931 resultados para FLUORIDE PEROVSKITES


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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Objective: This study evaluated the bioavailability of fluoride after topical application of a dual-fluoride varnish commercially available in Brazil, when compared to Duraphat T. Material and methods: The urinary fluoride output was evaluated in seven 5-year-old children after application of the fluoride varnishes, in two different phases. In the first phase (I), children received topical application of the fluoride varnish Duofluorid XII (2.92% fluorine, calcium fluoride + 2.71% fluorine, sodium fluoride, FGM (TM)). After 1-month interval (phase II), the same amount (0.2 mL) of the fluoride varnish Duraphat (2.26% fluorine, sodium fluoride, Colgate T) was applied. Before each application all the volunteers brushed their teeth with placebo dentifrice for 7 days. Urinary collections were carried out 24 h prior up to 48 h after the applications. Fluoride intake from the diet was also estimated. Fluoride concentration in diet samples and urine was analyzed with the fluoride ion-specific electrode and a miniature calomel reference electrode coupled to a potentiometer. Data were tested by ANOVA and Tukey's post hoc test (p < 0.05). Results: There were significant differences in the urinary fluoride output between phases I and II. The use of Duofluorid XII did not significantly increase the urinary fluoride output, when compared to baseline levels. The application of Duraphat caused a transitory increase in the urinary fluoride output, returning to baseline levels 48 h after its use. Conclusions: The tested varnish formulation, which has been shown to be effective in in vitro studies, also can be considered safe.

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The effect of mouth rinses containing fluoride (100 mu g/ml) and sodium trimetaphosphate (TMP) on enamel erosion was evaluated in vitro. Bovine enamel blocks were subjected to erosive challenges 4 times per day for 5 min, followed by treatment with placebo, 225 mu g F/ml, 100 mu g F/ml, 100 mu g F/ml and TMP (0.2, 0.4 and 0.6%) solutions (30 s) and storage in artificial saliva, over a duration of 5 days. TMP groups showed lower enamel wear than fluoride-only and placebo groups (p < 0.05). Addition of TMP at a TMP:NaF molar proportion between 1.24:1 and 3.72:1 to a solution containing 100 mu g F/ml presented a greater protective effect under erosive conditions than a solution containing 225 mu g F/ml, in the absence of TMP. Copyright (C) 2011 S. Karger AG, Basel

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Although the prevalence of caries has decreased dramatically over the past decades, it has become a polarised disease, with most of subjects presenting low caries levels and few individuals accounting for most of the caries affected surfaces. Thus it become evident for the need of clinical approaches directed at these high-risk patients, in order to overcome problems related to compliance and low attendance at dental care centres. Slow-release fluoride devices were developed based on the inverse relationship existing between intra-oral fluoride levels and dental caries experience. The two main types of slow-release devices - copolymer membrane type and glass bead - are addressed in the present review. A substantial number of studies have demonstrated that these devices are effective in raising intra-oral F concentrations at levels able to reduce enamel solubility, resulting in a caries-protective effect. Studies in animals and humans demonstrated that the use of these devices was able to also protect the occlusal surfaces, not normally protected by conventional fluoride regimens. However, retention rates have been shown to be the main problem related to these devices and still requires further improvements. Although the results of these studies are very promising, further randomised clinical trials are needed in order to validate the use of these devices in clinical practice. The concept of continuously providing low levels of intra-oral fluoride has great potential for caries prevention in high caries-risk groups.

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

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Objective: In this paper we evaluated the effect of two fluoridated agents and Nd:YAG irradiation separately and in combination on dentine resistance to erosion. Background Data: The morphological changes in dentin induced by laser treatment may reduce the progression of erosive lesions. Due to the possibility of a synergistic effect of laser with fluoride, this study was conducted. Materials and Methods: Eighty bovine dentine samples (4 x 4 mm) were randomly divided into eight groups, according to the following treatments: G1: untreated (control); G2: acidic phosphate fluoride gel (APF 1.23%) for 4 min; G3: fluoride varnish (NaF 2.26%) for 6 h; G4: 0.5 W Nd: YAG laser (250 mu sec pulse, 10 Hz, 35 J/cm(2), 30 sec); G5: 0.75 W Nd: YAG laser (52.5 J/cm(2)); G6: 1.0 W Nd: YAG laser (70 J/cm(2)); G7: APF + 0.75 W Nd: YAG laser; and G8: NaF + 0.75 W Nd: YAG laser. After the treatments, half of each dentine surface was protected with nail varnish. The samples were stored in artificial saliva (30 mL/sample) for 24 h and submitted to four erosive 1-min cycles. Between the erosive attacks, the blocks were maintained in artificial saliva for 59 min. The erosive wear was evaluated by profilometry. Results: The mean wear (+/- SD, mu m) was: G1: 1.20 +/- 0.20; G2: 0.47 +/- 0.06; G3: 0.81 +/- 0.11; G4: 1.47 +/- 0.32; G5: 1.52 +/- 0.24; G6: 1.49 +/- 0.30; G7: 0.49 +/- 0.11; and G8: 1.06 +/- 0.31 (Tukey's test, p < 0.05). Conclusions: Laser irradiation was not able to reduce dentine erosion. However, fluoride application was able to increase the dentine's resistance to erosion, and APF showed better results than fluoride varnish.

