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Sample records for calcium fluorides

  1. Observation of color center peaks in calcium fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, T. [LeRoy Eyring Center for Solid State Science, Arizona State University, Tempe, AZ 85287-1704, USA (United States); Garvie, L.A.J. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Rez, P., E-mail: Peter.Rez@asu.edu [Department of Physics, Arizona State University, Tempe, AZ 85287-1504 (United States)

    2015-06-15

    Alkali halides such as calcium fluoride all have color center defects that absorb light in the visible region. Using a moncochromator equipped, aberration corrected, scanning transmission electron microscope (STEM) we recorded spectra showing the time evolution of the generation of F and H centers in calcium fluoride. The final stage of electron beam irradiation is the formation of metallic calcium nanoparticles. High resolution low loss spectra for the Vacuum Ultraviolet region were also recorded. - Highlights: • Color center defects clearly identified by high resolution EELS of CaF{sub 2}. • Both F Centers and H Centers produced by electron beam irradiation. • Ultimately metallic calcium is left as evidenced by plasmon and density of states. • High resolution low loss (VUV) spectra also recorded.

  2. Observation of color center peaks in calcium fluoride

    International Nuclear Information System (INIS)

    Alkali halides such as calcium fluoride all have color center defects that absorb light in the visible region. Using a moncochromator equipped, aberration corrected, scanning transmission electron microscope (STEM) we recorded spectra showing the time evolution of the generation of F and H centers in calcium fluoride. The final stage of electron beam irradiation is the formation of metallic calcium nanoparticles. High resolution low loss spectra for the Vacuum Ultraviolet region were also recorded. - Highlights: • Color center defects clearly identified by high resolution EELS of CaF2. • Both F Centers and H Centers produced by electron beam irradiation. • Ultimately metallic calcium is left as evidenced by plasmon and density of states. • High resolution low loss (VUV) spectra also recorded

  3. The Effect of Calcium Pre-Rinse on Salivary Fluoride After 900 ppm Fluoride Mouthwash: A Randomized Clinical Trial

    Directory of Open Access Journals (Sweden)

    Nahid Ramazani

    2013-01-01

    Full Text Available Objective: Calcium fluoride deposit during fluoride application. Uptake and retention of fluoride by saliva depends generally on the concentration of calcium. In this study, the ef-fect of calcium pre-rinse on salivary fluoride concentration after a 900 ppm fluoride mouthwash was investigated.Materials and Methods: This cross-over double-blind randomized clinical trial was con-ducted in a girls' dormitory in Zahedan University of Medical Sciences, southeast Iran. In this study, 42 female dental students were chosen using simple randomization. During the first phase, 21 subjects (group A used fluoride rinse (F regimen and the remaining (group B used calcium pre-rinse followed immediately by fluoride rinse (Ca + F regi-men. In the second phase, participants rinsed using the mouthwashes not previously used. Prior to each phase prophylaxis was performed and no fluoridated product was used dur-ing a two-week interval between the phases. Salivary samples were taken immediately be-fore (baseline, 1 and 12 hours after rinsing. The salivary fluoride concentration was de-termined using fluoride sensitive electrode. Repeated measures ANOVA was used for sta-tistical analysis and the significance level was set at P<0.05.Results: There was significant difference between fluoride concentrations at different time points (P< 0.001. Significant differences were observed when the different time points of two regimens were examined. In contrast to this, the baseline before using F regimen and the baseline before using Ca + F regimen did not show any significance (P= 0.070.Conclusion: Pre-rinsing with calcium before fluoride is recommended because of signifi-cant increases in salivary fluoride concentration.

  4. Characterization and biocompatibility of fluoridated biphasic calcium phosphate ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Z.L. [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China); Yu, H.Y. [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China)], E-mail: yhyang6812@tfol.com; Zeng, Q. [Institute for Nanobiomedical Technology and Membrane Biology, Sichuan University, Chengdu 610041 (China); He, H.W. [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China)

    2008-11-15

    Biphasic calcium phosphate ceramics (BCP) has been widely used in tooth and bone implants due to its excellent biocompatibility. Incorporation of fluorine ions in BCP has drawn much attention because of the beneficial role played by the fluorine ions in bone and tooth growth. The aim of this study was to obtain fluoridated biphasic calcium phosphate (FBCP) by immersing BCP into saturated ZnF{sub 2} solution with F{sup -} concentration of 3500 mg/l at different times. The phase and incorporation of fluoride into BCP were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). The biomineralization and influence of FBCP on osteoblastic behavior were evaluated and compared with that of biphasic calcium phosphate (BCP). The results exhibited that the phase evolution of the BCP was affected by the fluoride incorporation and the FBCP significantly improved the differentiation and proliferation of osteoblasts. These findings suggest that the FBCP would be very useful as a bone reconstructive material.

  5. PHz current switching in calcium fluoride single crystal

    Science.gov (United States)

    Kwon, Ojoon; Kim, D.

    2016-05-01

    We demonstrate that a current can be induced and switched in a sub-femtosecond time-scale in an insulating calcium fluoride single crystal by an intense optical field. This measurement indicates that a sizable current can be generated and also controlled by an optical field in a dielectric medium, implying the capability of rapid current switching at a rate of optical frequency, PHz (1015 Hz), which is a couple of orders of magnitude higher than that of contemporary electronic signal processing. This demonstration may serve to facilitate the development of ultrafast devices in PHz frequency.

  6. Physical vapor deposition and patterning of calcium fluoride films

    International Nuclear Information System (INIS)

    Physical vapor deposition of calcium fluoride (CaF2) thin films was performed via electron beam evaporation, resistive/thermal evaporation, and nonreactive radio frequency sputtering. Patterning of the resultant ''usable'' thin films was then also attempted in several ways, including by shadow mask deposition, liftoff, and direct chemical etching. Resistive evaporation produced the most stable films, having polycrystalline morphology with a moderately strong preference to the 331 orientation. The cleanest patterning results were obtained via a polymer/metal liftoff. The results and implications of each of the various deposition and patterning techniques are discussed.

  7. Effect of Fluoride, Casein Phosphopeptide–Amorphous Calcium Phosphate and Casein Phosphopeptide–Amorphous Calcium Phosphate Fluoride on Enamel Surface Microhardness After Microabrasion: An In Vitro Study

    OpenAIRE

    Ghazaleh Ahmadi Zenouz; Fariba Ezoji; Seyede Anese Enderami; Soraya Khafri

    2016-01-01

    Objectives: This study aimed to assess the effect of applying casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) paste, casein phosphopeptide–amorphous calcium phosphate fluoride (CPP-ACPF) paste and sodium fluoride gel on surface microhardness of enamel after microabrasion.Materials and Methods: Thirty freshly extracted human premolars were selected. All samples were subjected to hardness indentations made with the Vickers hardness machine and the average value was recorded as the i...

  8. Preliminary Study on Chemical Components and Uranium Content of Calcium Fluoride Waste

    Institute of Scientific and Technical Information of China (English)

    LIANG; Xiao-hu; YANG; Lei; YANG; Jin-ling; SONG; Zhi-jun

    2013-01-01

    In the uranium conversion process,UF4 reduction is needed using calcium as reduction regent,so a great deal of calcium fluoride are generated,in which a no negligible amount of uranium(about 5%alleged)can be left in the calcium fluoride wastes by the entrainment effect.It is meaningful to extract and purify the uranium from these wastes,but chemical components of these waste is needed primarily.

  9. Fluoride concentrations in dental plaque and saliva after the use of a fluoride dentifrice preceded by a calcium lactate rinse.

    Science.gov (United States)

    Pessan, Juliano P; Sicca, Cristina M; de Souza, Tatiana S; da Silva, Salete M B; Whitford, Gary M; Buzalaf, Marília A R

    2006-12-01

    Plaque fluoride concentrations ([F]) are directly related to plaque calcium concentrations [Ca]. Attempts to increase plaque F uptake from dentifrices or rinses have used methods designed to increase plaque [Ca] but with inconsistent results. This double-blind, double-crossover study tested the effect of a 150 mM calcium lactate rinse used prior to brushing with placebo or fluoridated dentifrices (1030 p.p.m. as NaF) on plaque and salivary [F] and [Ca]. Sixteen children (8-10 yr of age) were randomly assigned to four different groups according to the four treatments (placebo dentifrice or fluoridated dentifrice preceded by calcium lactate or deionized water prerinses). Plaque and saliva were collected 1 and 12 h after brushing on day 7 after starting to use the dentifrices. F was determined using the electrode and Ca was determined using atomic absorption spectrometry. Plaque and salivary [Ca] were not significantly increased after use of the calcium lactate prerinse, except for plaque [Ca] 1 h after the use of the placebo dentifrice. A significant increase in salivary [F] was associated with the calcium lactate prerinse only at 1 h after the use of the fluoridated dentifrice. The the calcium lactate prerinse did not significantly affect plaque [F] under any condition. PMID:17184230

  10. Synthesis of Calcium Silicate (Casio3 Using Calcium Fluoride, Quartz and Microbes

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    B. Gopal Krishna

    2015-09-01

    Full Text Available Microbes like bacteria, algae, fungi and virus play an important role to catalyst chemical reactions. In Nature, ores or minerals of different compounds are formed due to microbial environment and other factors like weathering. Microbial environment is also instrumental in forming calcium containing silicate minerals. Chemical reactions occur under microbial environment because microbes have the ability to control or modify different factors like pH, chemical potential and temperature during reactions. In this paper, synthesis of calcium silicate (CaSiO3 using calcium fluoride (CaF2 and quartz (SiO2 under microbial environment in a laboratory is being adopted to produce the required material. XRD technique is used to confirm the formation of CaSiO3.

  11. Mechanism of Calcium Fluoride Acceleration for Vacuum Carbothermic Reduction of Magnesia

    Science.gov (United States)

    Jiang, Yun; Liu, Yu-qin; Ma, Hong-wen; Zhou, Wei-gong

    2016-04-01

    The use of a small amount of calcium fluoride as an additive greatly accelerated the reduction of magnesia during the preparation of magnesium from magnesia using the vacuum carbothermic reduction method. At 1573 K (1300 °C), the magnesia reaction rates of the samples with 1, 3, and 5 pct CaF2 were all approximately 26 pct, three times that of free CaF2, and they were arranged in order of the calcium fluoride weight percentages at 1673 K (1400 °C). The residues were analyzed using chemical analysis, XRD, SEM, EDS, and XRF. The possible acceleration mechanism was discussed. Calcium fluoride combined with magnesia and silicon dioxide to form a eutectic that melted as a channel to aid the solid-solid reaction between carbon and magnesia at approximately 1573 K (1300 °C). Calcium fluoride in the molten state offered free calcium ions and fluorine ions. Fluorine ions entered and distorted the magnesia crystal lattice. The structural strength and chemical stability of the magnesia crystal lattice decreased, which facilitated the magnesia reduction by carbon. Calcium ions were employed to generate the calcium and magnesium silicate. The easyly evaporating fluorides, including magnesium fluoride and silicon tetrafluoride, were regarded as the main reason for the loss of fluorine.

  12. Effect of Fluoride, Casein Phosphopeptide–Amorphous Calcium Phosphate and Casein Phosphopeptide–Amorphous Calcium Phosphate Fluoride on Enamel Surface Microhardness After Microabrasion: An In Vitro Study

    Directory of Open Access Journals (Sweden)

    Ghazaleh Ahmadi Zenouz

    2016-03-01

    Full Text Available Objectives: This study aimed to assess the effect of applying casein phosphopeptide–amorphous calcium phosphate (CPP-ACP paste, casein phosphopeptide–amorphous calcium phosphate fluoride (CPP-ACPF paste and sodium fluoride gel on surface microhardness of enamel after microabrasion.Materials and Methods: Thirty freshly extracted human premolars were selected. All samples were subjected to hardness indentations made with the Vickers hardness machine and the average value was recorded as the initial surface microhardness. The specimens were then randomly divided into three groups (n=10 of CPP-ACPF, fluoride and CPP-ACP. The teeth were micro-abraded with Opalustre. Microhardness test was performed to assess the post-abrasion hardness. Three remineralization modalities were performed on samples of each group. The enamel surface microhardness measurements were performed. To compare the difference between groups, the rehardening and softening values were defined. One-way ANOVA and Tukey’s post hoc test at a significance level of 5% were used for statistical analysis.Results: The mean microhardness value (MMV had a significant decrease after microabrasion from baseline. The MMV had a significant increase after remineralization in all groups. The MMV of CPP-ACPF group was significantly more than that of fluoride group (P=0.027. The rehardening value of fluoride group was significantly more than that of other groups (P<0.001.Conclusion: All the remineralizing agents were effective for rehardening the enamel after microabrasion. The CPP-ACP and CPP-ACPF pastes are effective, but to a lesser extent than neutral sodium fluoride gel in remineralizing enamel surface. Incorporation of fluoride to CPP-ACP formulation does not provide any additional remineralizing potential.Keywords: Casein phosphopeptide-amorphous calcium phosphate nanocomplex; Enamel Microabrasion; Hardness; Sodium Fluoride

  13. The effect of fluoride on the serum level of calcium in the rat (Rattus norvegicus

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    Fočak M.

    2012-01-01

    Full Text Available The effect of fluoride on the calcium level in serum was analyzed in the laboratory rat Rattus norvegicus. The control group consisted of 10, and the experimental group of 15 animals. In the experimental group, fluoride at a concentration of 3 mg/100 g body weight of rats was intramuscularly injected into the musculus gluteus maximus. The concentration of calcium was measured by the CPC method. The average serum calcium concentration was 2.46 mmol/l, with female rats having higher values of serum calcium than male rats. Fluoride caused the reduction of calcium concentration in serum (p<0.05; the reduction was significantly expressed in female rats (p<0.000.

  14. Thermoluminescence studies of natural and doped calcium fluoride phosphors

    International Nuclear Information System (INIS)

    The various aspects of thermoluminescence (TL) of calcium fluoride phosphors obtained both from natural and laboratory-grown CaF2 crystals have been investigated in the temperature range from room temperature to 750 deg C. Dopants used in these studies were Mn, Y and lanthanide series rare earths. The aspects which have been investigated are : (1) effect of single and double doping on TL glow curves and TL emission spectra after gamma irradiation, (2) TL traps : their kinetics including evaluation of the activation energy using different techniques, their decay kinetics and their behaviour under partially filled conditions, and (3) effect of temperature on emission of intensity of X-ray induced luminescence and TL. During the course of these investigations, a new glow peak was observed at 650 deg C in natural CaF2. It was found that this peak could also be produced in synthetic CaF2 doped with (Y + Sm). A new model for the TL trap has also been proposed. (M.G.B.)

  15. Apatite precipitation on a novel fast-setting calcium silicate cement containing fluoride

    Science.gov (United States)

    Ranjkesh, Bahram; Chevallier, Jacques; Salehi, Hamideh; Cuisinier, Frédéric; Isidor, Flemming; Løvschall, Henrik

    2016-01-01

    Abstract Aim: Calcium silicate cements are widely used in endodontics. Novel fast-setting calcium silicate cement with fluoride (Protooth) has been developed for potential applications in teeth crowns including cavity lining and cementation. Objective: To evaluate the surface apatite-forming ability of Protooth compositions as a function of fluoride content and immersion time in phosphate-buffered saline (PBS). Material and methods: Three cement compositions were tested: Protooth (3.5% fluoride and 10% radiocontrast), ultrafast Protooth (3.5% fluoride and 20% radiocontrast), and high fluoride Protooth (15% fluoride and 25% radiocontrast). Powders were cap-mixed with liquid, filled to the molds and immersed in PBS. Scanning electron microscopy, energy dispersive X-ray analysis, and Raman spectroscopy were used to characterize the precipitations morphology and composition after 1, 7, 28, and 56 days. Apatite/belite Raman peak height indicated the apatite thickness. Results: Spherical calcium phosphate precipitations with acicular crystallites were formed after 1-day immersion in PBS and Raman spectra disclosed the phosphate band at 965 cm−1, supporting the apatite formation over Protooth compositions. The apatite deposition continued and more voluminous precipitations were observed after 56 days over the surface of all cements. Raman bands suggested the formation of β-type carbonated apatite over Protooth compositions. High fluoride Protooth showed the most compact deposition with significantly higher apatite/belite ratio compared to Protooth and ultrafast Protooth after 28 and 56 days. Conclusions: Calcium phosphate precipitations (apatite) were formed over Protooth compositions after immersion in PBS with increasing apatite formation as a function of time. High fluoride Protooth exhibited thicker apatite deposition. PMID:27335901

  16. Dielectric spectra of doped and X-ray irradiated calcium fluoride crystals

    International Nuclear Information System (INIS)

    Calcium fluoride crystals doped with PbF2 and codoped with LiF, NaF have been grown using the vertical Bridgman method. The frequency (1-100 kHz) dependence of the real and imaginary parts of the complex dielectric constant, ε1 and ε2, have been studied in the temperature range 160-300 K; the activation parameters of the relaxation process have been determined for various doped and X-irradiated calcium fluoride crystals. The optical absorption spectra of the crystals are also investigated. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Study of calcium solid phase reactions with terbium and scandium fluorides and oxygen mixtures

    International Nuclear Information System (INIS)

    The interaction of calcium with TbF3-Tb2O3 and ScF3-Sc2O3 binary mixtures is investigated using the method of isothermal kinetics and thermogravimetry. It is revealed that the curve of calcium reaction rate depending on the composition of fluoride-oxide mixture has an extremum, the position of the extremum shifting to the side of more inert oxides

  18. 78 FR 59731 - License Amendment Request for Closure of Calcium Fluoride Ponds at Honeywell Metropolis Works...

    Science.gov (United States)

    2013-09-27

    ... COMMISSION License Amendment Request for Closure of Calcium Fluoride Ponds at Honeywell Metropolis Works... Honeywell International, Inc. (Honeywell) for its Metropolis Works Facility (MWF) in Metropolis, Illinois...: (1) License Amendment Request Report NRC License Number SUB-526, Closure of Retention Ponds B, C,...

  19. Thermodynamics of the conversion of calcium and magnesium fluorides to the parent metal oxides and hydrogen fluoride

    Energy Technology Data Exchange (ETDEWEB)

    West, M.H.; Axler, K.M.

    1997-02-01

    The authors have used thermodynamic modeling to examine the reaction of calcium fluoride (CaF{sub 2}) and magnesium fluoride (MgF{sub 2}) with water (H{sub 2}O) at elevated temperatures. The calculated, equilibrium composition corresponds to the global free-energy minimum for the system. Optimum, predicted reaction temperatures and reactant mole ratios are reported for the recovery of hydrogen fluoride (HF), a valuable industrial feedstock. Complete conversion of MgF{sub 2} is found at 1,000 C and a ratio of 40 moles of H{sub 2}O per 1 mole of MgF{sub 2}. For CaF{sub 2}, temperatures as high as 1,400 C are required for complete conversion at a corresponding mole ratio of 40 moles of H{sub 2}O per 1 mole of CaF{sub 2}. The authors discuss the presence of minor chemical constituents as well as the stability of various potential container materials for the pyrohydrolysis reactions at elevated temperatures. CaF{sub 2} and MgF{sub 2} slags are available as wastes at former uranium production facilities within the Department of Energy Complex and other facilities regulated by the Nuclear Regulatory Commission. Recovery of HF from these wastes is an example of environmental remediation at such facilities.

  20. Fluoride

    Science.gov (United States)

    Fluoride is used to prevent tooth decay. It is taken up by teeth and helps to strengthen ... and block the cavity-forming action of bacteria. Fluoride usually is prescribed for children and adults whose ...

  1. Sodium fluoride and casein phosphopeptide-amorphous calcium phosphate cream plus sodium fluoride efficacy in preventing enamel erosion in a simulated oral environment study model

    OpenAIRE

    Cristiane Mariote Amaral; Maria Elisa da Silva NG Miranda; Danielly S Correa; Eduardo M. Silva

    2014-01-01

    Aim: The aim of this study was to evaluate the effectiveness of dentifrices containing high concentrations of sodium fluoride (NaF) and casein phosphopeptide-amorphous calcium phosphate cream plus fluoride (CPP-ACPF) in prevention of the erosion in a simulated oral environment study model. Subjects and Methods: Fifteen flat human enamel specimens were polished and half of the surfaces were protected with adhesive tape. Initial Knoop microhardness (KHN) and surface roughness (SR) were meas...

  2. Loss on drying, calcium concentration and pH of fluoride dentifrices

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    Arella Cristina Muniz Brito

    2015-01-01

    Full Text Available Introduction: Fluoride dentifrices containing calcium carbonate have advantages such as control of dental plaque and progression of dental caries, also contributing to oral hygiene, represent most dentifrices marketed in Brazil. Aim: To evaluate the physicochemical properties of seven fluoride dentifrices containing calcium carbonate in relation to hydrogen potential (pH, loss on drying and calcium concentration. Materials and Methods: Data collection was performed using the potentiometric method for pH ranges, gravimetric analysis for loss on drying and atomic absorption spectrometry for the concentration of calcium ions. All tests were performed in triplicate and the analysis was performed entirely at random according to one-way analysis of variance at 5% significance level. Results: The pH values were alkaline and ranged from 8.67 (Oral-B 123® to 10.03 (Colgate Mαxima Proteηγo Anticαries® . The results of loss on drying ranged from 33.81% (Oral-B 123® to 61.13% (Close Up® , with significant differences between brands tested. In relation to the calcium content, the highest and lowest concentrations were found in dentifrices Even® (155.55 g/kg and Colgate Ultra Branco® (129 g/kg, respectively, with significant difference (P < 0.05. Conclusion: Fluoride dentifrices analyzed showed alkaline pH and high levels of loss on drying and calcium concentration. However, these physicochemical characteristics differed according to the different brands tested.

  3. Report on the Study of Radiation Damage in Calcium Fluoride and Magnesium Fluoride Crystals for use in Excimer Laser Applications

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    1999-10-04

    A study was performed to investigate the effects of radiation damage in calcium fluoride and magnesium fluoride crystals caused by gamma rays and UV photons from excimer lasers. The purpose was to study and correlate the damage caused by these two different mechanisms in various types of material used for fabricating optical elements in high power excimer lasers and lens systems of lithography tools. These optical systems are easily damaged by the laser itself, and it is necessary to use only the most radiation resistant materials for certain key elements. It was found that a clear correlation exists between the, radiation induced damage caused by high energy gamma rays and that produced by UV photons from the excimer laser. This correlation allows a simple procedure to be developed to select the most radiation resistant material at the ingot level, which would be later used to fabricate various components of the optical system. This avoids incurring the additional cost of fabricating actual optical elements with material that would later be damaged under prolonged use. The result of this screening procedure can result in a considerable savings in the overall cost of the lens and laser system.

  4. Tamarind (Tamarindus indica) fruit shell carbon: A calcium-rich promising adsorbent for fluoride removal from groundwater

    International Nuclear Information System (INIS)

    Highlights: ► The carbonization of Tamarind fruit shell improved its defluoridation efficiency. ► Calcium carbonate particles were involved in the defluoridation process. ► Adsorbent dose, pH, and fluoride concentration showed significant effects. ► Maximum adsorption of fluoride was achieved at pH 7–8. ► Prepared carbons were efficient in treating three natural waters. - Abstract: Tamarindus indica fruit shells (TIFSs) are naturally calcium rich compounds. They were impregnated with ammonium carbonate and then carbonized, leading to ammonium carbonate activated ACA-TIFS carbon. The resulting materials and carbon arising from virgin fruit shells V-TIFS were characterized and assayed as adsorbent for the removal of fluoride anions from groundwater. The fluoride scavenging ability of TIFS carbons was due to naturally dispersed calcium compounds. X-ray diffraction (XRD) showed that TIFS carbon contained a mixture of calcium oxalate and calcium carbonate. Batch studies on the fluoride removal efficiency of TIFS carbons with respect to contact time, pH, initial fluoride concentration, and co-ion interference were conducted. Applicability of various kinetic models (viz., pseudo-first-order, pseudo-second-order, intra-particle diffusion and Elovich) and sorption isotherms were tested for batch techniques. The fluoride removal capacity of TIFS carbons was found to be 91% and 83% at a pH of 7.05 for V-TIFS and ACA-TIFS carbons, respectively. The practical applicability of TIFS carbons using groundwater samples was approved. The fluoride removal was greater in groundwater without hydrogen carbonate ions than those containing these ions. The characterizations of fluoride unloaded and loaded TIFS carbons were done by SEM and XRD studies.

  5. Tamarind (Tamarindus indica) fruit shell carbon: A calcium-rich promising adsorbent for fluoride removal from groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Sivasankar, V., E-mail: vsivasankar@tce.edu [Department of Chemistry, Thiagarajar College of Engineering (Autonomous), Madurai 625015, Tamil Nadu (India); Rajkumar, S. [Department of Chemistry, Thiagarajar College of Engineering (Autonomous), Madurai 625015, Tamil Nadu (India); Murugesh, S. [Department of Chemistry, SACS M.A.V.M.M. Engineering College, Madurai 625301, Tamil Nadu (India); Darchen, A. [UMR CNRS No. 6226 Sciences Chimiques de Rennes, ENSCR, Avenue du General Leclerc, CS 50837, 35708 Rennes, Cedex 7 (France)

    2012-07-30

    Highlights: Black-Right-Pointing-Pointer The carbonization of Tamarind fruit shell improved its defluoridation efficiency. Black-Right-Pointing-Pointer Calcium carbonate particles were involved in the defluoridation process. Black-Right-Pointing-Pointer Adsorbent dose, pH, and fluoride concentration showed significant effects. Black-Right-Pointing-Pointer Maximum adsorption of fluoride was achieved at pH 7-8. Black-Right-Pointing-Pointer Prepared carbons were efficient in treating three natural waters. - Abstract: Tamarindus indica fruit shells (TIFSs) are naturally calcium rich compounds. They were impregnated with ammonium carbonate and then carbonized, leading to ammonium carbonate activated ACA-TIFS carbon. The resulting materials and carbon arising from virgin fruit shells V-TIFS were characterized and assayed as adsorbent for the removal of fluoride anions from groundwater. The fluoride scavenging ability of TIFS carbons was due to naturally dispersed calcium compounds. X-ray diffraction (XRD) showed that TIFS carbon contained a mixture of calcium oxalate and calcium carbonate. Batch studies on the fluoride removal efficiency of TIFS carbons with respect to contact time, pH, initial fluoride concentration, and co-ion interference were conducted. Applicability of various kinetic models (viz., pseudo-first-order, pseudo-second-order, intra-particle diffusion and Elovich) and sorption isotherms were tested for batch techniques. The fluoride removal capacity of TIFS carbons was found to be 91% and 83% at a pH of 7.05 for V-TIFS and ACA-TIFS carbons, respectively. The practical applicability of TIFS carbons using groundwater samples was approved. The fluoride removal was greater in groundwater without hydrogen carbonate ions than those containing these ions. The characterizations of fluoride unloaded and loaded TIFS carbons were done by SEM and XRD studies.

  6. Study of changes in phosphate, calcium and fluoride ions in plaque and saliva after the administration of a fluoride mouth rinse

    Directory of Open Access Journals (Sweden)

    Poureslami H

    2007-09-01

    Full Text Available In this study, the effects of 0.2% sodium fluoride mouthwash solution on calcium, phosphate and fluoride ion contents of saliva and microbial plaque was assessed. Fourteen volunteer students (7-12 years of age of a boarding educational centre in Kerman City (Iran were selected and under defined conditions, their saliva and plaque samples were collected. The concentrations of fluoride, calcium and phosphate ions of the samples were determined, and after 14 days, under the same conditions, the students were asked to rinse their mouth with 0.2% sodium fluoride mouthwash solution. The second set of saliva and plaque samples were collected and the concentrations of the ions were determined. Data was analyzed using paired t-test and the results were presented as tables. P < 0.05 was considered as statistically significant. After using 0.2% sodium fluoride mouthwash solution, a significant increase was observed in the F 2 ion concentration both plaque ( P < 0.000 and saliva ( P < 0.000 of all the studied subjects, while the concentration of phosphate decreased in both saliva and plaque; however, this decrease was significant only in plaque ( P < 0.01. The calcium ion concentration decreased in both plaque and saliva; however, in none of them, the decrease was significant ( P >0.09 and P >0.2, respectively.

  7. Efficacy of calcium- and fluoride-containing materials for the remineralization of primary teeth with early enamel lesion.

