956 resultados para silane grafting


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

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Objective: The purpose of this study was to assess the influence of conditioning methods and thermocycling on the bond strength between composite core and resin cement. Material and Methods: Eighty blocks (8x8x4 mm) were prepared with core build-up composite. The cementation surface was roughened with 120-grit carbide paper and the blocks were thermocycled (5,000 cycles, between 5 degrees C and 55 degrees C, with a 30 s dwell time in each bath). A layer of temporary luting agent was applied. After 24 h, the layer was removed, and the blocks were divided into five groups, according to surface treatment: (NT) No treatment (control); (SP) Grinding with 120-grit carbide paper; (AC) Etching with 37% phosphoric acid; (SC) Sandblasting with 30 mm SiO2 particles, silane application; (AO) Sandblasting with 50 mu m Al2O3 particles, silane application. Two composite blocks were cemented to each other (n=8) and sectioned into sticks. Half of the specimens from each block were immediately tested for microtensile bond strength (mu TBS), while the other half was subjected to storage for 6 months, thermocycling (12,000 cycles, between 5 degrees C and 55 degrees C, with a dwell time of 30 s in each bath) and mu TBS test in a mechanical testing machine. Bond strength data were analyzed by repeated measures two-way ANOVA and Tukey test (alpha=0.05). Results: The mu TBS was significantly affected by surface treatment (p=0.007) and thermocycling (p=0.000). Before aging, the SP group presented higher bond strength when compared to NT and AC groups, whereas all the other groups were statistically similar. After aging, all the groups were statistically similar. SP submitted to thermocycling showed lower bond strength than SP without thermocycling. Conclusion: Core composites should be roughened with a diamond bur before the luting process. Thermocycling tends to reduce the bond strength between composite and resin cement.

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This study sought to evaluate the resin micro-tensile bond strength (MTBS) stability of a leucite-reinforced ceramic after different ceramic etching protocols. The microtensile test had 40 ceramic blocks (5x5x6 mm) assigned to five groups (n=8), in accordance with the following surface etching protocols: NE nonetched (control); 9HF: hydrofluoric (HF) acid etching (9% HF)+wash/dry; 4HF: 4%HF+wash/dry; 5HF: 5%HF+wash/dry; and 5HF+N: 5%HF+neutralizer+wash/dry+ultrasonic-cleaning. Etched ceramic surfaces were treated with a silane agent. Next, resin cement blocks were built on the prepared ceramic surface and stored for 24 hours in distilled water at 37 degrees C. The specimens were then sectioned to obtain microtensile beams (32/block), which were randomly assigned to the following conditions, nonaged (immediate test) and aged (water storage for 150 days plus 12,000 thermal cycles), before the microtensile test. Bond strength data were submitted to one-way analysis of variance and Tukey test (alpha=0.05). Additional ceramic samples were subjected to the different ceramic etching protocols and evaluated using a scanning electron microscope (n=2) and atomic force microscopy (n=2). Aging led to a statistically significant decrease in the MTBS for all groups, except the untreated one (NE). Among the groups submitted to the same aging conditions, the untreated (NE) revealed inferior MTBS values compared to the 9HF and 4HF groups. The 5HF and 5HF+N groups had intermediate mean values, being statistically similar to the higher values presented by the 9HF and 4HF groups and to the lower value associated with the NE group. The neutralization procedure did not enhance the ceramic/resin cement bond strength. HF acid etching is a crucial step in resin/ceramic bonding.

