Este estudo avaliou, in vitro, a influência da radioterapia na resistência de união (RU) e na interface adesiva entre diferentes cimentos resinosos e dentina radicular. Sessenta caninos superiores foram distribuídos em 2 grupos (n=30) de acordo com a irradiação: não irradiados e irradiados. Os dentes do grupo irradiado foram submetidos à radioterapia com raios-X de 6 MV em frações de 2 Gy, com 30 ciclos, perfazendo 60 Gy. Os dentes foram seccionados para obtenção de raízes com 16 mm de comprimento, sendo realizado em seguida o preparo biomecânico com instrumento Reciproc R50 e obturação pela técnica de condensação lateral com cimento a base resina epóxica. Cada grupo foi subdividido de acordo com o cimento resinoso utilizado para a cimentação dos pinos de fibra de vidro (n=10): RelyX U200; Panavia F 2.0; RelyX ARC. Os pinos foram submetidos a tratamento de superfície com ácido fluorídrico 10% e cimentados de acordo com as recomendações de cada fabricante. Após a cimentação dos pinos, os dentes foram seccionados transversalmente em slices de 1 mm de espessura, obtendo-se 3 slices de cada terço da raiz. Os slices mais cervicais de cada terço foram utilizados para avaliar a RU, por meio do teste de push-out com velocidade de 0,5 mm/min, e posterior análise do padrão de falha em estereomicroscópio. Os slices mais apicais de cada terço foram selecionados para análise da interface cimento/dentina em MEV com aumentos de 100, 1000, 2000 e 4000X. Os dados de RU e adaptação da interface cimento/dentina foram submetidos à análise estatística pelos testes de ANOVA e Tukey, e Kruskal-Wallis e Duns, respectivamente. Os espécimes irradiados apresentaram menores valores de RU (8,23&plusmn;4,26) comparados aos dentes não irradiados (11,88&plusmn;6,42) (p<0,00001). Quanto aos cimentos resinosos, o RelyX U200 apresentou maiores valores na RU (15,17&plusmn;5,89) comparado aos cimentos RelyX ARC (7,68&plusmn;4,22) (p<0,0001) e Panavia F 2.0 (7,32&plusmn;2,71) (p<0,0001). O terço cervical apresentou maiores valores de RU (13,08&plusmn;6,10) comparado aos terços médio (9,72&plusmn;5,03) e apical (7,38&plusmn;4,53) (p<0,0001). O padrão de falhas mostrou ocorrência de falhas coesivas na dentina para os espécimes irradiados. Na análise da interface cimendo/dentina por MEV, observou-se maior desadaptação nos dentes submetidos à radioterapia. Em relação aos cimentos resinosos, foi observada maior adaptação com RelyX U200 e RelyX ARC comparados à Panavia F 2.0. Na análise qualitativa em MEV observou-se presença de fraturas e microfraturas na dentina radicular e menor presença de fibras colágenas em dentes irradiados. Para o cimento resinoso RelyX U200 e Panavia F 2.0 observou-se interface justaposta do cimento com a dentina radicular em dentes irradiados e não irradiados, sendo que para o cimento resinoso RelyX ARC foi observada formação de camada híbrida e tags de maneira similar para dentes irradiados e não irradiados. Concluiu-se que a radioterapia resultou na redução da resistência de união e na maior desadaptação da interface cimento resinoso/dentina radicular e que o cimento resinoso autoadesivo se apresentou como melhor alternativa para cimentação de pinos de fibra de vidro em dentes irradiados. / This in vitro study, evaluated the influency of radiotherapy on bond strength (BS) and adhesive interface between different resin cements and root dentin. Sixty maxillary canines were selected and distributed into two groups (n = 30) according to the irradiation protocol: non-irradiated and irradiated. The irradiated group were submitted to X-ray radiotherapy of 6 MV in fractions of 2 Gy, with 30 cycles, until complete 60 Gy. The teeth were sectioned to obtain 16 mm of root length, followed by biomechanical preparation with R50 reciproc instrument and obturation using the lateral condensation technique with epoxy resin-based sealer. Then, each group was subdivided according to the resin cement used for the glass fiber post cementation (n = 10): RelyX U200, Panavia F 2.0 and RelyX ARC. The posts were submitted to surface treatment with 10% hydrofluoric acid, and then cemented according to the manufacturer instructions. After the posts cementation, the teeth were sectioned transversely into 1 mm thick slices, and 3 slices were obtained from each root third. The most cervical slice of each third was used to evaluate the BS by the push-out test at 0.5 mm/min of