    Science.gov (United States)

    Memarpour, Mahtab; Soltanimehr, Elham; Sattarahmady, Naghmeh

    2015-09-01

    The aim of the study was to determine the efficacy of different products containing fluoride, calcium and phosphate for enamel remineralization in eroded primary teeth. A total of 90 sound primary canine teeth were randomly divided into 5 groups of 18 teeth each: 1) control (polished enamel), 2) 5% DuraShield sodium fluoride varnish, 3) 500 ppm fluoridated toothpaste, 4) casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) cream, and 5) Clinpro White varnish containing functionalized tri-calcium phosphate (fTCP). Enamel microhardness (EMH) was measured in all samples before and after demineralization and after 28 days of remineralization. Also 8 samples in groups 2 to 5 and four samples of sound and demineralized enamel were examined with atomic force microscopy (AFM). All data were analyzed with one-way ANOVA (p<0.05). Mean microhardness of demineralized enamel was significantly lower than in enamel at baseline (p<0.001). Remineralization significantly increased microharness in groups 2 to 5 compared to the control group (p<0.001). Percent EMH after remineralization with CPP-ACP was significantly higher than after fTCP (p=0.029), toothpaste (p< 0.001) or fluoride varnish (p<0.001); however, there was no significant difference between toothpaste and fluoride varnish (p=0.062). Microhardness increased more after fTCP treatment than after treatment with sodium fluoride varnish (p<0.001) or fluoridated toothpaste (p=0.045). AFM images showed that enamel roughness decreased most after treatment with fTCP, followed by CPP-ACP, toothpaste and fluoride varnish. The efficacy of CPP-ACP cream for remineralizing eroded enamel was greater than fluoride toothpaste, fluoride varnish or fTCP varnish. PMID:26179280

  8. CHARACTERISTICS OF FLUORIDE EMISSION FROM FIVE CLAY MINERALS AS AFFECTED BY TEMPERATURE,HEATING TIME AND ADDITION OF CALCIUM COMPOUNDS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Characteristics of fluoride emission from five clay minerals (montmorillonite, kaolinite, vermiculite, geothite, and allophane) as affected by temperature, heating time and addition of calcium compounds were studied. Marked increase of the fluoride emission rate was noticed with increase of temperature. The fluoride release, began at 500 ℃-600 ℃, and the main bulk of the fluoride emission occurred at the temperature of about 800 ℃. The loss of crystalline water was primarily responsible for the increase of fluoride emission. When minerals were heated at 800 ℃, The fluoride emission rate from the clay minerals reached the highest after heating for 1 hour. The samples treated by CaO, CaCO3, Ca(OH)2, Ca3(PO4)2, and CaSO4 had 55.45%, 59.58%, 46.45%, 54.31%, 31.25% reduction in the fluoride emission from montmorillonite at the temperature of 800 ℃, respectively. CaCO3 had the highest fluoride fixing capacity compared to other calcium compounds.

  9. A study of some calcium dihalides and strontium fluoride halides systems

    International Nuclear Information System (INIS)

    The CaX2-CaY2 and SrF2-SrX2 (where X and Y represent halide anions) systems were investigated by the Guinier powder X-ray diffraction technique. In the calcium dihalide systems only solid solutions were found. In the strontium fluoride - strontium chloride and strontium fluoride - strontium bromide systems the dihalides and the PbFCl-type SrFX phases were observed. The preparation, crystallographic data and atom distribution of the mixed halides, SrFCl/sub 0.5/Br/sub 0.5/, Ca/sub 0.5/Sr/sub 0.5/FCl, Ca/sub 0.5/Yb/sub 0.5/FCl and Sr/sub 0.5/Eu/sub 0.5/FBr are presented and discussed. (author)

  10. Effect of casein phosphopeptide-amorphous calcium phosphate and acidulated phosphate fluoride gel on erosive enamel wear

    OpenAIRE

    Maryam HajeNorouz Ali Tehrani; Maryam Ghafournia; Pouran Samimi; Omid Savabi; Iman Parisay; Navid Askari; Seyed-Hossein Abtahi

    2011-01-01

    Background: Some studies have shown that casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and acidulated phosphate fluoride (APF) gel can protect teeth against erosion. The aim of this study was to assess whether CPP-ACP and fluoride could reduce enamel wear rates under erosive conditions simulating abrasion and acidic diet regimen. Materials and Methods: Enamel specimens consisted of 3 experimental groups (receiving CPP-ACP, APF or both) and a control group. Specimens were sub...

  11. Effect of casein phosphopeptide-amorphous calcium phosphate and acidulated phosphate fluoride gel on erosive enamel wear

    OpenAIRE

    Tehrani, Maryam HajeNorouz Ali; Ghafournia, Maryam; Samimi, Pouran; Savabi, Omid; Parisay, Iman; Askari, Navid; Abtahi, Seyed-Hossein

    2011-01-01

    Background: Some studies have shown that casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and acidulated phosphate fluoride (APF) gel can protect teeth against erosion. The aim of this study was to assess whether CPP-ACP and fluoride could reduce enamel wear rates under erosive conditions simulating abrasion and acidic diet regimen. Materials and Methods: Enamel specimens consisted of 3 experimental groups (receiving CPP-ACP, APF or both) and a control group. Specimens were subject...

  12. Effect of fluoridated casein phospopeptide-amorphous-calcium phosphate complex, chlorhexidine fluoride mouthwash on shear bond strength of orthodontic brackets: A comparative in vitro study

    Directory of Open Access Journals (Sweden)

    C A Abdul Shahariyar

    2016-01-01

    Full Text Available Objective: The aim of the current study was to determine the effects of casein phosphopeptide amorphous calcium-phosphate (CPP-ACP complex, chlorhexidine fluoride mouthwash on shear bond strengths (SBSs of orthodontic brackets. Materials and Methods: About sixty extracted healthy human premolar teeth with intact buccal enamel were divided into two equal groups to which brackets were bonded using self-etching primers (SEPs and conventional means respectively. These were further equally divided into three subgroups - (1 control (2 CPP-ACP (3 chlorhexidine fluoride mouthwash. The SBSs were then measured using a universal testing machine. Results: SBS of the conventional group was significantly higher than the self-etching group. The intragroup differences were statistically insignificant. Conclusion: CPP-ACP, chlorhexidine fluoride mouthwash did not adversely affect SBS of orthodontic brackets irrespective of the method of conditioning. Brackets bonded with conventional technique showed greater bond strengths as compared to those bonded with SEP.

  13. Effect of fluoridated casein phospopeptide-amorphous-calcium phosphate complex, chlorhexidine fluoride mouthwash on shear bond strength of orthodontic brackets: A comparative in vitro study

    OpenAIRE

    C A Abdul Shahariyar; Anurag D Mahale; Kishore Kumar; Rohan Rai

    2016-01-01

    Objective: The aim of the current study was to determine the effects of casein phosphopeptide amorphous calcium-phosphate (CPP-ACP) complex, chlorhexidine fluoride mouthwash on shear bond strengths (SBSs) of orthodontic brackets. Materials and Methods: About sixty extracted healthy human premolar teeth with intact buccal enamel were divided into two equal groups to which brackets were bonded using self-etching primers (SEPs) and conventional means respectively. These were further equally divi...

  14. Synthesis of Calcium Silicate (Casio3) Using Calcium Fluoride, Quartz and Microbes

    OpenAIRE

    B. Gopal Krishna; M. Jagannadha Rao

    2015-01-01

    Microbes like bacteria, algae, fungi and virus play an important role to catalyst chemical reactions. In Nature, ores or minerals of different compounds are formed due to microbial environment and other factors like weathering. Microbial environment is also instrumental in forming calcium containing silicate minerals. Chemical reactions occur under microbial environment because microbes have the ability to control or modify different factors like pH, chemical potential and tempera...

  15. Properties of calcium fluoride up to 95 kbar: A theoretical study

    Indian Academy of Sciences (India)

    Chun-Sheng Wang

    2010-08-01

    We have studied the high-pressure and high-temperature behaviour of calcium fluoride (CaF2) using molecular dynamics simulations with the Born–Mayer–Huggins potentials. The thermal (pressure-volume) equation of state, radial distribution functions (RDFs) just nearby the melting temperature, isothermal bulk modulus, and volume thermal expansion coefficients were calculated from the isobaric and isothermal ensemble. Structural and thermodynamical properties at ambient temperature were well reproduced for the cubic fluorite-type phase of CaF2. At an extended pressure and temperature ranges, the thermal expansivity and bulk modulus of CaF2 have also been predicted. The RDFs indicated that the melting temperature is bracketed between 1600 and 1700 K, and the thermodynamic properties of CaF2 with fluorite-type cubic structure are investigated in the pressure range 0–95 kbar and temperature up to 1600 K.

  16. Fabrication of three-dimensional microdisk resonators in calcium fluoride by femtosecond laser micromachining

    CERN Document Server

    Lin, Jintian; Tang, Jialei; Wang, Nengwen; Song, Jiangxin; He, Fei; Fang, Wei; Cheng, Ya

    2014-01-01

    We report on fabrication of on-chip calcium fluoride (CaF2) microdisk resonators using water-assisted femtosecond laser micromachining. Focused ion beam (FIB) milling is used to create ultra-smooth sidewalls. The quality (Q)-factors of the fabricated microresonators are measured to be 4.2x10^4 at wavelengths near 1550 nm. The Q factor is mainly limited by the scattering from the bottom surface of the disk whose roughness remains high due to the femtosecond laser micromachining process. This technique facilitates formation of on-chip microresonators on various kinds of bulk crystalline materials, which can benefit a wide range of applications such as nonlinear optics, quantum optics, and chip-level integration of photonic devices.

  17. Bones and Crohn's: No benefit of adding sodium fluoride oribandronate to calcium and vitamin D

    Institute of Scientific and Technical Information of China (English)

    Jochen Klaus; Max Reinshagen; Katharina Herdt; Christoph Schr(o)ter; Guido Adler; Georg BT von Boyen; Christian von Tirpitz

    2011-01-01

    AIM: To compare the effect of calcium and cholecalciferol alone and along with additional sodium fluoride or ibandronate on bone mineral density (BMD) and fractures in patients with Crohn's disease (CD).METHODS: Patients (n =148) with reduced BMD (T-score< -1) were randomized to receive cholecalciferol (1000 IU) and calcium citrate (800 mg) daily alone(group A, n =32) or along with additional sodium fluoride (25 mg bid ) (group B, n = 62) or additional ibandronate (1 mg iv/3-monthly) (group C, n = 54). Dual energy X-ray absorptiometry of the lumbar spine (L1-L4) and proximal right femurand X-rays of the spine were performed at baseline and after 1.0, 2.25 and 3.5 years. Fracture-assessment included visual reading of X-rays and quantitative morphometry of vertebral bodies (T4-L4).RESULTS: One hundred and twenty three (83.1%) patients completed the first year for intention-to-treat (ITT) analysis. Ninety two (62.2%) patients completed thesecond year and 71 (47.8%) the third year available for per-protocol (PP) analysis. With a significant increase in T-score of the lumbar spine by +0.28 ± 0.35 [95%confidence interval (CI): 0.162-0.460, P < 0.01], +0.33 ± 0.49 (95% CI: 0.109-0.558, P < 0.01), +0.43 ± 0.47 (95% CI: 0.147-0.708, P < 0.01) in group A, +0.22 ±0.33 (95% CI: 0.125-0.321, P < 0.01); +0.47 ± 0.60 (95% CI: 0.262-0.676, P < 0.01), +0.51 ± 0.44 (95%CI: 0.338-0.682, P < 0.01) in group B and +0.22 ±0.38 (95% CI: 0.111-0.329, P < 0.01), +0.36 ± 0.53(95% CI: 0.147-0.578, P < 0.01), +0.41 ± 0.48 (95%CI: 0.238-0.576, P < 0.01) in group C, respectively, duringthe 1.0, 2.25 and 3.5 year periods (PP analysis), no treatment regimen was superior in any in- or betweengroup analyses. In the ITT analysis, similar results in allin- and between-group analyses with a significant ingroup but non-significant between-group increase in T-score of the lumbar spine by 0.38 ± 0.46 (group A,P < 0.01), 0.37 ± 0.50 (group B, P < 0.01) and 0.35 ±0.49 (group C, P < 0.01) was

  18. Quantitative microradiographic analysis of remineralization of enamel lesions promoted by casein phosphopeptide amorphous calcium phosphate and fluoride

    International Nuclear Information System (INIS)

    Objective: To evaluate the remineralization effect of casein phosphopeptide amorphous calcium phosphate (CPP-ACP) and fluoride complex on artificial enamel subsurface white spot lesions in vitro in order to provide a new method to treat the postorthodontic enamel demineralization. Methods: Extracted premolar teeth for orthodontic reason were immersed into lactic acid gel to prepare artificial white spot lesions. Then the specimens were randomly assigned to seven groups: 5.0% CPP-ACFP group, 1.0% CPP-ACP group, 0.1% CPP-ACPgroup, calcium phosphate saturated solution group, calcium phosphate saturated solution plus fluorid group, deionized water group. Lesion depths and mineral loss were quantitatively determined by microradiography in various groups. Results: The lesion depths and mineral loss after remineralization in each group were significantly reduced (P0.05), but the lesion depths and mineral loss in these three groups were significantly lower than those in deionized water group (P<0.05, P<0.01). Conclusion: CPP-ACP has the ability of promoting remineralization of enamel artificial white spot lesions which can be enhanced by fluorid. The remineralization ability depends on the concentration of calcium phosphate stabilized by CPP-ACP. (authors)

  19. Fluoride-containing nanoporous calcium-silicate MTA cements for endodontics and oral surgery: Early fluorapatite formation in a phosphate-containing solution

    OpenAIRE

    Gandolfi, M.G.; Taddei, P.; Siboni, F.; Modena, E.; Ginebra Molins, Maria Pau; Prati, Claudio

    2011-01-01

    Gandolfi MG, Taddei P, Siboni F, Modena E, Ginebra MP, Prati C. Fluoride-containing nanoporous calcium-silicate MTA cements for endodontics and oral surgery: early fluorapatite formation in a phosphate-containing solution. International Endodontic Journal, 44, 938–949, 2011. Aim To test the chemical–physical properties and apatite-forming ability of experimental fluoride-doped calcium silicate cements designed to create novel bioactive materials for use in endodontics ...

  20. An AC phase measuring interferometer for measuring dn/dT of fused silica and calcium fluoride at 193 nm

    Energy Technology Data Exchange (ETDEWEB)

    Shagam, R.N.

    1998-09-01

    A novel method for the measurement of the change in index of refraction vs. temperature (dn/dT) of fused silica and calcium fluoride at the 193 nm wavelength has been developed in support of thermal modeling efforts for the development of 193 nm-based photolithographic exposure tools. The method, based upon grating lateral shear interferometry, uses a transmissive linear grating to divide a 193 nm laser beam into several beam paths by diffraction which propagate through separate identical material samples. One diffracted order passing through one sample overlaps the undiffracted beam from a second sample and forms interference fringes dependent upon the optical path difference between the two samples. Optical phase delay due to an index change from heating one of the samples causes the interference fringes to change sinusoidally with phase. The interferometer also makes use of AC phase measurement techniques through lateral translation of the grating. Results for several samples of fused silica and calcium fluoride are demonstrated.

  1. Calcium Prerinse before Fluoride Rinse Reduces Enamel Demineralization: An in situ Caries Study.

    Science.gov (United States)

    Souza, João Gabriel S; Tenuta, Livia Maria Andaló; Del Bel Cury, Altair Antoninha; Nóbrega, Diego Figueiredo; Budin, Renan R; de Queiroz, Mateus X; Vogel, Gerald L; Cury, Jaime A

    2016-01-01

    A calcium (Ca) prerinse before a fluoride (F) rinse has been shown to increase oral F levels. We tested the anticaries effect of this combination in a dose-response in situ caries model. In a double-blind, crossover experiment, 10 volunteers carried enamel slabs in palatal appliances for 14 days, during which they rinsed twice/day with one of four rinse combinations: (1) a placebo prerinse (150 mM sodium lactate) followed by a distilled water rinse (negative control); (2) a placebo prerinse followed by a 250 ppm F rinse; (3) a placebo prerinse followed by a 1,000 ppm F rinse, or (4) a Ca prerinse (150 mM Ca, as calcium lactate) followed by a 250 ppm F rinse. Sucrose solution was dripped onto the slabs 8×/day to simulate a high cariogenic challenge. The percent surface hardness loss (%SHL) was significantly lower in the Ca prerinse used with the 250 ppm F rinse group (%SHL = 38.0 ± 21.0) when compared with the F rinse alone (%SHL = 59.5 ± 24.1) and similar to the 1,000 ppm F rinse group (%SHL = 42.0 ± 18.3). Compared with the 250 ppm F rinse, the Ca prerinse increased biofilm fluid F only twice (nonsignificant). However, it greatly increased F in biofilm solids (∼22×). The Ca prerinse had little effect on loosely or firmly bound enamel F. The results showed an increased level of protection against demineralization by the use of a Ca prerinse, which seems to be caused by the enhancement of F concentration in the biofilm. PMID:27355353

  2. Effect of Rare Earth Elements on The Thermoluminescent Properties of Locally Prepared Calcium Fluoride Phosphor

    International Nuclear Information System (INIS)

    Synthetic Calcium Fluoride ( CaF2 ) doped with rare earth elements (RE) have been prepared in the form of single and double doped TL materials. The single doped CaF2 phosphors with RE3+ dopants show multi- peak TL glow curves after irradiation by gamma rays. It could be concluded that the peak temperatures corresponding to the different traps are basically a nature of the host lattice ( CaF2 ). While the influence of the impurities (RE) is to provide efficient luminescent centers and efficient traping sites. The most sensitive dopants seems to be Dy, Gd, Ho and Sm. While elements like Er and Tm are seen to be inefficient as TL activator in CaF2. All these dopants exhibit the phenomenon of concentration quenching. The optimum concentration being in the range of 0.05% to 0.1% by weight. The double doping of (RE) in CaF2 as (CaF2:Ho + Tb of conc. 0.05% by wt.) improves its TL sensitivity by one decade than the individual doping. Also the case of CaF2:Sm + Y gave a new high temperature peak at 650 degree C. The activation energy of this newly peak could be calculated and found it ranges between 2.85 eV and 2.99 eV. The characteristics of this peak have been discussed in some details

  3. Comparative evaluation of the remineralizing efficacy of calcium sodium phosphosilicate agent and fluoride based on quantitative and qualitative analysis

    Directory of Open Access Journals (Sweden)

    Saranya Mony

    2015-01-01

    Full Text Available Background: Calcium sodium phosphosilicate (NovaMin is an agent that is claimed to release calcium and phosphate ions intraorally to help the self-repair process of enamel. It is used extensively as a desensitizing agent, but the chemical reactions that occur may promote apatite formation enhancing remineralization. The present study was undertaken to evaluate the ability of NovaMin to remineralize an experimentally induced demineralized lesion. The evaluation was done based on the quantitative and qualitative analysis of enamel over the period of 15 and 30 days. Materials and Methods: A sample of 120 noncarious premolar teeth extracted for orthodontic reasons were used for the study. Baseline data for hardness, Ca/PO 4 , and surface characteristics before and after demineralization process was obtained. All the teeth were brushed twice daily at 12 h interval with the test agents using a powered toothbrush for 2 min. The samples were tested on the 15 th and 30 th day. Results: Calcium phosphate ratio and hardness in both the groups improved during the study period. Fluoride group showed higher values for Ca/PO 4 and hardness but was not statistically significant with the P > 0.05. Scanning electron microscope pictures showed that the deposition of the material over the decalcified enamel is more smoother and uniform with NovaMin and more irregular with fluoride. Relevance: NovaMin is found to be as effective in improving the Ca/PO 4 ratio and hardness in a demineralized enamel as fluoride. Hence, it can be a new alternate material for remineralization of enamel with less toxic effects compared to fluorides.

  4. Pulp response to high fluoride releasing glass ionomer, silver diamine fluoride, and calcium hydroxide used for indirect pulp treatment: An in-vivo comparative study

    Directory of Open Access Journals (Sweden)

    Atish Korwar

    2015-01-01

    Full Text Available Aims and Objectives: The study aims at determining pulp response of two high fluoride releasing materials silver diamine fluoride (SDF and Type VII glass ionomer cement (GIC when used as indirect pulp treatment (IPT materials. Materials and Methods: Deep Class V cavities were made on four first premolars indicated for extraction for orthodontic reasons. SDF, Type VII GIC, and calcium hydroxide base are given in three premolars, and one is kept control. Premolars were extracted 6 weeks after the procedure and subjected to histopathological examination to determine the pulp response. The results were analyzed using Chi-square test. Results: No inflammatory changes were observed in any of the groups. Significantly more number of specimens in SDF and Type VII GIC groups showed tertiary dentin deposition (TDD when compared to control group. No significant difference was seen in TDD when intergroup comparison was made. Odontoblasts were seen as short cuboidal cells with dense basophilic nucleus in SDF and Type VII GIC group. Conclusion: The study demonstrated TDD inducing ability of SDF and Type VII GIC and also established the biocompatibility when used as IPT materials.

  5. Strontium hydroxyapatite and strontium carbonate as templates for the precipitation of calcium-phosphates in the absence and presence of fluoride

    Science.gov (United States)

    Sternitzke, Vanessa; Janousch, Markus; Heeb, Michèle B.; Hering, Janet G.; Johnson, C. Annette

    2014-06-01

    The heterogeneous precipitation of calcium-phosphates on calcium hydroxyapatite (Ca10(PO4)6(OH)2 or HAP) in the presence and absence of fluoride is important in the formation of bone and teeth, protection against tooth decay, dental and skeletal fluorosis and defluoridation of drinking water. Strontium hydroxyapatite (Sr10(PO4)6(OH)2 or SrHAP) and strontium carbonate (SrCO3) were used as calcium-free seed templates in precipitation experiments conducted with varying initial calcium-to-phosphate (Ca/P) or calcium-to-phosphate-to-fluoride (Ca/P/F) ratios. Suspensions of SrHAP or SrCO3 seed templates (which were calcium-limited for both templates and phosphate-limited in the case of SrCO3) were reacted at pH 7.3 (25 °C) over 3 days. The resulting solids were examined with Scanning Transmission Electron Microscopy (STEM), X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR), and X-ray Photoelectron Spectroscopy (XPS), X-ray Absorption Near Edge Structure (XANES), and Extended X-ray Absorption Fine Structure spectroscopy (EXAFS). Calcium apatite was the predominant phase identified by all techniques independent of the added Ca/P ratios and of the presence of fluoride. It was not possible to make an unambiguous distinction between HAP and fluorapatite (Ca10(PO4)6F2, FAP). The apatite was calcium-deficient and probably contained some strontium.

  6. Mechanisms of Intracellular Calcium Homeostasis in MC3T3-E1 Cells and Bone Tissues of Sprague-Dawley Rats Exposed to Fluoride.

    Science.gov (United States)

    Duan, Xiao-Qin; Li, Yan-Hui; Zhang, Xiu-Yun; Zhao, Zhi-Tao; Wang, Ying; Wang, Huan; Li, Guang-Sheng; Jing, Ling

    2016-04-01

    Calcium homeostasis of osteoblasts (OBs) has an important role in the physiology and pathology of bone tissue. In order to study the mechanisms of intracellular calcium homeostasis, MC3T3-E1 cells and Sprague-Dawley rats were treated with different concentrations of fluoride. Then, we examined intracellular-free calcium ion ([Ca(2+)]i) in MC3T3-E1 cells as well as mRNA and protein levels of Cav1.2, the main subunit of L-type voltage-dependent calcium channels (VDCCs), Na(+)/Ca(2+) exchange carriers (NCS), and plasma membrane Ca(2+)-ATPase (PMCA), inositol 1,4,5-trisphosphate receptor (IP3R) channels, sarco/endoplasmic reticulum calcium ATPase 2b (SERCA2b)/ATP2A2 in vitro, and rat bone tissues in vivo. Our results showed that [Ca(2+)]i of fluoride-treated OBs increased in a concentration-dependent manner with an increase in the concentration of fluoride. We also found that the low dose of fluoride led to high expression levels of Cav1.2, NCS-1, and PMCA and low expression levels of IP3R and SERCA2b/ATP2A2, while the high dose of fluoride induced an increase in SERCA2b/ATP2A2 levels and decrease in Cav1.2, PMCA, NCS-1, and IP3R levels. These results demonstrate that calcium channels and calcium pumps of plasma and endoplasmic reticulum (ER) membranes keep intracellular calcium homeostasis by regulating Cav1.2, NCS-1, PMCA, IP3R, and SERCA2b/ATP2A2 expression. PMID:26276564

  7. Biocompatibility of fluoride-coated magnesium-calcium alloys with optimized degradation kinetics in a subcutaneous mouse model.

    Science.gov (United States)

    Drynda, Andreas; Seibt, Juliane; Hassel, Thomas; Bach, Friedrich Wilhelm; Peuster, Matthias

    2013-01-01

    The principle of biodegradation has been considered for many years in the development of cardiovascular stents, especially for patients with congenital heart defects. A variety of materials have been examined with regard to their suitability for cardiovascular devices. Iron- and magnesium-based stents were investigated intensively during the last years. It has been shown, that iron, or iron based alloys have slow degradation kinetics whereas magnesium-based systems exhibit rapid degradation rates. Recently we have developed fluoride coated binary magnesium-calcium alloys with reduced degradation kinetics. These alloys exhibit good biocompatibility and no major adverse effects toward smooth muscle and endothelial cells in in vitro experiments. In this study, these alloys were investigated in a subcutaneous mouse model. Fluoride coated (fc) magnesium, as well as MgCa0.4%, MgCa0.6%, MgCa0.8%, MgCa1.0%, and a commercially available WE43 alloy were implanted in form of (fc) cylindrical plates into the subcutaneous tissue of NMRI mice. After a 3 and 6 months follow-up, the (fc) alloy plates were examined by histomorphometric techniques to assess their degradation rate in vivo. Our data indicate that all (fc) alloys showed a significant corrosion. For both time points the (fc) MgCa alloys showed a higher corrosion rate in comparison to the (fc) WE43 reference alloy. Significant adverse effects were not observed. Fluoride coating of magnesium-based alloys can be a suitable way to reduce degradation rates. However, the (fc) MgCa alloys did not exhibit decreased degradation kinetics in comparison to the (fc) WE43 alloy in a subcutaneous mouse model. PMID:22767427

  8. Titanium dioxide/calcium fluoride nanocrystallite for efficient dye-sensitized solar cell. A strategy of enhancing light harvest

    Science.gov (United States)

    Wang, Zubin; Tang, Qunwei; He, Benlin; Chen, Xiaoxu; Chen, Haiyan; Yu, Liangmin

    2015-02-01

    Enhancement of light harvest for dye excitation is a persistent objective in dye-sensitized solar cell (DSSC). We present here the fabrication of titanium dioxide/calcium fluoride (TiO2/CaF2) photoanodes for efficient DSSC applications. Owing to the interference effect of incident light beams reflected from TiO2/CaF2 and CaF2/electrolyte interfaces, the light intensity and therefore dye excitation have been markedly enhanced. The crystal structure and therefore photovoltaic performance are optimized by adjusting CaF2 dosage. A maximum power conversion efficiency of 7.66% is measured from the DSSC employing TiO2/0.5 wt% CaF2 nanocrystallite in comparison with 6.02% for the solar cell with pristine TiO2 anode.

  9. Reducing the detection limit of neptunium determination by luminescence method with the use of calcium fluoride tablets

    International Nuclear Information System (INIS)

    When appliying neptunium solution on calcium fluoride tablet, its concentration in near the surface layer is observed, which corresponds to the effective layer of luminescence excitation. It permits to increase specific intensity of luminescence per neptunium mass unity, which is more than an order higher, as compared with concentional way of crystallophosphor preparation. The influence of neptunium oxidation degree in solution, solution composition and conditions of crystallophosphor preparation on the intensity by Np luminescence are studied. Admissible concentration of quenchers as regards neptunium is 103-105 depending on their nature. The limit of neptunium determination is 5x10-13 g, relative root-mean-square deviation at the level of 0.1 ng Np equals 0.12

  10. Combining casein phosphopeptide-amorphous calcium phosphate with fluoride: synergistic remineralization potential of artificially demineralized enamel or not?

    Science.gov (United States)

    Elsayad, Iman; Sakr, Amal; Badr, Yahia

    2009-07-01

    Recaldent is a product of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). The remineralizing potential of CPP-ACP per se, or when combined with 0.22% Fl gel on artificially demineralized enamel using laser florescence, is investigated. Mesial surfaces of 15 sound human molars are tested using a He-Cd laser beam at 441.5 nm with 18-mW power as an excitation source on a suitable setup based on a Spex 750-M monochromator provided with a photomultiplier tube (PMT) for detection of collected autofluorescence from sound enamel. Mesial surfaces are subjected to demineralization for ten days. The spectra from demineralized enamel are measured. Teeth are divided into three groups according to the remineralizing regimen: group 1 Recaldent per se, group 2 Recaldent combined with fluoride gel and ACP, and group 3 artificial saliva as a positive control. After following these protocols for three weeks, the spectra from the remineralized enamel are measured. The spectra of enamel autofluorescence are recorded and normalized to peak intensity at about 540 nm to compare spectra from sound, demineralized, and remineralized enamel surfaces. A slight red shift occurred in spectra from demineralized enamel, while a blue shift may occur in remineralized enamel. Group 2 shows the highest remineralizing potential. Combining fluoride and ACP with CPP-ACP can give a synergistic effect on enamel remineralization.

