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The aim of this study was to compare the effect of posts systems and the luting agent on bond strength. Thirty single-rooted bovine teeth were used. The specimens were randomly grouped into: Rely X Ultimate- shaped pin (ULT-M), ULT- accessory pin (ULT-A), ULT- Splendor SAP (ULT-S), Rely X U200 (U200-M), U200-A and U200-S. The specimens were sectioned (cervical, middle and apical thirds) and submitted to the push-out test using the universal testing machine EMIC DL200MF. The data obtained were submitted to the Kolmogorov-Smirnov test, and later to the analysis of variance (ANOVA), complemented by the Student-Newman-Kells (SNK) multiple comparison test. The proportions of the type of failure were compared using the Z test. The significance level was 5% for all tests. The interaction Rely-X U200 and Splendor SAP System was the only group with no statistically significant difference, in all thirds. With the use of the Rely-X U200, the modeled retainer performed better in the middle third. The lowest bond values were in the apical region. The use of accessory retainers promoted adequate values in the cervical and middle thirds. For Rely-X Ultimate, the modeled retainer had the lowest strength values. The same happened with the middle and apical third of the group with accessory pins. There is an influence of luting agents and posts systems on bond strength values. The failure pattern is directly related to the retention system*luting agents*root third interaction. El objetivo de este estudio es comparar el efecto de los sistemas de retención intrarradicular y del agente de cementación sobre la fuerza de adhesión. Se utilizaron 30 dientes de bovino no enraizados. Los especímenes se agruparon aleatoriamente en: Rely X Ultimate- pasador modelado (ULT-M), ULT- pasador accesorio (ULT-A), ULT- Splendor SAP (ULT-S), Rely X U200 (U200-M), U200-A y U200-S. Las muestras se seccionaron (tercios cervical, medio y apical) y se sometieron a la prueba de empuje con la máquina de ensayo universal EMIC DL200MF. Los datos obtenidos se sometieron a la prueba de Kolmogorov-Smirnov y, posteriormente, al análisis de la varianza (ANOVA), complementado con la prueba de comparaciones múltiples de Student-Newman-Kells (SNK). Las proporciones del tipo de fallo se compararon mediante la prueba Z. El nivel de significación fue del 5% para todas las pruebas. La interacción Rely-X U200 y el sistema SAP Splendor fue el único grupo sin diferencias estadísticamente significativas, en todos los tercios. Con el uso de Rely-X U200, el retenedor modelado presentó un mejor rendimiento en el tercio medio. Los valores de unión más bajos se encontraban en la región apical. El uso de retenedores accesorios proporcionó valores adecuados en los tercios cervical y medio. Para el Rely-X Ultimate, el retenedor modelado obtuvo los valores más bajos de resistencia. Lo mismo ocurrió en los tercios medio y apical del grupo con clavijas accesorias. Se puede concluir que existe una influencia de los agentes de cementación y de los sistemas de retención en los valores de resistencia de la adhesión. El patrón de fallo está directamente relacionado con la interacción sistema de retención*agente cementante*tercera. Este estudo teve por objetivo comparar o efeito dos sistemas de retenção intra-radicular e o agente cimentante na resistência de união. Foram utilizados trinta dentes bovinos unirradiculares. Os corpos-de-prova foram randomicamente agrupados em: Rely X Ultimate- pino modelado (ULT-M), ULT- pino acessório (ULT-A), ULT- Splendor SAP (ULT-S), Rely X U200 (U200-M), U200-A e U200-S. Os espécimes foram seccionados (terços cervical, médio e apical), e submetidos ao teste de push-out través da máquina de ensaio universal EMIC DL200MF. Os dados obtidos foram submetidos ao teste de Kolmogorov-Smirnov, e posteriormente a análise de variância (ANOVA), complementada pelo teste de comparações múltiplas de Student-Newman-Kells (SNK). O as proporções do tipo de falha foram comparadas pelo teste Z. O nível de significância foi de 5% para todos os testes. A interação Rely-X U200 e Sistema Splendor SAP foi o único grupo sem diferença estatística significativa, em todos os terços. Com a utilização do Rely-X U200, o retentor modelado apresentou melhor desempenho no terço médio. Os menores valores de união foram na região apical. A utilização de retentores acessórios promoveu adequados valores nos terços cervicais e médio. Para o Rely-X Ultimate, o retentor modelado obteve os menores valores de resistência. O mesmo ocorreu com o terço médio e apical do grupo com pinos acessórios. Conclui-se que há influência dos agentes cimentantes e dos sistemas de retenção nos valores de resistência de união. O padrão de falha está diretamente relacionado com a interação sistema de retenção*agente cimentantes*terço.

Mechanical compatibility with the human dentin is a considerable issue when fabricating dental fiber posts. To this purpose, this study introduces a new method of fabricating compatible dental posts using braiding techniques of thermoplastic fibers (matrix) with glass fibers (reinforcement). Fifty fiber-reinforced composite (FRC) posts of thermoplastic yarns polypropylene (PP) braided with continuous filaments glass fibers (GFs) for reinforcement, varying in fiber volume fraction (FVF), and core types are fabricated and tested. Posts are performed using a braiding machine, and braids are placed in an aluminum mold. The filled mold is playced inside an oven at the melting temperature of the polypropylene to produce the final post’s shape. An ultrasonic test is conducted to measure the shear modulus and Young’s modulus of FRC post specimens by measuring the velocities of both the P-wave and S-wave. In order to ensure the accuracy of the measurements, each sample is measured three times, and then the means and standard deviations of each sample are calculated before analyzing the test results using the means of two steps, namely, clustering and comparing the P and R² values of each cluster, which revealed that FVF, fiber mass, and core type of the specimen had a significant effect on the resulted Young’s and shear modulus. The results indicate that the proposed method can fabricate competitive dental posts with regard to different fabricating variables. The samples show Young’s modulus ranges of from 10.08 GPa to 31.83 GPa. The following tested hypothesis is supported: the braiding technique of thermoplastic fibers with glass fibers will improve the mechanical compatibility of the resulting posts (ex vivo)., Ministry of Science and Innovation, Spain grant numbers DPI2017-83859-R, PID2019-106947RA-C22, (FEDER) EQC2018-004508-P, Ministry of Health, Spain, grant number PI16/00339, Junta de Andalucía IE2017-5537 and PI-0107-201, Erasmus+