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

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Objectives: The aim of this in vitro study was to assess the effects of saliva substitutes (modified with respect to calcium, phosphates, and fluorides) in combination with a high-concentrated fluoride toothpaste on demineralised dentin.Methods: Before and after demineralisation of bovine dentin specimens (subsurface lesions; 37 degrees C, pH 5.0, 5 d), one-quarter of each specimen's surface was covered with nail varnish (control of sound/demineralised tissue). Subsequently, specimens were exposed to original Saliva natura (saturation with respect to octacalciumphosphate [S(OCP)]: 0.03; SN 0), or to three lab-produced Saliva natura modifications (S(OCP): 1, 2, and 3; SN 1-3) for 2 and 5 weeks (37 degrees C). An aqueous solution (S(OCP): 2.5) served as positive control (PC). Two times daily (2 min each), Duraphat toothpaste (5000 ppm F(-); Colgate)/saliva substitute slurry (ratio 1:3) was applied gently. Differences in mineral losses (Delta Delta Z) and lesion depths (Delta LD) between values before and after exposure were microradiographically evaluated.Results: After both treatment periods specimens immersed in SN 0 revealed significantly higher mineral losses (lower Delta Delta Z values) and lesion depths (lower Delta LD) compared to PC (p < 0.05; ANOVA). After 5 weeks, specimens stored in SN 1 and 2 showed significantly higher mineral losses compared to PC (p < 0.05), while those stored in SN 3 showed similar results (p > 0.05). No differences in mineral loss could be observed between SN 2 and 3 (p > 0.05).Conclusions: Under the conditions of this limited protocol, the combination of Saliva natura solutions slightly saturated with respect to OCP in combination with a high-concentrated fluoride toothpaste enabled remineralisation of dentin in vitro. Crown Copyright (c) 2009 Published by Elsevier Ltd. All rights reserved.

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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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The aim of this study was to evaluate in vivo the use of low-level galium-aluminium-arsenide (GaAlAs) (BDP 600) laser and sodium fluoride varnish (Duraphat((R))) in the treatment of cervical dentine hypersensitivity. Twelve patients, with at least two sensitive teeth were selected. A total of 60 teeth were included in the trial. Prior to desensitizing treatment, dentine hypersensitivity was assessed by a thermal stimulus and patients' response to the examination was considered to be a control. The GaAlAs laser (15 mW, 4 J/cm(2)) was irradiated on contact mode and fluoride varnish was applied at cervical region. The efficiency of the treatments was assessed at three examination periods: immediately after first application, 15 and 30 days after the first application. The degree of sensitivity was determined following predefined criteria. Data were submitted to analysis and no statistically significant difference was observed between fluoride varnish and laser. Considering the treatments separately, there was no significant difference for the fluoride varnish at the three examination periods, and for laser therapy, significant difference (P < 0.05) was found solely between the values obtained before the treatment and 30 days after the first application. It may be concluded that both treatments may be effective in decreasing cervical dentinal hypersensitivity. Moreover, the low-level GaAlAs laser showed improved results for treating teeth with higher degree of sensitivity.

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Objectives. The purpose of this paper is to modify the conventional calcium fluoro-aluminosilicate glass, which is used in the formation of glass ionomer cements (CIGs) by the niobium addition and to study the properties of GICs obtained.Materials and methods. Sol-gel process was used to prepare the powder at lower temperature than fusion method. Glass-ceramic powder obtained in this way was used to prepare the GICs. The properties such as working and setting times, microhardness and diametral tensile strength were evaluated for the experimental GICs and a commercial luting cement.Results. The ideal powder:liquid (P:L) ratio determined to prepare the experimental GICs was equal to 1:1. The cements prepared using this ratio showed working and setting times similar to the commercial GICs. in mechanical tests it was observed that microhardness and diametral tensile strength of the experimental GICs decreased significantly with the reduction of P:L ratio. on the other hand, the results obtained in microhardness tests indicated that the presence of niobium was a positive factor.Significance. The chemical process allows the development of glass-ceramic powder at 600 degrees C which is the goal of the present paper. It was concluded that GICs containing niobium might be used in dental applications and these results encourage further researches on other compositions. (c) 2007 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.