  11. Selective reflection spectroscopy of a vapour at a calcium fluoride interface

    CERN Document Server

    De Silans, Thierry Passerat; Romanelli, Marco; Segundo, Pedro Chaves De Souza; Maurin, Isabelle; Bloch, Daniel; Ducloy, Martial; Sarkisyan, Asphet; Sarkisyan, David

    2007-01-01

    Fluoride materials exhibit surface resonances located in the thermal infrared. This makes them interesting to search for a fundamental temperature dependence of the atom-surface interaction, originating in the near-field thermal emissivity of the surface. Preliminary selective reflection experiments performed on a special Cs vapour cell that includes a CaF2 interface show a temperature dependence, yet to be analyzed

  12. Improved laser damage threshold performance of calcium fluoride optical surfaces via Accelerated Neutral Atom Beam (ANAB) processing

    Science.gov (United States)

    Kirkpatrick, S.; Walsh, M.; Svrluga, R.; Thomas, M.

    2015-11-01

    Optics are not keeping up with the pace of laser advancements. The laser industry is rapidly increasing its power capabilities and reducing wavelengths which have exposed the optics as a weak link in lifetime failures for these advanced systems. Nanometer sized surface defects (scratches, pits, bumps and residual particles) on the surface of optics are a significant limiting factor to high end performance. Angstrom level smoothing of materials such as calcium fluoride, spinel, magnesium fluoride, zinc sulfide, LBO and others presents a unique challenge for traditional polishing techniques. Exogenesis Corporation, using its new and proprietary Accelerated Neutral Atom Beam (ANAB) technology, is able to remove nano-scale surface damage and particle contamination leaving many material surfaces with roughness typically around one Angstrom. This surface defect mitigation via ANAB processing can be shown to increase performance properties of high intensity optical materials. This paper describes the ANAB technology and summarizes smoothing results for calcium fluoride laser windows. It further correlates laser damage threshold improvements with the smoothing produced by ANAB surface treatment. All ANAB processing was performed at Exogenesis Corporation using an nAccel100TM Accelerated Particle Beam processing tool. All surface measurement data for the paper was produced via AFM analysis on a Park Model XE70 AFM, and all laser damage testing was performed at Spica Technologies, Inc. Exogenesis Corporation's ANAB processing technology is a new and unique surface modification technique that has demonstrated to be highly effective at correcting nano-scale surface defects. ANAB is a non-contact vacuum process comprised of an intense beam of accelerated, electrically neutral gas atoms with average energies of a few tens of electron volts. The ANAB process does not apply mechanical forces associated with traditional polishing techniques. ANAB efficiently removes surface

  13. The role of fluoride and casein phosphopeptide/amorphous calcium phosphate in the prevention of erosive/abrasive wear in an in vitro model using hydrochloric acid

    OpenAIRE

    Wegehaupt, F J; Attin, T.

    2010-01-01

    OBJECTIVE: To investigate the effect of various fluoride compounds and casein phosphopeptide/amorphous calcium phosphate (CPP-ACP) on the reduction of erosive/abrasive tooth wear. METHODS: Forty enamel samples were prepared from bovine lower incisors, stratified and allocated to 4 groups (1-4). Samples in group 1 remained untreated and served as negative controls. The test samples were treated for 2 min/day as follows: group 2 amine/sodium fluoride gel (pH 4.8; 12,500 ppm), group 3 sodium flu...

  14. The effect of casein phosphopeptide-amorphous calcium phosphate paste and sodium fluoride mouthwash on the prevention of dentine erosion: An in vitro study

    OpenAIRE

    Maryam Moezizadeh; Azar Alimi

    2014-01-01

    Aim: The purpose was to compare the effect of 0.2% sodium fluoride mouthwash and casein phosphopeptide-amorphous calcium phosphate paste on prevention of dentin erosion. Materials and Methods: Buccal surfaces of 36 sound premolar teeth were ground flat and polished with abrasive discs. Half the polished surfaces were covered with tape to maintain a reference surface. Samples were randomly allocated into three groups. Group A was pretreated with tooth mousse (TM) 4 times a day for 5 days. ...

  15. In vivo Spectrophotometric Assessment of the Tooth Whitening Effectiveness of Nite White 10% with Amorphous Calcium Phosphate, Potassium Nitrate and Fluoride, Over a 6-month Period

    OpenAIRE

    Grobler, Sias R; MAJEED, Abdul; Moola, Mohamad H; Rossouw, Roelof J; van Wyk Kotze, Theuns

    2011-01-01

    To clinically evaluate the effectiveness of Nite White 10% carbamide peroxide with amorphous calcium phosphate, potassium nitrate and fluoride over a 6-month follow-up period. Nite White was applied nightly for 14 days, according to the manufacturer’s instructions. The color of teeth 11 and 21 of twenty one subjects was measured with a spectrophotometer (L*; a*; b*). Subjects were instructed to take note of any tooth sensitivity and gingival irritation. For all three components (L*, a* and b*...

  16. Ab-initio Calculations of Electronic Properties of Calcium Fluoride (CaF2)

    Science.gov (United States)

    Bohara, Bir; Franklin, Lashounda; Malozovsky, Yuriy; Bagayoko, Diola

    We have performed first principle, local density approximation (LDA) calculations of electronic and related properties of cubic calcium fluorite (CaF2) . Our non-relativistic computations employed the Ceperley and Alder LDA potential and the linear combination of atomic orbitals (LCAO) formalism. The implementation of the LCAO formalism followed the Bagayoko, Zhao, and Williams (BZW) method, as enhanced by Ekuma and Franklin (BZW-EF). We discuss the electronic energy bands, including the large band gap, total and partial density of states, electron and hole effective masses, and the bulk modulus. Our calculated, indirect (X- Γ) band gap is 12.98 eV; it is 1 eV above an experimental value of 11.8 eV. The calculated bulk modulus (82.89 GPA) is excellent agreement with the experimental result of 82.0 +/-0.7. Our predicted equilibrium lattice constant is 5.42Å. Acknowledgments: This work is funded in part by the National Science Foundation (NSF) and the Louisiana Board of Regents, through LASiGMA [Award Nos. EPS- 1003897, NSF (2010-15)-RII-SUBR], and NSF HRD-1002541, the US Department of Energy, National, Nuclear Security Administration (NNSA) (Award No. DE-NA-0002630), LaSPACE, and LONI-SUBR.

  17. Physiologic Conditions Affect Toxicity of Ingested Industrial Fluoride

    OpenAIRE

    Richard Sauerheber

    2013-01-01

    The effects of calcium ion and broad pH ranges on free fluoride ion aqueous concentrations were measured directly and computed theoretically. Solubility calculations indicate that blood fluoride concentrations that occur in lethal poisonings would decrease calcium below prevailing levels. Acute lethal poisoning and also many of the chronic effects of fluoride involve alterations in the chemical activity of calcium by the fluoride ion. Natural calcium fluoride with low solubility and toxicity ...

  18. Lubricating Properties of Ceramic-Bonded Calcium Fluoride Coatings on Nickel-Base Alloys from 75 to 1900 deg F

    Science.gov (United States)

    Sliney, Harold E.

    1962-01-01

    The endurance life and the friction coefficient of ceramic-bonded calcium fluoride (CaF2) coatings on nickel-base alloys were determined at temperatures from 75 F to 1900 F. The specimen configuration consisted of a hemispherical rider (3/16-in. rad.) sliding against the flat surface of a rotating disk. Increasing the ambient temperature (up to 1500 F) or the sliding velocity generally reduced the friction coefficient and improved coating life. Base-metal selection was critical above 1500 F. For instance, cast Inconel sliding against coated Inconel X was lubricated effectively to 1500 F, but at 1600 F severe blistering of the coatings occurred. However, good lubrication and adherence were obtained for Rene 41 sliding against coated Rene 41 at temperatures up to 1900 F; no blisters developed, coating wear life was fairly good, and the rider wear rate was significantly lower than for the unlubricated metals. Friction coefficients were 0.12 at 1500 F, 0.15 at 1700 F, and 0.17 at 1800 F and 1900 F. Because of its ready availability, Inconel X appears to be the preferred substrate alloy for applications in which the temperature does not exceed 1500 F. Rene 41 would have to be used in applications involving higher temperatures. Improved coating life was derived by either preoxidizing the substrate metals prior to the coating application or by applying a very thin (less than 0.0002 in.) burnished and sintered overlay to the surface of the coating. Preoxidation did not affect the friction coefficient. The overlay generally resulted in a higher friction coefficient than that obtained without the overlay. The combination of both modifications resulted in longer coating life and in friction coefficients intermediate between those obtained with either modification alone.

  19. The effect of casein phosphopeptide-amorphous calcium phosphate paste and sodium fluoride mouthwash on the prevention of dentine erosion: An in vitro study

    Directory of Open Access Journals (Sweden)

    Maryam Moezizadeh

    2014-01-01

    Full Text Available Aim: The purpose was to compare the effect of 0.2% sodium fluoride mouthwash and casein phosphopeptide-amorphous calcium phosphate paste on prevention of dentin erosion. Materials and Methods: Buccal surfaces of 36 sound premolar teeth were ground flat and polished with abrasive discs. Half the polished surfaces were covered with tape to maintain a reference surface. Samples were randomly allocated into three groups. Group A was pretreated with tooth mousse (TM 4 times a day for 5 days. Group B was pretreated with 0.2% sodium fluoride mouthwash 4 times a day for 5 days. Group C was considered as the control group with no pretreatment. In the next step, the samples were exposed to Coca-Cola 4 times a day for 3 days. After each erosive cycle, the samples were rinsed with deionized water and stored in artificial saliva. The surface loss was determined using profilometry. Results: The erosion in both Groups A and B was less than the control group. The surface loss in mouthwash group was significantly lower than in the control group. Erosion in TM group was more than the mouthwash group and less than the control group. Conclusion: Sodium fluoride mouthwash is more effective for prevention of dentin erosion.

  20. URINARY FLUORIDE OUTPUT IN CHILDREN FOLLOWING THE USE OF A DUAL-FLUORIDE VARNISH FORMULATION

    OpenAIRE

    Kelly Polido Kaneshiro Olympio; Vanessa Eid da Silva Cardoso; Maria Fernanda Borro Bijella; Juliano Pelim Pessan; Alberto Carlos Botazzo Delbem; Marília Afonso Rabelo Buzalaf

    2009-01-01

    OBJECTIVE: This study evaluated the bioavailability of fluoride after topical application of a dual-fluoride varnish commercially available in Brazil, when compared to DuraphatTM. 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, s...

  1. Remineralization potential of fluoride and amorphous calcium phosphate-casein phospho peptide on enamel lesions: An in vitro comparative evaluation

    Directory of Open Access Journals (Sweden)

    Lata S

    2010-01-01

    Full Text Available Aim: This in vitro study was conducted on enamel blocks of human premolars with the aim of evaluating the remineralization potential of fluoride and ACP-CPP and the combination of ACP-CPP and fluoride on early enamel lesions. Materials and Methods: Fifteen intact carious free human premolars were selected. The coronal part of each tooth was sectioned into four parts to make 4 enamel blocks. The baseline SMH (surface microhardness was measured for all the enamel specimens using Vickers microhardness (VHN testing machine. Artificial enamel carious lesions were created by inserting the specimens in demineralization solution for 3 consecutive days. The SMH of the demineralised specimens was evaluated. Then the four enamel sections of each tooth were subjected to various surface treatments , i.e. Group 1- Fluoride varnish, Group 2- ACP-CPP cream, Group 3- Fluoride + ACP-CPP & Group 4- Control (No surface treatment. A caries progression test (pH cycling was carried out, which consisted of alternative demineralization (3hours and remineralization with artificial saliva (21 hours for five consecutive days. After pH cycling again SMH of each specimen was assessed to evaluate the remineralization potential of each surface treatment agent. Then, to asses the remineralization potential of various surface treatments at the subsurface level, each enamel specimen was longitudinally sectioned through the centre to expose the subsurface enamel area. Cross-sectional microhardness (CSMH was evaluated to assess any subsurface remineralization Results: Statistical analysis using one-way ANOVA followed by multiple comparisons test was applied to detect significant differences at P ≤ 0.05 levels between various surface treatments at different phases. Conclusions: With in the limits, the present study concludes that; ACP-CPP cream is effective, but to a lesser extent than fluoride in remineralizing early enamel caries at surface level. Combination of fluoride and ACP

  2. Fluoridated Water

    Science.gov (United States)

    ... Cancer Prevention Overview–for health professionals Research Fluoridated Water On This Page What is fluoride, and where is it found? What is water fluoridation? When did water fluoridation begin in the ...

  3. The Impact of pH and Calcium on the Uptake of Fluoride by Tea Plants (Camellia sinensis L.)

    OpenAIRE

    Ruan, Jianyun; Ma, Lifeng; Shi, Yuanzhi; HAN, WENYAN

    2004-01-01

    • Background and Aims Tea plants (Camellia sinensis L.) accumulate large amounts of fluoride (F) from soils containing normal F concentrations. The present experiments examined the effects of pH and Ca on F uptake by this accumulating plant species.

  4. Effect of calcium fluoride on sintering behaviour of SiO2-CaO-Na2O-MgO glass-ceramic system

    Directory of Open Access Journals (Sweden)

    Bahman Mirhadi

    2012-09-01

    Full Text Available The crystallization characteristics of glasses based on the SiO2-CaO-Na2O-MgO (SCNM system containing calcium fluoride (CaF2 have been investigated by differential thermal analysis (DTA, X-ray diffraction (XRD and scanning electron microscopy (SEM. The partial replacement of CaO by CaF2 in the studied glass-ceramics led to the development of different crystalline phase assemblages, including wollastonite and diopside using various heat-treatment processes. With the increase of CaF2 content, the crystallization temperature of the glass and the strength of the crystallization peak temperature decreases. Addition of CaF2 up to 6.0 mol%, as expected, improved the sinterability. This sample reached to maximum density by sintering at 950 °C.

  5. Analysis of bone formation on porous and calcium phosphate-coated acetabular cups: a randomised clinical [18F]fluoride PET study.

    Science.gov (United States)

    Ullmark, Gösta; Sörensen, Jens; Nilsson, Olle

    2012-01-01

    We present a study using Fluoride-Positron Emission Tomography (F-PET/CT) to analyse new bone formation in periacetabular bone adjacent to press fit cups following THA. In 16 THA (8 patients) with bilateral hip osteoarthritis simultaneous bilateral total hip arthroplasty (THA) was performed, employing electrochemically applied calcium phosphate coated (HA) cups or porous-coated (PC) cups allocated at random to compare the two sides. A reference group of 13 individuals with a normal healthy hip was used to determine 'normal' bone metabolism. [18F]fluoride -PET/CT was used to analyze bone formation adjacent to the cups 1 week, 4 months and 12 months after surgery. Clinical and radiographic evaluation was performed preoperatively, postoperatively and at 2 years. Bone forming activity had a mean of 5.71, 4.69 and 3.47 SUV around the HA- and 5.04, 4.80 and 3.50 SUV around the PC-cups at 1 week, 4 months and 12 months respectively. Normal bone metabolism was 3.68 SUV. After 1 year activity had declined to normal levels for both groups. The clinical results were good in all cases. HA coating resulted in higher uptake indicating higher bone forming activity after 1 week. F-PET/CT is a valuable tool to analyse bone formation and secondary stabilisation of an acetabular cup. PMID:22547382

  6. Evaluation and comparison of the efficacy of low fluoridated and calcium phosphate-based dentifrice formulations when used with powered and manual toothbrush in children with autism

    Directory of Open Access Journals (Sweden)

    Prateek Awasthi

    2015-01-01

    Full Text Available Background: Autism is a neurobiological disorder characterized by impaired social interaction, communication difficulties, and lacking manual dexterity. These limitations make the oral hygiene maintenance very difficult. Aim: The aim of this present study is to evaluate and compare the efficacy of low fluoridated and calcium phosphate-based dentifrice formulations when used with powered and manual toothbrush in children with autism. Setting and Design: Sample comprised 22 children with autism who daily visited a day care and education center named ARUSHI - a center for children with special health care needs in Bhopal. Methods: Children were divided into two groups (Group A and B according to toothbrush used and further divided into subgroups (A1 and B1 [low fluoridated − Pediflor toothpaste] and A2 and B2 [calcium sucrose phosphate − Enafix toothpaste]. Oral hygiene instructions and brushing technique demonstration were given every day for a period of 1-month. Oral health status was evaluated before and after the study using simplified oral hygiene index (OHI-S and its Miglani's modification for primary dentition, plaque index (PI, gingival index (GI, and decayed, missing, and filled teeth (DMFT/deft index. The perception of parents regarding oral hygiene practices for their kids was also evaluated by an awareness and attitude questionnaire. Statistical Analysis: OHI-S, GI, PI, and DMFT/deft were statistically evaluated using Mann–Whitney U- test. Results and Conclusion: Mean value of OHI-S decreased significantly with powered toothbrush (0.035 [P < 0.05] in both groups. However, PI decreased significantly for Enafix when used with powered toothbrush (0.042 [P < 0.05]. Perception of parents was seen to improve significantly after 1-month study (0.000 [P < 0.05].

  7. Physiologic Conditions Affect Toxicity of Ingested Industrial Fluoride

    Directory of Open Access Journals (Sweden)

    Richard Sauerheber

    2013-01-01

    Full Text Available The effects of calcium ion and broad pH ranges on free fluoride ion aqueous concentrations were measured directly and computed theoretically. Solubility calculations indicate that blood fluoride concentrations that occur in lethal poisonings would decrease calcium below prevailing levels. Acute lethal poisoning and also many of the chronic effects of fluoride involve alterations in the chemical activity of calcium by the fluoride ion. Natural calcium fluoride with low solubility and toxicity from ingestion is distinct from fully soluble toxic industrial fluorides. The toxicity of fluoride is determined by environmental conditions and the positive cations present. At a pH typical of gastric juice, fluoride is largely protonated as hydrofluoric acid HF. Industrial fluoride ingested from treated water enters saliva at levels too low to affect dental caries. Blood levels during lifelong consumption can harm heart, bone, brain, and even developing teeth enamel. The widespread policy known as water fluoridation is discussed in light of these findings.

  8. Atomic force microscopic comparison of remineralization with casein-phosphopeptide amorphous calcium phosphate paste, acidulated phosphate fluoride gel and iron supplement in primary and permanent teeth: An in-vitro study

    OpenAIRE

    Nikita Agrawal; N D Shashikiran; Shilpy Singla; Ravi, K.S.; Vinaya Kumar Kulkarni

    2014-01-01

    Context: Demineralization of tooth by erosion is caused by frequent contact between the tooth surface and acids present in soft drinks. Aim: The present study objective was to evaluate the remineralization potential of casein-phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste, 1.23% acidulated phosphate fluoride (APF) gel and iron supplement on dental erosion by soft drinks in human primary and permanent enamel using atomic force microscopy (AFM). Materials and Methods: Specimens were...

  9. HOUSEHOLD PURIFICATION OF FLUORIDE CONTAMINATED MAGADI (TRONA)

    DEFF Research Database (Denmark)

    Nielsen, Joan Maj; Dahi, Elian

    1997-01-01

    Purification of fluoride contaminated magadi is studied using bone char sorption and calcium precipitation. The bone char treatment is found to be workable both in columns and in batches where the magadi is dissolved in water prior to treatment. The concentrations in the solutions were 89 g magadi...... treatment method. A procedure for purification of fluoride contaminated magadi at household level is described....

  10. Bottled Water and Fluoride

    Science.gov (United States)

    ... Fluoridation Journal Articles for Community Water Fluoridation Bottled Water Recommend on Facebook Tweet Share Compartir Consumers drink ... questions about bottled water and fluoride. Does bottled water contain fluoride? Bottled water products may contain fluoride, ...

  11. Metal fluorides

    International Nuclear Information System (INIS)

    Systems formed by fluorides of alkali, alkali earth, rare earth elements, yttrium, zirconium, hafnium, bismuth, antimony are investigated with the aim of preparing new fluoride materials and studying their thermodynamic and other physical and chemical properties. The respective phase diagrams are plotted. On the basis of the research fluoroberyllate glasses with rare earth additions of improved qualities (moisture resistance, crystallization resistance, resistance against radiation up to 100 Mrad) are prepared. The rho-T-x phase diagrams of the systems studied show that many compounds are sublimated congruently at certain temperatures and incongruently - above them. The existence of congruently sublimated compounds and azeotropically sublimated compositions provides for the preparation of uniform optical films. In connection with the search for new materials-luminophores and matrices of optical quantum generators - the fluoride systems of alkali metals and lanthanides are studied; the formation of binary fluorides of M3LnF6, M2LnF5, MLnF4, MLn2F7, MLn3F10 compositions is established. To search for new solid electrolytes, the solid-phase interaction of Sb-and Bi trifluorides with their oxides and alakali metal fluorides is studied. The electric conductivity of the compounds obtained is studied

  12. Urinary fluoride output in children following the use of a dual-fluoride varnish formulation

    Directory of Open Access Journals (Sweden)

    Kelly Polido Kaneshiro Olympio

    2009-06-01

    Full Text Available OBJECTIVE: This study evaluated the bioavailability of fluoride after topical application of a dual-fluoride varnish commercially available in Brazil, when compared to DuraphatTM. 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, ColgateTM 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.

  13. 添加含钙化合物对茶园土壤pH及有效氟的影响%Influence of Addition of Calcium compounds on pH and Available Fluoride Content in Tea Garden Soil

    Institute of Scientific and Technical Information of China (English)

    张永利; 廖万有; 王烨军; 苏有健; 孙力

    2013-01-01

    鉴于长期饮用高氟茶可引起饮茶型氟中毒,拟通过探明茶园土壤有效氟的调控机制,为治理土壤氟污染并降低茶叶中氟含量提供理论依据.以湖南某茶园0~20 cm和20~40 cm土壤为对象,通过室内模拟培养,研究不同形态和添加量的钙离子对土壤pH和有效氟含量的影响.结果表明,添加200~400 mg/kg Ca2+[Ca(NO3)2]和100~1000 mg/kg Ca2+[CaCl2]后2层土壤pH由4.0降至3.5~3.7,土壤水溶态氟含量明显增加;添加60~1400 mg/kg Ca2+[Ca(OH)2]时,随Ca(OH)2添加量的增加,2层土壤pH分别升至5.13、5.23,土壤水溶态氟含量呈现先增加再降低最后增加的趋势;添加3种形态含钙化合物均降低土壤交换态氟含量.当土壤pH在3.5~6.0间变化时,以pH 5.0为拐点,土壤pH降低或升高水溶态氟含量均增加,土壤酸化时尤甚.因此,可在酸性土壤上施用白云石粉、Ca(OH)2,在偏碱性土壤上施用Ca(NO3)2、CaCl2,调整土壤pH至5.0左右,以有效降低茶园土壤有效氟含量.%Long-term consumption of high-fluoride tea probably causes drinking tea fluorosis. This article ascertained the regulation mechanism of available fluoride content in tea garden soil, to provide theory of controlling soil fluoride pollution and reducing fluoride content of tea leaves. Laboratory incubation tests were conducted, using 0-20 cm and 20-40 cm layers soils from two tea gardens of Hunan Province as experiment materials, to study the influence of different forms and addition amount of calcium ion on soil pH and available fluoride content. The results showed that soil pH value fell to 3.5 from 4.0-3.7 and soil water soluble fluoride content increased obviously when the addition amount of Ca(NO3)2 and CaCl2 was increased. With the increase of addition amount of Ca(OH)2, the soil pH value change ranged from 4.0 to 5.2, soil water soluble fluorine content was decreased obviously at first, then increased. Soil exchangeable fluoride content was

  14. Fluoridation Basics

    Science.gov (United States)

    ... level in water is not enough to prevent tooth decay; however, some groundwater and natural springs can have ... the tooth’s surface, or enamel. Water fluoridation prevents tooth decay by providing frequent and consistent contact with low ...

  15. A health risk assessment for fluoride in Central Europe

    OpenAIRE

    Fordyce, Fiona; Vrana, K.; Zhovinsky, E.; Povoroznuk, V.; Toth, G.; Hope, B.C.; Iljinsky, U.; Baker, J.

    2007-01-01

    Like many elements, fluorine (which generally occurs in nature as fluoride) is beneficial to human health in trace amounts, but can be toxic in excess. The links between low intakes of fluoride and dental protection are well known; however, fluoride is a powerful calcium-seeking element and can interfere with the calcified structure of bones and teeth in the human body at higher concentrations causing dental or skeletal fluorosis. One of the main exposure routes is via drinking water and the ...

  16. Atomic force microscopic comparison of remineralization with casein-phosphopeptide amorphous calcium phosphate paste, acidulated phosphate fluoride gel and iron supplement in primary and permanent teeth: An in-vitro study

    Directory of Open Access Journals (Sweden)

    Nikita Agrawal

    2014-01-01

    Full Text Available Context: Demineralization of tooth by erosion is caused by frequent contact between the tooth surface and acids present in soft drinks. Aim: The present study objective was to evaluate the remineralization potential of casein-phosphopeptide-amorphous calcium phosphate (CPP-ACP paste, 1.23% acidulated phosphate fluoride (APF gel and iron supplement on dental erosion by soft drinks in human primary and permanent enamel using atomic force microscopy (AFM. Materials and Methods: Specimens were made from extracted 15 primary and 15 permanent teeth which were randomly divided into three treatment groups: CPP-ACP paste, APF gel and iron supplement. AFM was used for baseline readings followed by demineralization and remineralization cycle. Results and Statistics: Almost all group of samples showed remineralization that is a reduction in surface roughness which was higher with CPP-ACP paste. Statistical analysis was performed using by one-way ANOVA and Mann-Whitney U-test with P < 0.05. Conclusions: It can be concluded that the application of CPP-ACP paste is effective on preventing dental erosion from soft drinks.

  17. Effect of titanium tetrafluoride, amine fluoride and fluoride varnish on enamel erosion in vitro

    OpenAIRE

    Vieira, A; Ruben, JL; Huysmans, MCDNJM

    2005-01-01

    This study aimed at evaluating the effect of 1 and 4% titanium tetrafluoride (TiF4) gels, amine fluoride (AmF) 1 and 0.25% and a fluoride varnish (FP) on the prevention of dental erosion. Two experimental groups served as controls, one with no pretreatment and another one pre-treated with a fluoride-free varnish (FP-blanco). Dental erosion was modelled using bovine enamel samples submitted to alternate cycles of acid exposure in citric acid and remineralization in artificial saliva. Calcium l...

  18. Fluoride Uptake Level of the Enamel by a Fluoride Varnish and a Fluoride Gel (APF

    Directory of Open Access Journals (Sweden)

    Navabi B.

    2011-07-01

    Full Text Available Statement of Problem: Various forms of fluoride-contained products are used to increase the resistance of the tooth against caries for preventive purposes. Furthermore, studies demonstrated higher fluoride uptake with varnish and gel among the wide range of products.Purpose: This study compared fluoride uptake of Duraflor® varnish (Practicon Dent, USA with fluoride gel (APF, Sultan®, used on the enamel surface of the intact teeth.Materials and Method: In this experimental in-vitro study, 20 intact pre-molar teeth extracted for orthodontic purposes were randomly assigned to two groups of 10 teeth. The teeth were sectioned into two mesial and distal halves as the control and experimental sides. Defined semi-circular areas on the enamel surface of the experimental halves were treated with gel or varnish for 1 hour. The sample halves were stored in artificial saliva for 24 hours at 37°c, etched for 30 seconds by 0.5 M perchloric acid, and washed by 0.2 m KOH after each etching process. Biopsies of the samples were obtained by Acid Etch Enamel Biopsy technique and the fluoride and calcium concentrations were calculated by potentiometer and spectrophotometer, respectively. Kolmogorov-smirnov, Paired t-test and Student t- test were used for statistical analyses.Results: The results demonstrated an increase in the enamel fluoride content after exposure of the teeth to both Duraflor® varnish and APF gel (Sultan®. The results of the paired t-test revealed significant differences between the experimental and control halves in both groups (varnish: p =0.002, gel: p =0.039. The fluoride uptake value in varnish and gel groups was 2069.78 ppm and 1050.99 ppm, respectively. The student t-test showed a statistically significant difference ( p =0.01.Conclusion: Both APF gel and Duraflor® varnish increased the fluoride content of the tooth enamel after application, although Duraflor® varnish had a higher fluoride uptake level than APF gel.

  19. [Comparative in vitro evaluation of modern glass ionomer cements for adhesion strength and fluoride release].