velocity and the failure pattern was analyzed using stereomicroscopy. The most apical slice of each third was selected for SEM analysis, which were prepared and metalized. The dentin/cement interface analysis was performed at the following magnification: 100, 1000, 2000 and 4000X. The BS data and dentin/cement interface adaptation were submitted to statistical analysis by ANOVA, Tukey and Kruskal-Wallis, and Duns tests respectively. The irradiated specimens had lower BS values (8.23 &plusmn; 4.26) compared to non-irradiated group (11.88 &plusmn; 6.42) (p <0.00001). Regarding the resin cements, the RelyX U200 showed the higher values in BS (15.17 &plusmn; 5.89) compared to RelyX ARC (7.68 &plusmn; 4.22) and Panavia F 2.0 (7 , 32 &plusmn; 2.71) (p <0.0001). In addition, the cervical third presented higher BS values (13.08 &plusmn; 6.10) when compared to the middle (9.72 &plusmn; 5.03) and apical (7.38 &plusmn; 4.53) thirds (p <0.0001). The failure pattern showed cohesive failures in root dentin of the irradiated specimens. In the SEM dentin/cement interface analysis, a greater misadaptation was observed for the teeth submitted to radiotherapy. Regarding the resin cements, a better adaptation was observed for the RelyX U200 and RelyX ARC compared to the Panavia F 2.0. In the SEM qualitative analysis of the irradiated teeth, was possible to observe the presence of fractures and microfractures in the root dentin and a small number of collagen fibers. The resin cements RelyX U200 and Panavia F 2.0 showed a juxtaposed interface of the cement with the root dentin in irradiated and non-irradiated teeth, being that for the RelyX ARC cement the presence of hybrid layer and tags was similar for irradiated and non-irradiated groups. It was concluded that the radiotherapy promoted reduction of the bond strength and increase the gaps in the dentin/resin cement interface and the self-adhesive resin cement is the best alternative for glass fiber posts cementation in irradiated teeth.

Preparos para retentores intra-radiculares mais conservadores evitam desgaste desnecessário da estrutura dentinária, requer menos cimento e podem melhorar a retenção adesiva do pino. Assim o objetivo deste estudo foi avaliar a espessura de cimento ea resistência adesiva de pinos de fibra de vidro cônicos em preparo para retentor intra-radicular realizados com uma ponta ultrassônica desenvolvida. Trinta incisivos laterais superiores foram preparados com limas reciprocantes Wave One Gold (Dentsply Sirona, Ballaigues, Suiça) e aleatoriamente divididos em 2 grupos (n=15) de acordo com a técnica de preparo para pino: grupo US foram preparados com uma ponta ultrassônica desenvolvida, e grupo WP (controle) com a broca recomendada pelo fabricante do pino. Os pinos de fibra de vidro cônicos WhitePost DC 0.5 (FGM, Joinville, SC, Brasil) foram cimentados utilizando cimento resinoso dual nos terços cervical e médio do canal radicular. Isto posto, todos os espécimes foram seccionados transversalmente em três seções (cervical, média e apical do pino) para análise da área de cimento resinoso ao redor do pino que foi calculada através do programa AutoCAD, em seguida, para avaliar a resistência adesiva, o teste de cisalhamento por extrusão foi aplicado através de uma maquina de ensaio universal numa velocidade média de 0.5 mm/min até o deslocamento do conjunto restaurador intra-radicular e o tipo de falha avaliado por estereomicroscopia. A comparação entre grupos e entre terços da área de cimento e resistência adesiva foram analisadas pelo teste t independente e Anova com Tukey; e os tipos de falha entre os grupos por Mann-Whitney, todos com nível de significância de 5%. No grupo ultrassônico foi observado a menor quantidade de cimento (p<0.05) e a resistência adesiva nos diferentes grupos e terços se manifestou maior somente no terço apical do grupo ultrassônico (p<0.05). Falha adesiva entre cimento e dentina foi a mais prevalente do terço cervical e apical do grupo US e cervical de grupo WP. Falha adesiva entre cimento e pino foi a mais prevalente nos demais terços. Conclui-se que o preparo para retentor com a ponta ultrassônica desenvolvida requer menor quantidade de cimento e influencia na melhor resistência de união no terço apical do pino de fibra de vidro. / Conservative post space preparations for intra-radicular retainers prevent unnecessary desgaste of the dentin structure, require