Effects of glass-ceramic produced by the sol-gel route in macrophages recruitment and polarization into bone tissue regeneration.

Effective bone substitute biomaterials remain an important challenge in patients with large bone defects. Glass ceramics produced by different synthesis routes may result in changes in the material physicochemical properties and consequently affect the success or failure of the bone healing response. To investigate the differences in the orchestration of the inflammatory and healing process in bone grafting and repair using different glass-ceramic routes production. Thirty male Wistar rats underwent surgical unilateral parietal defects filled with silicate glass-ceramic produced by distinct routes: BS - particulate glass-ceramic produced via the fusion/solidification route, and BG - particulate glass-ceramic produced via the sol-gel route. After 7, 14, and 21 days from biomaterial grafting, parietal bones were removed to be analyzed under H&E and Massons' Trichome staining, and immunohistochemistry for CD206, iNOS, and TGF-ß. Our findings demonstrated that the density of lymphocytes and plasma cells was significantly higher in the BS group at 45, and 7 days compared to the BG group, respectively. Furthermore, a significant increase of foreign body giant cells (FBGCs) in the BG group at day 7, compared to BS was found, demonstrating early efficient recruitment of FBGCs against sol-gel-derived glass-ceramic particulate (BS group). According to macrophage profiles, CD206+ macrophages enhanced at the final periods of both groups, being significantly higher at 45 days of BS compared to the BG group. On the other hand, the density of transformation growth factor beta (TGF-ß) positive cells on 21 days were the highest in BG, and the lowest in the BS group, demonstrating a differential synergy among groups. Noteworthy, TGF-ß+ cells were significantly higher at 21 days of BG compared to the BS group. Glass-ceramic biomaterials can act differently in the biological process of bone remodeling due to their route production, being the sol-gel route more efficient to activate M2 macrophages and specific FBGCs compared to the traditional route. Altogether, these features lead to a better understanding of the effectiveness of inflammatory response for biomaterial degradation and provide new insights for further preclinical and clinical studies involved in bone healing.

Geometria das roscas dos implantes:revisão de literatura / Geometry of implant threads: a review of the literature

Os aspectos biomecânicos de um implante são fundamentalmente diferentes daqueles de um dente natural, circundado por ligamento periodontal. Esse mecanismo de transferência de forças por meio do implante para os tecidos circundantes é um determinante claramente importante no desenvolvimento da interface osso-implante e na longevidade deste. Portanto, é essencial conhecer os fatores relacionados à geometria do implante que influenciam a distribuição do estresse, para determinar o ótimo desenho do implante que minimizará as tensões. O objetivo deste trabalho foi o de realizar uma revisão de literatura para conhecer os diferentes tipos de roscas e sua influência na transmissão das tensões aos tecidos circundantes. Para isso, foi realizada uma busca em 2 bases de dados: MEDLINE e Biblioteca Cochrane desde 1977 a 2008. Os critérios de inclusão e exclusão foram: artigos clínicos, laboratoriais e de revisão que estudavam ou comparavam a geometria das roscas dos implantes. Foram localizados 156 artigos, sendo seleccionados 31. Conclui-se que o formato das roscas deve objetivar maximizar a força e estabilidade interfacial assim como a transferência de cargas para o osso de forma mais bem distribuída, melhorando, assim, o prognóstico do implante em longo prazo.

The biomechanical aspects of an implant are fundamentally different from those of a natural tooth, surrounded by a periodontal ligament. This mechanism of the transfer of forces by means of the implant to the surrounding tissues is a clearly important determinant in the development of the bone-implant interface and in longevity of the implant. It is therefore essential to know the factors relating to the geometry of the implant that influence the distribution of stress in order to determine an implant design that will minimize the stress. The purpose of this study was to undertake a review of the literature in order to become acquainted with the different types of implant threads and their influence on the transmission of stress to the surrounding structures. To this end two data bases were consulted: MEDLINE and the Cochrane Library from 1977 to 2008. The inclusion and exclusion criteria were as follows: clinical, laboratory and review articles that examined or compared the geometry of implant threads. Of the 156 articles found, 31 were selected. It was concluded that thread format should maximize strength and interfacial stability, as well as load transfer to the bone in the best distributed manner, thereby improving the long-term prognosis of the implant.

Tratamentos de superfície nos implantes dentários / Surface treatments in dental implants

As modificações no desenho do corpo e na superfície do implante têm sido sugeridas para aumentar o sucesso em ossos menos densos por meio do hipotético ganho de uma melhor ancoragem e uma maior área de superfície para a distribuição das cargas oclusais. O presente estudo revisa e discute as diferentes superfícies de implante citadas na literatura assim como seus efeitos na qualidade da osseointegração, na biomecânica da distribuição de forças e no sucesso em longo prazo. Foram utilizadas as seguintes bases de dados: MEDLINE, BIREME, Biblioteca Cochrane, BBO e LILACS, nos últimos 27 anos. Os critérios de inclusão e exclusão foram: artigos clínicos, laboratoriais e de revisão com metodologia adequada que estudavam ou comparavam tratamentos de superfícies dos implantes osseointegráveis disponíveis no mercado. De um total de 267 artigos, foram selecionados 36. A literatura demonstra que os implantes com superfície rugosa apresentam uma maior área de contato osso-implante e melhores características biomecânicas. Os implantes mais utilizados nas pesquisas de análise de superfície foram os de titânio comercialmente puro. Os tipos de superfície mais estudados na literatura foram a usinada, seguida da SPT e da com cobertura com hidroxiapatita. Os testes mais utilizados foram análise histométrica e de torque reverso.

Changes in the design of the body and on the surface of the implant have been suggested to increase the success rate in less dense bones, through the hypothetical gain of a better anchorage and greater surface area for the distribution of occlusal loads. This study reviews and discusses the different dental implant surfaces cited in the literature, as well as their effects on the quality of osseointegration, on the biomechanics of load distribution and on success in the long term. The following databases were used: MEDLINE, BIREME, Cochrane Library, LILACS and BBO in the last 27 years. The criteria for inclusion and exclusion were: clinical, laboratory and review articles with appropriate methodology that studied and compared the surfaces of the implants available on the market. From a total of 267 articles, 36 were selected. The literature shows that the implants with a rough surface have a larger contact area and better bone-implant contact, as well as better biomechanical characteristics. The most frequently used implants in the surface analysis studies were commercially pure titanium. The types of surface treatment most studied in the literature were the machined, followed by TPS and coverage with hydroxyapatite. The most commonly used tests were histometric analysis and reverse torque analysis.