Made available in DSpace on 2014-06-11T19:27:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-06-29Bitstream added on 2014-06-13T20:35:16Z : No. of bitstreams: 1 oishi_ss_me_guara.pdf: 1972224 bytes, checksum: 3c999656c713b895ba43f4e61fdba9fd (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Em função da crescente importância do material carbono vítreo em áreas estratégicas, devido às suas características intrínsecas, tais como menor massa específica e bons valores de condutividades térmica e elétrica, tem se observado vários estudos na busca de novos precursores poliméricos, assim como no ajuste mais sistemático de seu processamento. Nesse sentido, este trabalho tem como objetivo o estabelecimento de rotas de síntese de resinas furfurílica e fenol-furfurílica e suas dopagens com partículas de cobre, visando o processamento de eletrodos de carbono vítreo reticulado (CVR). Neste contexto foram sintetizadas diferentes formulações de resinas furfurílica e fenol-furfurílica a partir da variação dos monômeros – álcool furfurílico, fenol e formaldeído, respectivamente. A confirmação do sucesso das sínteses foi realizada por análises de espectroscopia de infravermelho com transformada de Fourier, cromatografia gasosa, análises térmicas por calorimetria exploratória diferencial e medidas dos teores de carbono fixo, que mostram resultados entre 27 e 45% em carbono. Em seguida, estas amostras foram dopadas com um colóide contendo as partículas de cobre. As resinas, com e sem dopagem, foram catalisadas, impregnadas em espumas de poliuretano (PU) e carbonizadas, obtendo-se assim, o CVR. Análises por microscopias óptica e eletrônica de varredura mostram a homogeneidade na impregnação das espumas de PU e a textura uniforme das amostras de CVR. Os resultados de resistência à compressão apresentam os melhores valores para o CVR resultante da carbonização com a resina furfurílica ácida (0,55 MPa). / Due to the growing importance of glassy carbon material in strategic areas, due to its intrinsic characteristics, such as lower density and good thermal and electrical conductivities values, has been observed several studies looking for new polymeric precursors and tighter processing parameters. In this way, this study aims on the establishment of synthesis routes of furfuryl and phenol-furfuryl alcohol resins and their doping with cupper particles, in order to produce reticulated glassy carbon (RGC) electrodes. Inside of this context were synthesized different formulations of furfuryl and phenol-furfuryl alcohol resins by the monomers variation – furfuryl alcohol, phenol and formaldehyde, respectively. The success confirmation of the synthesis has been done by using FT-IR spectroscopy, gas chromatography, thermal analyses by differential scanning calorimetry (DSC) and carbon yield content measurements that present results between 27 and 45% of carbon. After this, the specimens were doped with a colloid contend the copper particles. The doped and non doped resins were catalyzed, impregnated in polyuretane (PU) foams and carbonized, in order to obtain the reticulated glassy carbon. Optical and Scanning Electron Microscopy analysis show the homogeneity of PU foams impregnation and uniform texture of RGC specimens. Compression results present the best values for RGC resulting from the carbonization with furfuryl alcohol acid resin (0,55 MPa).

OBJECTIVES: Dental wear is considered one of the reasons for composite restorations failure. Several clinical problems may arise as result of uncontrolled wear process, including compromising masticatory function, poor aesthetics, loss of interocclusal space, teeth pain and sensitivity, and tempromandibular problems. Newly released flowable composites have been introduced to the market, that are indicated for occlusal class I and II cavity restorations. The purposes of this study are (1) to evaluate the wear resistance of newly released flowable composites against two antagonists, and compare them to universal packable composite, (2) to compare the wear properties of the two different types of antagonists, (3) to evaluate mechanical and esthetic properties, including microhardness, gloss, and surface roughness, of all resin composites and correlate it to wear characteristics of the materials. MATERIALS AND METHODS: (1) Five flowable composites were used in this study: 1. Filtek Supreme Ultra Flow (3M ESPE), 2. NovaPro Flow (Nanova Biomaterials), 3. SureFil SDR Flow (Dentsply), 4. Clearfil Majesty Flow (Kuraray), and 5. G-aenial Universal Flo (GC). One universal resin composite (Filtek Supreme Ultra Universal) was used as control group. 