973 resultados para microtensile bond strength test
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Pós-graduação em Odontologia Restauradora - ICT
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Pós-graduação em Odontologia Restauradora - ICT
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Pós-graduação em Odontologia Restauradora - ICT
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The aim of the present study was to determine the association between abdominal muscle strength and quality of life among older adults with lumbar osteoarthritis. A blind, cross-sectional study was conducted involving 40 older adults: 20 with lumbar osteoarthritis (12 women and 8 men, mean age of 65.90 ± 4.80 years) and 20 controls (14 women and 6 men, mean age of 67.90 ± 4.60 years). The volunteers were submitted to an abdominal muscle strength test. Quality of life was evaluated using the SF-36 questionnaire. Both abdominal muscle strength and quality of life scores were significantly lower in the group with lumbar osteoarthritis in comparison to the controls (p < 0.05). Moreover, significant and positive associations were found between abdominal muscle strength and the subscales of the SF-36 questionnaire (p < 0.05, 0.421 ≥ rs ≤ 0.694). Based on the present findings, older adults with lumbar osteoarthritis with greater abdominal muscle strength have a better quality of life.
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Pós-graduação em Ciências Odontológicas - FOAR
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O sucesso das restaurações metálicas indiretas depende, dentre outros fatores, de uma união eficaz entre a estrutura metálica e o cimento dentário empregados. Sabe-se que os primers para metal atuam com comprovada eficácia na resistência adesiva dos cimentos resinosos às ligas nobres. Entretanto, pouco foi estudado sobre o efeito de tais materiais em ligas não nobres. O propósito deste estudo foi avaliar a eficácia de primers para metal na resistência ao cisalhamento da união entre cimentos resinosos e metais não nobres. Discos (9 mm de diâmetro e 3 mm de altura) foram fundidos em liga de NiCr (n=80) e em titânio comercialmente puro (Ti c.p.) (n=80) e foram incluídos em anel de PVC com resina acrílica quimicamente ativada. As superfícies dos discos foram regularizadas com lixas de carbeto de silício de granulação 320, 400 e 600 e jateadas com partículas de óxido de alumínio de 50 µm. Espécimes de cada metal foram divididos em quatro grupos (n=20). Uma matriz metálica bi-partida (5 mm de diâmetro interno e 2 mm de altura) foi posicionada na superfície do espécime. As áreas adesivas receberam um dos seguintes tratamentos: 1) Panavia F; 2) Alloy Primer e Panavia F; 3) Bistite DC e 4) Metaltite e Bistite DC. Para evitar a exposição dos cimentos à luz, estes foram espatulados e inseridos na matriz dentro de uma câmara de revelação radiográfica. Quarenta minutos após a confecção, os espécimes foram armazenados em água destilada a 37ºC por 24 horas e então termociclados (1.000 ciclos, 5ºC e 55ºC, 30 segundos cada banho). Após a termociclagem, os espécimes foram armazenados novamente nas mesmas condições descritas anteriormente por um período de 24 horas (n=10) ou de 6 meses (n=10) antes do ensaio de cisalhamento em uma máquina de ensaios mecânicos (Material Test System 810).
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O objetivo do presente estudo foi investigar a influência da pressão intrapulpar e da profundidade dentinária sobre o desempenho adesivo de dois agentes de união à dentina, Single Bond (3M ESPE, St. Paul, MN, EUA) e Clearfil SE Bond (Kuraray, Tokyo, Japão), aplicados in vitro e in vivo. Quarenta e oito prémolares superiores hígidos foram selecionados e os pares pertencentes aos mesmos pacientes foram aleatoriamente distribuídos em 4 grupos experimentais de acordo com o sistema adesivo e a pressão intrapulpar, presente ou ausente. Dos dentes pertencentes ao mesmo par, um foi tratado in vivo e o outro in vitro. A ausência ou presença de pressão intra-pulpar foi determinada in vivo pelo uso de anestésicos locais com ou sem vasoconstritor, respectivamente. In vitro, os dentes foram mantidos sob pressão hidrostática de 15 cm de água por 24 horas. Cavidades de classe I foram preparadas e os sistemas adesivos aplicados de acordo com a recomendação dos fabricantes, seguidos da restauração incremental em resina composta. Para os dentes tratados in vitro, os mesmos procedimentos restauradores foram realizados após 6 meses de armazenagem em solução contendo timol 0,1%. Espécimes com área de secção transversal de 1 mm2 foram obtidos e submetidos ao ensaio mecânico de microtração. In vivo, ambos os sistemas adesivos apresentaram desempenho adesivo comparável, enquanto in vitro, o sistema Single Bond foi superior ao sistema Clearfil SE Bond. Esse último não foi influenciado por nenhuma das variáveis estabelecidas no estudo, ou seja, aplicação in vitro ou in vitro, presença de pressão intrapulpar e profundidade em dentina. O sistema Single Bond aplicado sob pressão intrapulpar positiva sofreu variação significante de resistência de união em função da profundidade da dentina, ou seja, em dentina profunda seu desempenho adesivo... (Resumo completo, clicar acesso eletrônico abaixo)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The aim of this study it was to evaluate the use of irrigating solution used during root canal preparation on the adhesive cementation of prefabricated fiberglass pins. The bond strength between different regions of