less cement and improve bond strength of the post. The aim of this study was to evaluate the influence of resin cement thickness and bond strength of prefabricated glass fiber circular postin post space preparations with an ultrasonic tip developed. Thirtymaxillarylateral incisors were prepared with Wave One Gold reciprocating files (Dentsply Sirona, Ballaigues, Switzerland) and randomly divided into 2 groups (n=15) according to the post preparation technique: gruoup US was prepared with an ultrasonic tip developed and group WP (control) with the drill recommended by the post fabricant. Every glass fiber posts WhitePost DC 0.5 (FGM, Joinville, SC, Brazil) was cemented using dual polymerizing resin cement in the cervical and middle thirdof the root canal. After that, every specimen was sectioned transversally into three sections(cervical, middle and apical of the post) and the resin cement thickness area was calculated with AutoCAD program, the bond strength test was done with an universal testing machineat medium velocity 0.5 mm/min and the failure pattern after the test was analyzed with stereomicroscopy. Datas obtained were analyzed statistically using Student\'s t-Test, ANOVA,andTukey\'s test. The comparison of failure modes between the groups in the different thirds was done using Mann-Whitney test, All of those at a 5% significance. Ultrasonic group presented thinnest layer of cement in all thirds (p<0,05), which also obtained a higher bond strength only in apical third (p<0,05). Adhesive failurebetween cement and dentinwas the most prevalent of the cervical and apical third of G1 and cervical of G2.Adhesive failure between cement and post was the most prevalent in the others thirds. It can be concluded that the postpreparation with the ultrasonic tip developed provides a smaller thickness of resin cement that influenced thebond strength in the apical third of the glass fiber post.

[pt] Este trabalho tem como objetivo investigar o desempenho de colunas com seção I em polímeros reforçados com fibra de vidro (pGFRP) submetidas a cargas de compressão concêntricas de curta duração. Uma revisão bibliográfica acerca das teorias existentes é apresentada, incluindo os conceitos básicos de instabilidade, teoria de flambagem global e local, modos de falha de colunas perfeitas, bem como o comportamento de colunas reais. Um programa experimental foi conduzido, incluindo a caracterização dos materiais. Vinte e nova colunas – com três diferentes seções I e diferentes tipos de resina, propriedades mecânicas, bem como comprimentos – foram testadas. Do ponto de vista global, as colunas foram biengastadas. As placas constituintes, por sua vez, foram testadas com três diferentes condições de contorno: biengastadas (CC), biapoiadas (SS) e simplesmente em contato com as chapas de base da máquina de compressão (CB). Foi observado que a condição de contorno CB – a mais adotada em estudos anteriores -, se aproxima mais de um engaste do que de uma condição simplesmente apoiada. A distribuição não linear de deformações elásticas ao longo da seção também foi investigada. Finalmente, recomendações para um ensaio de flambagem local apropriado foram propostas. / [en] This work aims to investigate the performance of pultruded glass fiber reinforced polymer (pGFRP) I-section columns subject to short term concentric compression. A review of existing theories is presented, including the instability concepts, global and local buckling theories, perfect columns failure modes and the behavior of real columns. An experimental program including material characterization was conducted. Twenty-nine stubs – with three different I-sections geometries, having distinct flange width-to-section depth ratios (bf/d = 0.5; 0.75 and 1.0), mechanical properties, overall lengths and matrices – were tested. In a global point of view, the columns were fixed at both ends. The constituent plates, on the other hand, were tested with different end-conditions: clamped (CC), simply supported (SS) and simply in contact with base plates of the universal machine (CB). The third analyzed boundary condition, which is the most adopted in previous studies, was concluded to be closer to a clamped end-condition. The non-linear elastic strains distribution throughout the cross-section was also investigated. Finally, guideline recommendations for successful local buckling tests were proposed.

