complejidad, dando lugar a prótesis implantosoportadas fresadas en PMMA, instaladas a carga inmediata. Se probó la planificación, instalación guiada de los implantes y adaptación transquirúrgica del prototipo de prótesis, utilizando guías apilables. La preparación protésica anterior consistió en la fabricación de un dispositivo hecho de silicona densa, basada en condensación, que estableció la correcta recomposición del labio, la relación de la longitud del diente con el labio superior en reposo y en la sonrisa, la dimensión vertical de la oclusión y el registro de la posición de la relación de oclusión céntrica. Se utilizó el diseño previo de las prótesis para comprobar el diseño y así se obtuvo el CAD final, permitiendo el fresado de las prótesis temporales en polimetilmetacrilato, con protocolo de carga inmediata. El análisis del resultado obtenido nos permitió observar que la técnica es predecible, ya que el uso de guías apilables facilitó las etapas de tratamiento, reduciendo considerablemente el tiempo quirúrgico y también el tiempo de instalación de las prótesis. Con base en el caso clínico realizado, es posible concluir que el flujo de trabajo digital fue efectivo para la doble rehabilitación de los arcos totales del paciente.O objetivo do presente artigo é descrever um fluxo digital desenvolvido para testar o uso de softwares da empresa Nemotec (Madrid, Espanha) para a reabilitação de um caso de edentulismo total maxilar e parcial mandibular com alto grau de complexidade, resultando em próteses implantossuportadas fresadas em PMMA, instaladas em carga imediata. Foi testado o planejamento, instalação guiada dos implantes e adaptação transcirúrgica do protótipo da prótese, utilizando guias empilháveis (stackable guides). O preparo protético prévio consistiu na fabricação de um dispositivo realizado em silicone denso, à base de condensação, que estabeleceu a correta recomposição labial, a relação do comprimento dentário com o lábio superior em repouso e no sorriso, a dimensão vertical de oclusão e o registro da posição de relação de oclusão cêntrica. O projeto prévio das próteses foi utilizado para conferir o desenho e assim o CAD final foi obtido, permitindo a fresagem das próteses provisórias em polimetilmetacrilato, com protocolo de carregamento imediato. A análise do resultado obtido permitiu observar que a técnica é previsível, uma vez que o emprego dos guias empilháveis facilitou as etapas do tratamento, diminuindo consideravelmente o tempo cirúrgico e também o tempo para instalação das próteses. Com base no caso clínico realizado, é possível concluir que o fluxo de trabalho digital foi efetivo para a reabilitação dupla de arcos totais do paciente.O objetivo do presente artigo é descrever um fluxo digital desenvolvido para testar o uso de softwares da empresa Nemotec (Madrid, Espanha) para a reabilitação de um caso de edentulismo total maxilar e parcial mandibular com alto grau de complexidade, resultando em próteses implantossuportadas fresadas em PMMA, instaladas em carga imediata. Foi testado o planejamento, instalação guiada dos implantes e adaptação transcirúrgica do protótipo da prótese, utilizando guias empilháveis (stackable guides). O preparo protético prévio consistiu na fabricação de um dispositivo realizado em silicone denso, à base de condensação, que estabeleceu a correta recomposição labial, a relação do comprimento dentário com o lábio superior em repouso e no sorriso, a dimensão vertical de oclusão e o registro da posição de relação de oclusão cêntrica. O projeto prévio das próteses foi utilizado para conferir o desenho e assim o CAD final foi obtido, permitindo a fresagem das próteses provisórias em polimetilmetacrilato, com protocolo de carregamento imediato. A análise do resultado obtido permitiu observar que a técnica é previsível, uma vez que o emprego dos guias empilháveis facilitou as etapas do tratamento, diminuindo consideravelmente o tempo cirúrgico e também o tempo para instalação das próteses. Com base no caso clínico realizado, é possível concluir que o fluxo de trabalho digital foi efetivo para a reabilitação dupla de arcos totais do paciente