    Science.gov (United States)

    Zhitkov, M Yu; Rusanov, F S; Poyurovskaya, I Ya

    2016-01-01

    The study proved similar adhesion strength and fluoride release level in aqueous extracts of glass ionomer cements Cemion (VladMiVa, Russia), Glassin Rest (Omega-Dent, Russia), Cemfil 10 (StomaDent, Russia) and Fuji VIII (GC Corporation, Japan). Despite of close concentrations of fluoride in glasses, the rate of fluoride release in water from calcium and calcium-barium glasses is much higher than that of strontium glasses. PMID:27239999

  20. Bioactivity of Sodium Free Fluoride Containing Glasses and Glass-Ceramics

    OpenAIRE

    Xiaojing Chen; Xiaohui Chen; Brauer, Delia S.; Rory M. Wilson; Hill, Robert G.; Natalia Karpukhina

    2014-01-01

    The bioactivity of a series of fluoride-containing sodium-free calcium and strontium phosphosilicate glasses has been tested in vitro. Glasses with high fluoride content were partially crystallised to apatite and other fluoride-containing phases. The bioactivity study was carried out in Tris and SBF buffers, and apatite formation was monitored by XRD, FTIR and solid state NMR. Ion release in solutions has been measured using ICP-OES and fluoride-ion selective electrode. The results show that...

  1. Effect of sodium fluoride in maternal and offspring rats and its amelioration

    Directory of Open Access Journals (Sweden)

    Sneha Panchal

    2014-03-01

    Full Text Available High fluoride content is known to cause dental and skeletal abnormalities. In addition, present review indicates that sodium fluoride consumption caused increased number of r=esorptions and dead foetuses. Various skeletal anomalies such as wavy ribs, presence of 14th ribs, lacking 6th sternebrae and incompete ossification of skull occur. All these changes could be due to oxidative stress caused by fluoride consumption. Fluoride-induced changes could be successfully ameliorated by cotreatment with vitamins and calcium.

  2. The Effect of Acute Fluoride Poisoning on Nitric Oxide and Methemoglobin Formation in the Guinea pig

    OpenAIRE

    ŞİRELİ, Meltem

    2004-01-01

    To study the effect of acute fluoride poisoning on nitric oxide and methemoglobin formation, 250 mg/kg bw sodium fluoride was applied alone and verapamil was applied together with fluoride. Blood nitric oxide (Griess reaction) and calcium levels; hemoglobin, methemoglobin and hematocrit values; and erythrocyte counts were determined and compared with those of the controls. After the fluoride application it was found that there was a relative relationship between the increase in nitric oxide a...

  3. Oxidative stress in cases of chronic fluoride intoxication

    OpenAIRE

    Ailani, Vinita; R. C. Gupta; Gupta, Sunil Kumar; Gupta, Kapil

    2009-01-01

    This study was conducted to find out the level of oxidative stress and effect of supplementation of vitamin C, D and Calcium on levels of SOD, serum and urinary fluoride in children residing in endemic fluorosis area. For this the fluoride belt of Jaipur district was selected. The parameters selected were Super oxide dismutase, serum fluoride and urinary fluoride. The study was conducted on one hundred children, selected from four areas (25 from each area) consuming water containing 1.2, 2.4,...

  4. How Does Fluoride Work?

    Science.gov (United States)

    ... the mid-1940s, communities started to put more fluoride in their water supplies to protect people against tooth decay. Fluoride ... might suggest supplements — which are like vitamins containing fluoride. Just how effective is fluoridated water? Thanks to it, dentists say half of kids ...

  5. A glass-encapsulated calcium phosphate wasteform for the immobilization of actinide-, fluoride-, and chloride-containing radioactive wastes from the pyrochemical reprocessing of plutonium metal

    International Nuclear Information System (INIS)

    Chloride-containing radioactive wastes are generated during the pyrochemical reprocessing of Pu metal. Immobilization of these wastes in borosilicate glass or Synroc-type ceramics is not feasible due to the very low solubility of chlorides in these hosts. Alternative candidates have therefore been sought including phosphate-based glasses, crystalline ceramics and hybrid glass/ceramic systems. These studies have shown that high losses of chloride or evolution of chlorine gas from the melt make vitrification an unacceptable solution unless suitable off-gas treatment facilities capable of dealing with these corrosive by-products are available. On the other hand, both sodium aluminosilicate and calcium phosphate ceramics are capable of retaining chloride in stable mineral phases, which include sodalite, Na8(AlSiO4)6Cl2, chlorapatite, Ca5(PO4)3Cl, and spodiosite, Ca2(PO4)Cl. The immobilization process developed in this study involves a solid state process in which waste and precursor powders are mixed and reacted in air at temperatures in the range 700-800 deg. C. The ceramic products are non-hygroscopic free-flowing powders that only require encapsulation in a relatively low melting temperature phosphate-based glass to produce a monolithic wasteform suitable for storage and ultimate disposal

  6. A glass-encapsulated calcium phosphate wasteform for the immobilization of actinide-, fluoride-, and chloride-containing radioactive wastes from the pyrochemical reprocessing of plutonium metal

    Science.gov (United States)

    Donald, I. W.; Metcalfe, B. L.; Fong, S. K.; Gerrard, L. A.; Strachan, D. M.; Scheele, R. D.

    2007-03-01

    Chloride-containing radioactive wastes are generated during the pyrochemical reprocessing of Pu metal. Immobilization of these wastes in borosilicate glass or Synroc-type ceramics is not feasible due to the very low solubility of chlorides in these hosts. Alternative candidates have therefore been sought including phosphate-based glasses, crystalline ceramics and hybrid glass/ceramic systems. These studies have shown that high losses of chloride or evolution of chlorine gas from the melt make vitrification an unacceptable solution unless suitable off-gas treatment facilities capable of dealing with these corrosive by-products are available. On the other hand, both sodium aluminosilicate and calcium phosphate ceramics are capable of retaining chloride in stable mineral phases, which include sodalite, Na 8(AlSiO 4) 6Cl 2, chlorapatite, Ca 5(PO 4) 3Cl, and spodiosite, Ca 2(PO 4)Cl. The immobilization process developed in this study involves a solid state process in which waste and precursor powders are mixed and reacted in air at temperatures in the range 700-800 °C. The ceramic products are non-hygroscopic free-flowing powders that only require encapsulation in a relatively low melting temperature phosphate-based glass to produce a monolithic wasteform suitable for storage and ultimate disposal.

  7. Fluoride and Dental Health

    OpenAIRE

    Nikiforuk, Gordon

    1988-01-01

    Studies conducted under the widest variety of controlled conditions attest to the safety, efficacy, and cost benefits of fluoridation. A program that combines the use of systemic and topical fluoride results in maximum benefits. The author of this article reviews the metabolism of fluoride and its mechanism of action, and discusses practical modes of employing fluoride in caries prevention with special emphasis on the use of fluoride supplements for infants and young children in areas of non-...

  8. 氟化钙参与石煤提钒过程的浸出行为研究%Acid-Leaching of Vanadium from Stone Coal with Calcium Fluoride Addition

    Institute of Scientific and Technical Information of China (English)

    王非; 张一敏; 黄晶; 刘涛; 赵杰; 张国斌

    2013-01-01

    The behavior of leaching vanadium from stone coal with calcium fluoride was researched under the conditions of 95 ℃,4 h,1 ml·g-1,15% (volume fraction) H2SO4 and 5% (mass fraction) calcium fluoride.The leaching rate of vanadium could reach 92.39%.Through the analyses of inductively coupled plasma atomic emission spectroscopy (ICP-AES),valence state vanadium and X-ray diffractometry (XRD) for the raw ore of stone coal,ICP-AES,X-ray photoelectron spectroscopy (XPS) and 19F liquid nuclear magnetic resonance (NMR) for the leachate,and XRD and scanning electron microscope (SEM) for the leaching residue,the whole leaching process could be summarized that calcium fluoride reacted with sulfuric acid to generate hydrofluoric acid and the hydrofluoric acid solution (HF) could enhance the leaching process owing to its strong destructiveness to vanadium-bearing minerals; calcite consumed part of acid to generate CaSO4 and CO2 ; chlorite and vanadium-bearing phlogopite were thoroughly broken down and released V,Al,K,Mg,Si etc.[AlF5] 2-and [SiF6] 2-were generated and left in the leachate after F-reacted with other elements in the vanadium leaching.In the process of intense stir,the released Ⅴ(Ⅲ) was oxidized into VO2+ by O2 from air to exist in leachate.Part of the released Al existed in leachate as Al3 + and others combined with F to generate [AlF5] 2-.Part of the released Si existed in residue as SiO2,and the rest combined with F to generate [SiF6] 2-.It was because the bond energies of Al-F and Si-F were bigger than that of Al-O and Si-O,and the generation of [AlF5] 2-and [SiF6] 2-made the leaching system more stable and facilitated leaching vanadium.%研究了氟化钙参与石煤提钒过程的浸出行为,浸出条件为95℃,4h,1ml·g-1,15%(体积分数)硫酸和5%(质量分数)氟化钙.在此条件下钒的浸出率可达到92.39%.通过对石煤原矿进行电感耦合等离子体原子发射光谱分析(ICP-AES)、钒价态分析和X射线衍射(XRD

  9. Effect of different fluoride varnishes on mineralization of artificial enamel carious lesions

    OpenAIRE

    Mohd Said, Siti Norhazlin Binti

    2015-01-01

    The chalky white appearance on enamel is known as White Spot Lesion (WSL). This initial caries lesion involves the dynamic process of demineralization and remineralization. Fluoride varnish has been shown to prevent WSL in post-eruptive tooth. The literature review summarized the available evidence on the various agents added to topical fluoride varnish, such as casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), xylito-coated calcium and phosphate, amorphous calcium phosphate (A...

  10. Fluoride stimulates [3H]thymidine incorporation and alkaline phosphatase production by human osteoblasts

    International Nuclear Information System (INIS)

    The effect of sodium fluoride on alkaline phosphatase (ALP) release and [3H]thymidine uptake by human osteoblasts in culture was investigated. Sodium fluoride stimulated both ALP release and [3H]thymidine uptake at concentrations of sodium fluoride greater than 250 mumol/L. This stimulation was similar in magnitude to that induced by 1,25-dihydroxycholecalciferol. The fluoride-induced increase in ALP was inhibited by verapamil, a calcium channel blocker. We conclude that sodium fluoride stimulates osteoblasts to proliferate and to release ALP. This stimulation by fluoride is dependent on calcium influx. Fluoride-induced stimulation of human osteoblasts may be relevant to its effect in enhancing bone formation in patients with osteoporosis

  11. Prevention and management of osteoporosis: consensus statements from the Scientific Advisory Board of the Osteoporosis Society of Canada. 7. Fluoride therapy for osteoporosis.

    OpenAIRE

    T.M. Murray; Ste-Marie, L G

    1996-01-01

    OBJECTIVE: To present the latest findings on the use of fluoride in the treatment of osteoporosis. OPTIONS: Plain sodium fluoride (NaF), enteric-coated sodium fluoride (EC-NaF), sodium monofluorophosphate (Na2FPO4), slow-release sodium fluoride (SR-NaF); fluoride with a calcium supplement. OUTCOMES: Fracture and loss of bone mineral density in osteoporosis; increased bone mass, prevention of fractures and improved quality of life associated with treatment. EVIDENCE: Relevant clinical studies ...

  12. Hair as Biomarker of Fluoride Exposure in a Fluoride Endemic Area and a Low Fluoridated Area

    OpenAIRE

    Parimi, Nalini; V. Viswanath; Kashyap, Bina; Patil, Pavan Uday

    2013-01-01

    Aim: The aim of the present study was to determine whether hair could be used as biomarker of fluoride exposure. Materials and Methods: The study was carried out on 30 people living in an endemically fluoridated area and a low fluoridated area. Samples of hair from the occipital were taken and subjected to fluoride analysis by a fluoride ion electrode. Results: Lower fluoride levels in water supplies correlated with lower levels of fluoride in hair and more over higher fluoride levels in wate...

  13. Effect of fluoride dentifrices on salivary fluoride levels in children.

    OpenAIRE

    Paul S; Tandon S; Murthy K

    1993-01-01

    Fluoride dentifrices are well accepted for their caries preventive effects. The fluoride concentration in the oral fluids after tooth brushing with fluoride dentifrices may have an important relationship to the caries reducing capacity. The present study was aimed to clinically evaluate the salivary fluoride retention of dentifrices containing low fluoride concentration in 50 children, aged 7-9 years before, during and after the use of fluoride toothpaste. Estimation of fluoride in saliva was...

  14. Preparation of uranium ingots from double fluorides

    International Nuclear Information System (INIS)

    A simple method has been developed for the preparation of uranium double fluorides and has given a new impetus to the study of the reduction of these compounds with a view to obtaining very pure uranium ingots. This reduction can be carried out using calcium or magnesium as the reducing agent, this latter metal being very interesting from the practical point of view. A comparative study of the heat balances of the reduction processes for the double fluorides and for uranium tetrafluoride has shown that reduction of the double fluorides is possible. The exact experimental conditions for these reductions have been determined. Our study has shown in particular that the reduction of the double salt UF4, CaF2 by magnesium leads to the production of small (20 to 500 g) samples of high-purity uranium with a yield of 99 per cent. (author)

  15. Enhancing Fluoride: Clinical Human Studies of Alternatives or Boosters for Caries Management.

    Science.gov (United States)

    Fontana, Margherita

    2016-01-01

    Dental caries remains a major public health problem, especially for certain high-risk population groups. The goal of this study was to assess the evidence regarding strategies meant to be used as alternatives or booster/supplements to fluoride for caries prevention and management. Articles were selected for inclusion if they had a prospective longitudinal design, with a fluoride control arm, and were conducted in human subjects. Of the included studies, 7/18 studies on calcium-based strategies favored the test product (the majority of studies included exposure of fluoride in all groups). All the arginine studies (8/8) included a combination of arginine and a calcium base, and concluded that this has the potential to significantly boost the performance of fluoride. The remaining included studies focused on the addition of microbial-related strategies to a fluoride-containing vehicle (2 xylitol studies and 1 study using a probiotic milk), and all favored the combination as a booster to fluoride. Thus, the current study did not identify evidence for any strategy to effectively be used as a substitute or alternative to fluoride, but identified some consistent evidence derived from the use of prebiotic strategies (primarily from use of arginine combined with calcium) to support their potential use to boost the mechanism of action of fluoride. Thus, fluoride-based strategies remain the standard for caries prevention and management, with some evidence that boosting the effects of fluoride by the use of prebiotic strategies is a promising possibility. PMID:27100833

  16. Fluoride glass fiber optics

    CERN Document Server

    Aggarwal, Ishwar D

    1991-01-01

    Fluoride Glass Fiber Optics reviews the fundamental aspects of fluoride glasses. This book is divided into nine chapters. Chapter 1 discusses the wide range of fluoride glasses with an emphasis on fluorozirconate-based compositions. The structure of simple fluoride systems, such as BaF2 binary glass is elaborated in Chapter 2. The third chapter covers the intrinsic transparency of fluoride glasses from the UV to the IR, with particular emphasis on the multiphonon edge and electronic edge. The next three chapters are devoted to ultra-low loss optical fibers, reviewing methods for purifying and

  17. Synthesis of reagents for fluoride technologies

    Institute of Scientific and Technical Information of China (English)

    Gordienko; P.; S.; Kolzunov; V.; A.; Dostovalov; V.; A.; Kaidalova; T.; A.

    2005-01-01

    Growing demand for fluorinating reagents to be used in rare-metal industry has stimulated conducting research in the field of production for these reagents. That is why the fluorinating reagents production has recently formed an independent segment of industry. Main industrial fluorinating reagents include hydrofluoric acid, anhydrous hydrogen fluoride, technical ammonium hydrodifluoride, fluorosilicic acid and its salts. To produce technical etching acid, fluor-spar with calcium fluoride content at least 92% is used in most cases. To produce anhydrous hydrogen fluoride, fluor-spar with calcium fluoride content 96 %-97 % is necessary. The fluorine-containing raw materials refinement from silica by means of flotation makes the fluorinating reagents production substantially more expensive. In this work we have attempted to process unconcentrated raw materials by fluorine removal in the form of volatile silicon tetrafluoride. In this process silicon tetrafluoride was recovered by liquid ammonia with subsequent hydrolysis of the formed ammonia hexafluorosilicate. Hydrolysis occurred according to the reaction:(NH4)2 SiF6 + 4NH3 + 2 H2O= 6NH4F+ SiO2 The products of the ammonia hexafluorosilicate hydrolysis included ammonia fluoride and amorphous silica gel ("white soot") as by-product. This "white soot" was of high purity-with main component content 99.95% and total admixture content 0.05%. Silica gel is a superfine material with specific surface of 267.6 m2/g and is recommended as filler in the production of rubber, plastics and for other applications.Ammonia fluoride was transformed into ammonia hydrodifluoride (main processing product) according to the reaction:2NH4F→NH3+NH4 HF2 It was stated that the NH4F: NH4 HF2 ratio depends on boiling point temperature-with its increase the ammonia hydrofluoride concentration in solution increases as well.

  18. Thermoluminescence from europium doped calcium fluoride crystals

    International Nuclear Information System (INIS)

    Thermoluminescence (TL) from CaF2:Eu2+ irradiated with γ-rays is investigated. While undoped crystals show colouration above a threshold exposure, no such effect is observed with europium doped samples. For doped samples five prominent TL glow peaks are recorded for the temperature range 30 to 400degC. The TL emission spectra resemble the characteristic fluorescence emission of Eu2+. The optical absorption studies show that no charge conversion on irradiation or on heating the irradiated CaF2:Eu2+ samples takes place. However charge conversion for some other rare earth ions stabilizing in the trivalent state in CaF2 on irradiation is indeed observed. The results show that the extended Merz and Pershan model fails to account for the observed TL emission from CaF2:Eu2+. The present investigations point toward the existence of some kind of defect equilibria associated with the presence of Eu2+ in the lattice. This defect equilibria is different from that observed for rare earth ions stabilizing in CaF2 in the trivalent state. (orig.)

  19. Laser-Induced Damage of Calcium Fluoride

    International Nuclear Information System (INIS)

    Radiation damage of materials has long been of fundamental interest, especially since the growth of laser technology. One such source of damage comes from UV laser light. Laser systems continue to move into shorter wavelength ranges, but unfortunately are limited by the damage threshold of their optical components. For example, semiconductor lithography is making its way into the 157nm range and requires a material that can not only transmit this light (air cannot), but also withstand the highly energetic photons present at this shorter wavelength. CaF2, an alkaline earth halide, is the chosen material for vacuum UV 157 nm excimer radiation. It can transmit light down to 120 nm and is relatively inexpensive. Although it is readily available through natural and synthetic sources, it is often times difficult to find in high purity. Impurities in the crystal can result in occupied states in the band gap that induce photon absorption [2] and ultimately lead to the degradation of the material. In order to predict how well CaF2 will perform under irradiation of short wavelength laser light, one must understand the mechanisms for laser-induced damage. Laser damage is often a two-step process: initial photons create new defects in the lattice and subsequent photons excite these defects. When laser light is incident on a solid surface there is an initial production of electron-hole (e-h) pairs, a heating of free electrons and a generation of local heating around optically absorbing centers [3]. Once this initial excitation converts to the driving energy for nuclear motion, the result is an ejection of atoms, ions and molecules from the surface, known as desorption or ablation [3]. Secondary processes further driving desorption are photoabsorption, successive excitations of self-trapped excitons (STE's) and defects, and ionization of neutrals by incident laser light [3]. The combination of laser-induced desorption and the alterations to the electronic and geometrical structure of the lattice result in defect formation. In the material CaF2 some of these defects take the form of F-centers, an electron trapped at a halogen vacancy [4], and H-centers, a F2- molecular ion at a single lattice site [5]. While the F-centers are stable, the H-centers are transient but can form into aggregates that are stable. There are many different configurations the defects can take based on the relative position of F and H centers in the lattice and this is extensively discussed in literature [1,4,5]. Once these defects have formed they cause further absorption of light, which ultimately induces particle emission and the production of even more defects. Various forms of laser-induced damage of CaF2 have been studied. For example, the mechanism for photon-stimulated desorption (PSD) of F+ from CaF2 (111) is discussed in ref. 6 and the energy threshold, distribution and kinetics governing electron-stimulated desorption (ESD) is investigated in ref. 7. The desorption of neutral Ca and F atoms has also been explored [1]. In this paper I focus on the emission of ions and neutrals from CaF2 under the irradiation of pulsed laser light at 266 nm, in addition to a brief study of its purity and transmittance

  20. Fluoride levels and osteosarcoma

    Directory of Open Access Journals (Sweden)

    Simmi Kharb

    2012-01-01

    Full Text Available Context: Osteosarcoma is a rare malignant bone tumor, commonly occurring in the age group of 10 to 24 years. Recent reports have indicated that there is a link between fluoride exposure and osteosarcoma. Aims: The present study was planned to analyze serum levels of fluoride in patients of osteosarcoma and fluoride content of their drinking water. Settings and Design: The present study was carried out comparing 10 patients of osteosarcoma and 10 healthy volunteers (who served as controls. Materials and Methods: Serum and drinking water fluoride levels were estimated by ion selective electrode. Statistical analysis used: The data were computed as mean ± SD and Student′s t test was applied. Results: Both, the serum and drinking water fluoride levels, were significant by higher in patients with osteosarcoma as compared to controls (P < 0.05, P < 0.001, respectively. Conclusions: These results suggest a link between fluoride exposure and osteosarcoma.

  1. Fluoride toothpastes and fluoride mouthrinses for home use

    OpenAIRE

    Andrew Rugg-Gunn; Jolan Bánóczy

    2013-01-01

    Objective. To provide a brief commentary review of fluoride-containing toothpastes and mouthrinses with emphasis on their use at home. Toothpastes and mouthrinses are just two of many ways of providing fluoride for the prevention of dental caries. The first investigations into incorporating fluoride into toothpastes and mouthrinses were reported in the middle 1940s. Unlike water fluoridation (which is ‘automatic fluoridation’), fluoride-containing toothpastes and fluoride-containing mouthrins...

  2. Effects of oral doses of fluoride on nestling European starlings

    Science.gov (United States)

    Fleming, W.J.; Grue, C.E.; Schuler, C.A.; Bunck, C.M.

    1987-01-01

    Nestling European starlings (Sturnus vulgaris), raised and fed by free-living adults, were given daily oral doses of either distilled water, 193 mg sodium as Na2CO3 per kg of body weight (sodium control group), or 6, 10, 13, 17,23, 30, 40, 80, 160 mg of the fluoride ion as NaF in distilled water per kg of body weight (mg/kg). Dosing began when nestlings were 24-48 hr old and continued for 16 days. The 24-hr LD50 of fluoride for day-old starlings was 50 mg/kg. The 16-day LD50 was 17 mg/kg. The sodium control group did not differ from the water control group with respect to any of the measured variables. Growth rates were significantly reduced in the 13 and 17 mg of fluoride/kg groups; weights of birds given higher dose levels were omitted from growth comparisons because of high, fluoride-induced mortality. Although pre-fledging weights for the 10, 13, and 17 mg of fluoride/kg groups averaged 3.6 to 8.6% less than controls at 17 days, this difference was not significant. Feather and bone growth of the fluoride and control groups were not different, except for keel length measured at 17 days of age which averaged less in the fluoride groups. Liver and spleen weights were not affected by fluoride treatments. No histological damage related to fluoride treatments was found in liver, spleen, or kidney. The logarithm of bone fluoride and magnesium concentration increased with the logarithm of increasing fluoride treatment levels and were significantly correlated with each other. Fluoride treatments had no effect on percent calcium or phosphorus in bone or plasma alkaline phosphatase activity. Oral doses of fluoride appear to be more toxic than equivalent dietary levels. Most birds probably acquire fluoride through their diet. Therefore, the results of the study may overestimate the potential effects of fluorides on songbirds living in fluoride-contaminated environments.

  3. Fluoride and Oral Health.

    Science.gov (United States)

    O'Mullane, D M; Baez, R J; Jones, S; Lennon, M A; Petersen, P E; Rugg-Gunn, A J; Whelton, H; Whitford, G M

    2016-06-01

    The discovery during the first half of the 20th century of the link between natural fluoride, adjusted fluoride levels in drinking water and reduced dental caries prevalence proved to be a stimulus for worldwide on-going research into the role of fluoride in improving oral health. Epidemiological studies of fluoridation programmes have confirmed their safety and their effectiveness in controlling dental caries. Major advances in our knowledge of how fluoride impacts the caries process have led to the development, assessment of effectiveness and promotion of other fluoride vehicles including salt, milk, tablets, toothpaste, gels and varnishes. In 1993, the World Health Organization convened an Expert Committee to provide authoritative information on the role of fluorides in the promotion of oral health throughout the world (WHO TRS 846, 1994). This present publication is a revision of the original 1994 document, again using the expertise of researchers from the extensive fields of knowledge required to successfully implement complex interventions such as the use of fluorides to improve dental and oral health. Financial support for research into the development of these new fluoride strategies has come from many sources including government health departments as well as international and national grant agencies. In addition, the unique role which industry has played in the development, formulation, assessment of effectiveness and promotion of the various fluoride vehicles and strategies is noteworthy. This updated version of 'Fluoride and Oral Health' has adopted an evidence-based approach to its commentary on the different fluoride vehicles and strategies and also to its recommendations. In this regard, full account is taken of the many recent systematic reviews published in peer reviewed literature. PMID:27352462

  4. Fluoride varnishes and enamel caries

    OpenAIRE

    De Bruyn, Hugo

    1987-01-01

    Topical fluoride applications have the aim of increasing the fluoride uptake in enamel and consequently reducing caries. In the early ‘60s fluoride varnishes were introduced because they had a long contact period with the enamel which resulted in a higher fluoride uptake than from other topical applications. Recently the importance of small amounts of fluoride in caries prevention and remineralization has been stressed and the importance of large arnounts of fluoride acquired in the teeth is ...

  5. Preparation and chemical crystallographic study of new hydrides and hydro-fluorides of ionic character

    International Nuclear Information System (INIS)

    Within the context of a growing interest in the study of reversible hydrides with the perspective of their application in hydrogen storage, this research thesis more particularly addressed the case of ternary hydrides and fluorides, and of hydro-fluorides. The author reports the development of a method of preparation of alkaline hydrides, of alkaline earth hydrides and of europium hydride, and then the elaboration of ternary hydrides. He addresses the preparation of caesium fluorides and of calcium or nickel fluorides, of Europium fluorides, and of ternary fluorides. Then, he addresses the preparation of hydro-fluorides (caesium, calcium, europium fluorides, and caesium and nickel fluorides). The author presents the various experimental techniques: chemical analysis, radio-crystallographic analysis, volumetric mass density measurement, magnetic measurements, ionic conductivity measurements, Moessbauer spectroscopy, and nuclear magnetic resonance. He reports the crystallographic study of some ternary alkaline and alkaline-earth hydrides (KH-MgH2, RbH-CaH2, CsH-CaH2, RbH-MgH2 and CsH-MgH2) and of some hydro-fluorides (CsCaF2H, EuF2H, CsNiF2H)

  6. Fluoride in the drinking water of Pakistan and the possible risk of crippling fluorosis

    Directory of Open Access Journals (Sweden)

    M. A. Tahir

    2013-02-01

    Full Text Available To explore the possibility of fluoride toxicity, 747 water samples were collected from surface water and groundwater sources of 16 major cities of Pakistan, adopting a uniform sampling design with distribution of samples: Lahore (79, Kasur (46, Faisalabad (30, Khushab (50, Chakwal (51, Mianwali (30, Jhelum (53, Bahawalpur (60, Karachi (60, Mirpur Khas (55, Peshawar (38, Risalpur (35, Quetta (81, Ziarat (21, Loralai (21, and Mastung (37. Comparison of analytical findings with WHO Guidelines of Drinking Water for Fluoride (i.e., 1.5 ppm has concluded that 16% of the monitored water sources have fluoride concentration beyond the permissible safe limit of 1.5 mg L−1 falling in the concentration range of 1.6–25 mg L−1. The highest fluoride contamination (22% is detected in the Balochistan province followed by 19% in Punjab province. Comparatively higher fluoride levels of > 20% in the groundwater sources like hand pumps supported the possibility of increased groundwater contamination as excessive fluoride concentrations are expected to come from calcium-poor aquifers and in areas where fluoride-bearing minerals are common or where cation exchange of sodium for calcium occurs. Field observations have also indicated the prevalence of fluoride-associated health implications in the study areas with excessive fluoride in water sources. Findings of this study have provided bidirectional vision for the epidemiological investigations as well as to mitigate the issues in the affected vicinities of fluoride-rich areas.

