967 resultados para electrolytic etching
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Background. We sought to establish an anesthetic protocol to evaluate the hemodynamic, metabolic, and electrolytic changes after graft reperfusion in pigs undergoing orthotopic intestinal transplant (ITX).Methods. Fifteen pigs were distributed into two groups: GI (n = 6), without immunosuppression, and GII (n = 9), immunosuppressed before surgery with tacrolimus (0.3 mg/kg). The animals were premedicated at 1 hour before surgery with IM acepromazine (0.1 mg/kg), morphine (0.4 mg/kg), ketamine (10 mg/kg), and atropine (0.044 mg/kg IM). Anesthesia induction used equal proportions of diazepam and ketamine (0.1-0.15 mL/kg/IV) and for maintenance in IV infusion of xylazine (1 mg/mL), ketamine (2 mg/mL), and guaiacol glyceryl ether 5% (50 mg/mL), diluted in 250 mL of 5% glucose solution. In addition, recipient pigs were treated with isofluorane inhalation. Heart rate (HR), systolic (SAP), mean (MAP), and diastolic (DAP) arterial pressure, pulse oximetry, respiratory frequency (f), capnography, body temperature (T), blood gas analysis (pH, PaCO(2), PaO(2), base excess, BE; HCO(3)(-), SatO(2)), serum potassium (K), calcium (Ca), sodium, hematocrit (Hct), and glucose (Glu) were measured at four times; MO: after incision (basal value); M1: 10 minutes before reperfusion; and M2 and M3: 10 and 20 minutes after graft reperfusion.Results. All groups behaved in a similar pattern. There was significant hypotension after graft reperfusion in GI and GII (M2 = 56.2 +/- 6.4 and M3 = 57.2 +/- 8.3 mm Hg and M2 = 65.7 +/- 10.2 and M3 = 67.8 +/- 16.8 mm Hg, respectively), accompanied by elevated HR. The ETCO(2) was elevated at M2 (42 mm Hg) and M3 (40 mm Hg). Metabolic acidosis was observed after reperfusion, with significant increase in K levels.Conclusion. The anesthetic protocol for donors and recipients was safe to perform the procedure, allowing control of hemodynamic and metabolic changes after reperfusion without differences regarding immunosuppression.
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The purpose of this study was to evaluate the effect of erbium:yttrium-aluminum-garnet (Er:YAG) laser (2.94 mu m) irradiation on the removal of root surface smear layer of extracted human teeth and to compare its efficacy with that of citric acid, ethylenediamine tetra-acetic acid (EDTA), or a gel containing a mixture of tetracycline hydrochloride (HCl) and citric acid, using scanning electron microscopy (SEM). Thirty human dentin specimens were randomly divided into six groups: G1 (control group), irrigated with 10 ml of physiologic saline solution; G2, conditioned with 24% citric acid gel; G3, conditioned with 24% EDTA gel; G4, conditioned with a 50% citric acid and tetracycline gel; G5, irradiated with Er:YAG laser (47 mJ/10 Hz/5.8 J/cm(2)/pulse); G6, irradiated with Er:YAG laser (83 mJ/10 Hz/10.3 J/cm(2)/pulse). Electron micrographs were obtained and analyzed according to a rating system. Statistical analysis was conducted with Kruskal-Wallis and Mann-Whitney tests (P < 0.05). G1 was statistically different from all the other groups; no statistically significant differences were observed between the Er:YAG laser groups and those undergoing the other treatment modalities. When the two Er:YAG laser groups were compared, the fluency of G6 was statistically more effective in smear layer removal than the one used in G5 (Mann-Whitney test, P < 0.01). Root surfaces irradiated by Er:YAG laser had more irregular contours than those treated by chemical agents. It can be concluded that all treatment modalities were effective in smear layer removal. The results of our study suggest that the Er:YAG laser can be safely used to condition diseased root surfaces effectively. Furthermore, the effect of Er:YAG laser irradiation on root surfaces should be evaluated in vivo so that its potential to enhance the healing of periodontal tissues can be assessed.