Strong Electronic Identification: Survey & Scenario Planning

The deployment of more high-risk services such as online banking and government services on the Internet has meant that the need and demand for strong electronic identity is bigger today more than ever. Different stakeholders have different reasons for moving their services to the Internet, including cost savings, being closer to the customer or citizen, increasing volume and value of services among others. This means that traditional online identification schemes based on self-asserted identities are no longer sufficient to cope with the required level of assurance demanded by these services. Therefore, strong electronic identification methods that utilize identifiers rooted in real world identities must be provided to be used by customers and citizens alike on the Internet. This thesis focuses on studying state-of-the-art methods for providing reliable and mass market strong electronic identity in the world today. It looks at concrete real-world examples that enable real world identities to be transferred and used in the virtual world of the Internet. The thesis identifies crucial factors that determine what constitutes a strong electronic identity solution and through these factors evaluates and compares the example solutions surveyed in the thesis. As the Internet become more pervasive in our lives; mobile devices are becoming the primary devices for communication and accessing Internet services. This has thus, raised the question of what sort of strong electronic identity solutions could be implemented and how such solutions could adapt to the future. To help to understand the possible alternate futures, a scenario planning and analysis method was used to develop a series of scenarios from underlying key economic, political, technological and social trends and uncertainties. The resulting three future scenarios indicate how the future of strong electronic identity will shape up with the aim of helping stakeholders contemplate the future and develop policies and strategies to better position themselves for the future

Comparação entre enxerto ósseo autógeno e rhMP-2 (infuse Bone Graft) na reconstrução de maxila atrófica anterior

The objective of this study was to compare bone augmentation in the anterior maxilla following implantation of rhBMP2/ACS vs. autogenous bone graft. In this study, 24 patients were selected and equally randomized into 2 groups: Group 1 - rhBMP2/ACS or Group 2 - intraoral particulated autogenous bone graft. A titanium mesh was used for space provision in both Groups. Average clinical bone gain, histological/histomorphometrical (core biopsy obtained at 6 month), CBCT (preoperative, 3 and 6 months follow-up) and real time PCR (new bone scraped at 6 months) were used as evaluation methods. Clinical healing was generally uneventful. Mean clinical ridge width increased 3.2±0.9 vs. 3.7±2.1 mm (p=0.31) for Group 1 and Group 2, respectively. Group 1 yielded statistically significant CBCT bone gain only at subcrestal level compared with Group 2 (1.5±0.7 vs. 0.5±0.9mm; p=0.01). In the histological analysis, specimens from group 1 showed bone marrow significant richer in cells and capillaries (p=0.002) than Group 2, however no difference was found in other parameters. Real time PCR showed higher expression of genes BMP2 and Runx2 in Group 1 (p=0,001 e p=0,0021, respectively) and RANKL:OPG, BSP and OPN in Group 2 (p=0,01, p=0,005 and p=0,0009, respectively). A total of 62 implants were installed after 6 months. In conclusion, Group 1 supported clinically and tomographically relevant alveolar ridge augmentation of comparable magnitude to Group 2, presenting more favorable histological and gene expression results, suggesting an alternative for autogenous bone graft.O objetivo do estudo foi comparar o uso de rhBMP-2/ACS com o do enxerto ósseo autógeno para aumento ósseo em espessura na região anterior de maxila. 24 pacientes foram selecionados e divididos de forma randomizada em 2 grupos: Grupo 1 – rhBMP-2/ACS ou Grupo 2 – enxerto ósseo autógeno intraoral particulado. Uma malha de titânio foi utilizada para manutenção do arcabouço dos enxertos. O ganho ósseo clínico, a análise histológica/histomorfométrica (biópsia aos 6 meses), tomografias (pré-operatória, 3 e 6 meses) e PCR em tempo real (raspagem de osso neoformado obtida aos 6 meses) foram os métodos de avaliação. Clinicamente, o pós-operatório foi estável. O aumento ósseo médio em espessura clínica foi 3,2±0,9 vs. 3,7±2,1mm (p=0,31) para o Grupo 1 e Grupo 2, respectivamente. O Grupo 1 apresentou aumento ósseo tomográfico significante aos 2mm da crista óssea quando comparado ao Grupo 2 (1,5±0,7 vs. 0,5±0,9mm; p=0,01). Na análise histológica, o Grupo 1 apresentou uma medula óssea significativamente rica em células e vasos sanguíneos (p=0,002) quando comparado ao Grupo 2, entretanto, nenhuma diferença estatística foi encontrada para os outros parâmetros. PCR em tempo real resultou em maior expressão gênica de BMP2 e Runx2 (p=0,001 e p=0,0021, respectivamente) no Grupo 1 e RANKL:OPG, BSP e OPN no Grupo 2 (p=0,01, p=0,005 e p=0,0009, respectivamente). Um total de 62 implantes foram instalados aos 6 meses. Em conclusão, o Grupo 1 apresentou um aumento ósseo clínico e tomográfico comparável ao Grupo 2, apresentando um resultado histológico e de expressão gênica superior, sugerindo ser uma alternativa viável ao enxerto ósseo autógeno