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Objectives: This study investigated the repairs of resin composite restorations after using different surface treatments.Design: Eighty four truncated cones of Filtek Z350 were prepared and thermo-cycled (20,000 cycles). Surfaces were roughened with diamond bur and etched with 37% phosphoric acid. Those cones were divided into 7 groups (N=12): 1) Prime&Bond 2.1; 2) aluminum oxide sandblasting+Prime&Bond 2.1; 3) Er:YAG laser treatment+Prime&Bond 2.1; 4) 9.6% hydrofluoric acid for 2 min-Fsilane coupling agent.; 5) silane coupling agent; 6) auto-polymerized acrylic monomer+Prime&Bond 2.1; 7) Adper Scothbond SE. Teflon device was used to fabricate inverted truncated cones of repair composite over the surface-treated. The bonded specimens were stressed to failure under tension. The data were analyzed with oneway ANOVA and Tukey tests.Results: Mean repair strengths (SD, in MPa) were, Group-2: 18.8a; Group-1: 18.7a; Group-6: 13.4ab; Group-7: 9.5bc; Group-3: 7.5bcd; Group-4: 5.2cd; Group-5: 2.6d.Conclusions: The use of diamond bur and a conventional adhesive and the use of aluminum oxide sandblasting prior to adhesive provided a simple and cost-effective solutions to composite repair. Er:YAG laser, silane alone, 9.6% hydrofluoric acid plus silane or a self-etching adhesive results in inferior composite repair strengths. (C) 2015 Elsevier Ltd. All rights reserved.

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There is great genetic diversity of rambutan plants, thus, to establish commercial orchards culture, it is recommended the use of plants vegetatively propagated. Therefore, this research aimed to determine the best method of grafting, graft protection and type of rootstock for its propagation. The experiment was repeated in two seasons (autumn/winter and spring/summer). The experimental design was completely randomized in both experiments, with four replicates, each experimental unit consisted of 10 plants analyzed in a 4x2x2 factorial with four types of grafting (whip graft-WG; cleft graft -CG; wedge graft-WG; and inverted wedge graft-IWG;), 2 types of graft protection (Biodegradable and plastic) and 2 types of rootstock (without or with leaves). The variables analyzed in this study were: percentage of grafting success, number and length of buds (cm). For grafting performed in autumn /winter, both by cleft grafting as whip graft with biodegradable strip and rootstock leafless provided the best results in propagation of rambutan tree. The best results were observed during the autumn / winter.

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Statement of problem. Surface transformation with nonthermal plasma may be a suitable treatment for dental ceramics, because it does not affect the physical properties of the ceramic material.Purpose. The purpose of this study was to characterize the chemical composition of lithium disilicate ceramic and evaluate the surface of this material after nonthermal plasma treatment.Material and methods. A total of 21 specimens of lithium disilicate (10 mm in diameter and 3 mm thick) were fabricated and randomly divided into 3 groups (n=7) according to surface treatment. The control group was not subjected to any treatment except surface polishing with abrasive paper. In the hydrofluoric acid group, the specimens were subjected to hydrofluoric acid gel before silane application. Specimens in the nonthermal plasma group were subjected to the nonthermal plasma treatment. The contact angle was measured to calculate surface energy. In addition, superficial roughness was measured and was examined with scanning electron microscopy, and the chemical composition was characterized with energy-dispersive spectroscopy analysis. The results were analyzed with ANOVA and the Tukey honestly significant difference test (alpha=.05).Results. The water contact angle was decreased to 0 degrees after nonthermal plasma treatment. No significant difference in surface roughness was observed between the control and nonthermal plasma groups. Scanning electron microscopy and energy-dispersive spectroscopy images indicated higher amounts of oxygen (O) and silicon (Si) and a considerable reduction in carbon (C) in the specimens after nonthermal plasma treatment.Conclusions. Nonthermal plasma treatment can transform the characteristics of a ceramic surface without affecting its surface roughness. A reduction in C levels and an increase in 0 and Si levels were observed with the energy-dispersive spectroscopy analysis, indicating that the deposition of the thin silica film was efficient.

