Fluid-tight obturation of the root canal space is an important requirement for successful root canal treatment. Gutta percha, used as a core material in combination with different sealers, is the most commonly used root filling material and is considered the gold standard. However, it does not possess all the properties of the ideal obturation material. Mineral trioxide aggregate (MTA) is a cement material based on calcium silicates (CSC). It sets by hydration, provides excellent sealing ability, is biocompatible/bioactive and has performed successfully in different clinical applications. The use of MTA as an orthograde obturation material has been proposed. However, MTA is difficult to handle and very little is known about the most appropriate technique to ensure good compaction within the shaped root canal. This research aims to investigate the performance of MTA when used as an orthograde obturation material. The effect of different times of ultrasonic activation of unset material on the incidence of voids in root canals was investigated. Manual compaction of MTA using hand pluggers without ultrasonic activation resulted in minimal void formation. Ultrasonic activation resulted in significantly higher incidence of voids. The removal of the smear layer prior to obturation with MTA resulted in a significantly reduced push-out bond strength between the MTA and radicular dentine. The apical sealing ability of MTA orthograde filling was assessed in comparison with gutta percha and sealer using a dye leakage model. It was concluded that MTA provides a better apical seal against dye penetration over a 30-day observation period. The ability of MTA to reinforce the remaining root structure in comparison with gutta percha and sealer was investigated. MTA significantly increased the resistance to vertical root fracture after one month of storage in synthetic tissue fluid. The radiopacity of MTA together with new calcium silicate cements was assessed and it was concluded that MTA was more radiopaque than gutta percha but less radiopaque than AH-plus sealer. The use of MTA as an orthograde obturation material has shown some potential of enhanced clinical performance in comparison with gutta percha and sealer in terms of sealing ability and bioactivity. However, there are certain disadvantages for obturation with this category of materials in its present form. It is important to point out that MTA is still in its early stages of development. With further improvements to its physical properties, MTA can present a valuable option for obturation of the root canal space.

Os biomateriais podem ser definidos como substâncias de origem natural ou sintética que são tolerados de forma transitória ou permanente pelos diversos tecidos que constituem os órgãos dos seres vivos. Dentre esses biomateriais podemos citar o Agregado de Trióxido Mineral (ATM), que foi desenvolvido na Universidade de Loma Linda na década de 90. Desde então, não cessaram trabalhos de pesquisa envolvendo esse material e o Cimento Portland (CP); que embora não seja um material de uso odontológico direto, pode-se afirmar que possui basicamente os mesmos componentes químicos do ATM. O objetivo da presente pesquisa foi avaliar a biocompatibilidade do cimento Portland comum (CP-I) e do cimento Portland branco (CPB) não estrutural, incluídos na calvária de ratos. Foram selecionados vinte ratos, dois foram previamente utilizados como grupo piloto; os dezoito restantes foram distribuídos em três grupos de seis ratos que avaliados nos tempos experimentais de 30, 60, 90 dias foram mortos para análise histopatológica. Cada animal recebeu um implante, sendo três de Cimento Portland Comum (CP-I) e três de Cimento Portland Branco (CPB). Os resultados mostraram que não houve conseqüências de uma proliferação microbiológica em nenhum dos cimentos e tempos pesquisados. Observou-se tecido conjuntivo denso, celular e ricamente vascularizado. Também foi visualizado uma matriz óssea recém formada, adjacente aos osteoblastos ativos e que não estava ainda calcificada; apresentava-se menos mineralizada e com ausência de lamelas. Durantes os tempos histológicos de 30, 60 e 90 dias, o infiltrado inflamatório disperso no tecido apresentou-se: intenso, moderado e discreto. Sugerindo a mudança do processo inflamatório de agudo a crônico respectivamente / The biomaterials can be defined as substances of natural or synthetic origin that are tolerated on a temporary or permanent by the various tissues that make up the organs of living beings. Among these biomaterials can quote the mineral trioxide aggregate (MTA), which was developed at the University of Loma Linda, in the 90s. Since then, it stopped work on research involving this material and Portland cement (PC), which although not a dental material to use direct, one can say that basically has the same chemical components of the ATM. The purpose of this study was to evaluate the biocompatibility of common Portland cement (PC-I) and the white Portland cement (CPB) no structural, included in the skull of rats. Twenty rats were selected, two were previously used as a pilot group and the eighteen others were divided into three groups of six rats that were killed and evaluated in experimental stroke, 30, 60, and 90 days. Each animal received an implant, three of Common Portland Cement (PC-I) and three of White Portland Cement (CPB). The results show that there were no consequences of a microbial proliferation in any of cement and times searched. There was also the formation of bone tissue with characteristics of immaturity, showing gaps in some areas without osteocytes; presence of moderate and cell tissue, richly vascularized, showing characteristics of biocompatibility, and the potential for bone and cell differentiation.