Incisive Canal Deflation for Correct Implant Placement: Case Report

Aim: This article is a case report of a patient in whom the prosthetic planning indicated the necessity of an incisive canal deflation for the correct installation of all implant that is to be osseointegrated.Case Report. In the reopening phase after the bone graft installation, the incisive canal deflation (biopsy of its content) was done and titanium implants were installed with one of them invading the anatomical space occupied previously by the incisive canal. The biopsy analysis showed fragments of the incisive artery and nerve., which are responsible for the anterior upper-tooth pulp, the periodontium vascularization. and the innervation. Front the anastomosis present along with other structures allied with the absence of teeth in the region, there was no detriment to the patient caused by the deflation.Conclusion: Incisive canal deflation is a viable technique in implantology. It can permit ideal prosthetic planning with no detriment to the patient. (Implant Dent 2009;18:473-479

Chitosan-based biomaterials used in critical-size bone defects: radiographic study in rat's calvaria

OBJECTIVE: This study evaluated, using digital radiographic images, the action of chitosan and chitosan hydrochloride biomaterials, with both low and high molecular weight, used in the correction of critical-size bone defects (CSBD's) in rat's calvaria. MATERIAL AND METHOD: CSBD's with 8 mm in diameter were surgically created in the calvaria of 50 Holtzman rats and these were filled with a blood clot (Control), low molecular weight chitosan, high molecular weight chitosan, low molecular weight chitosan hydrochloride and high molecular weight chitosan hydrochloride, for a total of 10 animals, which were divided into two experimental periods (15 and 60 days), for each biomaterial. The radiographic evaluation was made using two digital radiographs of the animal's skull: one taken right after the bone defect was created and the other at the moment of the sacrifice, providing the initial and the final radiographic bone density in the area of the defect, which were compared. RESULT: Analysis of radiographic bone density indicated that the increase in the radiographic bone density of the CSBD's treated with the proposed biomaterials, in either molecular weight, in both observed periods, where similar to those found in control group. CONCLUSION: Tested chitosan-based biomaterials were not able to enhance the radiographic density in the CSBD's made in rat's calvaria

Histological Analysis And Gene Expression Profile Following Augmentation Of The Anterior Maxilla Using Rhbmp-2/acs Versus Autogenous Bone Graft