Electromagnetic interference (EMI) is one of the most common problems encountered in microwave applications. Interaction of electromagnetic (EM) waves from different sources may result in device malfunction due to misinterpretation of the transferred data or information loss. On the other hand, development of materials with reduced radar detectability is desired in defense applications. Considering the limitations in weight and thickness, development of lightweight structural materials with enhanced electromagnetic absorption potential is needed. In this study, development and characterization of glass fiber-reinforced polymer (GFRP) composite materials to be used in EM wave absorbing or EMI shielding applications was aimed. Incorporation of electromagnetic wave absorption characteristic has been achieved by the application of conductive thin film on fiber glass woven fabric reinforcement layers. Characterization of EM wave absorption potential was conducted using &ldquo / free-space method&rdquo / in 18 &ndash / 27 GHz frequency range. Single and multilayered combinations of surface-modified fiber glass woven fabrics were characterized in terms of their EM wave interaction properties and design principles for efficient broadband EM wave absorbing multilayered GFRP composite material have been presented. A computer aided computation method has also developed in order to predict EM wave transmission, reflection, and hence absorption characteristics of multilayered structures from single layer properties. Estimated results were verified compared to free-space measurement results. In the current study, up to 85% electromagnetic wave absorption has been obtained within 18-27 GHz frequency range (K band). Enhancement of EM wave absorption potential of multilayer structure has also been demonstrated by computer aided computation.

Im Rahmen des Transferprojektes T01 „Textilbeschichtung mit hochviskosen Massen“ des Sonderforschungsbereiches 532 (SFB 532) wird die Realisierung und Bewertung eines integrierten Beschichtungskonzeptes zur nachhaltigen Verbesserung der Tragfähigkeit von textilbewehrten Betonbauteilen an der RWTH Aachen University untersucht. Dazu wird eine neue Auftragstechnik für hochviskose Beschichtungsmassen entwickelt, die eine vollständige Penetration von Multifilamentgarnen mit großen Garntitern und einer hohen Anzahl an Filamenten in textilen Gelegen erzielt. Des Weiteren werden aktive Beschichtungsmassen auf der Basis von Polyvinylalkohol-Zement-Compositen, die eine homogene Anbindung aller Einzelfilamente an die Zementmatrix ermöglichen, erforscht.