16 Specimens were prepared from each composite by injecting into aluminum molds, then divided into two groups for two types of antagonists (n=8). The first antagonist from natural enamel cusps, the other type was from feldspar ceramic block, Vitabloc Mark II. Both were standardized and polished. After mounting the antagonists in the wear-testing machine, a uniform sliding abrasion was applied up to 200k sliding cycles. Then the measurement of dry weight, wear depth and surface roughness of the specimens and the antagonist cusps were conducted at 3 different intervals, baseline, 100k, and 200k cycles. The amount of wear was determined by measuring the weight loss and calculating volume loss. One representative sample was randomly selected from each group for scanning electron microscope examination of the surface morphology. (2) 3 samples were prepared from each resin composite material for the microhardness and gloss test. The composite specimens were finishing and polishing by Buehler grinding-polishing system for four minutes each, then rinsed and ultrasonically cleaned in distilled water for 4 minutes. The surface gloss test was performed by using Novo Curve glossmeter. Five gloss readings were taken from each specimen at different locations, and the mean value was calculated and recorded as the GU reading of each specimen. The Knoop’s microhardness was measured on a MICROMET 2003 microhardness tester. Five indentations at different locations with at least 100 μm apart were performed on each specimen. The five readings were averaged to produce a single hardness value for each specimen. RESULTS: (1) In general, statistical analysis revealed a significantly higher surface roughness and higher weight loss of all resin composites when opposed by ceramic antagonists compared to the samples opposed by enamel antagonists. Among the tested resin composites, there were significant differences in regards to specimen wear depth, weight loss, volume loss, and surface roughness, regardless of the antagonist type used. Both Filtek supreme universal and Filtek supreme ultra flow groups showed significantly deeper wear compared to the other flowable materials, regardless of the antagonist type used. Moreover, there were statistically significant differences in antagonist’s weight and height loss between the groups. The control group universal composite caused significantly higher weight and height loss of both antagonists. (2) The microhardness and gloss results demonstrated statistical significant differences between all the composite materials. Clearfil Majesty Flow and Filtek Supreme Universal groups exhibited a significantly higher surface gloss compared to the other materials with the exception of the Filtek Supreme Ultra Flow group. Filtek Supreme Universal group exhibited a significantly higher Knoop’s hardness compared to the other materials. CONCLUSIONS: Despite the limitation of this study, less weight loss and surface roughness of the flowable composites were shown when opposed by dental enamel antagonists. A significantly deeper wear was noticed on both Filtek supreme universal and flowable composites when opposed by ceramic antagonists, indicating the detrimental effect of the Feldspathic ceramic on the nanohybrid composites compared to the other nanofilled flowable composites used in the study.

Submitted by Suelen Reis (suziy.ellen@gmail.com) on 2013-04-23T13:28:37Z No. of bitstreams: 1 Altair Soares Moura.pdf: 1162342 bytes, checksum: 441e2dd313cf9d6697463b4ebb97043e (MD5) / Approved for entry into archive by Rodrigo Meirelles(rodrigomei@ufba.br) on 2013-05-08T11:59:03Z (GMT) No. of bitstreams: 1 Altair Soares Moura.pdf: 1162342 bytes, checksum: 441e2dd313cf9d6697463b4ebb97043e (MD5) / Made available in DSpace on 2013-05-08T11:59:04Z (GMT). No. of bitstreams: 1 Altair Soares Moura.pdf: 1162342 bytes, checksum: 441e2dd313cf9d6697463b4ebb97043e (MD5) Previous issue date: 2004 / O reparo de restaurações em resina composta é uma prática muito empregada, sendo o Laser de Er:YAG uma das possibilidades de tratamento. Este estudo visa analisar ?in vitro? a microinfiltração em reparos de restaurações com resina composta (resina/resina) cuja superfície foi tratada com Laser de Er:YAG. Quarenta terceiros molares humanos receberam preparos cavitários na face vestibular que foram restaurados com resina composta. Os dentes foram divididos em oito grupos de cinco dentes cada em função do tratamento da superfície que variou em: G1 e 2 foram repreparados com ponta diamantada esférica e reparados com resina, sendo utilizado no G1 - ácido fosfórico 37% + sistema adesivo, G2 - sistema adesivo. Nos grupos 3 a 8, o Laser de Er:YAG foi usado na produção de um defeito da seguinte maneira: G3 (3hZ,60mJ,6J,103 pulsos). G4 (4hZ, 60mJ, 6J, 103 pulsos), G5 (3hZ, 100mJ, 6J, 63 pulsos). G6 (4hZ, 100mJ, 6J, 63 pulsos). G7 (3hZ, 120mJ, 6J, 54 pulsos), e G8 (4hZ, 120mJ, 6J, 55 pulsos); e reparados com resina empregando sistema adesivo sem condiconamento ácido prévio. Os corpos de prova foram termociclados (500 ciclos) e imersos em Nitrato de Prata a 50% por 24 horas. Os resultados da análise (ANOVA) evidenciaram que a menor microinfiltração foi observada quando 4Hz, 60mJ, 6J e 103 pulsos e 4 Hz, 120mJ, 6J e 55 pulsos foram utilizados. / Salvador