  7. Removal of fluoride from semiconductor wastewater by electrocoagulation-flotation.

    Science.gov (United States)

    Hu, C Y; Lo, S L; Kuan, W H; Lee, Y D

    2005-03-01

    This work employs an anodic surfactant, sodium dodecyl sulfate (SDS), to improve the flotation performance of the electrocoagulation-flotation (ECF) process to treated fluoride containing semiconductor wastewater following calcium precipitation. The dissolved fluoride ions and CaF(2) particles in the wastewater after calcium precipitation were effectively removed in the ECF process simultaneously. The dosage of SDS required for ECF was much less than those for dispersed air flotation (DiAF) or dissolved air flotation (DAF) processes because the CaF(2) particles can be collected by hydro-fluoro-aluminum flocs in ECF. Thus, SDS only served as a frother to make the bubbles tiny and stable in the ECF defluoridation process. The interference of co-existing anions can be overcome by increasing the dosage of calcium ions and SDS. The optimum initial acidity for ECF is close to the initial fluoride concentration after calcium precipitation; the amount of SS removed dropped rapidly if the initial acidity exceeded the optimal value because the surface charge of the hydro-fluoro-aluminum particles increased. The initial acidity of the wastewater after calcium precipitation can be modified by changing the [Ca(OH)(2)]/[Ca(2+)](T) ratio and the appropriate ratio is approximately given by the acid dissociation constant of hydrofluoric acid and the initial pH of the wastewater before calcium precipitation. PMID:15743636

  8. Study of Nd-Co alloy production by means of fluoride technique

    International Nuclear Information System (INIS)

    Fluoride method of neodymium-cobalt alloy preparation consisting in fluorination of cobalt-containing raw materials and calcium-thermal reduction of neodymium and cobalt fluorides mixture has been proposed, theoretically substantiated and studied. Results of thermodynamic, kinetic and phase studies of cobalt and neodymium oxides fluorination, as well as of joint reduction of neodymium and cobalt fluorides, are presented. Flowsheets of the facilities for producing the above-mentioned fluorides and alloys are described. Potentiality of producing Nd-Co alloy with a higher neodymium content (up to 85% compared with Nd-Fe alloy) and ingot yield of 93-95% is shown

  9. Fluoride and Water (For Parents)

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy Fluoride and Water KidsHealth > For Parents > Fluoride and Water Print A ... thirds of 16- to 19-year-olds continue Fluoride and the Water Supply For more than 60 years, water fluoridation ...

  10. The cariostatic mechanisms of fluoride

    OpenAIRE

    Kata Rošin-Grget; Kristina Peroš; Ivana Šutej; Krešimir Bašić

    2013-01-01

    This article discusses the possible cariostatic mechanisms of the action of fluoride. In the past, fluoride inhibition of caries was ascribed to reduced solubility of enamel due to incorporation of fluoride (F–) into the enamel minerals. The present evidence from clinical and laboratory studies suggests that the caries-preventive mode of action of fluoride is mainly topical. There is convincing evidence that fluoride has a major effect on demineralisation and remineralisation of dental hard t...

  11. Fluoride in diet

    Science.gov (United States)

    ... broken through the gums have changes in the enamel that covers the teeth. Faint white lines or streaks may appear, but ... regarding fluoride intake from reconstituted infant formula and ... Dental Association Council on Scientific Affairs. J Am Dent ...

  12. Fluoride toothpastes and fluoride mouthrinses for home use

    Directory of Open Access Journals (Sweden)

    Andrew Rugg-Gunn

    2013-11-01

    Full Text Available Objective. To provide a brief commentary review of fluoride-containing toothpastes and mouthrinses with emphasis on their use at home. Toothpastes and mouthrinses are just two of many ways of providing fluoride for the prevention of dental caries. The first investigations into incorporating fluoride into toothpastes and mouthrinses were reported in the middle 1940s. Unlike water fluoridation (which is ‘automatic fluoridation’, fluoride-containing toothpastes and fluoride-containing mouthrinses are, primarily, for home use and need to be purchased by the individual. By the 1960s, research indicated that fluoride could be successfully incorporated into toothpastes and clinical trials demonstrated their effectiveness. By the end of the 1970s, almost all toothpastes contained fluoride. The widespread use of fluoride-containing toothpastes is thought to be the main reason for much improved oral health in many countries. Of the many fluoride compounds investigated, sodium fluoride, with a compatible abrasive, is the most popular, although amine fluorides are used widely in Europe. The situation is similar for mouthrinses. Concentrations of fluoride (F, commonly found, are 1500 ppm (1500 μg F/g for toothpastes and 225 ppm (225 μg F/ml for mouthrinse. Several systematic reviews have concluded that fluoride-containing toothpastes and mouthrinses are effective, and that there is added benefit from their use with other fluoride delivery methods such as water fluoridation. Guidelines for the appropriate use of fluoride toothpastes and mouthrinses are available in many countries.Conclusion. Fluoride toothpastes and mouthrinses have been developed and extensive testing has demonstrated that they are effective and their use should be encouraged.

  13. Water Fluoridation Statistics - Percent of PWS population receiving fluoridated water

    Data.gov (United States)

    U.S. Department of Health & Human Services — 2000-2014 Water Fluoridation Statistics is a biennial report of the percentage and number of people receiving fluoridated water from 2000 through 2014, originally...

  14. Fluoridated elastomers: in vivo versus in vitro fluoride release

    OpenAIRE

    Tinsley, D.; O'Dwyer, J. J.; Benson, P.E.

    2003-01-01

    OBJECTIVES: To compare (i) the in vivo release of fluoride from fluoridated elastomers to the in vitro release, and (ii) the residual fluoride content of the elastomers after 1 week in the mouth with and without fluoride toothpaste and mouthrinse. DESIGN: A prospective, longitudinal, cross-over study. Subjects and method: Six subjects were recruited by poster to take part in the study. Each subject had one premolar in each quadrant to which a bracket could be fixed and exemplar...

  15. Calcium - urine

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003603.htm Calcium - urine To use the sharing features on this ... enable JavaScript. This test measures the amount of calcium in urine. All cells need calcium in order ...

  16. Calcium supplements

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007477.htm Calcium supplements To use the sharing features on this page, please enable JavaScript. WHO SHOULD TAKE CALCIUM SUPPLEMENTS? Calcium is an important mineral for the ...

  17. Calcium Oscillations

    OpenAIRE

    Dupont, Geneviève; Combettes, Laurent; Bird, Gary S.; Putney, James W.

    2011-01-01

    Calcium signaling results from a complex interplay between activation and inactivation of intracellular and extracellular calcium permeable channels. This complexity is obvious from the pattern of calcium signals observed with modest, physiological concentrations of calcium-mobilizing agonists, which typically present as sequential regenerative discharges of stored calcium, a process referred to as calcium oscillations. In this review, we discuss recent advances in understanding the underlyin...

  18. Fluoride retention by kaolin clay

    DEFF Research Database (Denmark)

    Kau, P. M. H.; Smith, D. W.; Binning, Philip John

    1997-01-01

    To evaluate the potential effectiveness of kaolin clay liners in storage of fluoride contaminated waste, an experimental study of the sorption and desorption behaviour of fluoride in kaolin clay was conducted. The degree of fluoride sorption by kaolin was found to depend on solution pH and...

  19. EFFECT OF CALCIUM ADDITION ON THE DEFLUORIDATION CAPACITY OF BONE CHAR

    DEFF Research Database (Denmark)

    Jacobsen, P.; Dahi, Elian

    1997-01-01

    Dosage of small amounts of calcium chloride to fluoride water prior to contact with bone char which has already been saturated with fluoride is shown to provide an additional fluoride removal capacity. The additionally obtained removal capacity increases with slower filtration velocities and...... capable of reducing the fluoride concentration form 10 to about 0.5 mgF/L. The additionally saturated column is shown to be regenerated by simple adjustment of the pH of the water to 11 and allowing to flow for a few bed volumes. The useful regeneration capacity, where the fluoride concentration is...

  20. Fluoride Uptake Level of the Enamel by a Fluoride Varnish and a Fluoride Gel (APF)

    OpenAIRE

    Navabi B; Ansari G.; Khan Z; Kheirieh P.; Najafi B.

    2011-01-01

    Statement of Problem: Various forms of fluoride-contained products are used to increase the resistance of the tooth against caries for preventive purposes. Furthermore, studies demonstrated higher fluoride uptake with varnish and gel among the wide range of products.Purpose: This study compared fluoride uptake of Duraflor® varnish (Practicon Dent, USA) with fluoride gel (APF, Sultan®), used on the enamel surface of the intact teeth.Materials and Method: In this experimental in-vitro study, 2...

  1. Caries-­preventive Effect of 1300ppm Fluoride and Carrageenan Containing Toothpaste

    Directory of Open Access Journals (Sweden)

    Anton Rahardjo

    2013-07-01

    Full Text Available 72 1024x768 Various studies stated that the increase concentration of fluoride in toothpastes leads to the reduction of calcium loss in enamel. Objective: The purpose of this study was to test the difference between the effect of 1300ppm fluoride with carrageenan toothpaste and 1000ppm fluoride only toothpaste on roughness and hardness of enamel surface. Methods: Enamel specimens were obtained from 30 extracted human premolars. The enamel specimens were randomly assigned to one of the three groups, 1300ppm fluoride with carrageenan toothpaste, 1000ppm fluoride only toothpaste and toothpaste with no fluoride as a negative control. The samples were immersed in 1% citric acid with pH 4 for 150 seconds for demineralization, afterwards exposed to each toothpaste for 6 minutes. Results: The results demonstrated that toothpaste with 1300ppm fluoride with carregeenan has two times greater efficacy in triggering remineralization than toothpaste with 1000ppm fluoride only, with regards to surface roughness and hardness recovery in an in vitro caries model. Conclusion: The results suggested that treatment of enamel with toothpaste containing 1300ppm fluoride with carrageenan has high potential in inducing remineralization on enamel.DOI: 10.14693/jdi.v20i1.125

  2. A Comparison of Fluoride Uptake by Sound Enamel Following Application of Sodium Fluoride Mouthrinses and APF Gels Produced in Iran with Standardized Foreign Samples

    Directory of Open Access Journals (Sweden)

    A Kowsari

    2002-02-01

    Full Text Available The goal of this investigation is to compare the extent of fluoride uptake by sound enamel following application of two commercial mouthrinses containing sodium fluoride (0.2% and a topical gel containing APF (1.23% produced in Iran with those of foreign standardized ones. Sixty extracted premolars were used. Each tooth was divided into two lingual and buccal halves, one half as control, the other one as experimental. Enamel biopsy technique (two- step acid etching was used to determine the concentration of fluoride and calcium in each sample. For data comparison and fluoride uptake estimation, the depths of layers with the use of linear regression analysis were standardized to 25 and 50um. The analysis showed that in Iranian mouthrinse no. 1, there is linear correlation between fluoride concentration and enamel depth, in both control and experimental group at the first and second layers, while, in other groups, this correlation was observed just at the first layer (superficial enamel layer. The greatest fluoride uptake was seen at Iranian mouthrinse no.2 and the least was seen at foreign mouthrinse no. 3. From among two APF gels, the greatest uptake was observed at gel no. 1 (Iranian. The results showed that all three Iranian products increase fluoride content of enamel, moreover the level of fluoride uptake, while applying Iranian products, in comparison with foreign ones, shows considerable increase.

  3. Efecto de la arginina 8%-carbonato de calcio y del fluoruro de sodio al 5% en la reducción de la hipersensibilidad dentinaria post terapia periodontal: ensayo clínico Effect of 8% arginine, calcium carbonate and 5% sodium fluoride on the reduction of the dentine hipersensitivity post periodontal therapy: clinical trial

    Directory of Open Access Journals (Sweden)

    M Márquez

    2011-04-01

    embargo, se logró una mayor reducción del dolor en aquellos pacientes que utilizaron la terapia de arginina al 8% y carbonato de calcio, con un 60% de los individuos sin dolor y con una mediana final de 0 en comparación al grupo con barniz de flúor al 5% y un dentrífico fluorado que mantuvieron en el 100% de los sujetos algún grado de dolor y presentando una mediana final en la escala VAS de 2.Aim: The aim of this clinical study was to evaluate and to compare the efficacy in reducing the dentine hypersensitivity of an 8% arginine, calcium carbonate, 1.450 ppm sodium monofluorophosphate dentifrice with topical application and twice-daily brushing, with a negative control toothpaste containing calcium carbonate and 1.450 ppm fluoride as MFP, after periodontal treatment (baseline and four weeks respectively. Methods: A four-week clinical study with 20 subjects with diagnosis of slight to moderate chronic periodontitis under mechanical periodontal treatment and presence of gingival recessions in incisors, canines or premolars, stratified based on baseline tooth sensitivity. Subjects brushed with either a 1.450 ppm fluoride dentifrice or a marketed 8% arginine calcium carbonate dentifrice twice daily for approximately one minute. At screening, baseline and weeks four, subjects' tooth sensitivity was determined through both evaporative (Schiff and Visual Analogue Scale [VAS]. The same examiner throughout the study performed subject assessments using each stimulus. Results: Both subject groups exhibited significant reductions from baseline to four weeks in dentine hypersensitivity. However, patients who received 8% arginine calcium carbonate therapy, exhibited a greater reduction, with a 60% of individuals lacking of pain and with a final median of 0 in comparison with the 5% fluoride varnish and fluoride toothpaste group in which a 100% of subjects felt some degree of pain, presenting a final medium VAS scale of 2.

  4. Other Fluoride Products

    Science.gov (United States)

    ... in preventing tooth decay in people of all ages. Use the information listed below to compare the other fluoride products ... even among children younger than 6 years of age. Proper application technique ... cleared for marketing by the Food and Drug Administration (FDA) as ...

  5. Salt fluoridation and oral health

    Directory of Open Access Journals (Sweden)

    Thomas M. Marthaler

    2013-11-01

    Full Text Available The aim of this paper is to make known the potential of fluoridated salt in community oral health programs, particularly in South Eastern Europe. Since 1922, the addition of iodine to salt has been successful in Switzerland. Goiter is virtually extinct. By 1945, the cariesprotective effect of fluorides was well established. Based on the success of water fluoridation, a gynecologist started adding of fluoride to salt. The sale of fluoridated salt began in 1956 in the Swiss Canton of Zurich, and several other cantons followed suit. Studies initiated in the early seventies showed that fluoride, when added to salt, inhibits dental caries. The addition of fluoride to salt for human consumption was officially authorized in 1980-82. In Switzerland 85% of domestic salt consumed is fluoridated and 67% in Germany. Salt fluoridation schemes are reaching more than one hundred million in Mexico, Colombia, Peru and Cuba. The cost of salt fluoridation is very low, within 0.02 and 0.05 € per year and capita. Children and adults of the low socio-economic strata tend to have substantially more untreated caries than higher strata. Salt fluoridation is by far the cheapest method for improving oral health. Conclusions. Salt fluoridation has cariostatic potential like water fluoridation (caries reductions up to 50%. In Europe, meaningful percentages of users have been attained only in Germany (67% and Switzerland (85%. In Latin America, there are more than 100 million users, and several countries have arrived at coverage of 90 to 99%. Salt fluoridation is by far the cheapest method of caries prevention, and billions of people throughout the world could benefit from this method.

  6. Water fluoridation and oral health

    Directory of Open Access Journals (Sweden)

    Máiréad Antoinette Harding

    2013-11-01

    Full Text Available Water fluoridation, is the controlled addition of fluoride to the water supply, with the aim of reducing the prevalence of dental caries. Current estimates suggest that approximately 370 million people in 27 countries consume fluoridated water, with an additional 50 million consuming water in which fluoride is naturally occurring. A pre-eruptive effect of fluoride exists in reducing caries levels in pit and fissure surfaces of permanent teeth and fluoride concentrated in plaque and saliva inhibits the demineralisation of sound enamel and enhances the remineralisation of demineralised enamel. A large number of studies conducted worldwide demonstrate the effectiveness of water fluoridation. Objections to water fluoridation have been raised since its inception and centre mainly on safety and autonomy. Systematic reviews of the safety and efficacy of water fluoridation attest to its safety and efficacy; dental fluorosis identified as the only adverse outcome. Conclusion: Water fluoridation is an effective safe means of preventing dental caries, reaching all populations, irrespective of the presence of other dental services. Regular monitoring of dental caries and fluorosis is essential particularly with the lifelong challenge which dental caries presents.

  7. Health Effects Associated with Water Fluoridation.

    Science.gov (United States)

    Richmond, Virginia L.

    1979-01-01

    Discussion is presented concerning fluoridation of water supplies. Correlation between fluoride in drinking water and improved dental health is reviewed. Relationship is expressed between fluoridation and reduced tooth decay. Use of fluoride in treating skeletal disorders is discussed. Author advocates fluoridating water supplies. (SA)

  8. Fluoride and dental caries

    OpenAIRE

    Camilleri, George E.

    1998-01-01

    Fluorine was probably discovered by the chemist Scheele in 1771, and eventually isolated in 1886 by Moissan. Its presence in bones and teeth was initially disputed but eventually confirmed in the middle of the eighteenth century. In this article the author discusses the few epidemiological studies which confirm the relationship between fluoride concentration in drinking water, mottled enamel and the incidence of dental caries and also describes the Maltese scene in regards the caries level in...

  9. Fluoride in dental erosion

    OpenAIRE

    Magalhães, A C; Wiegand, A.; Rios, D.; Buzalaf, M.A.R.; Lussi, A.

    2011-01-01

    Dental erosion develops through chronic exposure to extrinsic/intrinsic acids with a low pH. Enamel erosion is characterized by a centripetal dissolution leaving a small demineralized zone behind. In contrast, erosive demineralization in dentin is more complex as the acid-induced mineral dissolution leads to the exposure of collagenous organic matrix, which hampers ion diffusion and, thus, reduces further progression of the lesion. Topical fluoridation inducing the formation of a protective l...

  10. Strontium-90 fluoride data sheet

    International Nuclear Information System (INIS)

    This report is a compilation of available data and appropriate literature references on the properties of strontium-90 fluoride and nonradioactive strontium fluoride. The objective of the document is to compile in a single source pertinent data to assist potential users in the development, licensing, and use of 90SrF2-fueled radioisotope heat sources for terrestrial power conversion and thermal applications. The report is an update of the Strontium-90 Fluoride Data Sheet (BNWL-2284) originally issued in April 1977

  11. Fluoride remediation using floating macrophytes

    OpenAIRE

    Naba Kumar Mondal; Ria Bhaumik; Uttiya Dey; Kartick Chandra Pal; Chittaranjan Das; Anindita Maitra; Jayanta Kumar Datta

    2014-01-01

    Six aquatic macrophytes, such as Pistia stratiotes, Ceratophyllum demersum, Nymphoides indica, Lemna major, Azolla pinnata,and Eichhornia crassipes were considered for remove fluoride from aqueous solution. Five different concentrations (10, 30, 50, and 100 ppm) of fluoride solution were taken in 1 L plastic container. Fixed weight (20 g) of macrophytes along with 500 ml fluoride solution was taken in each plastic container for 72 hours observation. Results demonstrated all the macrophytes sh...

  12. Fluoride Rinses, Gels and Foams

    DEFF Research Database (Denmark)

    Twetman, Svante; Keller, Mette K

    2016-01-01

    electronic search for literature published in English between 2003 and 2014. The included papers were assessed for their risk of bias and the results were narratively synthesized due to study heterogeneity. The quality of evidence was expressed according to GRADE. RESULTS: A total of 19 papers were included......, previously established in systematic reviews. The lack of clinical trials free from bias is, however, still a concern, especially for fluoride mouth rinses and fluoride foam. There is also a scientific knowledge gap on the benefit and optimal use of these fluoride supplements in combination with daily tooth...... brushing with fluoride toothpaste....

  13. Private Well Water and Fluoride

    Science.gov (United States)

    ... it is the responsibility of the homeowner to know and understand the quality of the water from their well. The U.S. ... or area. Additional information on testing well water quality in private wells ... do I need to know about fluoride and groundwater from a well? Fluoride ...

  14. Study of interaction of uranium, plutonium and rare earth fluorides with some metal oxides in fluoric salt melts

    International Nuclear Information System (INIS)

    Interaction of plutonium, uranium, and rare-earth elements (REE) fluorides with aluminium and calcium oxides in melts of eutectic mixture LiF-NaF has been studied at 800 deg C by X-ray diffraction method. It has been shown that tetravalent uranium and plutonium are coprecipitated by oxides as a solid solution UO2-PuO2. Trivalent plutonium in fluorides melts in not precipitated in the presence of tetravalent uranium which can be used for their separation. REE are precipitated from a salt melt by calcium oxide and are not precipitated by aluminium oxide. Thus, aluminium oxide in a selective precipitator for uranium and plutonium in presence of REE. Addition of aluminium fluoride retains trivalent plutonium and REE in a salt melt in presence of Ca and Al oxides. The mechanism of interacting plutonium and REE trifluorides with metal oxides in fluoride melts has been considered

  15. Fabrication and characterization of fluoridated hydroxyapatite nanopowders via mechanical alloying

    International Nuclear Information System (INIS)

    The aim of this work was preparation and characterization of fluoridated hydroxyapatite (FHA) nanopowders with different degrees of fluoridation via mechanical alloying (MA) method. FHA nanopowders with a chemical composition of Ca10(PO4)6OH2-xFx (where x values were selected equal to 0.0, 0.5, 1.0, 1.5, and 2.0) were synthesized using a mixture of appropriate amounts of calcium hydroxide, phosphorous pentoxide, and calcium fluoride powders by 6 h of mechanical alloying at 300 rpm, using eight balls with a diameter of 20 mm, and the ball-to-powder weight ratio equal to 35:1. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and ICP-OES analysis techniques were utilized in order to evaluate phase composition, agglomerates size distribution, morphology and particle size, functional groups, and purity of synthesized FHA nanopowders. The FTIR result combined with the X-ray diffraction indicated that single phase of homogeneous FHA with the carbonate peaks in the FTIR spectrum could be prepared after 6 h MA. TEM photomicrograph revealed that obtained powder after 6 h of MA was composed of FHA nanoparticles (35-65 nm). The results of ICP-OES analysis illustrated that synthesized nanopowder could fulfill the requirement of ASTM F1185-88 to be used as a biomaterial.

  16. Urinary Fluoride Concentration in Children with Disabilities Following Long-Term Fluoride Tablet Ingestion

    Science.gov (United States)

    Liu, Hsiu-Yueh; Chen, Jung-Ren; Hung, Hsin-Chia; Hsiao, Szu-Yu; Huang, Shun-Te; Chen, Hong-Sen

    2011-01-01

    Urine is the most commonly utilized biomarker for fluoride excretion in public health and epidemiological studies. Approximately 30-50% of fluoride is excreted from urine in children. Urinary fluoride excretion reflects the total fluoride intake from multiple sources. After administering fluoride tablets to children with disabilities, urinary…

  17. 49 CFR 173.163 - Hydrogen fluoride.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Hydrogen fluoride. 173.163 Section 173.163... Hydrogen fluoride. (a) Hydrogen fluoride (hydrofluoric acid, anhydrous) must be packaged as follows: (1) In... filling ratio of 0.84. (b) A cylinder removed from hydrogen fluoride service must be condemned...

  18. High Fluoride Dentifrices for Elderly and Vulnerable Adults: Does It Work and if So, Then Why?

    Science.gov (United States)

    Ekstrand, Kim Rud

    2016-01-01

    The primary aim of this work is to present the available evidence that toothpastes containing >1,500 ppm fluoride (2,500-2,800 and 5,000 ppm F) provide an additional caries preventive effect on root caries lesions in elderly patients compared to traditional dentifrices (1,000-1,450 ppm F). The secondary aim of this paper is to discuss why high fluoride dentifrices in general should perform better than traditional F-containing toothpaste. When examining the few studies that have considered the preventive benefits of high fluoride products on root caries the relative risk appears to be around 0.5, and the risk can thus be halved by exchanging traditional F-containing toothpaste for toothpaste containing 5,000 ppm F. There is reasonable evidence that high fluoride dentifrices significantly increase the fluoride concentration in saliva during the day and the fluoride concentration in plaque compared to traditional F toothpaste. Furthermore, the use of toothpaste with 5,000 ppm F significantly reduces the amount of plaque accumulated, decreases the number of mutans streptococci and lactobacilli and possibly promotes calcium fluoride deposits to a higher degree than after the use of traditional F-containing toothpaste. PMID:27101401

  19. Silver nano-particles in fluoride films fabricated by Pulsed Laser Deposition with auxiliary Electron Beam Evaporation

    Czech Academy of Sciences Publication Activity Database

    Novotný, Michal; Lančok, Ján; Bulíř, Jiří; Hruška, Petr; Fekete, Ladislav; Fitl, Přemysl

    Strasbourg: European Materials Research Society, 2013. [E- MRS 2013 Spring Meeting. 27.05.2013-31.05.2013, Strasbourg] R&D Projects: GA MŠk(CZ) 7AMB12FR034; GA ČR(CZ) GAP108/11/1312 Grant ostatní: AVČR(CZ) M100101271 Institutional support: RVO:68378271 Keywords : lanthanum fluoride * calcium fluoride * thin film * silver nanoparticles * pulsed laser deposition * electron beam evaporation Subject RIV: BM - Solid Matter Physics ; Magnetism

  20. Active biomonitoring of airborne fluoride near an HF producing factory using standardised grass cultures

    Science.gov (United States)

    Franzaring, J.; Klumpp, A.; Fangmeier, A.

    In order to study the pollution gradient in the vicinity of an HF producing factory, a biomonitoring programme was performed employing VDI standardised grass cultures. Specimen plants of Lolium multiflorum cv. Lema were exposed at 11 sites over five monthly periods and the biomass produced was used for subsequent F-analyses. Meteorological data from the study region confirmed that wind direction accounted for changes in the pollution pattern over periods of time. Fluoride concentrations in the grass cultures, however, were unrelated to temperature and precipitation sums during the exposures. The biomass production of the grass cultures proved to be unrelated to these parameters as well but, with the enhanced growth of the plants, the fluoride concentrations were lower due to the dilution of the element with higher biomass accumulation. Because the contribution of particulate fluoride was unknown, both the washed grass cultures and the washing water were analysed in order to determine the amount of external fluoride. Washing reduced the fluoride concentrations by 22% on average, indicating that most of the element was internal fluoride stemming from stomatal uptake. Larger amounts of fluoride, however, could be washed off from grass cultures exposed at sites close to the factory indicating that dust emissions played a greater role at these locations. Because particulate emissions were supposed to arise from CaF 2 and the waste-product anhydrite, grass cultures were also analysed for calcium and sulphur. While calcium concentrations were generally high but unrelated to fluoride, sulphur concentrations showed a slight relationship to the F-concentrations determined in the unwashed plants. Latter findings indicate the co-deposition of the two elements as surface bound, external loads, but bioindication could not clarify to what extent both elements were partitioned in the gas-to-particle phase. We therefore recommend using the grass culture method in air quality

  1. Molten fluoride fuel salt chemistry

    International Nuclear Information System (INIS)

    The chemistry of molten fluorides is traced from their development as fuels in the Molten Salt Reactor Experiment with important factors in their selection being discussed. Key chemical characteristics such as solubility, redox behavior, and chemical activity are explained as they relate to the behavior of molten fluoride fuel systems. Fission product behavior is described along with processing experience. Development requirements for fitting the current state of the chemistry to modern nuclear fuel system are described. It is concluded that while much is known about molten fluoride behavior, processing and recycle of the fuel components is a necessary factor if future systems are to be established

  2. Mechanochemical-hydrothermal synthesis and characterization of fluoridated hydroxyapatite

    International Nuclear Information System (INIS)

    Fluoridated hydroxyapatite (FHAp) was successfully synthesized from the starting materials of CaCO3, CaHPO4.2H2O, and CaF2 via a mechanochemical-hydrothermal route. X-ray diffraction, infrared spectroscopy, surface area measurements, and scanning electron microscopy identified the resultant powders as FHAp nanocrystals with the specific surface areas of up to 114.72 m2/g. The mechanism study revealed that under such mechanochemical-hydrothermal conditions the formation reactions of FHAp were completed in two stages. The starting materials firstly reacted into a poorly crystallized calcium-deficient apatite and the complete incorporation of fluoride ions into apatite occurred in the second stage

  3. Trabecular stress fractures during fluoride therapy for osteoporosis

    Energy Technology Data Exchange (ETDEWEB)

    Schnitzler, C.M.; Solomon, L.

    1985-10-01

    Joint pain and swelling in patients on fluoride therapy are generally attributed to rheumatic phenomena; however, their occurrence exclusively in the lower limbs suggests a mechanical cause. Eight patients receiving daily doses of sodium fluoride 1.09 mg/kg, elemental calcium 1 gm, and vitamin D 1000-2800 units for osteoporosis spontaneously developed 17 episodes of periarticular pain and swelling in the lower limbs. Radiographs taken within two weeks of the onset of pain were negative, but when repeated 4-6 weeks later showed features of healing stress fractures in the periarticular cancellous bone at the following sites: distal femur (2) proximal tibia (3), distal tibia (6), calcaneum (6). Bone scintigraphy was positive on five occasions, two before radiographic signs had appeared. (orig.).