Fiber reinforcement is being widely used in concrete tunnel linings these days. Using fiber reinforcement can save not only cost, but also labor and time spent on construction. However, many owners hesitate to incorporate fiber reinforcement in tunnel lining due to lack of experience with and knowledge of the behavior of fiber reinforced concrete (FRC) In this study, fiber reinforced concrete was made with various kinds of fibers such as steel fiber, macro-synthetic fiber and hybrid fiber (a blend of macro-synthetic fiber and glass fiber). Many experimental tests were performed to investigate the compressive, flexural and shear behavior of fiber reinforced concrete. In addition to the structural capacity of FRC, the distribution of fiber reinforcement inside the concrete matrix was investigated. Test results of these experimental tests were thoroughly examined to compare and quantify the effects of fiber reinforcement. Next, the test results were used to generate axial force-bending moment interaction diagrams based on current design approaches. In addition, the current design approaches were modified to estimate the accurate and exact value of bending moment. Fiber reinforcement clearly improved the structural performance of tunnel lining. The post-peak flexural and shear strength was significantly influenced by the type and amount of fiber reinforcement. / text

This thesis investigates the performance of GFRP pretensioned concrete slabs and compares their flexural behaviour with GFRP reinforced and steel prestressed concrete slabs. A total of 12 slabs were cast in this program. The slab mid-span deflections are theoretically predicted and the results indicate that the short-term response of GFRP prestressed concrete slabs can be predicted well by the existing methods. Long-term deflection behaviour has been estimated using the Age Adjusted Effective Modulus Method by incorporating three creep and shrinkage models. A large influence of creep and shrinkage models on the theoretical determination is observed and the use of long term multipliers is not suitable for GFRP prestressed concrete members. The slabs were instrumented for long-term monitoring using strain gauges and fibre-optic sensors. It was concluded that the electrical strain gauges can be successfully used for long-term strain monitoring.

Hybride Oberflächenaktivierungen von Glasfaserrovings mittels Polymer/Zement-Kompositen ermöglichen eine komplette Durchdringung des Rovings mit Beton von der Matrix bis zu den innenliegenden Einzelfilamenten. Dies erlaubt einen deutlich verbesserten Lasteintrag in den gesamten Rovingquerschnitt bei der Verwendung als Faserverstärkung in textilbewehrten Betonen. Auf Grund von ausgeprägten Domänen hydratisierter Zementsteinphasen innerhalb des Rovings ergibt sich eine komplexe, multiskalige Verbundstruktur, die sich in ihren Eigenschaften deutlich von klassischen polymerbeschichteten Rovings unterscheidet. Wir diskutieren diesen Ansatz in Bezug auf Herstellung, nano-/mikroskopische Charakterisierung, sowie der mechanischen Eigenschaften der Probenkörper unter beschleunigten Alterungsbedingungen. Die mikroskopischen Untersuchungen mittels höchstauflösender Elektronenmikroskopie und Nanoindentation zielen darauf ab, die Grenzflächenanbindung, die veränderte Struktur in Abhängigkeit des verwendeten Polymers und der Additive sowie die Korrosionsmechanismen aufzuklären. / Hybrid surface modifications of glass fiber rovings with polymer/cement-composites allow the generation of extended cement phases within the roving and an activation of the innermost filaments to the surrounding concrete matrix. This enables enhanced load transfer across the full roving cross section when used as fibrous reinforcement in textile-reinforced concrete. Due to the presence of extended concrete domains within the roving, a complex multiscale composite structure develops, displaying distinctly different properties as compared to standard polymer impregnation routes. We discuss this approach in terms of production, nano/microscopic characterization of the concrete composites and mechanical properties of the resulting specimens under accelerated aging conditions. The microscopy studies using highest resolution electron microscopy and nanoindentation aim to elucidate the interface connection, the changes in morphology of the concrete as a function of the polymer and additives used, as well as shedding light on the corrosion mechanisms.