Made available in DSpace on 2014-06-11T19:24:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-02-18Bitstream added on 2014-06-13T20:31:08Z : No. of bitstreams: 1 rastelli_ans_me_arafo.pdf: 843933 bytes, checksum: 3b62898b2965cd923e0392e3b0cc6a96 (MD5) / O objetivo desse trabalho foi avaliar a capacidade de polimerização, através da estrutura dental, de três diferentes fontes de luz (Halógena, Laser de Argônio e LEDs), por meio do teste de microdureza. Para isto, foram confeccionados corpos-de-prova em uma matriz metálica circular contendo um orifício na porção central com 4 mm de diâmetro e 2 mm de profundidade. Utilizou-se a resina composta microhibrida Charisma (Heraeus-Kulzer), na cor A2, para a confecção dos corpos-de-prova. Cinco corpos-de-prova foram confeccionados para cada situação diferente, perfazendo um total de 140 corpos-de-prova, distribuídos em 3 grupos da seguinte maneira: GRUPO I - fonte de luz halógena utilizada pelos tempos de exposição de 20 e 40 segundos, para as espessuras de 0 (grupo controle); 1,2 mm; 1,5 mm e 2,0 mm de faceta de estrutura dental; GRUPO II - fonte de luz de laser de argônio utilizada pelos tempos de exposição de 20 e 40 segundos, para as espessuras de 0 (grupo controle); 1,2 mm; 1,5 mm e 2,0 mm de faceta de estrutura dental e GRUPO III - fonte de luz à base de LEDs utilizada pelos tempos de 20, 40 e 60 segundos, para as espessuras de 0 (grupo controle); 1,2 mm; 1,5 mm e 2,0 mm de faceta de estrutura dental. Após a confecção dos corpos-de-prova, estes foram armazenados em estufa a 37ºC durante 24 horas. Após o período de armazenamento, procedeu-se o teste de microdureza Vickers, realizando-se 12 impressões para a superfície de topo (voltada à fonte de luz) e 12 para a superfície de base (oposta à fonte de luz). Os dados foram submetidos à Análise Estatística de Variância (P<0,05). Os valores dos desvios padrão das medidas de microdureza foram menores do que 1% da média, indicando diferença estatisticamente significante entre quase todos os grupos. Baseados nos resultados encontrados, pudemos concluir que... . / The objective of this study was evaluate the light-curing capacity, throught dental structure, of three differents light-curing device (Halogen, Argon Laser and LEDs), by microhardness testing. The specimes were made in a circular metallic mold with a of orifice in the cental portion measuring 4 mm in diameter and 2 mm in thickness. The composite resin was used the Charisma (Heraeus-Kulzer) at collor A2. Five samples was made by situation analyzed, adding up one hundred and forty samples: GROUP I - halogen light-curing device by exposure times of 20 and 40 seconds for the thickness 0 (control group); 1,2 mm; 1,5 mm and 2,0 mm of the structure dental facet; GROUP II - argon laser light-curing device by exposure times of 20 and 40 seconds for the thickness 0 (control group); 1,2 mm; 1,5 mm and 2,0 mm of the structure dental facet and GROUP III - LEDs light-curing device by exposure times of 20, 40 and 60 seconds for the thickness 0 (control group); 1,2 mm; 1,5 mm and 2,0 mm of the dental structure facet. After the polymerization procedures the specimes were stored at room temperature of 37ºC for 24 hours. After the storing, the microhardness testing was made, take effecting 12 impressions for the top surface and 12 for the botton surface. The hardness values means obtained were calculed and the statistically analised using Anova (P<0,05). According to the results, it was conclude that: 1) highest the thickness of the dental estructure face, have been a decreasing of the means values of microhardness, independent of the light-cured device utilized; 2) highest exposure times provided higher values means of the microhardness, independent of the light-cured device utilized; 3) the top surface showed the highest means values of hardness, independent of the light-cured device utilized; 4) the halogen light-cured device raised suitable... (Complete abstract, click electronic address below).