Os biomateriais podem ser definidos como substâncias de origem natural ou sintética que são tolerados de forma transitória ou permanente pelos diversos tecidos que constituem os órgãos dos seres vivos. Dentre esses biomateriais podemos citar o Agregado de Trióxido Mineral (ATM), que foi desenvolvido na Universidade de Loma Linda na década de 90. Desde então, não cessaram trabalhos de pesquisa envolvendo esse material e o Cimento Portland (CP); que embora não seja um material de uso odontológico direto, pode-se afirmar que possui basicamente os mesmos componentes químicos do ATM. O objetivo da presente pesquisa foi avaliar a biocompatibilidade do cimento Portland comum (CP-I) e do cimento Portland branco (CPB) não estrutural, incluídos na calvária de ratos. Foram selecionados vinte ratos, dois foram previamente utilizados como grupo piloto; os dezoito restantes foram distribuídos em três grupos de seis ratos que avaliados nos tempos experimentais de 30, 60, 90 dias foram mortos para análise histopatológica. Cada animal recebeu um implante, sendo três de Cimento Portland Comum (CP-I) e três de Cimento Portland Branco (CPB). Os resultados mostraram que não houve conseqüências de uma proliferação microbiológica em nenhum dos cimentos e tempos pesquisados. Observou-se tecido conjuntivo denso, celular e ricamente vascularizado. Também foi visualizado uma matriz óssea recém formada, adjacente aos osteoblastos ativos e que não estava ainda calcificada; apresentava-se menos mineralizada e com ausência de lamelas. Durantes os tempos histológicos de 30, 60 e 90 dias, o infiltrado inflamatório disperso no tecido apresentou-se: intenso, moderado e discreto. Sugerindo a mudança do processo inflamatório de agudo a crônico respectivamente / The biomaterials can be defined as substances of natural or synthetic origin that are tolerated on a temporary or permanent by the various tissues that make up the organs of living beings. Among these biomaterials can quote the mineral trioxide aggregate (MTA), which was developed at the University of Loma Linda, in the 90s. Since then, it stopped work on research involving this material and Portland cement (PC), which although not a dental material to use direct, one can say that basically has the same chemical components of the ATM. The purpose of this study was to evaluate the biocompatibility of common Portland cement (PC-I) and the white Portland cement (CPB) no structural, included in the skull of rats. Twenty rats were selected, two were previously used as a pilot group and the eighteen others were divided into three groups of six rats that were killed and evaluated in experimental stroke, 30, 60, and 90 days. Each animal received an implant, three of Common Portland Cement (PC-I) and three of White Portland Cement (CPB). The results show that there were no consequences of a microbial proliferation in any of cement and times searched. There was also the formation of bone tissue with characteristics of immaturity, showing gaps in some areas without osteocytes; presence of moderate and cell tissue, richly vascularized, showing characteristics of biocompatibility, and the potential for bone and cell differentiation.

Objetivo: Avaliar se a adição de nanopartículas de prata ao cimento MTA branco irá melhorar a ação antimicrobiana sobre Enterococcus faecalis e prevenir a aderência deste microrganismo ao material. Método: Teste de contato direto utilizando corpos de prova dos materiais: MTA branco (n=10) grupo B, MTA cinza (n=10) grupo C, MTA branco + NPAg em pó a 1% em peso (n=10) grupo P, MTA branco + solução de NPAg 50ppm (n=10) grupo L, que foram mantidos a 35˚C por 72 horas na suspensão de Enterococcus faecalis em SBF (0.085 UA; 660nm). Alíquotas de 100μL foram tomadas da suspensão a cada 24 horas, realizadas as diluições seriadas e semeadas em triplicata em placa de Petri contendo meio Nutriente acrescido de azul de bromotimol a 0,001%. As placas foram incubadas a 35˚C por 48 horas e então realizadas as contagens de UFC. Ao final de 72 horas, corpos de prova em resina (n=10), que haviam sido mantidos na mesma suspensão juntamente com os demais grupos, tiveram a suspensão renovada, tendo sido ajustada para 0.1 UA (660nm). Permaneceram por mais 72 horas em estufa a 35˚C e então foram submetidos ao teste de aderência. Resultados: Para a comparação intergrupos considerando a variação do número de UFC em dois períodos houve diferença significante entre o grupo P e demais grupos no intervalo (T0-24h) e no intervalo (48-72h) para o grupo C comparado ao grupo L e P (Teste Anova teste t; α=0.01). Conclusões: Os cimentos MTA cinza e branco, com ou sem nanopartículas, apresentaram ação antimicrobiana sobre Enterococcus faecalis em todos os períodos do teste de contato direto; A adição da nanopartícula de prata em pó promoveu um efeito antimicrobiano em menor tempo sobre o Enterococcus faecalis, no teste de contato direto; O MTA branco, com nanopartículas não permitiu a aderência bacteriana ao final de 72 horas em contato com a suspensão bacteriana de Enterococcus faecalis. / Aim: To evaluate if the addition of silver nanoparticles to white MTA cement will improve the antimicrobial action of Enterococcus faecalis and prevent adherence of this microorganism to the material. Method: Direct contact test using samples of materials: white MTA (n=10) B group, gray MTA (n=10) C group, white MTA + NPAG powder to 1wt% (n=10) P group, white MTA + solution NPAG of 50ppm (n=10) L group were kept at 35˚C for 72 hours in Enterococcus faecalis in SBF(0.085AU; 660nm). Aliquots of the suspension were taken every 24 hours, serial dilutions carried out in triplicate and plated on Petri dishes containing nutrient medium plus bromothymol blue 0.001%. The plates were incubated at 35˚C for 48 hours and then the CFU counts performed. At the end of 72 hours resin specimens (n=10) which had been kept at the same suspension together with the remaining groups all had renewed suspension having been adjusted to 0.1AU (660nm). Lasted for over 72 hours in an oven at 35˚C and then were tested for adhesion. Results: Comparing between those groups consider the variation of numbers of CFU in two periods there was significant differente between the P group and other groups in the interval (T0-24h) and range (48-72h) for group C compared with group L and P (Anova test - t test; α=00:01). Conclusions: The gray and white MTA, with or without nanoparticles showed antimicrobial activity on Enterococcus faecalis at all periods of direct contact test; the silver nanoparticle powder addition promoted an antimicrobial effect in less time on the Enterococcus faecalis in test direct contact; white MTA with nanoparticles prevented bacterial adherence at the end of 72 hours in contact with the bacterial suspension of Enterococcus faecalis.