978 resultados para symboles de condensation


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Introduction: Lateral condensation effectiveness may be influenced by the gutta-percha and finger spreader taper used during root canal obturation. Objective: To evaluate the penetration ability of finger spreader into simulated root canals prepared using MTwo rotary system and filled with different gutta-percha and finger spreader tapers. Material and methods: Resin blocks with curved root canals had the apical diameter enlarged up to #25.06 and distributed into groups (n = 6) according to the gutta-percha taper (#25.02, #25.04, and #25.06) and the finger spreader (#30 and #35 NiTi, and stainless steel B) used to perform cold lateral condensation. After applying a load of 1.5 Kg over the finger spreaders’ head, the distance between the finger spread tip and the apical limit of the root canal preparation were obtained. The data were submitted to Anova and Tukey-Krammer’s test, with 5% of significance. Results: The gutta-percha cones with 0.02 taper enabled higher finger spreader penetration when compared to 0.04 and 0.06 tapers (p < 0.05), which were similar between each other (p > 0.05), regardless of the type and diameter of the finger spreader used. When different finger spreaders were compared among themselves, stainless steel B showed higher penetration ability (p < 0.05). Conclusion: It was concluded that the stainless-steel finger spreaders showed superior penetration ability and gutta-percha with lower tapers enabled a more effective lateral condensation at the apical third.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Engenharia Mecânica - FEIS

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Pós-graduação em Medicina Veterinária - FCAV

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Objectives: This report highlights phytoconstituents present in Cissus quadrangularis (CQ) extract and examines biphasic (proliferative and anti-proliferative) effects of its extract on bone cell proliferation, differentiation, mineralization, ROS generation, cell cycle progression and Runx2 gene expression in primary rat osteoblasts. Materials and methods: Phytoconstituents were identified using gas chromatography-mass spectroscopy (GC-MS). Osteoblasts were exposed to different concentrations (10-100g/ml) of CQ extract and cell proliferation and cell differentiation were investigated at different periods of time. Subsequently, intracellular ROS intensity, apoptosis and matrix mineralization of osteoblasts were evaluated. We performed flow cytometry for DNA content and real-time PCR for Runx2 gene expression analysis.Results: CQ extract's approximately 40 bioactive compounds of fatty acids, hydrocarbons, vitamins and steroidal derivatives were identified. Osteoblasts exposed to varying concentrations of extract exhibited biphasic variation in cell proliferation and differentiation as a function of dose and time. Moreover, lower concentrations (10-50g/ml) of extract slightly reduced ROS intensity, although they enhanced matrix mineralization, DNA content in S phase of the cell cycle, and levels of Runx2 expression. However, higher concentrations (75-100g/ml) considerably induced the ROS intensity and nuclear condensation in osteoblasts, while it reduced mineralization level, proportion of cells in S phase and Runx2 level of the osteogenic gene.Conclusions: These findings suggest that CQ extract revealed concentration-dependent biphasic effects, which would contribute notably to future assessment of pre-clinical efficacy and safety studies.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The aims of this study were to evaluate the effect of root canal filling techniques on root fracture resistance and to analyze, by finite element analysis (FEA), the expansion of the endodontic sealer in two different root canal techniques. Thirty single-rooted human teeth were instrumented with rotary files to a standardized working length of 14 mm. The specimens were embedded in acrylic resin using plastic cylinders as molds, and allocated into 3 groups (n=10): G(lateral) - lateral condensation; G(single-cone) - single cone; G(tagger) - Tagger's hybrid technique. The root canals were prepared to a length of 11 mm with the #3 preparation bur of a tapered glass fiber-reinforced composite post system. All roots received glass fiber posts, which were adhesively cemented and a composite resin core was built. All groups were subjected to a fracture strength test (1 mm/min, 45°). Data were analyzed statistically by one-way ANOVA with a significance level of 5%. FEA was performed using two models: one simulated lateral condensation and Tagger's hybrid technique, and the other one simulated the single-cone technique. The second model was designed with an amount of gutta-percha two times smaller and a sealer layer two times thicker than the first model. The results were analyzed using von Mises stress criteria. One-way ANOVA indicated that the root canal filling technique affected the fracture strength (p=0.004). The G(lateral) and G(tagger) produced similar fracture strength values, while G(single-cone) showed the lowest values. The FEA showed that the single-cone model generated higher stress in the root canal walls. Sealer thickness seems to influence the fracture strength of restored endodontically treated teeth.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Odontologia Restauradora - ICT