Orientador: Newton Luiz Dias Filho / Banca: Devaney Ribeiro do Carmo / Banca: Adley Forti Rubira / Resumo: Resinas epoxídicas são uma das mais importantes classes de polímeros termorrígidos usados para aplicações estruturais e como adesivos. Entretanto, os problemas em aplicações de resinas epoxídicas na engenharia incluem a baixa resistência à propagação de trincas devido a sua fragilidade. Para superar esta fragilidade, muitas vezes, dentre os aditivos em formulações multicomponentes de resinas epoxídicas, é utilizado um componente para aumentar a resistência, tais como enchimentos, oligosilsesquioxanos poliédricos (POSS), dendrímeros, etc. POSS (RSiO1,5)n podem ser incorporados em polímeros termorrígidos para melhoramento de suas propriedades térmicas e mecânicas. O uso de POSS nanoestruturados na preparação de polímeros orgânicos pode levar a materiais nanocompósitos. Neste trabalho, um POSS contendo oito grupos ésteres por molécula (MDPS) foi incorporado a uma matriz de polímeros termorrígidos epoxídicos DGEBA/TETA para melhorar suas propriedades mecânicas. Através de ensaios mecânicos foi observado um aumento de aproximadamente 90% (formulação 0,67/5) na resistência a fratura (K1C) com um leve decréscimo no modulo de Young (E). Os valores de Tg, verificados por DMTA mostraram pequeno decréscimo nas composições modificadas. As análises termogravimétricas mostraram que a adição de silsesquioxano não influenciou na estabilidade térmica do material. A cinética de cura foi analisada pelo método de Ozawa. As possíveis e prováveis causas deste significante reforço podem ser atribuídas à formação de uma segunda fase, à miscibilidade residual dos grupos ésteres com a matriz epoxídicas e às interações interfaciais entre a matriz epoxídicas e os cubos de silsesquioxanos devido as suas dimensões nanométricas. / Abstract: Epoxy resins are one of the most important classes of thermosetting polymers used for structural and adhesive applications. However, the current problems in engineering applications of epoxy thermosets include the poor resistance to the crack propagation because they are brittle. To overcome brittleness, among other additives of the multicomponented formulation of the epoxy resin, a toughening agent is often used, such as fillers, polyhedral oligosilsesquioxanes (POSS), dendrimers, etc. POSS, (RSiO1.5)n, can be incorporated into thermosetting polymers to improve their thermal and mechanical properties. The use of such nanosized POSS in the preparation of an organic polymer can lead to a nanocomposite materials. In this work, a POSS containing eight ester groups per molecule (MDPS) was incorporated to an epoxy matrix of DGEBA/TETA thermosetting polymers to improve their mechanical properties. Through the mechanical tests an increase of about 90% (formulation 0,67/5) was observed in the fracture toughness (K1C) with a little decreasing in the module of Young (E). The Tg values verified by DMTA showed smaller values for the compositions with the modifier. The thermogravimetric analyses showed that the addition of the silsesquioxane ester did not influence on the thermal stability of the material. The cure kinetics was analyzed by Ozawa's method. The probable and possible causes of this significant reinforcement can be attributed to the formation of a second inorganic phase, residual miscibility of the ester groups with the epoxy matrix and to interfacial interactions between the epoxy matrix and silsesquioxanes cubes due their nanometric dimensions. / Mestre

The aerospace industry is steadily increasing its use of polymer-matrix composites (PMCs) in airframe structures as it seeks to benefit from the high specific in-plane strength of laminated structural PMCs. However, PMC laminates suffer from low interlaminar shear strength due to their weaker polymer-matrix. Minimising risks of delamination is of paramount importance towards improving the safety of PMC structures. Multi-scale composites that are reinforced by both continuous fibres and nano-particles were identified as a potential solution for improving toughness and reducing risks of delamination in PMCs. An important challenge in the fabrication of multi-scale PMCs is to ensure that nano-particles are dispersed uniformly within the matrix. This is only achieved through minimal filtration of nano-particles during processing. The short resin flow lengths enabled by the resin film infusion (RFI) process make this process a prime candidate for the fabrication of multi-scale PMCs. The main objective of this thesis is to validate the possibility of using out-of-autoclave RFI for fabricating multi-scale carbon fibre composites featuring epoxy resins modified with carbon nanotubes (CNTs). The work is accomplished in 5 phases. In phase 1, preliminary work investigates the fabrication of PMCs with and without CNTs, using out-of-autoclave RFI. Results show that the types of reinforcement and matrix have strong effects on the porosity and interlaminar strength of PMCs. These results ushered the need for more thorough investigation and understanding of the RFI process, beyond what is available in the literature. Phases 2 to 4 focus on understanding how the choices of materials and types of stacking configuration can affect parts made using RFI. Phase 2, the in-situ characterisation of resin saturation during RFI is performed. Results enable a detailed analysis of the way in which resin flows around and inside yarns. Phase 3 consists in the characterisation of