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The purpose of this study was to evaluate stress distribution in the hybrid layer produced by two adhesive systems using three-dimensional finite element analysis (FEA). Four FEA models (M) were developed: Mc, a representation of a dentin specimen (41 x 41 x 82 mu m) restored with composite resin, exhibiting the adhesive layer, hybrid layer (HL), resin tags, peritubular dentin, and intertubular dentin to simulate the etch-and-rinse adhesive system; Mr, similar to Mc, with lateral branches of the adhesive; Ma, similar to Mc, however without resin tags and obliterated tubule orifice, to simulate the environment for the self-etching adhesive system; Mat, similar to Ma, with tags. A numerical simulation was performed to obtain the maximum principal stress (sigma(max)). The highest sigma(max) in the HL was observed for the etch-and-rinse adhesive system. The lateral branches increased the sigma(max) in the HL. The resin tags had a little influence on stress distribution with the self-etching system. (C) 2012 Elsevier Ltd. All rights reserved.
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Objectives: the purpose of this study is to employ optical microscopy to measure the thickness of the hybrid layer and the penetration (tags) of an aggressive self-etching adhesive system into sound dentin.Methods: occtusat cavities were prepared in 40 extracted human posterior teeth. The prepared teeth were randomly assigned to four experimental groups with 10 specimens each. The self-etching adhesive system Adper Prompt L-Pop was applied to the dentin surface as follows: Group 1: cavosurface enamel was etched for 60 s and dentin for 20 s with 35% phosphoric acid get, immediately followed by application of the self -etching adhesive with a brush to the entire cavity for 15 s; Groups 2, 3, and 4: no pre-etching was performed, and the self -etching adhesive was applied to both enamel and dentin for 15, 30 and 45 s, respectively. After curing, the cavities were fitted with composite resin Fittek Z250. Afterwards, the teeth were decalcified and the restorations were carefully removed for later embedding in paraffin. The specimens were serially sectioned at 6 mu m of thickness and sequentially mounted in glass slides. These sections were stained with Brown and Brenn staining for posterior analysis and measurement of the hybrid layer and resin tags on a tight microscope with a micrometric ocular 40/075. The results were submitted to analysis of variance at the 5% level.Results: whenever there was significance, the Tukey test was applied at the 5% level. The specimens receiving application of acid etching before the selfetching. adhesive displayed a larger thickness of the hybrid layer; on the other hand, specimens receiving only application of the self -etching adhesive on dentin for 15, 30 and 45 s exhibited similar thickness of the hybrid layer. As regards the resin tags, no statistically significant differences could be found between the study groups.Conclusions: it could be concluded that the increase in the time of application of the self-etching adhesive Adper Prompt L-Pop did not significantly influence the formation and thickness of hybrid layer, as well as its penetration into the sound dentin surface. (c) 2005 Elsevier Ltd. All rights reserved.
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Objective. The aim of this study was to investigate the influence of shortening the etching time on the bond strength of a conventional and a self-etching primer adhesive system used in primary tooth dentin.Methods. Flat dentin surfaces were obtained from 24 primary molars, randomly assigned to 4 experimental groups. The adhesive systems Single Bond and Clearfil SE Bond were applied in two groups according to the manufacturers' recommendations. In the other two groups, the adhesives were applied after half-time of acid etching, 7 s for Single Bond and 10 s for Clearfil SE Primer. Resin crowns were built up and after 24 h storage in water at 37 &DEG; C, the teeth were sectioned to produce beams with cross-sectional area of approximately 0.49 mm(2). Specimens were tested in tension at 0.5 mm/min until failure. Fractured specimens were analyzed to determine the failure mode.Results. Tensile bond strengths for Single Bond in primary dentin were higher than for Clearfil SE Bond. Shortening of acid etching time improved bond strength only for Single Bond, while no statistically significant difference was observed for Clearfil SE Bond when both etching times were compared.Significance. No detrimental effect on bond strength was observed when the time of acid etching was shortened in 50%. Shortening the time for a procedure in a small child without compromising the quality of the work is a very important finding for the practicing pediatric dentist. © 2004 Elsevier Ltd. All rights reserved.