Submitted by Milena Rubi ( ri.bso@ufscar.br) on 2017-10-17T17:05:25Z No. of bitstreams: 1 ALVES_Jose_2017.pdf: 5435239 bytes, checksum: 2763493f52fe9331545e1498f4c97f81 (MD5) / Approved for entry into archive by Milena Rubi ( ri.bso@ufscar.br) on 2017-10-17T17:08:12Z (GMT) No. of bitstreams: 1 ALVES_Jose_2017.pdf: 5435239 bytes, checksum: 2763493f52fe9331545e1498f4c97f81 (MD5) / Approved for entry into archive by Milena Rubi ( ri.bso@ufscar.br) on 2017-10-17T17:10:15Z (GMT) No. of bitstreams: 1 ALVES_Jose_2017.pdf: 5435239 bytes, checksum: 2763493f52fe9331545e1498f4c97f81 (MD5) / Made available in DSpace on 2017-10-17T17:11:44Z (GMT). No. of bitstreams: 1 ALVES_Jose_2017.pdf: 5435239 bytes, checksum: 2763493f52fe9331545e1498f4c97f81 (MD5) Previous issue date: 2017-05-29 / Não recebi financiamento / At last years due to increasing use of composite materials of synthetic fibers with thermosetting matrix, several alterative have been sought trying to minimize the impacts generated by both the dispose of this material at the end of their useful life and by its heavy dependency of non-renewable resources as petroleum based products for the production of raw materials. As alternative to introduce composites materials that have least environmentally impact natural fibers have drawn attention of researchers. In this work the aim is to manufacture by vacuum infusion process, composite laminates hybrid adding woven jute fiber in structural weaving fiberglass with epoxy resin matrix. The quality of laminate was analyzed by fiber weight fraction determining and thermal analysis by DSC (Differential Scanning Calorimetry) and DMTA (Dynamic Mechanical Thermal Analysis). It was possible to manufacture hybrids laminates by vacuum infusion with fiber fraction in about 60%. Hybrids laminates presented had a reduction of density of 20% with relation to the glass reinforced plastic. Regarding to mechanical properties, the laminates were characterized by tensile, compression and ILSS testing. With respect to hybrid laminates, the better results of tensile properties such as strength and young's modulus was achieved by the laminates with fiber oriented in 0/90° (H0/90) with maximum strength value near to 200 MPa, while for orientation ±45° (H45 e H45/0/90) the strength results were 68 MPa and 84 MPa, respectively. In this case can be highlighted the hybrid laminate H45, whose tensile strength (83,9 MPa) has not present significant changes with the introduction of jute fiber (with increase of 60% its thickness) compared with glass reinforced plastic (84,5 MPa) for the same fiber orientation. For compressive strength the best result was presented by the laminates H0/90 (fibers in 0/90°) as well, with values close to 150 MPa while the laminates to ±45° (H45 e H45/0/90) presented values of 90 MPa. Regarding to ILSS the variation of strength was smaller, 25 MPa to direction 0/90° and 23 MPa and 21 MPa to H45 and H45//0/90 laminates, respectively. Therefore, mechanical properties were significantly influenced by plies orientation in the laminates and by the hybridization with jute fibers. / Nos últimos anos, devido ao crescente consumo de compósitos de fibras sintéticas com matriz termorrígida, várias alternativas têm sido buscadas a fim de minimizar os impactos gerados tanto pelo descarte desse material ao fim de sua vida útil, quanto pela grande dependência de derivados de recursos não renováveis, como o petróleo para a produção das matérias-primas. Como uma das alternativas de introduzir na área de compósitos, materiais que tenham menores impactos ambientais, as fibras naturais têm recebido atenção de pesquisadores. Assim, neste trabalho foram moldados pelo processo de infusão à vácuo, compósitos de laminados híbridos através da utilização de tecidos de fibras de juta e tecidos estruturais de fibras de vidro com matriz de resina epóxi. A qualidade dos laminados foi analisada por meio da determinação da fração mássica de fibra e por análise térmica de DSC (Differential Scanning Calorimetry) e DMTA (Dynamic Mechanical Thermal Analysis. Foi possível moldar laminados híbridos pelo processo de infusão com fração de fibra em cerca de 60%. Os laminados híbridos apresentaram uma redução na densidade de 20% em relação aos compósitos contendo somente fibras