void formation during RFI. Two types of voids are observed: flow-induced voids resulting from either the merging of resin flow fronts or the drainage from capillary action; and gas-induced voids resulting from resin volatiles going out of solution and remaining in the resin matrix. In this work, the greatest source of porosity was caused by volatiles. In phase 4, the distribution and filtration of CNTs during RFI processing is characterised. Results show that processing choices can limit filtration and that clustering of CNTs prevents a uniform dispersion of CNTs in PMCs. Finally, the possibility of using RFI for making a multi-scale PMC demonstrator part is investigated. The work culminated with the successful fabrication of a delta-stringer panel. This thesis makes several important contributions to the knowledge pertaining to multi-scale PMC processing and performance, and to RFI. Firstly, it provides a robust description of RFI processing beyond was it available in literature, through in-situ observations of resin flow and void formation. Secondly, it assesses the viability of RFI for producing multi-scale PMCs featuring CNTs. In-situ observations of RFI processing enabled the identification of mechanisms leading to a loss of CNT dispersion during processing, partly explaining the minimal improvements in the interlaminar properties of composites observed when adding CNTs to the matrix. Thirdly, the fabrication of a delta-stringer panel made of a multi-scale PMC was successful, making it the first validation of the scalability of out-of-autoclave RFI processing for manufacturing multi-scale PMCs. The work presented herein contributed to the dissemination of knowledge; one conference paper was presented at ICCM20 (20th International Conference on Composite Materials), and another was presented at CANCOM2017 (10th Canadian-International Conference on Composites), and one journal article written in collaboration with project partners was submitted to Composites Science and Technology.

The epoxy resin mixture is used for wet filament winding load carrying and electrically insulating tubes for high voltage applications. The cured tubes are key parts of the final products which are subject to qualification. The safe function of the products generally depends on low moisture content. Visual inspection is also an important part of the quality inspection which requires some degree of transparency of the cured tubes. To prepare for future material modifications ABB wishes to evaluate the curing characteristics of some recently developed epoxy/hardener systems. The epoxy resin with the formulation E1/H1 is used as reference. Another type of base epoxy resin E2 and toughened epoxy resin E1 (E1T) are included in the study. Three alternative hardeners H2, H3, and H4 were evaluated. This project is to evaluate different alternative epoxy resin formulations that are promising to be used in the ABB products in the future. These alternative epoxy resin formulations and the reference epoxy resin with the formation E1/H1 were prepared to be compared and evaluated in terms of thermal properties, i.e., glass temperature (Tg), the heat of curing and color of cured epoxy resins. The epoxy resins with alternative formulations which shown relative high Tg values were selected to carry out other analysis, ie., mixing ration optimization, the influence of dissolved water on Tg values, degree of curing and water absorption behavior.

No description available.

Restoring both anterior and posterior teeth with resin-composite materials is now an established clinical procedure with almost universal acceptance. The clinical performance of these restorations in the patient’s mouth is determined by a number of factors including the clinical techniques involved in their placement, the patient’s oral habits, and the physical and mechanical properties of the restorative materials themselves. These materials are being increasingly used in load-bearing areas of the posterior dentition and are therefore inevitably subject to masticatory forces of varying magnitude. The success of different resin-composites in different applications is understood through their clinical performance and laboratory-based experimental evaluation.My research was divided into two parts; the first part was concerned with the examination of different types of contemporary restorative resin-composites and in the second part, I compared different methods of examination. In the first part, I investigated and compared different sets of varied types of resin-composites, such as flowable resin-composites, bulk-fill resin-composites and conventional resin-composites. Using different sets of these materials, I examined a number of properties that affect their clinical performance and durability.In the second part, I studied and compared the conventional (macroscopic) methods of investigation with nanoindentation method. Both methods were applied to examine and characterise different properties for some types of resin-composites.The flowable and the bulk-fill resin-composites exhibited satisfactory results comparable with conventional resin-composites. The properties investigated included strength properties, modulus of elasticity, hardness and viscoelastic time-dependent creep deformation. The results obtained by nanoindentation confirmed that this method of examination is a valuable experimental tool to investigate and characterise some mechanical properties of resin-composites.

