Pulp response after application of two resin modified glass ionomer cements (RMGICs) in deep cavities of prepared human teeth

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

IMPROVEMENT TO THE MARGINAL COPING FIT of COMMERCIALLY PURE TITANIUM CAST IN PHOSPHATE-BONDED INVESTMENT BY USING A SIMPLE PATTERN COATING TECHNIQUE

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

A study of a numerical solution of the steady two dimensions Navier-Stokes equations in a constricted channel problem by a compact fourth order method

We present a numerical solution for the steady 2D Navier-Stokes equations using a fourth order compact-type method. The geometry of the problem is a constricted symmetric channel, where the boundary can be varied, via a parameter, from a smooth constriction to one possessing a very sharp but smooth corner allowing us to analyse the behaviour of the errors when the solution is smooth or near singular. The set of non-linear equations is solved by the Newton method. Results have been obtained for Reynolds number up to 500. Estimates of the errors incurred have shown that the results are accurate and better than those of the corresponding second order method. (C) 2002 Elsevier B.V. All rights reserved.

Effect of splinting in accuracy of two implants impression techniques

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

Comparison between two methods for cardiac output measurement in propofol-anesthetized dogs: thermodilution and Doppler

ObjectiveTo compare cardiac output (CO) measured by Doppler echocardiography and thermodilution techniques in spontaneously breathing dogs during continuous infusion of propofol. To do so, CO was obtained using the thermodilution method (CO(TD)) and Doppler evaluation of pulmonary flow (CO(DP)) and aortic flow (CO(DA)).Study designProspective cohort study.AnimalsEight adult dogs weighing 8.3 +/- 2.0 kg.MethodsPropofol was used for induction (7.5 +/- 1.9 mg kg-1 IV) followed by a continuous rate infusion at 0.7 mg kg-1 minute-1. The animals were positioned in left lateral recumbency on an echocardiography table that allowed for positioning of the transducer at the 3rd and 5th intercostal spaces of the left hemithorax for Doppler evaluation of pulmonary and aortic valves, respectively. CO(DP) and CO(DA) were calculated from pulmonary and aortic velocity spectra, respectively. A pulmonary artery catheter was inserted via the jugular vein and positioned inside the lumen of the pulmonary artery in order to evaluate CO(TD). The first measurement of CO(TD), CO(DP) and CO(DA) was performed 30 minutes after beginning continuous infusion (T0) and then at 15-minute intervals (T15, T30, T45 and T60). Numeric data were submitted to two-way anova for repeated measurements, Pearson's correlation coefficient and Bland & Altman analysis. Data are presented as mean +/- SD.ResultsAt T0, CO(TD) was lower than CO(DA). CO(DA) was higher than CO(TD) and CO(DP) at T30, T45 and T60. The difference between the CO(TD) and CO(DP), when all data were included, was -0.04 +/- 0.22 L minute-1 and Pearson's correlation coefficient (r) was 0.86. The difference between the CO(TD) and CO(DA) was -0.87 +/- 0.54 L minute-1 and r = 0.69. For CO(TD) and CO(DP), the difference was -0.82 +/- 0.59 L minute-1 and r = 0.61.ConclusionDoppler evaluation of pulmonary flow was a clinically acceptable method for assessing the CO in propofol-anesthetized dogs.

Longitudinal study of daily variation of rats' behavior in the elevated plus-maze

We conducted a longitudinal study about daily variation of Wistar male rats' behavior in the elevated plus-maze (EPM) evaluated in the 1st, 2nd, 3rd, 6th, 12th, and 18th months of life. Animals were submitted to the plus-maze in 12 sessions at 2-h intervals (n=72, 6 per time point). Spontaneous rest-activity rhythm of four animals was assessed by observation of 24-h videotape records. Time series were analyzed by Cosinor method. Behavioral rates on the six occasions and in light and dark phases were compared by means of two-way ANOVA with repeated measures. Exploratory behavior in EPM was smaller in the light phase and in older animals. Higher values of open and closed arms exploration were observed in the first and third months of the dark phase, and in the first month of the light phase. Adjustment to the 24-h period was significant at all stages for rest-activity data, number of entries in closed arms, and time on center, and for three to five stages for open-arm exploration. In general, 24 h variability was more pronounced in younger animals compared with older ones. The present study showed that: (1) a significant amount of total variability of the behavioral indexes analyzed could be attributed to 24 h variation, (2) light/dark phases differences in EPM exploration were present at all developmental stages, (3) older Wistar rats explored less the EPM and were less active in their home cage compared with younger ones, and (4) behavioral indexes (EPM) decrease was phase related and partially related to a reorganization of rest-activity rhythm. (C) 2003 Elsevier B.V. All rights reserved.