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The present work aimed to evaluate the initial growth and leaf mineral levels in passion fruit trees (Passiflora edulis f. flavicarpa Deg., P. edulis f. edulis Sims. and P. alata Dryander) grafted onto Passiflora cincinnata. To obtain seedlings, seeds were sown in plastic bags (500 mL) and hypocotyl grafting was performed when seedlings reached the stage of two fully expanded leaves. Fifteen days after grafting, plants were transplanted to 10L pots filled with previously limed and fertilized soil. Each pot contained two plants and corresponded to one plot. For each commercial species studied as rootstock, experimental design was completely randomized, in 3x5 (plant type x time of harvest) factorial arrangement, with four replicates of two plants per plot and five destructive harvests. Plant types were ungrafted P. cincinnata, ungrafted commercial passion fruit tree and commercial passion fruit tree grafted onto P. cincinnata. The first harvest was performed at 15 days after transplanting and the remaining ones at 14-day intervals (60, 74, 88, 102 and 116 DAS). At each harvest, the number of leaves per plant was counted, and leaf area, stem length, and stem, root, leaf and total dry matter were estimated. At the last harvest, the mineral composition (macro and micronutrients) of plants was analyzed. In general, it was observed that grafting onto P. cincinnata did not interfere negatively with the initial development and mineral levels of commercial passion fruit trees, and this interference varied according to the used canopy.

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Nematodes severely attack net melon plants under protected cultivation conditions. The objective of this research was to select rootstocks with resistance to Meloidogyne incognita and M. javanica. The experiment was carried out under greenhouse conditions from October 2010 to April 2011 in Jaboticabal, Sao Paulo state, Brazil. Thirty-three cucurbitaceous genotypes were investigated as rootstocks; melons: CNPH 01-930 (Cucumis melo var. flexuosus), CNPH 01-962, 01-963 CNPH (Cucumis melo var. conomon), cvs. Gaucho Redondo, Gaucho Comprido, Redondo Amarelo, Gulfcoast, Chilton, Bonus no. 2, Fantasy; watermelons: cv. Charleston Gray, Progenie da Coreia (Citrullus lanatus); pumpkins: cvs. Mra. Ma, Ornamental, Howden, Mammoth, Kururu, Goianinha (Cucurbita moschata); gourd: Abobora de Porco, cvs. Maranhao, Brasileirinha (Lagenaria siceraria); squash: cv. Pataca Gigante (Cucurbita maxima); cucumber: cvs. Caipira, Branco Meio Comprido, Curumim (Cucumis sativus); loofah: Metro, Semente Branca, Semente Preta (Luffa cylindrica); wax gourd (Benincasa hispida); pumpkin rootstock: Hybrid cv. Keij; snake gourd (Trichosanthes cucumerins) and musk cucumber (Sicana odorifera). To evaluate the resistance, seedlings were transplanted to pots and the root inoculated with 3,000 eggs and second stage juveniles of M. incognita and M. javanica. Fifty days after the inoculation, the plants were evaluated for nematode resistance by means of the reproduction factor. The grafting compatibility between net melon cvs. Bonus no. 2 and Fantasy and the rootstocks previously characterized as resistant were evaluated by means of 60 graftings. CNPH 01-962, CNPH 01-963 and melon 'Gaucho Redondo', were considered resistant to M. incognita. Melon 'Redondo Amarelo', watermelon 'Charleston Gray', watermelon Progenie da Coreia, Trichosanthes cucumerins were considered resistant to M. javanica. Benincasa hispida was resistant to M. javanica and M. incognita. The compatibility between net melons and resistant rootstocks was higher than 98%.

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

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The correction of bone defects can be performed using autogenous or alloplastic materials, such as beta-tricalcium phosphate (β-TCP). This study compared the changes in bone volume (CBV) after maxillary sinus lifting using autogenous bone (n=12), autogenous bone associated with β-TCP 1:1 (ChronOS; DePuy Synthes, Paoli, CA, USA) (n=9), and β-TCP alone (n=11) as grafting material, by means of cone beam computed tomography (CBCT). CBV was evaluated by comparing CBCT scans obtained in the immediate postoperative period (5-7 days) and at 6 months postoperative in each group using OsiriX software (OsiriX Foundation, Geneva, Switzerland). The results showed an average resorption of 45.7±18.6% for the autogenous bone group, 43.8±18.4% for the autogenous bone+β-TCP group, and 38.3±16.6% for the β-TCP group. All bone substitute materials tested in this study presented satisfactory results for maxillary sinus lifting procedures regarding the maintenance of graft volume during the healing phase before the insertion of implants, as assessed by means of CBCT.