  4. Fluoride Concentration in Dentin of Exfoliated Primary Teeth as a Biomarker for Cumulative Fluoride Exposure

    OpenAIRE

    dela Cruz, G.G.; Rozier, R.G.; Bawden, J.W.

    2008-01-01

    A biomarker for lifetime fluoride exposure would facilitate population-based research and policy making but currently does not exist. This study examined the suitability of primary tooth dentin as a biomarker by comparing dentin fluoride concentration and fluoride exposures. Ninety-nine children's exfoliated primary teeth were collected from 2 fluoridated and 2 fluoride-deficient communities in North Carolina. Coronal dentin was isolated by microdissection and fluoride concentration assayed u...

  5. Fluoride retention in saliva and in dental biofilm after different home-use fluoride treatments

    OpenAIRE

    Souza, Daniela Correia Cavalcante; Marisa MALTZ; Lina Naomi HASHIZUME

    2014-01-01

    This single-blind, randomized, crossover study aimed at assessing the long-term fluoride concentrations in saliva and in dental biofilm after different home-use fluoride treatments. The study volunteers (n = 38) were residents of an area with fluoridated drinking water. They were administered four treatments, each of which lasted for one week: twice-daily placebo dentifrice, twice-daily fluoride dentifrice, twice-daily fluoride dentifrice and once-daily fluoride mouthrinse, and thrice-daily f...

  6. Fluoride glass: Crystallization, surface tension

    Science.gov (United States)

    Doremus, R. H.

    1988-01-01

    Fluoride glass was levitated acoustically in the ACES apparatus on STS-11, and the recovered sample had a different microstructure from samples cooled in a container. Further experiments on levitated samples of fluoride glass are proposed. These include nucleation, crystallization, melting observations, measurement of surface tension of molten glass, and observation of bubbles in the glass. Ground experiments are required on sample preparation, outgassing, and surface reactions. The results should help in the development and evaluation of containerless processing, especially of glass, in the development of a contaminent-free method of measuring surface tensions of melts, in extending knowledge of gas and bubble behavior in fluoride glasses, and in increasing insight into the processing and properties of fluoride glasses.

  7. Chronic Fluoride Toxicity: Dental Fluorosis

    OpenAIRE

    DenBesten, Pamela; Li, Wu

    2011-01-01

    Dental fluorosis occurs as a result of excess fluoride ingestion during tooth formation. Enamel fluorosis and primary dentin fluorosis can only occur when teeth are forming, and therefore fluoride exposure (as it relates to dental fluorosis) occurs during childhood. In the permanent dentition, this would begin with the lower incisors, which complete mineralization at approximately 2–3 years of age, and end after mineralization of the third molars. The white opaque appearance of fluorosed enam...

  8. Method of aluminium fluoride manufacture

    International Nuclear Information System (INIS)

    The manufacture of aluminium fluoride is based on waste processing in uranium hexafluoride conversion to uranium oxides within the fuel cycle. The conversion is the stoichiometric conversion of uranium hexafluoride with aluminium nitrate to uranyl nitrate. This is extracted from the water phase by phosphoric acid trialkyl ester to an organic solvent and further processed. The discharge water phase is solidified by evaporation to solid aluminium fluoride and nitric acid. (M.S.)

  9. Effect of water fluoridation on the development of medial vascular calcification in uremic rats

    International Nuclear Information System (INIS)

    Highlights: • F− prevents calcification in vitro, cell death and trans-differentiation. • Prevention is independent of cellular activity, with IC50 of 8.7 μM, similar to PPi. • In rats with experimental CKD F− dramatically increases aortic calcification. • This effect seems to be mediated through deterioration of residual renal function. • F− alters the crystallization, composition and shape of calcium phosphates. - Abstract: Public water fluoridation is a common policy for improving dental health. Fluoride replaces the hydroxyls of hydroxyapatite, thereby improving the strength of tooth enamel, but this process can also occur in other active calcifications. This paper studies the effects of water fluoridation during the course of vascular calcification in renal disease. The effect of fluoride was studied in vitro and in vivo. Rat aortic smooth muscle cells were calcified with 2 mM Pi for 5 days. Fluoride concentrations of 5–10 μM – similar to those found in people who drink fluoridated water – partially prevented calcification, death, and osteogene expression in vitro. The anticalcifying mechanism was independent of cell activity, matrix Gla protein, and fetuin A expressions, and it exhibited an IC50 of 8.7 μM fluoride. In vivo, however, fluoridation of drinking water at 1.5 mg/L (concentration recommended by the WHO) and 15 mg/L dramatically increased the incipient aortic calcification observed in rats with experimental chronic kidney disease (CKD, 5/6-nephrectomy), fed a Pi-rich fodder (1.2% Pi). Fluoride further declined the remaining renal function of the CKD animals, an effect that most likely overwhelmed the positive effect of fluoride on calcification in vitro. Ultrastructural analysis revealed that fluoride did not modify the Ca/P atomic ratio, but it was incorporated into the lattice of in vivo deposits. Fluoride also converted the crystallization pattern from plate to rode-like structures. In conclusion, while fluoride prevents

  10. The fluoride content of bottled drinking waters.

    Science.gov (United States)

    Toumba, K J; Levy, S; Curzon, M E

    1994-04-01

    Sales of bottled drinking waters in the United Kingdom have tripled over the last 5 years. The fluoride content of 12 bottled waters purchased from two Leeds supermarkets was determined by both the direct and acid diffusion methods and found to vary from 0.10-0.80 mg/l fluoride (ie ppm fluoride). This article shows that bottled drinking waters contain differing concentrations of fluoride. There is no apparent difference between the direct and acid diffusion methods for the determination of fluoride concentrations of drinking waters. The manufacturers' labelling of fluoride concentrations are mainly inaccurate. Dentists should be aware of the fluoride concentrations of the drinking water of their child patients, be they municipal or bottled drinking water, when prescribing fluoride supplements. Also, some parents are using bottled waters to prepare baby milk formulations which themselves may contain high levels of fluoride and subject their children to the risk of dental fluorosis. PMID:8186036

  11. Selective Adsorption of Sodium Aluminum Fluoride Salts from Molten Aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Leonard S. Aubrey; Christine A. Boyle; Eddie M. Williams; David H. DeYoung; Dawid D. Smith; Feng Chi

    2007-08-16

    Aluminum is produced in electrolytic reduction cells where alumina feedstock is dissolved in molten cryolite (sodium aluminum fluoride) along with aluminum and calcium fluorides. The dissolved alumina is then reduced by electrolysis and the molten aluminum separates to the bottom of the cell. The reduction cell is periodically tapped to remove the molten aluminum. During the tapping process, some of the molten electrolyte (commonly referred as “bath” in the aluminum industry) is carried over with the molten aluminum and into the transfer crucible. The carryover of molten bath into the holding furnace can create significant operational problems in aluminum cast houses. Bath carryover can result in several problems. The most troublesome problem is sodium and calcium pickup in magnesium-bearing alloys. Magnesium alloying additions can result in Mg-Na and Mg-Ca exchange reactions with the molten bath, which results in the undesirable pickup of elemental sodium and calcium. This final report presents the findings of a project to evaluate removal of molten bath using a new and novel micro-porous filter media. The theory of selective adsorption or removal is based on interfacial surface energy differences of molten aluminum and bath on the micro-porous filter structure. This report describes the theory of the selective adsorption-filtration process, the development of suitable micro-porous filter media, and the operational results obtained with a micro-porous bed filtration system. The micro-porous filter media was found to very effectively remove molten sodium aluminum fluoride bath by the selective adsorption-filtration mechanism.

  12. Chemical treatment of ammonium fluoride solution in uranium reconversion plant

    International Nuclear Information System (INIS)

    A chemical procedure is described for the treatment of the filtrate, produced from the transformation of uranium hexafluoride (U F6) into ammonium uranyl carbonate (AUC). This filtrate is an intermediate product in the U F6 to uranium dioxide (U O2) reconversion process. The described procedure recovers uranium as ammonium peroxide fluoro uranate (APOFU) by precipitation with hydrogen peroxide (H2 O2), and as later step, its calcium fluoride (CaF2) co-precipitation. The recovered uranium is recycled to the AUC production plant. (author)

  13. Calcium Carbonate

    Science.gov (United States)

    ... before being swallowed; do not swallow them whole. Drink a full glass of water after taking either the regular or chewable tablets or capsules. Some liquid forms of calcium carbonate must be shaken well before use.Do not ...

  14. Calcium Electroporation

    DEFF Research Database (Denmark)

    Frandsen, Stine Krog; Gibot, Laure; Madi, Moinecha;

    2015-01-01

    BACKGROUND: Calcium electroporation describes the use of high voltage electric pulses to introduce supraphysiological calcium concentrations into cells. This promising method is currently in clinical trial as an anti-cancer treatment. One very important issue is the relation between tumor cell kill...... efficacy-and normal cell sensitivity. METHODS: Using a 3D spheroid cell culture model we have tested the effect of calcium electroporation and electrochemotherapy using bleomycin on three different human cancer cell lines: a colorectal adenocarcinoma (HT29), a bladder transitional cell carcinoma (SW780......), and a breast adenocarcinoma (MDA-MB231), as well as on primary normal human dermal fibroblasts (HDF-n). RESULTS: The results showed a clear reduction in spheroid size in all three cancer cell spheroids three days after treatment with respectively calcium electroporation (p<0.0001) or...

  15. Calcium Calculator

    Science.gov (United States)

    ... Latvia - Lebanon - Libya - Lithuania - Luxembourg - Macedonia, Republic of - Malaysia - Malta - Mexico - Moldova - Morocco - Netherlands - New Zealand - Nigeria - ... and Statistics Popular content Calcium content of common foods What is Osteoporosis? The Board Introduction to Bone ...

  16. Mechanism of UV induced thermoluminescence in natural calcium fluoride

    International Nuclear Information System (INIS)

    Blue coloured natural CaF2 found at Criciuma, Brasil, shows TL peaks at about 3100C (3), 3500C (3), 5000C (5) and 5650C (6). After annealing the sample at 6000C for 10 min. and exposing to gamma-rays (6.7x105R), the sample was annealed at 4000C for 90 min., leaving TL peak 6, and probably part of 5, unbleached (residual peak). The TL response of the sample was measured as a function of 250 nm and 365 nm exposure intensity and the result is a decrease of the residual peak and an increase of the lower temperature peaks, suggesting a charge transfer process from deep traps to shallow ones. For larger intensities, the UV light also bleaches these shallow traps, having the released charges the probability to be recaptured by the deep ones. The 365 nm TL response shows a characteristic difference from the 250 nm curve, namely, a saturation followed by a further increase in the TL response. A decay curve was obtained as a function of the number of identical exposures to UV light for successive exposures and TL readings. This curve shows, generally, two different slopes, and similar behaviour is presented by the residual peak when bleached by UV light. In order to explain the results, a mathematical model is proposed based on the transfer mechanism, which fits satisfactorily the 250 nm TL curves. (author)

  17. Altered miRNAs expression profiling in sperm of mice induced by fluoride.

    Science.gov (United States)

    Sun, Zilong; Zhang, Wen; Li, Sujuan; Xue, Xingchen; Niu, Ruiyan; Shi, Lei; Li, Baojun; Wang, Xiaowen; Wang, Jundong

    2016-07-01

    The reproductive toxicity of fluoride has become a major concern in the world. Fluoride can decrease the abilities of sperm capacitation, hyperactivation, chemotaxis, acrosome reaction and fertilization, but the studies on the responses of sperm small noncoding RNAs (sncRNAs), especially miRNAs, to fluoride exposure are lacking. miRNAs are demonstrated to influence sperm quality and male fertility by regulating gene expression at post-transcriptional levels or translational repression. The objective of this study is to analyze miRNA profiling in sperm of mice administrated with 25 and 100 mg L(-1) sodium fluoride (NaF) for 60 d using high-throughput sequencing technology. Along with reduced sperm concentration, survival, motility, and mitochondrial membrane potential, 31 differentially expressed known miRNAs were identified in fluoride groups, compared with the control group. 671 predicted target genes against the 16 altered miRNAs were mainly involved in protease inhibitor activity, apoptosis, ubiquitin mediated proteolysis, and signaling pathways of calcium, JAK-STAT, MAPK, p53, Wnt, which were proved to be directly related to sperm quality. These findings suggested that the altered sperm miRNAs could be potential biomarkers for fluoride reproductive toxicity. PMID:27108368

  18. Dynamics of Fluoride Bioavailability in the Biofilms of Different Oral Surfaces after Amine Fluoride and Sodium Fluoride Application

    OpenAIRE

    Naumova, Ella A; Christoph Dickten; Rico Jung; Florian Krauss; Henrik Rübesamen; Katharina Schmütsch; Tudor Sandulescu; Stefan Zimmer; Arnold, Wolfgang H.

    2016-01-01

    It was the aim of this study to investigate differences in fluoride bioavailability in different oral areas after the application of amine fluoride (AmF) and sodium fluoride (NaF). The null hypothesis suggested no differences in the fluoride bioavailability. The tongue coating was removed and biofilm samples from the palate, oral floor and cheeks were collected. All subjects brushed their teeth with toothpaste containing AmF or NaF. Specimens were collected before, as well as immediately afte...

  19. Industrial fluoride pollution. Chronic fluoride poisoning in Cornwall Island cattle.

    Science.gov (United States)

    Krook, L; Maylin, G A

    1979-04-01

    An aluminum plant on the south bank of the St. Lawrence river, southwest of Cornwall Island, Ontario, Canada, has emitted 0.816 metric tons of fluoride daily since 1973; considerably higher amounts were emitted from 1959 to 1973. The plant has been designated as the "major source of fluoride emissions impacting on Cornwall Island." Chronic fluoride poisoning in Cornwall island cattle was manifested clinically by stunted growth and dental fluorosis to a degree of severe interference with drinking and mastication. Cows died at or were slaughtered after the third pregnancy. The deterioration of cows did not allow further pregnancies. Fluoride concentrations in ash of biopsied coccygeal vertebrae increased significantly with age and were dependent on distance from and direction to the aluminum plant. Fluoride in bone ash of a 7-month old-fetus exceeded 500 ppm; fluoride thus was passed transplacentally. Analyses of fluoride in ash of bones obtained at necropsy of cattle from 4 months of age to 4 to 5 years of age showed increased amounts with age. Cancellous bone retained far higher amounts than cortical bone, a reflection of the normally higher metabolic rate of cancellous bone. Concentrations exceeding 10,000 ppm fluoride were recorded in cancellous bone of a 4-to 5-year-old cow. The target cells for fluoride in chronic fluorosis were shown to be the ameloblasts, the dental pulp cells and the odontoblasts and, in bone, primarily the resorbing osteocytes and also the osteoblasts. Atrophy and necrosis of the ameloblasts were responsible for enamel defects. The existing enamel showed brown discoloration from fluoride deposits. The pulp cells underwent fibrous and osseous metaplasia and necrosis of the ectopic bone occurred. The odontoblasts were atrophic and the dentin showed brown discoloration. The resorbing osteocytes were inactive and osteosclerosis resulted. This was especially pronounced in areas of normally great apposition, i.e. in the metaphyses. The epiphyseal

  20. Fluoridering af drikkevandet i Danmark?

    DEFF Research Database (Denmark)

    Arvin, Erik; Spliid, Henrik; Bruvo, M.; Bardow, A.; Ekstrand, K.

    2010-01-01

    Første gang sammenhængen mellem caries (huller i tænderne) og fluoridindholdet i drikkevand blev diskuteret i vandværkskredse i Danmark var ved årsmødet i 1958. Her blev det oplyst, at fluorid i drikkevand beskytter mod caries, men man konstaterede også, at der nok ikke var stemning for fluorid......-tilsætning til drikkevandet (fluoridering). Siden da er emnet ikke taget op. Formålet med dette indlæg er at besvare spørgsmålene: 1. Er der behov for fluoridering af drikkevandet i Danmark? 2. Er der alternativer? Hvordan påvirker blødgøring af vand og andre vandbehandlingsmetoder dental caries hos børn og unge......? Som baggrund herfor vil vi redegøre for resultaterne af et netop afsluttet studium af sammenhængen mellem caries og drikkevandets sammensætning, specielt m.h.t. luoridindholdet og vandets calciumindhold (hårdhed). Undersøgelsen bekræfter, at fluorid i drikkevand i væsentlig grad beskytter mod caries...

  1. Acute toxicity of uranium hexafluoride, uranyl fluoride and hydrogen fluoride

    International Nuclear Information System (INIS)

    Uranium hexafluoride (UF6) released into the atmosphere will react rapidly with moisture in the air to form the hydrolysis products uranyl fluoride (UO2F2) and hydrogen fluoride (HF). Uranium compounds such as UF6 and UO2F2 exhibit both chemical toxicity and radiological effects, while HF exhibits only chemical toxicity. This paper describes the development of a methodology for assessing the human health consequences of a known acute exposure to a mixture of UF6, UO2F2, and HF. 4 refs., 2 figs., 5 tabs

  2. Intergranular fracture of lithium fluoride-22 percent calcium fluoride hypereutectic salt at 800 K

    Science.gov (United States)

    Raj, Subramanium V.; Whittenberger, J. Daniel

    1990-01-01

    Substantial strain-hardening was noted during the initial stages of deformation in constant-velocity compression tests conducted on as-cast samples of the LiF-22 mol pct CaF2 hypereutectic salt at 800 K. The deformed specimens exhibited extensive grain-boundary cracking and cavitation, suggesting that such cracking, in conjunction with interfacial sliding, is important for cavity nucleation at grain boundaries and at the LiF-CaF2 interfaces. Cavity growth and interlinkage occur through the preferential failure of the weaker LiF phase.

  3. IMPACT OF FLUORIDE ON DENTAL HEALTH QUALITY

    OpenAIRE

    Medjedovic, Eida; Medjedovic, Senad; Deljo, Dervis; Sukalo, Aziz

    2015-01-01

    Introduction: Fluoride is natural element that strengthens teeth and prevents their decay. Experts believe that the best way to prevent cavities is the use of fluoride from multiple sources. Studies even show that in some cases, fluoride can stop already started damage of the teeth. In children younger than 6 years fluoride is incorporated into the enamel of permanent teeth, making the teeth more resistant to the action of bacterial and acids in food. Goal: The aim of this study is to determi...

  4. Alimentary fluoride intake in preschool children

    OpenAIRE

    Lencova Erika; Ivancakova Romana; Oganessian Edgar; Broukal Zdenek

    2011-01-01

    Abstract Background The knowledge of background alimentary fluoride intake in preschool children is of utmost importance for introducing optimal and safe caries preventive measures for both individuals and communities. The aim of this study was to assess the daily fluoride intake analyzing duplicate samples of food and beverages. An attempt was made to calculate the daily intake of fluoride from food and swallowed toothpaste. Methods Daily alimentary fluoride intake was measured in a group of...

  5. Dietary Fluoride Intake and Associated Skeletal and Dental Fluorosis in School Age Children in Rural Ethiopian Rift Valley

    Directory of Open Access Journals (Sweden)

    Aweke Kebede

    2016-07-01

    Full Text Available An observational study was conducted to determine dietary fluoride intake, diet, and prevalence of dental and skeletal fluorosis of school age children in three fluorosis endemic districts of the Ethiopian Rift Valley having similar concentrations of fluoride (F in drinking water (~5 mg F/L. The duplicate plate method was used to collect foods consumed by children over 24 h from 20 households in each community (n = 60 and the foods, along with water and beverages, were analyzed for fluoride (F content. Prevalence of dental and skeletal fluorosis was determined using presence of clinical symptoms in children (n = 220. Daily dietary fluoride intake was at or above tolerable upper intake level (UL of 10 mg F/day and the dietary sources (water, prepared food and beverages all contributed to the daily fluoride burden. Urinary fluoride in children from Fentale and Adamitulu was almost twice (>5 mg/L the concentration found in urine from children from Alaba, where rain water harvesting was most common. Severe and moderate dental fluorosis was found in Alaba and Adamitulu, the highest severity and prevalence being in the latter district where staple foods were lowest in calcium. Children in all three areas showed evidence of both skeletal and non-skeletal fluorosis. Our data support the hypothesis that intake of calcium rich foods in addition to using rain water for household consumption and preparation of food, may help in reducing risk of fluorosis in Ethiopia, but prospective studies are needed.

  6. Dietary Fluoride Intake and Associated Skeletal and Dental Fluorosis in School Age Children in Rural Ethiopian Rift Valley.

    Science.gov (United States)

    Kebede, Aweke; Retta, Negussie; Abuye, Cherinet; Whiting, Susan J; Kassaw, Melkitu; Zeru, Tesfaye; Tessema, Masresha; Kjellevold, Marian

    2016-01-01

    An observational study was conducted to determine dietary fluoride intake, diet, and prevalence of dental and skeletal fluorosis of school age children in three fluorosis endemic districts of the Ethiopian Rift Valley having similar concentrations of fluoride (F) in drinking water (~5 mg F/L). The duplicate plate method was used to collect foods consumed by children over 24 h from 20 households in each community (n = 60) and the foods, along with water and beverages, were analyzed for fluoride (F) content. Prevalence of dental and skeletal fluorosis was determined using presence of clinical symptoms in children (n = 220). Daily dietary fluoride intake was at or above tolerable upper intake level (UL) of 10 mg F/day and the dietary sources (water, prepared food and beverages) all contributed to the daily fluoride burden. Urinary fluoride in children from Fentale and Adamitulu was almost twice (>5 mg/L) the concentration found in urine from children from Alaba, where rain water harvesting was most common. Severe and moderate dental fluorosis was found in Alaba and Adamitulu, the highest severity and prevalence being in the latter district where staple foods were lowest in calcium. Children in all three areas showed evidence of both skeletal and non-skeletal fluorosis. Our data support the hypothesis that intake of calcium rich foods in addition to using rain water for household consumption and preparation of food, may help in reducing risk of fluorosis in Ethiopia, but prospective studies are needed. PMID:27472351

  7. Molten fluorides for nuclear applications

    Directory of Open Access Journals (Sweden)

    Sylvie. Delpech

    2010-12-01

    Full Text Available The importance of pyrochemistry is being increasingly acknowledged and becomes unavoidable in the nuclear field. Molten salts may be used for fuel processing and spent fuel recycling, for heat transfer, as a homogeneous fuel and as a breeder material in fusion systems. Fluorides that are stable at high temperature and under high neutron flux are especially promising. Analysis of several field cases reveals that corrosion in molten fluorides is essentially due to the oxidation of metals by uranium fluoride and/or oxidizing impurities. The thermodynamics of this process are discussed with an emphasis on understanding the mass transfer in the systems, selecting appropriate metallic materials and designing effective purification methods.

  8. Fluoride: its role in dentistry

    Directory of Open Access Journals (Sweden)

    Livia Maria Andaló Tenuta

    2010-01-01

    Full Text Available In spite of decades of research on fluoride and the recognition of its role as the cornerstone of dental caries reduction in the last fifty years, questions still arise on its use at community, self-applied and professional application levels. Which method of fluoride delivery should be used? How and when should it be used? How can its benefits be maximized and still reduce the risks associated with its use? These are only some of the challenging questions facing us daily. The aim of this paper is to present scientific background to understand the importance of each method of fluoride use considering the current caries epidemiological scenario, and to discuss how individual or combined methods can be used based on the best evidence available.

  9. Corrosion resistant materials for fluorine and hydrogen fluoride

    International Nuclear Information System (INIS)

    Aluminum and Duralumin are resistant against fluorine and hydrogen fluoride up to 600 and 700 K, respectively. The resistance of nickel and its alloys, particularly monel, against fluorine and hydrogen fluoride is fairly good up to 900 and 800 K. During the attack of nickel-chromium alloys by fluorine between 1000 and 1300 K, it appears an inner fluorination similarly to the inner oxidation. The resistance of titanium in water-free liquid fluorine at lower temperatures with -1 is comparable to that of nickel and monel. However, the corrosion of titanium in gaseous fluorine amounts at 377 K only 0,0082 mm.a-1. In spite of their limited resistance against fluorine and hydrogen fluoride, very pure molybdenum and tungsten are employed as construction materials in the rocket technology because of their large strength at high temperatures if fluorine-hydrogen and fluorine-hydrazine flames are used. Lanthanum and calcium borides are only little attacked by fluorine hydrazine flames between 1400 and 1800 K; they are superior to all special grade alloys. The same is true in a lower temperature region (290-400 K) with fluorcarbon resins. Organic materials substitute in increasing extent metal alloys and non-metal inorganic materials. (orig.)

  10. Effect of fluoride on Treponema denticola.

    OpenAIRE

    Hughes, C A; Yotis, W W

    1986-01-01

    The effect of fluoride on the growth of Treponema denticola was studied. Fluoride, at a concentration of 20 micrograms/ml, was found to suppress the growth of all three strains tested. Growth was completely inhibited by 40 micrograms of fluoride per ml.

  11. Fluoride in African groundwater: Occurrence and mitigation

    NARCIS (Netherlands)

    Vasak, S.; Griffioen, J.; Feenstra, L.

    2010-01-01

    Fluoride in groundwater has both natural and anthropogenic sources. Fluoride bearing minerals, volcanic gases and various industrial and agricultural activities can contribute to high concentrations. High intake of fluoride from drinking water is the main cause of fluorosis and may lead to many othe

  12. Calcium pyrophosphate arthritis

    Science.gov (United States)

    Calcium pyrophosphate dihydrate deposition disease; CPPD disease; Acute CPPD arthritis; Pseudogout ... Calcium pyrophosphate arthritis is caused by the collection of salt called calcium pyrophosphate dihydrate (CPPD). The buildup ...

  13. Ultraviolet transmission of fluoride glasses

    International Nuclear Information System (INIS)

    In recent years there has been a great deal of interest in infrared-transmitting materials. However, with the commercial interest in excimer lasers and collection and utilization of solar energy, there is an increased interest in UV transmitting materials. In the absence of impurities, it has been observed that fluoride glasses are potentially very good UV transmitters. This paper reports the effects of intense UV radiation on fluoride glasses of various composition and on the status of dopants in those glasses. Possible limitations for these materials as UV transmission media are discussed

  14. Fluorine uptake into the human enamel surface from fluoride-containing sealing materials during cariogenic pH cycling

    Science.gov (United States)

    Yasuhiro, Matsuda; Katsushi, Okuyama; Hiroko, Yamamoto; Hisanori, Komatsu; Masashi, Koka; Takahiro, Sato; Naoki, Hashimoto; Saiko, Oki; Chiharu, Kawamoto; Hidehiko, Sano

    2015-04-01

    To prevent the formation of caries and reduce dentin hypersensitivity, sealing materials, either with or without fluoride, are generally applied on the tooth in clinical practice. Application of fluoride-free sealing materials results in the formation of an acid-resistant layer on the tooth surface. On the other hand, fluoride-containing sealing materials might not only form an acid-resistant layer but could possibly further provide fluoride to enhance remineralization and reduce demineralization. In this study, the demineralization prevention ability and fluorine uptake rate in human enamel of fluoride-containing sealing materials ["MS coats F" (MSF)] and fluoride-free sealing materials ("hybrid coats 2" [HI]) were evaluated using an automatic pH cycling system. Each material was applied to the original tooth surface, the cut surfaces were covered with sticky wax, and the automatic pH-cycling system simulated daily acid changes (pH 6.8-4.5) occurring in the oral cavity for 4 weeks. Caries progression was analyzed using transverse microradiography (TMR) taken pre and post the 4 weeks of pH cycling. The fluorine and calcium distributions in the carious lesion in each specimen were evaluated using the proton-induced gamma emission (PIGE) and proton-induced X-ray (PIXE) techniques, respectively. TMR analysis showed that both MSF and HI had a caries-preventing effect after 4 weeks of pH cycling. PIGE/PIXE analysis demonstrated that only MSF resulted in fluoride uptake in the enamel surface. Therefore, MSF can help to form an acid-resistant layer and provide fluoride to the enamel surface. The presence of fluoride on the enamel surface suggested that MSF could prevent demineralization, even if the acid-resistant layer was removed, in clinical settings. The data obtained using the PIGE and PIXE techniques are useful for understanding the benefits of the use of a fluoride-containing sealing material for preventing caries.

  15. Calcium and bones

    Science.gov (United States)

    Bone strength and calcium ... calcium (as well as phosphorus) to make healthy bones. Bones are the main storage site of calcium in ... your body does not absorb enough calcium, your bones can get weak or will not grow properly. ...

  16. Get Enough Calcium

    Science.gov (United States)

    ... Calcium Print This Topic En español Get Enough Calcium Browse Sections The Basics Overview Foods and Vitamins ... 2 of 4 sections Take Action! Take Action: Calcium Sources Protect your bones – get plenty of calcium ...