Scattering of neutral fermions by a pseudoscalar potential step in two-dimensional spacetime

The problem of scattering of neutral fermions in two-dimensional spacetime is approached with a pseudoscalar potential step in the Dirac equation. Some unexpected aspects of the solutions beyond the absence of Klein's paradox are presented. An apparent paradox concerning the uncertainty principle is solved by introducing the concept of effective Compton wavelength. Added plausibility for the existence of bound-state solutions in a pseudoscalar double-step potential found in a recent Letter is given. (C) 2003 Elsevier B.V. B.V. All rights reserved.

Confinement of spinless particles by Coulomb potentials in two-dimensional space-time

The problem of confinement of spinless particles in 1 + 1 dimensions is approached with a linear potential by considering a mixing of Lorentz vector and scalar couplings. Analytical bound-states solutions are obtained when the scalar coupling is of sufficient intensity compared to the vector coupling. (c) 2005 Elsevier B.V. All rights reserved.

Confinement of fermions by mixed vector-scalar linear potentials in two-dimensional space-time

The problem of confinement of fermions in 1 + 1 dimensions is approached with a linear potential in the Dirac equation by considering a mixing of Lorentz vector and scalar couplings. Analytical bound-states solutions are obtained when the scalar coupling is of sufficient intensity compared to the vector coupling. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Effects of low fat and babassu fat diets on nutritional status in obstructive cholestasis in young rats

OBJETIVO: Testar os efeitos de uma dieta com baixo teor de gordura comparada a uma dieta com gordura de babaçu sobre o estado nutricional em ratos jovens com colestase obstrutiva. MÉTODOS: Submetemos 40 ratos divididos em quatro grupos de 10 animais a partir do P21 (21º dia pós-natal) até o P49 a dois dos seguintes tratamentos: ligadura e ressecção do ducto biliar comum ou operação simulada e dieta com baixo teor de gordura (óleo de milho fornecendo 4,5% da quantidade total de calorias) ou dieta com gordura de babaçu (essa gordura fornecendo 32,7% e óleo de milho fornecendo 1,7% da quantidade total de calorias). Foi mensurado o ganho de peso a cada 4 dias do P25 ao P49. A função de crescimento de Verhulst foi ajustada aos valores de ganho de peso. A velocidade e a aceleração de crescimento nos mesmos momentos foram estimadas usando a mesma equação. Foram mensurados: quantidade de ração ingerida e ingestão energética total do P21 ao P49, utilização de energia do P25 ao P49, gordura absorvida e balanço de nitrogênio (BN) do P42 ao P49. A ANOVA com dois fatores e o método de S.N.K para comparações pareadas foram utilizados para estudar os efeitos, sobre as variáveis, da colestase e das dietas e sua interação (p<0,05). RESULTADOS: em ratos com colestase e dieta com baixo teor de gordura, houve maior velocidade de crescimento no P45, maior aceleração de crescimento no P41 e P45, maior utilização de energia, maior percentual de gordura absorvida e maior BN do que em ratos com colestase e dieta com gordura de babaçu. CONCLUSÃO: A dieta com baixo teor de gordura atenua a restrição de crescimento provocada pela colestase e proporciona melhor aproveitamento da dieta e maior incorporação da proteína ingerida do que a dieta com gordura de babaçu.

An acqueous extract of Bidens pilosa L. protects liver from cholestatic disease: experimental study in young rats