the root and the fiberglass pins cemented into the root canal were evaluated by push-out assay. For this study, 36 human teeth were used, all equally prepared. The irrigating solutions used for biomechanical preparation were: saline solution, sodium hypochlorite 2,5% and glycolic extract of salvia 20%. The dual cure resin cement was used for cementation of pins. After cementation, specimens were sectioned to give 3 slices of approximately 2 mm each (cervical, middle and apical), which were submitted to mechanical push-out test. Were performed ANOVA and Tukey's test with a significance level of 5%, for the analysis of mechanical test. Comparing the thirds we observed that the only solution that presented statistical difference in the bond strength was sodium hypochlorite, which showed higher values for the middle and apical third compared with the cervical third, but when compared without taking into consideration the dental thirds, solutions studied showed no differences in bond strength. Therefore, it was concluded that the solutions studied can be used during endodontic treatment without causing harmful effects on the final adhesive restoration
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To evaluate the effect of surface treatment with Er:YAG and Nd:YAG laser on resin composite bond strength to recently bleached dentin. Material and Methods: In this study 120 bovine incisors were used and distributed into two groups: Group C: without bleaching treatment; Group B: with bleaching treatment (35% hydrogen peroxide). Each group was divided into three subgroups: Subgroup N: without laser treatment; Subgroup Nd: irradiation with Nd:YAG laser; Subgroup Er: irradiation with Er:YAG laser. Next, the adhesive system (Adper Single Bond 2) was applied and composite buildups were constructed with Z350 composite. The teeth were sectioned to obtain dentin-resin sticks (1x1mm) and analyzed by microtensile bond testing. The data were statistically analyzed by the ANOVA and Tukey tests. Results: The results showed that the bond strength values in the bleached control group (16.17 MPa) presented no significant difference in comparison with the group bleached and irradiated with Er:YAG laser (14.69 MPa). The non bleached control group (26.79 MPa) presented significant difference in bond strength when compared with the non bleached group irradiated with Er:YAG laser (22.82 MPa) and with the group treated by bleaching and irradiation with Nd:YAG laser (28,792 MPa). The group without bleaching treatment and irradiated with Nd:YAG (36.1 MPa) presented a significant increase in bond strength in comparison with the other groups. Conclusion: The use of Nd:YAG laser on bleached specimens was able of completely reversing the immediate effects of bleaching, obtaining bond strength values similar to those of the control group
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Pós-graduação em Odontologia - FOAR
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Pós-graduação em Odontologia Restauradora - ICT
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This study evaluated in vitro the shear bond strength of brackets bonded with xenon plasma arc light, light-emitting diode (LED) and conventional halogen light using different curing times. Brackets were bonded to the buccal surface of 60 human maxillary premolars allocated to five groups. In groups 1 and 2, the resin was cured with the plasma arc for three and six seconds (s), respectively; in groups 3 and 4, the LED was used for five and ten s, respectively; and in group 5, the halogen light was used for 40 s. The specimens were stored in water for 24 hours and subjected to a shear force until bracket failure. The debonding pattern was classified according to the adhesive remnant index (ARI). The results were assessed by Anova and the SNK post-hoc test. No differences were detected among groups 2, 4 and 5, which showed higher averages than groups 1 and 3, which were not different between themselves. The ARI scores showed no differences among the three types of light sources in all times tested. Plasma arc and LED lights can be used with shorter curing times, within certain limits, than conventional halogen light for bonding orthodontic brackets, without decreasing bond strength.
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The purpose of this study was to use a fluorescent dye and CLSM microscope to observe the effect of different light intensities on dentin tensile bond strength. Flat dentin surfaces were created on 16 intact human third molars and divided in 4 groups: Group G1 - halogen - KM -200R®; Group G2 - LED - Ultraled®; Group G3 - LED - UltraLume LED5® and Group G4 - LED - Biolux Single V®. For all the groups, the restoration procedure used Single Bond® adhesive, mixed with rodamin B and InTen-S® composite resin. Then, they were cut on serial sections to obtain 1 mm2 area and submitted to micro tensile test and after words, the fractures were analyzed with a digital microscope and CLSM. The statistical analysis showed that all in all groups, except Group G2, which had a significant smaller tensile bond strength ratio. The fracture mode analysis showed that there were significant differences when comparing groups G1 / G2, and G2 / G4. There is no evidence of relevant differences among the other groups. With these results, we conclude that the use of fluorescent dye and CLSM demonstrated to be a simple and nondestructive technique, and that there are evidences that light intensities influenced the dentine tensile.