99 resultados para NAF


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

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Purpose: To evaluate the effect of the addition of sodium trimetaphosphate (TMP) with or without fluoride on enamel demineralization, and the hardness and release of fluoride and TMP of resin composites. Methods: Bovine enamel slabs (4x3x3 mm) were prepared and selected based on initial surface hardness (n= 96). Eight experimental resin composites were formulated, according to the combination of TMP and sodium fluoride (NaF): TMP/NaF-free (control), 1.6% sodium fluoride (NaF), and 1.5%, 14.1% and 36.8% TMP with and without 1.6% NaF. Resin composite specimens (n= 24) were attached to the enamel slabs with wax and the sets were subjected to pH cycling. Next, surface and cross-sectional hardness and fluoride content of enamel as well as fluoride and TNT release and hardness of the materials were evaluated. Data were statistically analyzed using ANOVA (P< 0.05). Results: The presence of fluoride in enamel was similar in fluoridated resin composites (P> 0.05), but higher than in the other materials (P< 0.05). The combination of 14.1% TMP and fluoride resulted in less demineralization, especially on lesion surface (P< 0.05). The presence of TMP increased fluoride release from the materials and reduced their hardness.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Objectives: This in vitro study assessed the effect of milk containing different fluoride concentrations on tooth erosion.Methods: Bovine enamel and root dentine specimens were treated with: (1) bovine whole milk with 0 ppmF; (2) 2.5 ppm F; (3) 5 ppmF;(4) 10 ppmF (all after erosion); (5) whole milk with 0 ppm F (before erosion); (6) NaF (0.05% F, positive control, after erosion) or (7) 0.9% NaCl (negative control, after erosion). The specimens were submitted to pH cycles (4 x 90 s in soft drink) and treatments for 5 days. The specimens were immersed in the treatment solutions for 1 min(only at the first cycle each day) with further exposition to 1: 1 milk: saliva slurry for 10 min. The tooth loss was measured using a contact profilometer and statistically analysed (p < 0.05).Results: Rinsing with milk before erosive challenge significantly reduced tooth loss compared to negative control (67% and 24% reduction in dentine and enamel loss, respectively) and to milk after erosive challenge, only for dentine. The addition of fluoride to milk also reduced tooth loss compared to negative control, but with no significant differences among fluoride concentrations for enamel and dentine (mu m), respectively: 0 ppm (3.63 +/- 0.04 and 2.51 +/- 0.53), 2.5 ppm F (2.86 +/- 0.42 and 1.96 +/- 0.47), 5 ppm F (2.81 +/- 0.27 and 1.77 +/- 0.44), 10 ppm F (2.03 +/- 0.49 and 1.68 +/- 0.59). There was a negative and significant correlation between [F] and the tooth loss.Conclusions: Daily rinse with milk containing F is able to reduce both enamel and dentine erosion in vitro.Clinical significance: Since the prevalence of dental erosion is steadily increasing, rinse with milk or its derivate might be an important strategy to reduce the progression of tooth erosion. (C) 2013 Elsevier Ltd. All rights reserved.

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

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This study investigated the effect of a calcium lactate pre-rinse on sodium fluoride protection in an in vitro erosion-remineralization model simulating two different salivary flow rates. Enamel and dentin specimens were randomly assigned to 6 groups (n = 8), according to the combination between rinse treatments - deionized water (DIW), 12 mm NaF (NaF) or 150 mm calcium lactate followed by NaF (CaL + NaF) and unstimulated salivary flow rates - 0.5 or 0.05 ml/min simulating normal and low salivary flow rates, respectively. The specimens were placed into custom-made devices, creating a sealed chamber on the specimen surface connected to a peristaltic pump. Citric acid was injected into the chamber for 2 min, followed by artificial saliva (0.5 or 0.05 ml/min) for 60 min. This cycle was repeated 4x/day for 3 days. Rinse treatments were performed daily 30 min after the 1st and 4th erosive challenges, for 1 min each time. Surface loss was determined by optical profilometry. KOH-soluble fluoride and structurally bound fluoride were determined in specimens at the end of the experiment. Data were analyzed by 2-way ANOVA and Tukey tests (alpha = 0.05). NaF and CaL + NaF exhibited significantly lower enamel and dentin loss than DIW, with no difference between them for normal flow conditions. The low salivary flow rate increased enamel and dentin loss, except for CaL + NaF, which presented overall higher KOH-soluble and structurally bound fluoride levels. The results suggest that the NaF rinse was able to reduce erosion progression. Although the CaL prerinse considerably increased F availability, it enhanced NaF protection against dentin erosion only under hyposalivatory conditions. (C) 2014 S. Karger AG, Basel

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Atualmente o titânio é empregado como biomaterial devido à sua biocompatibilidade e resistência à corrosão. Entretanto, íons fluoretos, freqüentemente empregados em dentifrícios bucais, podem interferir no processo de corrosão. O objetivo deste estudo foi analisar a influência de um meio fluoretado com diferentes pH nas propriedades mecânicas e na resistência à corrosão dos conjuntos implantes/componentes protéticos à base de Ti c.p., a partir dos testes de fadiga, microscopia eletrônica de varredura (MEV) e dureza. Foram simulados cinco anos de uso regular de meios de higiene oral com conteúdo de 1500 ppm de NaF, com dois diferentes pH, 7,4 e 5,3, mediante imersão das amostras nesses meios durante 184 horas e também em água destilada, grupo controle. As amostras foram testadas num durômetro Micromet 2001 (500gf/30s). Os dados dos testes de dureza foram analisados pelo teste de Wilcoxon, demonstrando que as amostras sofreram influência negativa na dureza após a ação dos íons fluoreto. Entretanto, essa influência não ocorreu nos testes de fadiga realizados em uma máquina de ensaios mecânicos MTS-810, fixada a 100.000 ciclos, 15Hz e programada com força de fadiga a 150 N. Pela análise de MEV foram constatadas evidências de corrosão na superfície das amostras após ação de íons fluoretos, entretanto pelo EDS não se verificou incorporação de íons fluoretos sobre a superfície dos conjuntos. Concluiu-se que a concentração de flúor e o pH das soluções não exerceram influência nas propriedades mecânicas.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)