de vidro. Em relação às propriedades mecânicas, os compósitos laminados foram caracterizados através dos ensaios de tração, compressão e cisalhamento interlaminar (ILSS). Entre os laminados híbridos, os melhores resultados de propriedades de tração, como resistência e módulo de elasticidade foram alcançados pelos laminados com ambas as fibras orientadas a 0/90° (H0/90), com valor de tensão máxima próximo a 200 MPa, enquanto que para as orientações ±45° (H45 e H45/0/90) os valores foram próximos de 68 e 84 MPa, respectivamente. No caso, pode ser destacado o laminado híbrido H45, cuja resistência a tração (83,9 MPa) não apresentou mudanças significativas com a introdução das fibras de juta (com acréscimo de 60% na espessura) quando comparado ao laminado de fibras de vidro (84,5 MPa) com mesma orientação. A melhor resistência à compressão também foi apresentada pelos laminados orientados a 0/90° (H0/90) com valores próximos a 150 MPa, enquanto os laminados a ±45° (H45 e H45/0/90) apresentaram os valores de 90 MPa. Em relação à resistência ao cisalhamento interlaminar, entre os laminados híbridos, a variação entre as orientações foi menor, 25 MPa para a direção 0/90° e, 23MPa e 21MPa para os laminados H45 e H45//0/90, respectivamente. Assim, as propriedades mecânicas foram influenciadas significativamente pela orientação das v camadas nos laminados e pela introdução das fibras de juta. Desta forma, conclui-se que a significativa redução de algumas propriedades possivelmente invalida a utilização das configurações híbridas estudadas para aplicações estruturais nas pás eólicas. No entanto, as configurações de laminados híbridos, desenvolvidas e analisadas neste trabalho podem ser aplicadas para moldar componentes em compósitos para peças não estruturais ou com menores requisitos de resistência, como para o segmento automotivo, e ainda com possibilidades de melhorias.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to assess the effect of instrument type (K-files and nickel-titanium rotary files) and the root canal filling technique (active and passive lateral condensation) on fracture resistance. Sixty eight teeth (canines and premolars) were divided into 4 groups (n=17): G1 - hand instrumentation and active lateral condensation; G2 - hand instrumentation and passive lateral condensation; G3 - rotary instrumentation and active lateral condensation; G4 - rotary instrumentation and passive lateral condensation. Before the filling, the roots were embedded in acrylic resin to simulate the periodontal ligament using a polyether impression material. Every root was restored with glass fiber post and metallic crown. The specimens were mechanical cycled (500.000 cycles, 45°, 37° C, 133 N, 2 Hz) and they were submitted to fracture test (45º, 1 mm/ min) until the fracture occurred. The Kruskal-Wallis test showed that the groups were not different from each other (p = 0. 247). In situations where an endodontic post is required, the instrument type and the obturation technique seem to have no influence on fracture resistance. / O objetivo deste estudo foi avaliar o efeito do tipo de instrumento (limas manuais tipo K e instrumentos rotatórios de NiTi) e da técnica obturadora (condensação lateral ativa e condensação lateral passiva) na resistência à fratura. Para isso, 68 dentes (caninos e pré-molares) foram divididos em 4 grupos (n=17): G1 - instrumentação manual e condensação lateral ativa; G2 - instrumentação manual e condensação lateral passiva; G3 - instrumentação rotatória e condensação lateral ativa; G4 - instrumentação rotatória e condensação lateral passiva. Antes da etapa obturadora, as raízes foram embutidas em resina acrílica para a simulação do ligamento periodontal com material de moldagem à base de poliéter. Todas as raízes foram restauradas com pino de fibra de vidro e coroa metálica. Os espécimes foram submetidos à ciclagem mecânica (500.000 ciclos, 45°, 37° C, 133 N, 2 Hz) e ao teste de resistência à fratura (45º, 1 mm/ min) até a falha ocorrer. O teste de Kruskal-Wallis mostrou que os grupos não foram diferentes entre si (p = 0, 247). Em situações em que há a necessidade de cimentação de pino intrarradicular, a escolha do tipo de instrumento e da técnica obturadora parece não ter influência na resistência à fratura.