Orientador: Flávio Henrique Baggio Aguiar / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-27T07:51:28Z (GMT). No. of bitstreams: 1 HernandesdaFonseca_NataliaMariaAparecida_D.pdf: 1562377 bytes, checksum: a4799c4175306d178b320a7dce350a1e (MD5) Previous issue date: 2015 / Resumo: Este estudo in vitro avaliou a influência do pré-aquecimento na resistência de união de três agentes utilizados para a cimentação de pinos de fibra de vidro Reforpost nº 2. Para tal propósito, foram utilizadas 42 raízes de pré-molares humanos previamente extraídos e com tratamento endodôntico realizado e foram divididos, aleatoriamente, em 6 grupos (n=7) de acordo com o agente de fixação (um cimento resinoso dual Rely X ARC; um cimento autoadesivo Rely X U200; e uma resina composta de baixa viscosidade SureFil SDR flow) e temperatura de pré-aquecimento (23ºC; 54ºC). Todos os agentes de cimentação foram fotoativados através de uma fonte de luz LED com irradiância de 1100 mW/cm² durante 40 segundos. As raízes foram armazenadas em água destilada à 37ºC por sete dias e foram cortadas em fatias com espessura de 1,0 mm cada, os quais foram divididos de acordo com o terço do canal radicular (cervical; médio; apical). Em seguida, as amostras foram submetidas ao teste de resistência ao cisalhamento por extrusão para a mensuração em cada terço do canal radicular. Os dados foram submetidos à ANOVA 3 critérios com parcelas subdivididas e teste de Tukey (? = 0,05). Foram encontradas diferenças significativas entre os três cimentos resinosos. (P < 0,0017); no entanto não foram encontradas diferenças entre os grupos não aquecidos e os grupos pré-aquecidos, diferentes regiões da raiz ou para qualquer interação entre os fatores (p > 0,05). Os grupos cimentados com o cimento resinoso Rely X ARC apresentou maiores resultados de resistência de união do que os grupos cimentados com a resina de baixa viscosidade SureFil SDR flow. O cimento autoadesivo Rely X U200 obteve resistência de união intermediária, sem diferença estatística para RelyX ARC ou SureFil SDR flow. Assim, conclui-se que, a utilização de cimento dual convencional pode ser indicada para cimentação de pinos de fibra de vidro e que o pré-aquecimento de cimentos resinosos não é efetivo para o aumento da resistência de união de pinos pré-fabricados / Abstract: This in vitro study investigated the influence of pre-heating on the bond strength of three agents used for cementing fiber posts Reforpost # 2. For that, forty-two human premolars roots with endodontic treatment performed were randomly divided into 6 groups (n = 7), according with the luting agent (a dual resin cement Rely X ARC; a self-adhesive cement Rely X U200; and a flowable composite SureFil SDR flow) and the pre-heating temperature (23° C; 54° C). All luting agents were light-cured with a LED unit ¿ 1,100 mW/cm² for 40 seconds. The roots were stored in distilled water at 37° C for seven days and after that, the roots were cut into slices of 1.0 mm thickness each, which were divided according to the third of the root canal (cervical; middle; apical). Then the specimens were submitted to push out test to measure the bond strength in each third of the root canal. Data were submitted to three-way split-spot ANOVA and Tukey's test (? = 0.05). Significant differences were found among the three luting agent studied (p < 0.0017); however, no difference was found among the pre-heating temperature, root segments or for any interaction between the factors (p > 0.05). Groups luted with resin cement Rely X ARC showed significant higher retentive strength than flowabe composite SureFil SDR flow. Rely X U200 showed intermediary retentive strength means, without statistical difference for Rely X ARC or SureFil SDR flow. Thus, it is concluded that the use of conventional dual cement should be indicated to luting fiber posts and the resin cement pre-heating is not effective to increase the retentive strength of fiber post / Doutorado / Dentística / Doutora em Clínica Odontológica