OBJETIVO: Testar o efeito hepatoprotetor do extrato aquoso de Bidens pilosa L. (EBP) na doença hepática induzida pela ligadura e ressecção do ducto biliar comum (LRDBC) em ratos jovens. MÉTODOS: Estudamos ratos Wistar com 21º. dia de vida (P21) divididos em quatro grupos de 10 animais, Grupo SA: operação simulada e água; Grupo SD: operação simulada e EBP (160mg de folhas frescas/100g de peso corporal/dia); Grupo LA: LRDBC e água e Grupo LD: LRDBC e EBP diariamente. O tempo de sono por pentobarbital (TSP), aspartato (AST) e alanina (ALT) aminotransferase foram determinadas após o sacrifício (P70). O Score de Ruwart (SR) para fibrose hepática foi atribuído para cada animal. Foi realizada análise de variância com dois fatores e pelo teste de Tukey para comparações múltiplas ou por teste não paramétrico. RESULTADOS: Houve diferença estatisticamente significativa entre LA e LD nas variáveis: TSP (médias LA=390; LD=173), AST (médias LA=8, LD=5), ALT (medianas LA=2; LD=1) e SR (medianas LA=2; LD=1). CONCLUSÃO: EBP poderá ser empregado na fitoterapia da doença hepática induzida pela colestase obstrutiva crônica, pois protege a função hepática, diminui a velocidade de necrose e a intensidade da fibrose hepática na obstrução biliar extra-hepática.

Effect of different concentrations of fluoride in dentifrices on dentin erosion subjected or not to abrasion in situ/ex vivo

This in situ/ex vivo study assessed the effect of different concentrations of fluoride in dentifrices on dentin subjected to erosion or to erosion plus abrasion. Ten volunteers took part in this crossover and double-blind study performed in 3 phases (7 days). They wore acrylic palatal appliances containing 4 bovine dentin blocks divided in two rows: erosion and erosion plus abrasion. The blocks were subjected to erosion by immersion ex vivo in a cola drink (60 s, pH 2.6) 4 times daily. During this step, the volunteers brushed their teeth with one of three dentifrices D (5,000 ppm F, NaF, silica); C (1,100 ppm F, NaF, silica) and placebo (22 ppm F, silica). Then, the respective dentifrice slurry (1: 3) was dripped on dentin surfaces. While no further treatment was performed in one row, the other row was brushed using an electric toothbrush for 30 s ex vivo. The appliances were replaced in the mouth and the volunteers rinsed with water. Dentin loss was determined by profilometry and analyzed by 2-way ANOVA/Bonferroni test (alpha = 0.05). Dentin loss after erosive-abrasive wear was significantly greater than after erosion alone. Wear was significantly higher for the placebo than for the D and C dentifrices, which were not significantly different from each other. It can be concluded that the presence of fluoride concentrations around 1,100 ppm in dentifrices is important to reduce dentin wear by erosion and erosion + abrasion, but the protective effect does not increase with fluoride concentration. Copyright (C) 2008 S. Karger AG, Basel.

Effect of 4% titanium tetrafluoride solution on the erosion of permanent and deciduous human enamel: an in situ/ex vivo study

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

In situ effect of an erosive challenge on different restorative materials and on enamel adjacent to these materials

Objectives: This in situ study evaluated the effect of an erosive challenge on different restorative materials and on enamel restored with these materials, as well as the ability of these materials to protect the adjacent enamel against erosion.Methods: Ten volunteers wore palatal devices with eight bovine enamel blocks, randomly selected and distributed into two vertical rows, corresponding to the following groups: GI/GV, resin-modified glass ionomer; GII/GVI, conventional glass ionomer; GIII/GVII, composite resin; GIV/GVIII, amalgam. one row (corresponding to groups I-IV) was immersed in a cola drink and the other row (corresponding to groups V-VIII) was subjected to saliva only. The palatal device was continuously worn for 7 days and only half of the appliance (groups I-IV) was immersed in the soft drink (Coca-Cola (R), 150 mL) for 5 min, three times a day. The study variables comprised the wear (profilometry, mu m) and the percentage of surface microhardness change (%SMHC). Data were tested for significant differences by two-way ANOVA and Tukey's tests (p < 0.05).Results: Considering the restorative materials, for %SMHC and wear, there were no differences among the materials and between the saliva and the erosive challenge. For enamel analyses, the erosive challenge promoted a higher wear and %SMHC of the enamel than did the saliva. There were no significant differences in wear and %SMHC of the enamel adjacent to the different restorative materials.Conclusion: This research data suggest that there is little %SMHC and wear of the studied restorative materials and none of them had a preventive effect against erosion on adjacent enamel, which showed a pronounced wear. (c) 2007 Elsevier Ltd. All rights reserved.

Exposed collagen in aged resin-dentin bonds produced on sound and caries-affected dentin in the presence of chlorhexidine

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