  17. Calcium carbonate overdose

    Science.gov (United States)

    Tums overdose; Calcium overdose ... Calcium carbonate can be dangerous in large amounts. ... Some products that contain calcium carbonate are certain: ... and mineral supplements Other products may also contain calcium ...

  18. Fluoride remediation using floating macrophytes

    Directory of Open Access Journals (Sweden)

    Naba Kumar Mondal

    2014-04-01

    Full Text Available Six aquatic macrophytes, such as Pistia stratiotes, Ceratophyllum demersum, Nymphoides indica, Lemna major, Azolla pinnata,and Eichhornia crassipes were considered for remove fluoride from aqueous solution. Five different concentrations (10, 30, 50, and 100 ppm of fluoride solution were taken in 1 L plastic container. Fixed weight (20 g of macrophytes along with 500 ml fluoride solution was taken in each plastic container for 72 hours observation. Results demonstrated all the macrophytes show highest fluoride removal during 24 h to 48 h, but after 72 h their efficiency reduced drastically. The species N. indica showed better removal efficiency than other experimental macrophytes. In general, pigment measurement data indicated higher concentration at 72 h. However, Pistia sp. showed higher concentration of pigmentation at intermediate time interval (48 h. Higher level of dry weight to fresh weight ratio was recorded for L. major and A. pinnata at all concentrations, excepting at 10 ppm. In addition, all macrophytes showed lower RGR at higher concentration. Isotherm study indicated that macrophyte C. demersum is a good fitted with Freundlich and Langmuir isotherm whereas L. major with Langmuir isotherm during 24 hours.

  19. Global affordability of fluoride toothpaste

    Directory of Open Access Journals (Sweden)

    Holmgren Christopher J

    2008-06-01

    Full Text Available Abstract Objective Dental caries remains the most common disease worldwide and the use of fluoride toothpaste is a most effective preventive public health measure to prevent it. Changes in diets following globalization contribute to the development of dental caries in emerging economies. The aim of this paper is to compare the cost and relative affordability of fluoride toothpaste in high-, middle- and low-income countries. The hypothesis is that fluoride toothpaste is not equally affordable in high-, middle- and low-income countries. Methods Data on consumer prices of fluoride toothpastes were obtained from a self-completion questionnaire from 48 countries. The cost of fluoride toothpaste in high-, middle- and low-income countries was compared and related to annual household expenditure as well as to days of work needed to purchase the average annual usage of toothpaste per head. Results The general trend seems to be that the proportion of household expenditure required to purchase the annual dosage of toothpaste increases as the country's per capita household expenditure decreases. While in the UK for the poorest 30% of the population only 0.037 days of household expenditure is needed to purchase the annual average dosage (182.5 g of the lowest cost toothpaste, 10.75 days are needed in Kenya. The proportion of annual household expenditure ranged from 0.02% in the UK to 4% in Zambia to buy the annual average amount of lowest cost toothpaste per head. Conclusion Significant inequalities in the affordability of this essential preventive care product indicate the necessity for action to make it more affordable. Various measures to improve affordability based on experiences from essential pharmaceuticals are proposed.

  20. Alimentary fluoride intake in preschool children

    Directory of Open Access Journals (Sweden)

    Lencova Erika

    2011-10-01

    Full Text Available Abstract Background The knowledge of background alimentary fluoride intake in preschool children is of utmost importance for introducing optimal and safe caries preventive measures for both individuals and communities. The aim of this study was to assess the daily fluoride intake analyzing duplicate samples of food and beverages. An attempt was made to calculate the daily intake of fluoride from food and swallowed toothpaste. Methods Daily alimentary fluoride intake was measured in a group of 36 children with an average age of 4.75 years and an average weight of 20.69 kg at baseline, by means of a double plate method. This was repeated after six months. Parents recorded their child's diet over 24 hours and collected duplicated portions of food and beverages received by children during this period. Pooled samples of food and beverages were weighed and solid food samples were homogenized. Fluoride was quantitatively extracted from solid food samples by a microdiffusion method using hexadecyldisiloxane and perchloric acid. The content of fluoride extracted from solid food samples, as well as fluoride in beverages, was measured potentiometrically by means of a fluoride ion selective electrode. Results Average daily fluoride intake at baseline was 0.389 (SD 0.054 mg per day. Six months later it was 0.378 (SD 0.084 mg per day which represents 0.020 (SD 0.010 and 0.018 (SD 0.008 mg of fluoride respectively calculated per kg bw/day. When adding the values of unwanted fluoride intake from the toothpaste shown in the literature (0.17-1.21 mg per day the estimate of the total daily intake of fluoride amounted to 0.554-1.594 mg/day and recalculated to the child's body weight to 0.027-0.077 mg/kg bw/day. Conclusions In the children studied, observed daily fluoride intake reached the threshold for safe fluoride intake. When adding the potential fluoride intake from swallowed toothpaste, alimentary intake reached the optimum range for daily fluoride intake

  1. Changes in mesophyll element distribution and phytometabolite contents involved in fluoride tolerance of the arid gypsum-tolerant plant species Atractylis serratuloides Sieber ex Cass. (Asteraceae).

    Science.gov (United States)

    Boukhris, Asma; Laffont-Schwob, Isabelle; Rabier, Jacques; Salducci, Marie-Dominique; El Kadri, Lefi; Tonetto, Alain; Tatoni, Thierry; Chaieb, Mohamed

    2015-05-01

    Atractylis serratuloides is an abundant native spiny species that grows in the surroundings of superphosphate factories in Tunisia. This plant species is adapted to arid environments and tolerates a high level of fluoride pollution in soils. The aim of this study was to better understand the physiological mechanisms of fluoride tolerance of this species, comparing the fluoride-contaminated sites of Gabes and Skhira with the reference site of Smara. Results demonstrated the involvement of leaf element and phytometabolite balances in the in situ response of A. serrulatoides to fluoride. Calcium, sulphur and magnesium were differently distributed between the sites of Gabes and Smara in all plant organs. No specific tissue fluorine accumulation in root, stem and leaf, even in the most contaminated site at Gabes, was detected by EDAX mapping. Lower anthocyan and flavonol levels but enhanced nitrogen balance index were found in A. serrulatoides leaves from Gabes compared to the two other sites. A. serratuloides appeared as a fluoride excluder and its tolerance involved calcium interactions with fluoride. Moreover, an occurrence of dark septate endophytes and arbuscular mycorhizal fungi in root systems of A. serratuloides was reported for the first time, and these symbioses were present but low at all sites. We suggest the use of this plant species for fluoride-polluted soil stabilization. PMID:25510616

  2. Bioactivity of Sodium Free Fluoride Containing Glasses and Glass-Ceramics

    Directory of Open Access Journals (Sweden)

    Xiaojing Chen

    2014-07-01

    Full Text Available The bioactivity of a series of fluoride-containing sodium-free calcium and strontium phosphosilicate glasses has been tested in vitro. Glasses with high fluoride content were partially crystallised to apatite and other fluoride-containing phases. The bioactivity study was carried out in Tris and SBF buffers, and apatite formation was monitored by XRD, FTIR and solid state NMR. Ion release in solutions has been measured using ICP-OES and fluoride-ion selective electrode. The results show that glasses with low amounts of fluoride that were initially amorphous degraded rapidly in Tris buffer and formed apatite as early as 3 h after immersion. The apatite was identified as fluorapatite by 19F MAS-NMR after 6 h of immersion. Glass degradation and apatite formation was significantly slower in SBF solution compared to Tris. On immersion of the partially crystallised glasses, the fraction of apatite increased at 3 h compared to the amount of apatite prior to the treatment. Thus, partial crystallisation of the glasses has not affected bioactivity significantly. Fast dissolution of the amorphous phase was also indicated. There was no difference in kinetics between Tris and SBF studies when the glass was partially crystallised to apatite before immersion. Two different mechanisms of apatite formation for amorphous or partially crystallised glasses are discussed.

  3. Enamel fluoride levels after orthodontic band cementation with glass ionomer cement.

    Science.gov (United States)

    Akkaya, S; Uner, O; Alaçam, A; Değim, T

    1996-02-01

    The aim of this investigation was to examine the fluoride uptake by enamel after application of glass ionomer cement for orthodontic band cementation compared with zinc phosphate cement. The study was conducted on 21 children whose mean age was 14 years. All the children were reared in the Middle Anatolian cities where the water fluoride concentration was below the level of 0.50 ppm. The subjects were randomly divided into three groups. The first experimental group, had seven subjects whose teeth were topically fluoridated with 2 per cent NaF solution, before orthodontic band cementation with zinc phosphate cement. The second experimental group also had seven subjects whose orthodontic bands were cemented with glass ionomer cement. The third group, consisted of seven control subjects and no dental procedures were performed in this group. All the participants were followed for 3 months and at the end of this period maxillary first premolars, which were in the ninth developmental stage according to Nolla (1960), were extracted for orthodontic purposes. The enamel fluoride concentrations were determined on the left maxillary first premolars at three successive etch depths by means of a fluor ion electrode, whereas the calcium concentrations were determined with an atomic absorption spectrophotometer. The results of this investigation showed that in both cementation groups enamel fluoride concentrations at three successive etch depths were highly increased compared with the control group. However, the difference between the cementation groups was not statistically significant. PMID:8746180

  4. Fluoride contamination in the lakes region of the Ethiopian rift: origin, mechanism and evolution

    International Nuclear Information System (INIS)

    The closed lake basins occupying the Main Ethiopian Rift are characterised by unique hydrogeological conditions which have resulted in very high contents of fluoride associated with highly concentrated sodium bicarbonate waters. The origin, mechanism and evolution of fluoride contents have been examined successively by studying (i) the reservoirs which provide this element in solution, (ii) the hydrochemical context, and (iii) the hydrological evolution which modifies the concentrations. Groundwaters of the ignimbrites present low values compared to those of the lacustrine sediments which can provide contents 5 to 10 times greater. The non equilibrium initial stage between the alkalinity and the calcium, derived from weathering of volcanic rocks, is responsible for the specific chemical evolution and the very high fluoride values. Furthermore, in the thermal waters, the high temperatures (especially those up to 100 deg. C) and the presence of large amounts of CO2 coming from depth increase significantly the fluoride contents. Finally, the fluoride concentrations can change depending on the interrelation of ancient or present surface waters and groundwaters (mixing) and on the hydrological balance (concentration and dilution processes). (author)

  5. In vitro assessment of an experimental coat applied over fluoride varnishes

    Directory of Open Access Journals (Sweden)

    Alberto Carlos Botazzo Delbem

    2009-08-01

    Full Text Available OBJECTIVE: The time of contact between the product and enamel surface is important in ensuring the efficacy of fluoride varnishes. Thus, some alternatives could avoid fluoride loss to saliva and improve the anticariogenic action of the product. This study evaluated the effect of an experimental coat on the anticariogenic action of fluoride varnishes. MATERIAL AND METHODS: Enamel bovine blocks were selected by evaluating surface microhardness and randomized into five groups (n=24: placebo, DuraphatTM, DuraphatTM with coat, DuofluoridTM and DuofluoridTM with coat. Twelve blocks from each group were used to analyze calcium fluoride (CaF2 formed on enamel after treatment. The other 12 blocks were subjected to pH cycling for 7 days. The varnishes were kept on enamel for 6 h. Next, the percentage change of surface microhardness (%SMHC and mineral loss (ΔZ were calculated. CaF2 retained and fluoride present in the pH-cycled solutions were also measured. RESULTS: The use of the coat did not decrease %SMHC and ΔZ, but all fluoride varnishes had better results when compared to the placebo (ANOVA and Kruskal-Wallis, respectively. The values from CaF2 formed were higher compared to the values of CaF2 retained (non-paired t test, p<0.05. There was a trend to decrease the amount of F in the solutions at the end of pH cycling (Kruskal-Wallis, p<0.05. CONCLUSIONS: Although the experimental coat increased the formation of CaF2 on the enamel surface, it did not significantly improve the anticariogenic action of fluoride varnishes.

  6. The effect of bicarbonate/fluoride dentifrices on human plaque pH.

    Science.gov (United States)

    Blake-Haskins, J C; Gaffar, A; Volpe, A R; Bánóczy, J; Gintner, Z; Dombi, C

    1997-01-01

    The acidogenic response in dental plaque after rinsing with sodium bicarbonate/fluoride dentifrice slurries was studied using three intra-oral models. In the first model, resting plaque pH was monitored in mesiobuccal plaque on upper molars and premolars in six healthy subjects after abstinence from normal oral hygiene for three days. These measurements were followed by a three-minute rinse with 10% sucrose and, following a two-minute interval, a three-minute rinse with a test dentifrice slurry. After the test dentifrice rinse, pH was monitored at regular intervals up to 60 minutes. Flow rate, pH and buffer capacity of stimulated saliva were also determined. Changes in resting pH, plaque pH minima, and maximum pH drop were calculated. A clear elevation in the resting pH was observed after bicarbonate/fluoride dentifrice rinses, and a significant increase was obtained in the pH minima. The smallest pH drop also was found after treatment with the bicarbonate/fluoride dentifrice rinse treatment (p antimony pH electrodes was used to study the effects of rinsing with increasing concentrations of sodium bicarbonate and calcium carbonate solutions, and with a fluoride dentifrice containing sodium bicarbonate. The response to these treatments was found to be rapid, dose-dependent, and was the greatest from the sodium bicarbonate. A third model used 24 subjects to assess the effects of sodium bicarbonate/fluoride dentifrice on plaque pH before and after a glucose challenge. The use of the bicarbonate/fluoride dentifrice resulted in significantly less measurable plaque acid than the fluoride dentifrice treatment. Collectively, these results indicate bicarbonate in dentifrice to be an effective buffering agent for stabilizing the pH and neutralizing plaque acids in dental plaque. PMID:9586535

  7. Fluoride retention in saliva and in dental biofilm after different home-use fluoride treatments

    Directory of Open Access Journals (Sweden)

    Daniela Correia Cavalcante SOUZA

    2014-08-01

    Full Text Available This single-blind, randomized, crossover study aimed at assessing the long-term fluoride concentrations in saliva and in dental biofilm after different home-use fluoride treatments. The study volunteers (n = 38 were residents of an area with fluoridated drinking water. They were administered four treatments, each of which lasted for one week: twice-daily placebo dentifrice, twice-daily fluoride dentifrice, twice-daily fluoride dentifrice and once-daily fluoride mouthrinse, and thrice-daily fluoride dentifrice. At the end of each treatment period, samples of unstimulated saliva and dental biofilm were collected 8 h after the last oral hygiene procedure. Fluoride concentrations in saliva and dental biofilm were analyzed using a specific electrode. The fluoride concentrations in saliva and dental biofilm 8 h after the last use of fluoride products did not differ among treatments. The results of this study suggest that treatments with home-use fluoride products have no long-term effect on fluoride concentrations in saliva and in dental biofilm of residents of an area with a fluoridated water supply.

  8. Calcium paradox and calcium entry blockers

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Slade, A.M.; Nayler, W.G.; Meijler, F.L.

    1984-01-01

    Reperfusion of isolated hearts with calcium-containing solution after a short period of calcium-free perfusion results in irreversible cell damage (calcium paradox). This phenomenon is characterized by an excessive influx of calcium into the cells, the rapid onset of myocardial contracture, exhausti

  9. Computer simulation of superionic fluorides

    CERN Document Server

    Castiglione, M

    2000-01-01

    experimentally gives an indication of the correlations between nearby defects is well-reproduced. The most stringent test of simulation model transferability is presented in the studies of lead tin fluoride, in which significant 'covalent' effects are apparent. Other similarly-structured compounds are also investigated, and the reasons behind the adoption of such an unusual layered structure, and the mobility and site occupation of the anions is quantified. In this thesis the nature of ion mobility in cryolite and lead fluoride based compounds is investigated by computer simulation. The phase transition of cryolite is characterised in terms of rotation of AIF sub 6 octahedra, and the conductive properties are shown to result from diffusion of the sodium ions. The two processes appear to be unrelated. Very good agreement with NMR experimental results is found. The Pb sup 2 sup + ion has a very high polarisability, yet treatment of this property in previous simulations has been problematic. In this thesis a mor...

  10. The role of casein phosphopeptide-amorphous calcium phosphate products in remineralization of incipient enamel lesions and its substantivity

    OpenAIRE

    Abhay Taranath; Deepika Pai; Kalyan Chakravarthy

    2014-01-01

    Objective: Milk derived calcium, phosphate and casein were known to be anti-cariogenic but in the modern era of early interception of caries the agents like casien phosphopeptide-amorphous calcium phosphate (CPP-ACP) derived from milk are known to also repair early lesions. This in vitro study was designed to evaluate the remineralizing potential of CPP-ACP and CPP-amorphous calcium phosphate fluoride (ACPF) on smooth surface carious lesions of the enamel and its substantivity following demin...

  11. Discovery of Interstellar Hydrogen Fluoride

    CERN Document Server

    Neufeld, D A; Schilke, P; Phillips, T G; Neufeld, David A.; Zmuidzinas, Jonas; Schilke, Peter; Phillips, Thomas G.

    1997-01-01

    We report the first detection of interstellar hydrogen fluoride. Using the Long Wavelength Spectrometer (LWS) of the Infrared Space Observatory (ISO), we have detected the 121.6973 micron J = 2 - 1 line of HF in absorption toward the far-infrared continuum source Sagittarius B2. The detection is statistically significant at the 13 sigma level. On the basis of our model for the excitation of HF in Sgr B2, the observed line equivalent width of 1.0 nm implies a hydrogen fluoride abundance of 3E-10 relative to H2. If the elemental abundance of fluorine in Sgr B2 is the same as that in the solar system, then HF accounts for ~ 2% of the total number of fluorine nuclei. We expect hydrogen fluoride to be the dominant reservoir of gas-phase fluorine in Sgr B2, because it is formed rapidly in exothermic reactions of atomic fluorine with either water or molecular hydrogen; thus the measured HF abundance suggests a substantial depletion of fluorine onto dust grains. Similar conclusions regarding depletion have previously...

  12. Daily Fluoride Intake from Iranian Green Tea: Evaluation of Various Flavorings on Fluoride Release

    OpenAIRE

    Afshin Maleki; Hiua Daraei; Elham Mohammadi; Shiva Zandi; Pari Teymouri; Amir Hossien Mahvi; Fardin Gharibi

    2016-01-01

    With increased awareness of the health benefits of the compounds in green tea, especially polyphenols, its consumption is rising. The main purpose of this study is to determine the effect of different additives on the released fluoride into tea liquor and also daily fluoride intake. The concentrations of fluoride, nitrate, sulfate, and chloride were measured in 15 different flavored green teas (Refah-Lahijan). The fluoride and other anion concentrations were measured by ion chromatography met...

  13. Fluoride Retention following the Professional Topical Application of 2% Neutral Sodium Fluoride Foam

    OpenAIRE

    Wenqun Song; Shinji Toda; Eri Komiyama; Karin Komiyama; Yuki Arakawa; Dawei He; Hirohisa Arakawa

    2011-01-01

    The objective of the present research was to determine the appropriate amount of fluoride to use professional topical application and the residual amounts of fluoride in the oral cavity using a 2% neutral sodium fluoride (NaF) foam with a dedicated tray. Using dentition study models, a method for determining the appropriate amount of NaF foam was investigated. In eight adult subjects, the appropriate amount of NaF foam, the concentration of fluoride in the saliva following professional topica...

  14. Comparison of salivary fluoride levels following use of dentifrices containing different concentrations of fluoride

    OpenAIRE

    Nagpal D; Damle S

    2007-01-01

    Many industrialized countries have reported a decline in caries prevalence over the past few decades. These reductions have been related to the regular use of fluoride dentifrices. Fluoride dentifrices are the most cost-effective and efficient means of caries prevention. However, there have been concerns regarding the risk of fluorosis in children due to the ingestion of dentifrices. This has led to the use of dentifrices with low concentration of fluoride. Salivary fluoride levels after toot...

  15. Ruthenium olefin metathesis catalysts containing fluoride

    OpenAIRE

    Guidone, Stefano; Songis, Olivier; Falivene, Laura; Nahra, Fady; Slawin, Alexandra Martha Zoya; Jacobsen, Heiko; Cavallo, Luigi; Cazin, Catherine S. J.

    2015-01-01

    The authors gratefully acknowledge the EC through the 7th framework program (grant CP-FP 211468-2 EUMET), the Royal Society (University Research Fellowship to CSJC) for financial support. The reaction of the ruthenium complex cis-Caz-1 with silver fluoride affords the first example of an active olefin metathesis pre-catalyst containing fluoride ligands. The cis geometry of the precursor complex is key to the successful fluoride exchange reaction. Computational studies highlight the stabili...

  16. Contamination of fluoride in groundwater and its effect on human health: a case study in hard rock aquifers of Siddipet, Telangana State, India

    Science.gov (United States)

    Narsimha, A.; Sudarshan, V.

    2016-06-01

    Hydrogeochemical investigation has been carried out in the granitic terrain of Siddipet area, Medak district, Telangana State, India with an aim to understand the distribution of fluoride in the groundwater and to understand the relationship of fluoride with other major ions, and also to identify the high fluoride-bearing groundwater zones. 104 groundwater samples were analyzed in the study area for fluoride and other major ions like calcium, magnesium, chloride, carbonate, bicarbonate, sodium, potassium, sulfate, and nitrate in addition to pH and electrical conductivity. The studies revealed that the concentration of fluoride in groundwater is ranging from 0.2 to 2.2 mg L-1 with a mean of 1.1 mg L-1. Nearly 22 % of groundwater has more than the permissible limit of fluoride (1.5 mg L-1), which is responsible for the endemic dental fluorosis in the area concerned. Geochemical classification of groundwater shows that Na-HCO3, Ca-Cl, and Ca-HCO3-Na are the dominant hydrochemical facies. Gibbs diagram shows rock-water interaction dominance and evaporation dominance, which are responsible for the change in the quality of water in the hard rock aquifer of the study area. The groundwater in villages and its environs are affected by fluoride contamination, and consequently majority of the population living in these villages suffer from dental fluorosis. Hence, they are advised to consume drinking water which has less than 1.5 mg L-1 fluoride to avoid further fluorosis risks.

  17. Calcium flouride (CaF2) from oyster shell as a raw material for thermoluminescence dosimeter

    International Nuclear Information System (INIS)

    This study aims to develop a thermoluminescence dosimeter raw material made of calcium fluoride from locally available seashells that is suitable for personal radiation monitoring. Oyster shells were collected and grounded as powder samples and analyzed for calcium fluoride (CaF2) content using XRF and XRD testing. Samples include pure CaF2, pure oyster shell, and oyster shells treated with acid. Based from the XRF results, natural oyster shell (w/ and w/o HNO3) had high percentage of calcium about 49.64% and 47.45%, next to the pure calcium fluoride of 51.08%. X-ray diffractrogram shows that oyster sample had the nearest desired structure of CaF2 compared with two seashells relative to the pure CaF2 as standard materials. Results show that all of the natural oyster samples displayed TL emission glow curves at the temperature range 200-300oC. It was also found that pure oyster sample has better TL response as compared to the treated ones. The researchers concluded that the calcium fluoride from oyster shells (without acid and heated) is a potentially good low-cost TLD raw material and may be used as an alternative for the much more expensive LiF dosimeters. (Authors)

  18. Estuarine response of fluoride - Investigations in Azhikode Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Balachandran, K.K.; Joseph, T.; Sankaranarayanan, V.N.

    Concentrations of fluoride in Azhikode estuarine region (Kerala, India) were measured as a function of chlorinity during the different seasons. The type of behaviour indicated that fluoride was regulated by sea water incursion alone. Fluoride...

  19. Fluoride bioavailability in saliva and plaque

    OpenAIRE

    Naumova Ella A; Kuehnl Phillip; Hertenstein Philipp; Markovic Ljubisa; Jordan Rainer A; Gaengler Peter; Arnold Wolfgang H

    2012-01-01

    Abstract Background Different fluoride formulations may have different effects on caries prevention. It was the aim of this clinical study to assess the fluoride content, provided by NaF compared to amine fluoride, in saliva and plaque. Methods Eight trained volunteers brushed their teeth in the morning for 3 minutes with either NaF or amine fluoride, and saliva and 3-day-plaque-regrowth was collected at 5 time intervals during 6 hours after tooth brushing. The amount of collected saliva and ...

  20. Effect of carbamide peroxide-based bleaching agents containing fluoride or calcium on tensile strength of human enamel Efeito de agentes clareadores à base de peróxido de carbamida contendo fluoreto e cálcio na resistência à tração do esmalte humano

    Directory of Open Access Journals (Sweden)

    Marcelo Giannini

    2006-04-01

    Full Text Available OBJECTIVE: The aim of this study was to evaluate the effects of carbamide peroxide-based bleaching agents (CPG containing fluoride (CF or calcium (CCa on the ultimate tensile strength of enamel (UTS. METHOD: A "cube-like" resin composite structure was built-up on the occlusal surface of twenty-two sound third molars to facilitate specimen preparation for the micro-tensile test. The restored teeth were serially sectioned in buccal-lingual direction in slices with approximate 0.7 mm thickness. Each slice was trimmed with a fine diamond bur to reduce the buccal, internal slope enamel of the cusps to a dumb-bell shape with a cross-sectional area at the "neck" of less than 0.5 mm². The samples were randomly divided into 12 groups (n=11. The control groups were not submitted to the bleaching regimen. Specimens were treated with 10% CPG gel or with 10% CPG formulations containing CF (0.2% and 0.5% or CCa (0.05% and 0.2%. Bleached groups received the application of the 10% CPGs for 6 hours/day at 37º C, during 14 consecutive days and were stored in artificial saliva (AS or 100% relative humidity (RH among each application. After bleaching, specimens were tested with the microtensile method at 0.5 mm/min. Data were analyzed by two-way ANOVA and Tukey test (5%. RESULTS: No significant difference was observed between groups stored in AS or RH. Specimens treated with CF or CCa presented similar UTS as unbleached control groups. CONCLUSION: Either 10% CPG formulations containing CF or CCa can preserve the UTS after bleaching regimen.OBJETIVO: O propósito deste estudo foi avaliar os efeitos de agents clareadores à base de peróxido de carbamida (CPG contendo fluoreto (CF e cálcio (CCa na resistência à tração do esmalte (UTS. MÉTODO: Um bloco de resina composta foi confeccionada na superfície oclusal de vinte e dois terceiros molars hígidos para facilitar a preparação dos espécimes para o teste de micro-tração. Os dentes restaurados foram

  1. Gramicidin D enhances the antibacterial activity of fluoride

    OpenAIRE

    Nelson1, James W.; ZHOU, ZHIYUAN; Breaker, Ronald R.

    2014-01-01

    Fluoride is a toxic anion found in many natural environments. One of the major bacterial defenses against fluoride is the cell envelope, which limits passage of the membrane-impermeant fluoride anion. Accordingly, compounds that enhance the permeability of bacterial membranes to fluoride should also enhance fluoride toxicity. In this study, we demonstrate that the pore-forming antibiotic gramicidin D increases fluoride uptake in B. subtilis and that the antibacterial activity of this compound...

  2. Analysis of 1-Minute Potentially Available Fluoride from Dentifrice

    OpenAIRE

    Carey, Clifton M.; Holahan, Erin C; Schmuck, Burton D

    2014-01-01

    Previous reports found that some fluoride-containing dentifrices do not release effective concentrations of fluoride during brushing. Failure to release fluoride can be due to dentifrice matrix components that interfere with the solubilization of the fluoride salts during brushing. A new generation of dentifrices has the capability to precipitate beneficial fluoride salts during tooth brushing. Therefore, a method that assesses the potentially available fluoride during the 1-minute brushing i...

  3. Fluoride in cerebrospinal fluid of patients with fluorosis.

    OpenAIRE

    Hu, Y H; Wu, S S

    1988-01-01

    The CSF fluoride level of individuals drinking water with normal fluoride content and of patients with endemic fluorosis were studied. For the purpose of studying the relationship between the dynamic equilibrium of the CSF fluoride and other body fluids, urine and blood fluoride were examined simultaneously. Fluoride was revealed in every CSF sample of the control group and its mean value was lower than that of the blood. The CSF fluoride concentration of patients with fluorosis was slightly ...

  4. Calcium and bones (image)

    Science.gov (United States)

    Calcium is one of the most important minerals for the growth, maintenance, and reproduction of the human ... body, are continually being re-formed and incorporate calcium into their structure. Calcium is essential for the ...

  5. Coronary Calcium Scan

    Science.gov (United States)

    ... the NHLBI on Twitter. What Is a Coronary Calcium Scan? A coronary calcium scan is a test ... you have calcifications in your coronary arteries. Coronary Calcium Scan Figure A shows the position of the ...

  6. Calcium hydroxide poisoning

    Science.gov (United States)

    Hydrate - calcium; Lime milk; Slaked lime ... Calcium hydroxide ... These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement ...

