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Navegando FO - Artigos publicados em periódicos por Assunto "Aging"
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Item Effect of instrumentation techniques, irrigants solutions and artificial accelerated aging on fiberglass post bond strength to intraradicular dentine(2015) Santana, Fernanda Ribeiro; Soares, Carlos José; Silva, Júlio Almeida; Alencar, Ana Helena Gonçalves; Renovato, Sara Rodrigues; Lopes, Lawrence Gonzaga; Estrela, CarlosObjective: To evaluate the effect of instrumentation techniques, irrigant solutions and specimen aging on fiberglass posts bond strength to intraradicular dentine. Materials and methods: A total of 120 bovine teeth were prepared and randomized into control and experimental groups resulting from three study factors (instrumentation techniques, irrigant solutions, specimen aging). Posts were cemented with RelyX U100. Samples were submitted to push-out test and failure mode was evaluated under a confocal microscope. Results: In specimens submitted to water artificial aging, nickel-titanium rotary instruments group presented higher bond strength values in apical third irrigated with NaOCl or chlorhexidine. Irrigation with NaOCl resulted in higher bond strength than ozonated water. Artificial aging resulted in significant bond strength increase. Adhesive cement-dentin failure was prevalent in all the groups. Conclusion: Root canal preparation with NiTi instruments associated with NaOCl irrigation and ethylenediaminetetra acetic acid (EDTA) increased bond strength of fiberglass posts cemented with self-adhesive resin cement to intraradicular dentine. Water artificial aging significantly increased postretention.Clinical significance: The understanding of factors that may influence the optimal bond between post-cement and cementdentin are essential to the success of endodontically treated tooth restoration.Item Effect of root canal sealer and artificial accelerated aging on fibreglass post bond strength to intraradicular dentin(2014) Santana, Fernanda Ribeiro; Soares, Carlos José; Ferreira, Josemar Martins; Valdivia, Andréa Dolores Correia Miranda; Souza, João Batista de; Estrela, CarlosObjectives: To evaluate the effect of root canal sealers (RCS) and specimen aging on the bond strength of fibre posts to bovine intraradicular dentin. Material and Methods: 80 teeth were used according the groups - Sealapextm, Sealer 26®, AH Plus® and specimens aging - test with no aging and with aging. The canals prepared were filled using one of each RCS. The posts were cemented. Roots were cross-sectioned to obtain two slices of each third. Samples were submitted to push-out test. Failure mode was evaluated under a confocal microscope. The data were analysed by ANOVA, Tukey’s, and Dunnet tests (α = 0.05). Results: No significant difference was detected among RCS. Aged control presented higher bond strength than immediate control. The aging did not result significant difference. Adhesive cement-dentin failure was prevalent in all groups. Conclusions: RCS interfered negatively with bonding of fibreglass posts cemented with self-adhesive resin cement to intraradicular dentin.Item Influence of the resin cement color on the shade of porcelain venners after accelerated artificial aging(2013) Magalhães, Ana Paula Rodrigues de; Siqueira, Patrícia Correia de; Cardoso, Paula de Carvalho; Souza, João Batista de; Fonseca, Rodrigo Borges; Pires-de-Souza, Fernanda de Carvalho Panzeri; Lopes, Lawrence GonzagaObjectives: The aim of this study was to evaluate the influence of the color of the resin luting cement in the final shade of minimally invasive porcelain veneers after accelerated artificial aging (AAA). Material and methods: 20 bovine teeth were collected, prepared and divided into two groups. The roots were removed and the buccal surfaces were polished to obtain a flat surface. Porcelain discs (IPS Empress Esthetic) were produced to a standardized shade (ET1) and thickness (0.6mm). The teeth and the veneers surfaces were prepared according to manufacturer recommendations. For group I (n=10), the White-Opaque (WO) base-paste was used and for group II (n=10) the Yellow (Y) base-paste. Each specimen was photocured for 60 s. The specimens were next subjected to AAA. They were submitted to color readings with a spectrophotometer in three moments: after the preparation (only the substrate), after the cementation and polymerization of the veneers and after the AAA. Were obtained values of L*, a* and b* and the total color change was calculated (ΔE*). Values obtained were subjected to statistical analysis in SPSS 17.0 for Windows with a significance of 0.05. Results: When comparing the cements, the Y cement showed higher ΔE*, lower L* and higher b* after AAA than the WO. Conclusion: Both cements could mask the substrate color. With AAA, only the Y shade showed a ΔE* clinically unacceptable, becoming more yellow (higher b*) and losing lightness (lower L*).Item Influence of the resin cements color on the shade of porcelain venners after acelerated artificial aging(2013) Magalhães, Ana Paula Rodrigues de; Siqueira, Patrícia Correia de; Cardoso, Paula de Carvalho; Souza, João Batista de; Fonseca, Rodrigo Borges; Pires-de-Souza, Fernanda de Carvalho Panzeri; Lopes, Lawrence GonzagaObjectives: The aim of this study was to evaluate the influence of the color of the resin luting cement in the final shade of minimally invasive porcelain veneers after accelerated artificial aging (AAA). Material and methods: 20 bovine teeth were collected, prepared and divided into two groups. The roots were removed and the buccal surfaces were polished to obtain a flat surface. Porcelain discs (IPS Empress Esthetic) were produced to a standardized shade (ET1) and thickness (0.6mm). The teeth and the veneers surfaces were prepared according to manufacturer recommendations. For group I (n=10), the White-Opaque (WO) base-paste was used and for group II (n=10) the Yellow (Y) base-paste. Each specimen was photocured for 60 s. The specimens were next subjected to AAA. They were submitted to color readings with a spectrophotometer in three moments: after the preparation (only the substrate), after the cementation and polymerization of the veneers and after the AAA. Were obtained values of L*, a* and b* and the total color change was calculated (ΔE*). Values obtained were subjected to statistical analysis in SPSS 17.0 for Windows with a significance of 0.05. Results: When comparing the cements, the Y cement showed higher ΔE*, lower L* and higher b* after AAA than the WO. Conclusion: Both cements could mask the substrate color. With AAA, only the Y shade showed a ΔE* clinically unacceptable, becoming more yellow (higher b*) and losing lightness (lower L*).