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The objective of this report was to present histological characteristics and gene expression profile of newly formed bone following horizontal augmentation of the atrophic anterior maxilla using recombinant human bone morphogenetic protein-2 in an absorbable collagen sponge carrier (rhBMP-2/ACS) versus an autogenous bone graft (ABG). Methods: Bone core biopsies from 24 subjects participating in a randomized clinical trial were obtained at dental implant placement, 6 months following alveolar ridge augmentation using rhBMP-2/ACS (rhBMP-2 at 1.5 mg/ml; total dose 4.2 mg) or a particulate ABG harvested from the mandibular retro-molar region. A titanium mesh was used to provide wound stability and space for bone formation. Analysis included histological/histometric observations and gene expression profile of the newly formed bone. Results: rhBMP-2/ACS yielded bone marrow rich in capillaries, undifferentiated cells and bone lining cells compared with the ABG (p = 0.002). Whereas no significant differences were observed in total bone fraction (p = 0.53), non-vital bone particles trapped in lamellar vital bone were observed in the ABG group (p < 0.001). Real-time PCR showed greater BMP-2 and RUNX2 expression for rhBMP-2/ACS over the ABG (p = 0.001 and 0.0021, respectively), while the ABG exhibited greater expression of RANKL: OPG, BSP and OPN over rhBMP-2/ACS (p = 0.01, 0.005 and 0.0009, respectively). Conclusions: Our observations suggest that formative biological processes explain bone formation following implantation of rhBMP-2/ACS, whereas remodelling, resorptive/formative processes, characterizes sites receiving ABGs.431212001207Sao Paulo Research Foundation (FAPESP), Sao Paulo, Brazil [2009/16016-8]CAPES, Brasilia, BrazilNobel Biocare, Zurich, SwitzerlandFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Horizontal ridge augmentation of the atrophic anterior maxilla using rhBMP-2/ACS or autogenous bone grafts: A proof-of-concept randomized clinical trial

Aim To compare the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge carrier (ACS) with autogenous bone graft for augmentation of the edentulous atrophic anterior maxilla. Methods Twenty-four subjects were enrolled in a randomized, controlled, parallel-group, open-label clinical trial. Subjects either received rhBMP-2/ACS (1.5 mg/ml) or particulated autogenous bone harvested from the mandibular retromolar region. A titanium-mesh was used to provide space and wound stability. A guide was used to standardize clinical recordings using an analogue caliper. Alveolar ridge width was also assessed using cone-beam computed tomography. Results rhBMP-2/ACS yielded significantly greater radiographic horizontal bone gain compared with autogenous bone graft at immediate subcrestal levels (1.5 ± 0.7 versus 0.5 ± 0.9 mm; p = 0.01); non-significant differences were observed at mid- (2.9 ± 0.8 versus 2.9 ± 0.9 mm; p = 0.98) and apical (1.7 ± 0.9 versus 1.8 ± 1.1 mm; p = 0.85) crestal levels. No significant differences in clinical horizontal bone gain were observed at 6 months between rhBMP-2/ACS and autogenous bone graft (3.2 ± 0.9 mm versus 3.7 ± 1.4 mm; p = 0.31). Sixty-two implants were placed after 6 month of healing with no significant differences between groups for number of implants, implant size, primary stability and survival. Conclusions rhBMP-2/ACS appears a realistic alternative for augmentation of the edentulous atrophic anterior maxilla. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd

Histological evaluation of chitosan-based biomaterials used for the correction of critical size defects in rat`s calvaria

Chitosan, a biopolymer obtained from chitin, and its derivates, such as chitosan hydrochloride, has been reported as wound healing accelerators and as possible bone substitutes for tissue engineering, and therefore these Substances could be relevant in dentistry and periodontology. The purpose of this investigation was to make a histological evaluation of chitosan and chitosan hydrochloride biomaterials (gels) used in the correction of critical size bone defects made in rat`s calvaria. Bone defects of 8 mm in diameter were surgically created in the calviria of 50 Holtzman (Rattus norvegicus) rats and filled with blood clot (control), low molecular weight chitosan, high molecular weight chitosan, low molecular weight chitosan hydrochloride, and high molecular weight chitosan hydrochloride, numbering 10 animals, divided into two experimental periods (15 and 60 days), for each biomaterial. The histological evaluation was made based on the morphology of the new-formed tissues in defect`s region, and the results indicated that there was no statistical difference between the groups when the new bone formation in the entire defect`s area were compared (p > 0.05) and, except in the control groups, assorted degrees of inflammation Could be Seen. In Conclusion, chitosan and chitosan hydrochloride biomaterials used in this study were not able to promote new bone formation in critical size defects made in rat`s calvaria. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res 93A: 107-114, 201