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Objectives: The incorporation of antibacterial agents into adhesive systems has been proposed to eliminate residual bacteria from dentine. This study used the agar diffusion method to evaluate the antibacterial activity of Clearfil Protect Bond (CPB), Clearfil SE Bond (CSEB), Clearfil Tri-S Bond (C3SB) and Xeno-III (XIII) self-etching adhesive systems, with or without light-activation, against cariogenic bacteria, and to assess the influence of human dentine on the antibacterial activity of these materials.Methods: An aliquot of 10 mu l per material (and individual components) were pipetted onto paper and dentine discs distributed in Petri dishes containing bacterial culture in BHI agar. Positive control was 0.2% chlorhexidine digluconate (CHX).Results: After incubation, the adhesive components of CPB and CSEB, liquid A of XIII and C3SB did not present antibacterial activity when applied to paper discs. The non-light-activated CPB primer + adhesive promoted the greatest inhibition of Streptococcus mutans (p < 0.05), whereas with light-activation, there was no significant difference between primer + adhesive and primer alone. For Lactobacillus acidophilus, CPB primer presented the greatest antibacterial activity in both light-activation conditions (p < 0.05). Regarding the dentine discs, only CHX promoted an inhibitory effect, though less intense than on paper discs (p < 0.05). CHX presented greater antibacterial activity against S. mutans than against L. acidophilus (p < 0.05).Conclusions: Light-activation significantly reduced the antibacterial activity of the self-etching adhesive systems; MDPB incorporation contributed to the effect of adhesive systems against cariogenic bacteria; the components eluted from the adhesive systems were not capable to diffuse through 400 mu m-thick dentine disc to exert their antibacterial activity against cariogenic bacteria. (C) 2008 Elsevier Ltd. All rights reserved.
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Water and sodium chloride intake was studied in male Holtzman rats weighing 250-300 g that had been subjected to electrolytic and chemical lesions of the septal area (SA). Water intake increased in animals with electrolytic lesion of the SA bilaterally from 169.37 +/- 8.55 (sham) to 214.87 +/- 23.10 ml/5 days (lesioned). Water intake decreased after ibotenic acid lesion of the SA from 229.33 +/- 27.60 to 127.33 +/- 22.84 ml/5 days. Sodium chloride intake (1.5%) increased in animals with electrolytic lesion of the SA from 10.0 +/- 1.73 to 15.5 +/- 1.95 ml/5 days after lesion. Also sodium chloride (1.5%) intake increased after ibotenic acid injection into the SA to a greater extent (from 7.83 +/- 1.25 to 14.33 +/- 1.87 ml/5 days). The results indicate that the water intake response may be due to lesions that involve cell bodies and fibers of passage and that the sodium intake response can also be induced by lesions which involve only cell bodies. Finally, these results led us to conclude that the SA uses its cell bodies and afferent bodies and fibers for processing inputs mediating water intake and salt appetite and that the cells bodies of the SA are implicated in increased water intake. (C) 1998 Elsevier B.V.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Purpose: The aim of this study was to evaluate the influence of dentin abrasion on the microshear bond strength of two self-etching adhesive systems, using either an ultrasound diamond bur or a high-speed diamond bur.Materials and Methods: Twenty noncarious human third molars were sectioned mesiodistally into halves. The enamel was ground to expose a flat dentin surface on both sections. The dentinal surfaces were randomly assigned to two groups, depending on the method of smear layer preparation: ultrasound diamond bur (UB) or conventional diamond bur (CB). The prepared dentin surfaces received one of two self-etching systems: Clearfil SE Bond (CF) and One-Up Bond F (OB). A composite cylinder with a 0.95-mm diameter was bonded to each specimen and the microshear bond test was performed. The results were expressed in MPa and were subjected to two-way analysis of variance (ANOVA) and Tukey's test (alpha = 0.05).Results: There was no significant difference in dentin bond strength when comparing the conventional and ultrasonic abrasion methods. When the adhesive systems were compared, Clearfil SE Bond achieved higher bond strength means than did One-Up Bond F.Conclusion: The dentin surface preparation method did not influence the microshear bond strength and the Clearfil SE Bond adhesive system, independent of bur type used, Clearfil SE Bond showed higher bond strengths than did the One-Up Bond F adhesive system.