  7. Calcium source (image)

    Science.gov (United States)

    Getting enough calcium to keep bones from thinning throughout a person's life may be made more difficult if that person has ... as a tendency toward kidney stones, for avoiding calcium-rich food sources. Calcium deficiency also effects the ...

  8. Calcium in diet

    Science.gov (United States)

    Diet - calcium ... Calcium is one of the most important minerals for the human body. It helps form and maintain healthy teeth and bones. A proper level of calcium in the body over a lifetime can help ...

  9. Calcium Pyrophosphate Deposition (CPPD)

    Science.gov (United States)

    ... Patient / Caregiver Diseases & Conditions Calcium Pyrophosphate Deposition (CPPD) Calcium Pyrophosphate Deposition (CPPD) Fast Facts The risk of ... young people, too. Proper diagnosis depends on detecting calcium pyrophosphate crystals in the fluid of an affected ...

  10. Stripping voltammetry analysis of metal fluorides for microimpurity content

    International Nuclear Information System (INIS)

    A diagram of sequential multielement stripping voltammetric analysis of a series of luminophors and optical materials-fluorides of sodium, calcium, barium, magnesium, strontium (macrosamples 0.01-0.1 g) and film structures on their bases (macrosamples 10-3-10-5 g) for content of microquantities of ''colouring'' and heavy elements (iron, cobalt, nickel, copper, antimony, bismuth, lead, cadmium, zinc) has been developed. Analysis includes sequential determination of all elements under optimal conditions to record analytical signals of each or a group of elements, which are established by substitution of a background electrolyte, electrode, electrolysis potential. Analyses of the objects given for microimpurity content of the above mentioned metals are carried out according to the diagram suggested

  11. Growth of hollow nickel fluoride whiskers

    International Nuclear Information System (INIS)

    Hollow nickel fluoride whiskers have been obtained by condensation from the vapor phase onto a platinum substrate in a flow of hydrogen fluoride. Crystals up to 5 mm in length have a square cross section with a 300 ± 30-μm side. The wall thickness is 85 ± 20 μm.

  12. Reaction of uranyl fluoride with sodium fluoride in aqueous solution

    International Nuclear Information System (INIS)

    The formation of complex uranyl fluorides in the system NaF-VO2F2-H2O has been studied and some of their properties have been investigated. It has been shown that, depending on the mole ratio of the components (from 0.5:1 to 5:1), fluorouranylates Na(VO2)2F5x4H2O, Na3(VO2)2F7x2H2O, and Na3VO2F5 are formed. Infrared spectra have demonstrated that H2O molecules are not coordinated by the central atom. Dehydration of hydrated complexes proceeds in two stages. Non-aqueous Na3(VO2)2F5 melts at 540 deg C. The synthesized complexes are studied by X-ray structural analysis. The compositions of complex uranyl fluorides formed in the systems MF-VO2F2-H2O (M=Na,K,Rb,Cs,NH4, CN3H6) have been compared

  13. Determination of fluoride content in drinking water and tea infusions using fluoride ion selective electrode

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2007-01-01

    Full Text Available Potentiometric analysis of fluoride content (as F- ion in solutions by using fluoride ion-selective electrode is simple, reliable and cheap. Very small concentrations of fluoride-ions (to 10-6 mol/dm3 can be determined by fluoride selective electrode, with regulation of ion strength of a solution and control of concentration of hydroxide ions and interfering ions of metals. The influence of pH and complexing ions of metals can be successfully regulated by the TISAB solution and by preserving pH value in the range from 5.00 to 7.00. The content of fluorides in the samples can be determined by the method of direct potentiometer, and in the case of very low concentration by standard addition method. In this paper it was analyzed the determination of fluoride ions concentration in bottled mineral waters and water from Belgrade plumbing in two Belgrade districts (Palilula and Novi Beograd and in tea, by using the fluoride selective electrode. It was determined that the content of fluoride ions in bottled mineral water significantly differs from values given on declaration, and that content of fluoride ions varies over a period of time. The content of fluoride ions in water from plumbing in two Belgrade districts at the time of analysis was significantly increased and exceeded values given in Regulation for drinking water quality. The received results from the analysis of fluorides in teas show that fluorides exist in teas in different concentrations. There are also differences between the same kinds of tea, which is noted with mint (Mentha piperitae folium, as a consequence of differences between soils where it was planted. As taking of fluorides, according to World Health Organisation recommendation (WHO, is limited in the range from 2 to 4 mg per day, it is necessary to give the content of fluorides on all products that are used in human consumption.

  14. Niobium electrodeposition from molten fluorides

    International Nuclear Information System (INIS)

    Niobium electrodeposition from molten alkali fluorides has been studied aiming the application of this technic to the processes of electrorefining and galvanotechnic of this metal. The effects of current density, temperature, niobium concentration in the bath, electrolysis time, substrate nature, ratio between anodic and cathodic areas, electrodes separation and the purity of anodes were investigated in relation to the cathodic current efficiency, electrorefining, electroplating and properties of the deposit and the electrolytic solution. The work also gives the results of the conctruction and operation of a pilot plant for refractory metals electrodeposition and shows the electrorefining and electroplating compared to those obtained at the laboratory scale. (author)

  15. Manufacture and properties of fluoride cement

    Science.gov (United States)

    Malata-Chirwa, Charles David

    This research work aimed at characterising composition, hydration and physical properties of fluoride cement, by studying samples of the cement obtained from Malawi, and comparing them to ordinary Portland cement. By confirming the suitable characteristics of fluoride cement through this work, the results of the research work provide a good basis for the wider adoption of fluoride cement as an alternative to ordinary Portland cement, especially in developing economies. Numerous accounts have been cited regarding the production and use of fluoride cement. Since there have not been conclusive agreement as to its properties, this study was limited to the theories of successful incorporation of fluoride compounds in the manufacture of fluoride cement. Hence, the properties and characteristics reported in this study relate to the cement currently manufactured in Malawi, and, on a comparative basis only, to that manufactured in other parts of the world. Samples of the fluoride cement used in the study were obtained by synthetic manufacture of the cement using common raw materials for the manufacture of fluoride cement that is limestone, silica sand, and fluorspar. These samples were subjected to several comparative tests used to characterise cements including examination under x-ray diffractometer, scanning electron microscopy and tests for setting time and compressive strength. Under similar laboratory conditions, it was possible to prove that fluoride cement hardens more rapidly than ordinary Portland cement. Also observed during the experimental work is that fluoride cement develops higher compressive strengths than ordinary Portland cement. The hardening and setting times are significantly different between the two cements. Also the nature of the hydration products, that is the microstructural development is significantly different in the two cements. The differences brought about between the two cements are because of the presence of fluorine during the clinkering

  16. Determination of Fluoride in Different Toothpaste Formulations

    International Nuclear Information System (INIS)

    Fluoride ion selective electrode was used to determine fluoride ion concentrations in seven brands of toothpaste. These were the only available formulations found in Kenya. The brands were classified into three groups-fluoridated, non fluoridated or not indicated. However, there was no independent indication of their quantitative composition. The analysed brands had fluoride content between 0.0033% and 0.096%. These values compared favourably with those obtained elsewhere. The calculated lowest limit of detection (LLD) was 0.01 ppmF- . The mean calibration curve gave a slope of of -50.0mV. which was not significantly different from the theoretical value of 5.88mV at 23 degrees celsius at 95% confidence level

  17. Substoichiometric precipitation of fluoride with lanthanum

    International Nuclear Information System (INIS)

    The substoichiometric precipitation of fluoride with lanthanum was studied by using 18F and 140La tracers. It was found that fluoride could be precipitated substoichiometrically with lanthanum and the reaction ratio between fluoride and lanthanum was 3:1. The pH range at which fluoride can be separated subsotichiometrically with lanthanum is between 2 and 8. Barium and indium interfere in the precipitation of fluoride, but sodium, copper and manganese do not. Fluorosilicate can also be precipitated subsotichiometrically by using lanthanum as a precipitant and the reaction ratio between fluorosilicate and lanthanum was 1:2. This separation was applied for the determination of oxygen in silicon crystals. The concentration of oxygen measured in some silicon crystals was between 5 and 27 ppm and was in good agreement with those by non-destructive method and infrared spectrophotometry. (author)

  18. Recent advancements in fluoride: A systematic review

    Science.gov (United States)

    Bansal, Ankita; Ingle, Navin Anand; Kaur, Navpreet; Ingle, Ekta

    2015-01-01

    To review advancements of fluoride in dentistry, a search of 21 electronic databases and World Wide Web was conducted. Relevant journals were hand searched and further information was requested from authors. Inclusion criteria were a predefined hierarchy of evidence and objectives. Study validity was assessed with checklists. Two reviewers independently screened sources, extracted data, and assessed validity. Fluoride has become an important tool in preventive dentistry. Current research is focused on the development of strategies to improve fluoride efficacy. Fluoride therapy in the form of varnish, gel, mouth rinse, or toothpaste has been used extensively as a caries-preventive intervention for over three decades. The purpose of this review is to inform the reader about new research related to the use of fluoride for the prevention of dental caries. PMID:26539383

  19. Method of treating fluoride contaminated wastes

    Energy Technology Data Exchange (ETDEWEB)

    Davis, P.K.; Kakaria, V.K.

    1988-04-05

    A method for treating spent aluminum smelting potliner material containing fluoride contaminants is described which comprises: adding silica to the material to form a mixture thereof; elevating the temperature of the mixture within the range of 1,000/sup 0/ to 1,700/sup 0/C. to form a slag; providing sufficient silica in the mixture and forming the slag in the presence of sufficient water for pyrohydrolysis conditions resulting in the volatilization of substantially all of the fluoride contaminants mostly in the form of hydrogen fluoride; and cooling the slag remaining after volatilizatiion of substantially all of the fluoride contaminants to produce an insoluble silicate glass-residue containing any remaining portion of the fluoride contaminants in an immobile state.

  20. Fluoride Importance in Controlling Caries and Fluorosis

    Directory of Open Access Journals (Sweden)

    Gaurav Solanki

    2012-04-01

    Full Text Available The use of fluorides for oral health has always involved a balance between the protective benefit against dental caries and the risk of developing fluorosis. The link between fluoride and dental health was established to determining the causes of dental fluorosis or enamel mottling. Fluorosis in Indian children was highly prevalent in the early 1990s. Policy were introduced to control fluoride exposure and to reduce the prevalence of fluorosis. The study aimed of describing the prevalence, severity and risk factors for fluorosis, and to describe the trend of fluorosis among Indian children. The study also aimed of exploring the effect of the change in fluoride exposure on dental fluorosis and caries. Establishing an appropriate use of fluoride toothpaste could be successful in reducing fluorosis without a significant increase in caries experience.

  1. Dental fluorosis and skeletal fluoride content as biomarkers of excess fluoride exposure in marsupials.

    Science.gov (United States)

    Death, Clare; Coulson, Graeme; Kierdorf, Uwe; Kierdorf, Horst; Morris, William K; Hufschmid, Jasmin

    2015-11-15

    Particulate and gaseous fluoride emissions contaminate vegetation near fluoride-emitting industries, potentially impacting herbivorous wildlife in neighboring areas. Dental fluorosis has been associated with consumption of fluoride-contaminated foliage by juvenile livestock and wildlife in Europe and North America. For the first time, we explored the epidemiology and comparative pathology of dental fluorosis in Australian marsupials residing near an aluminium smelter. Six species (Macropus giganteus, Macropus rufogriseus, Wallabia bicolor, Phascolarctos cinereus, Trichosurus vulpecula, Pseudocheirus peregrinus) demonstrated significantly higher bone fluoride levels in the high (n=161 individuals), compared to the low (n=67 individuals), fluoride areas (p<0.001). Necropsy examinations of all six species from the high-fluoride area near the smelter revealed dental lesions considered characteristic of dental fluorosis in eutherian mammals. Within the high-fluoride area, 67% of individuals across the six species showed dental enamel lesions, compared to 3% in the low-fluoride areas. Molars that erupted before weaning were significantly less likely to display pathological lesions than those developing later, and molars in the posterior portion of the dental arcade were more severely fluorotic than anterior molars in all six species. The severity of dental lesions was positively associated with increasing bone fluoride levels in all species, revealing a potential biomarker of excess fluoride exposure. PMID:26188404

  2. In vitro study of demineralization resistance and fluoride retention in dental enamel irradiated with Er,Cr: YSGG laser

    International Nuclear Information System (INIS)

    This study aimed to establish irradiation conditions of Er,Cr:YSGG laser (λ of 2.79 μm) which could propitiate changes on human dental enamel and increase its resistance to demineralization, when associated or not with topical application of acidulated phosphate fluoride (APF). Fluences of 2,8 J/cm2, 5,6 J/cm2 e 8,5 J/cm2 were selected; they were associated or not with previous application of a photo absorber (coal paste) and then APF was applied or not after laser irradiation. In a first step, the morphological findings, the surface temperatures, and the pupal temperatures were evaluated during laser irradiation. After that, the treated samples were submitted to a a ten-day pH-cycling model. After producing the incipient white-spots lesions, the following aspects were evaluated: the mineral loss, the loosely bound fluoride and the firmly bound fluoride. All the demineralizing and remineralizing pH-cycling solutions were evaluated with respect to their calcium (Ca), inorganic phosphorous (Pi) and fluoride (F-) concentrations. The data had their normality and homogeneity distribution statistically evaluated, and it was chosen an appropriated statistical test for each performed analysis according to the obtained results, considering 5% significant level. The fluences selected for this study created ablated surfaces; the fluences of 5.6 J/cm2 and 8.5 J/cm2 promoted increments in surface temperature above 110 deg C. The intrapupal temperature changes revealed that laser irradiation did not increase the pulpal temperatures above the critical threshold for induction of pulpitis. The coal paste did not promote any changes on surface morphology or in the intrapulpal temperature changes; however, this paste increased the surface temperatures during laser irradiation. Only laser irradiation at 8.5 J/cm2 was able to decrease the mineral loss when compared to the no-treatment group; although the association of coal paste + laser at 2.8 J/cm2 + APF application presented the

  3. Co-substitution of carbonate and fluoride in hydroxyapatite: Effect on substitution type and content

    Science.gov (United States)

    Zhu, Qing-Xia; Li, Ya-Ming; Han, Dan

    2015-04-01

    The nanosized hydroxyapatite substituted by fluoride and carbonate ions (CFHA) had been synthesized by aqueous precipitation method. CFHA had been considered as potential bone graft material for orthopedic and dental applications. The objective of this study was to determine the effects of simultaneously incorporated CO{3/2-} and F- on the substitution type and content. The morphologies of CFHAs were observed by TEM. The carbonate substitution type and content were characterized by FTIR. The fluoride contents were determined by F-selective electrode. The phase compositions and crystallinity of the samples were investigated by XRD. The fluoride and carbonate contents of CFHA increase with the dopant concentrations nonlinearly. The carbonate substitution has much more obvious effect on morphology compared with the fluoride substitution. The co-existence of CO{3/2-} and F- ions can influence the corresponding substitution fraction. The isomorphic substitution of sodium for calcium in the substitution process of CO{3/2-} can improve crystal degree and favor the B-type substitutions. Due to the closeness of the ion radii and equivalent substitution of F- and OH-, F- will occupy the OH- sites of HA crystals more easily, compelling most of the CO{3/2-} to be located in the B sites.

  4. Hydrogeochemistry and statistical analysis applied to understand fluoride provenance in the Guarani Aquifer System, Southern Brazil.

    Science.gov (United States)

    Marimon, Maria Paula C; Roisenberg, Ari; Suhogusoff, Alexandra V; Viero, Antonio Pedro

    2013-06-01

    High fluoride concentrations (up to 11 mg/L) have been reported in the groundwater of the Guarani Aquifer System (Santa Maria Formation) in the central region of the state of Rio Grande do Sul, Southern Brazil. In this area, dental fluorosis is an endemic disease. This paper presents the geochemical data and the combination of statistical analysis (Principal components and cluster analyses) and geochemical modeling to achieve the hydrogeochemistry of the groundwater and discusses the possible fluoride origin. The groundwater from the Santa Maria Formation is comprised of four different geochemical groups. The first group corresponds to a sodium chloride groundwater which evolves to sodium bicarbonate, the second one, both containing fluoride anomalies. The third group is represented by calcium bicarbonate groundwater, and in the fourth, magnesium is the distinctive parameter. The statistical and geochemical analyses supported by isotopic measurements indicated that groundwater may have originated from mixtures of deeper aquifers and the fluoride concentrations could be derived from rock/water interactions (e.g., desorption from clay minerals). PMID:23149723

  5. Arsenic and fluoride removal from groundwater by electrocoagulation using a continuous filter-press reactor.

    Science.gov (United States)

    Guzmán, Athziri; Nava, José L; Coreño, Oscar; Rodríguez, Israel; Gutiérrez, Silvia

    2016-02-01

    We investigated simultaneous arsenic and fluoride removal from ground water by electrocoagulation (EC) using aluminum as the sacrificial anode in a continuous filter-press reactor. The groundwater was collected at a depth of 320 m in the Bajío region in Guanajuato Mexico (arsenic 43 µg L(-1), fluoride 2.5 mg L(-1), sulfate 89.6 mg L(-1), phosphate 1.8 mg L(-1), hydrated silica 112.4 mg L(-1), hardness 9.8 mg L(-1), alkalinity 31.3 mg L(-1), pH 7.6 and conductivity 993 µS cm(-1)). EC was performed after arsenite was oxidized to arsenate by addition of 1 mg L(-1) hypochlorite. The EC tests revealed that at current densities of 4, 5 and 6 mA cm(-2) and flow velocities of 0.91 and 1.82 cm s(-1), arsenate was abated and residual fluoride concentration satisfies the WHO standard (CF silicates of calcium and magnesium. Arsenate removal by EC involves adsorption on aluminum flocs, while fluoride replaces a hydroxyl group from aluminum aggregates. The best EC was obtained at 4 mA cm(-2) and 1.82 cm s(-1) with electrolytic energy consumption of 0.34 KWh m(-3). PMID:26583293

  6. 21 CFR 175.270 - Poly(vinyl fluoride) resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Poly(vinyl fluoride) resins. 175.270 Section 175... Substances for Use as Components of Coatings § 175.270 Poly(vinyl fluoride) resins. Poly(vinyl fluoride... the purpose of this section, poly(vinyl fluoride) resins consist of basic resins produced by...

  7. Fluoride Programs in the School Setting: Preventive Dental Health.

    Science.gov (United States)

    Rebich, Theodore, Jr.; And Others

    1982-01-01

    Two types of school-based programs that increase students' use of fluoride for preventive dental health are described. In fluoride mouthrinse programs, teachers give their students a fluoride solution once a week in a paper cup. In areas where the level of fluoride in the water supply is insufficient, the flouride tablet program is used. (JN)

  8. Calcium and Vitamin D

    Science.gov (United States)

    ... Home › Patients › Treatment › Calcium/Vitamin D Calcium/Vitamin D Getting enough calcium and vitamin D is essential ... counter medications and calcium supplements. What is Vitamin D and What Does it Do? Vitamin D plays ...

  9. Evaluation of toxic action of fluorides on agricultural plants

    Directory of Open Access Journals (Sweden)

    V. N. Grishko

    2007-03-01

    Full Text Available The toxicity of potassium fluoride, sodium fluoride and ammonium fluoride for pea, maize, oat and onion was studied. It was found that the level of the toxic influence had grown with increase of fluoride concentration in the media of growth (from 5 to 100 mg of F–/l. By increase of the toxic influence the agricultural crops are disposed in the following row: oat < onion < maize < pea. Ammonium fluoride demonstrates lesser toxicity, than potassium and sodium fluorides. Under low concentrations of fluoride compounds (5 and 10 mg of F–/l stimulation of roots growth is noted only for the oat.

  10. Fluoride

    Science.gov (United States)

    ... is sometimes prescribed for other uses; ask your doctor or pharmacist for more information. ... on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. ...

  11. Importance of Calcium

    OpenAIRE

    TANDOĞAN, Berivan; ULUSU, N. Nuray

    2005-01-01

    Calcium is the most abundant mineral in the body. Calcium regulates many cellular processes and has important structural roles in living organisms. Skeletal muscle structure and function, polymerisation of fibrin and the conduction of impulses in the nervous system are regulated by calcium. Calcium is an important intracellular messenger in protozoa, plants, and animals. Calcium-transporting systems which are located in the plasma membrane and in the organelles, regulate the ionic concentrati...

  12. New Insight on the Response of Bacteria to Fluoride

    OpenAIRE

    Breaker, R R

    2012-01-01

    Fluoride has been used for decades to prevent caries and it is well established that this anion can inhibit the growth of bacteria. However, the precise effects that fluoride has on bacteria and the mechanisms that bacteria use to overcome fluoride toxicity have largely remained unexplored. Recently, my laboratory reported the discovery of biological systems that bacteria use to sense fluoride and reduce fluoride toxicity. These sensors and their associated genes are very widespread in biolog...

  13. Current Concept on the Anticaries Fluoride Mechanism of the Action

    OpenAIRE

    Rošin-Grget, K.; Linčir, I.

    2001-01-01

    The paper discusses a possible new concept of the role of fluoride and its mechanism of action in caries prevention. In the past fluoride inhibition of caries was ascribed to reduced solubility due to incorporation of fluoride (F–) into the enamel minerals (firmly bound fluoride or fluorapatite). Based on the new findings, it appears that fluoride, either released into or present in the fluid phase bathing the hard tissue, is more important for the reduction of caries developme...

  14. Topical fluoride as a cause of dental fluorosis in children

    OpenAIRE

    Wong, MCM; Lo, ECM; Glenny, AM; Tsang, BWK; Worthington, HV; Marinho, VCC

    2009-01-01

    BACKGROUND: For many years, topical use of fluorides has gained greater popularity than systemic use of fluorides. A possible adverse effect associated with the use of topical fluoride is the development of dental fluorosis due to the ingestion of excessive fluoride by young children with developing teeth. OBJECTIVES: To describe the relationship between the use of topical fluorides in young children and the risk of developing dental fluorosis. SEARCH STRATEGY: Electronic search of the Cochra...

  15. Technology of obtaining of cryolite and aluminium fluoride from alumina- and fluoride containing wastes of aluminium production

    International Nuclear Information System (INIS)

    This article is devoted to technology of obtaining of cryolite and aluminium fluoride from alumina- and fluoride containing wastes of aluminium production. Thus, the investigations on elaboration of technology of obtaining of cryolite and aluminium fluoride from alumina- and fluoride containing wastes of aluminium production by means of sulfuric acid decomposition method are carried out. The optimal parameters of technological processes are found. The physicochemical analysis of fluoride containing wastes is conducted. The flowsheet of obtaining of cryolite, aluminium fluoride and alumina from alumina- and fluoride containing wastes is presented.

  16. The Adsorption of Hydrogen Fluoride and Fluoride Ion on a Water Treatment Sludge

    OpenAIRE

    Oh, Taek-Keun; Saeki, Kazutoshi

    2009-01-01

    The hydrogen fluoride (HF) and fluoride ion (F^-) adsorption potentials of a water treatment sludge were investigated in a batch mode as a function of pH, contact time, initial fluoride concentrations, and other co-existing anions. The maximum removal of total fluoride was apparently observed at pH 5.1, whereas HF or F^- adsorptions showed nearly 100% in pH range from 2.2 to 4.3. The HF or F^- adsorption by the water treatment sludge has occurred rapidly during the initial 5.60 min and therea...

  17. Determination of fluoride content in drinking water and tea infusions using fluoride ion selective electrode

    OpenAIRE

    Rajković Miloš B.; Novaković Ivana D.

    2007-01-01

    Potentiometric analysis of fluoride content (as F- ion) in solutions by using fluoride ion-selective electrode is simple, reliable and cheap. Very small concentrations of fluoride-ions (to 10-6 mol/dm3) can be determined by fluoride selective electrode, with regulation of ion strength of a solution and control of concentration of hydroxide ions and interfering ions of metals. The influence of pH and complexing ions of metals can be successfully regulated by the TISAB solution and by preservin...

  18. Determination of trace contaminants of Cu, Pb, Cd and Zn in fluorides of alkaline metals by inversion voltammetry method

    International Nuclear Information System (INIS)

    The method of determination of n·10-5-n·10-6% trace contaminants of copper, lead, cadmium and zink by means of inversion voltammetry method in fluorides of calcium and lithium is elaborated. Researches are conducted with application of mercury-graphite electrodes on polarographic analyzer and oscillograph polarography. The influence of conditions of electrochemical concentration on characteristics of anode peaks of copper, lead, cadmium and zinc is studied.

  19. Study of fluoride corrosion of nickel alloys

    Science.gov (United States)

    Gunther, W. H.; Steindler, M. J.

    1969-01-01

    Report contains the results of an investigation of the corrosion resistance of nickel and nickel alloys exposed to fluorine, uranium hexafluoride, and volatile fission product fluorides at high temperatures. Survey of the unclassified literature on the subject is included.

  20. Recent advancements in fluoride: A systematic review

    OpenAIRE

    Bansal, Ankita; Ingle, Navin Anand; Kaur, Navpreet; Ingle, Ekta

    2015-01-01

    To review advancements of fluoride in dentistry, a search of 21 electronic databases and World Wide Web was conducted. Relevant journals were hand searched and further information was requested from authors. Inclusion criteria were a predefined hierarchy of evidence and objectives. Study validity was assessed with checklists. Two reviewers independently screened sources, extracted data, and assessed validity. Fluoride has become an important tool in preventive dentistry. Current research is f...

  1. Fluoride removal from water by nano filtration

    International Nuclear Information System (INIS)

    As any oligo element, fluoride is necessary and beneficial for human health to low concentrations, but an excess amount of fluoride ions in drinking water has been known to cause undesirable effects, especially tooth and bones fluoro sis. The maximum acceptable concentration of fluoride in drinking water was fixed by the World Health Organization according to the climate in the range of 1 mg.L-1 to 1,2 mg.L-1. Many methods have been used to remove fluoride from water such as precipitation, adsorption, electrocoagulation and membrane processes. Technologies using membrane processes are being used in many applications, particularly for brackish water desalination. Nano filtration seems to be the best process for a good selective defluorination of fluorinated waters. The main objective of this work was to investigate the retention of fluoride anions by nano filtration. The first part of this study deals with the characterisation of the NF HL2514TF membrane. The influence of various experimental parameters such as initial fluoride content, feed pressure, permeate flux, ionic strength, type of cation associated to fluoride and pH were studied in the second part. Results show that the retention order for the salts tested was TR(Na2SO4) > TR(CaCl2) > TR(NaCl), showing a retention sequence inversely proportional to the salt diffusion coefficients in water. It was also shown that charge effects could not be neglected, and a titration experiments confirmed that the NF membrane carry a surplus of negatively charged groups. Fluoride retention exceeds 60 pour cent, and increases with increasing concentration, where the rejection mechanism is related to the dielectric effects. Speigler-Kedem model was applied to experimental results in the aim to determine phenomenological parametersσand Ps respectively, the reflexion coefficient of the membrane and the solute permeability of ions. The convective and diffusive parts of the mass transfer were quantified with predominance of the

  2. Debating Water Fluoridation Before Dr. Strangelove.

    Science.gov (United States)

    Carstairs, Catherine

    2015-08-01

    In the 1930s, scientists learned that small amounts of fluoride naturally occurring in water could protect teeth from decay, and the idea of artificially adding fluoride to public water supplies to achieve the same effect arose. In the 1940s and early 1950s, a number of studies were completed to determine whether fluoride could have harmful effects. The research suggested that the possibility of harm was small. In the early 1950s, Canadian and US medical, dental, and public health bodies all endorsed water fluoridation. I argue in this article that some early concerns about the toxicity of fluoride were put aside as evidence regarding the effectiveness and safety of water fluoridation mounted and as the opposition was taken over by people with little standing in the scientific, medical, and dental communities. The sense of optimism that infused postwar science and the desire of dentists to have a magic bullet that could wipe out tooth decay also affected the scientific debate. PMID:26066938

  3. Well Waters Fluoride in Enugu, Nigeria

    Directory of Open Access Journals (Sweden)

    EI Ugwuja

    2012-03-01

    Full Text Available Abnormal fluoride levels in drinking water have been associated with adverse health effects. To determine the fluoride content of well waters in Enugu, southeastern Nigeria, water samples from 50 artisan wells chosen by multistage sampling procedure from the 5 zones of Enugu municipality were analyzed in duplicates for their fluoride content. The zonal mean values were 0.60, 0.70, 0.62, 0.62, and 0.63 mg/L for Abakpa Nike, Achara Layout, Obiagu/ Ogui, Trans Ekulu and Uwani, respectively (p<0.05. The mean value for the whole city was 0.63 mg/L. Although, the mean level of fluoride recorded in this study is currently within safe limits (1.5 mg/L, WHO 2011, it is important to monitor continuously the fluoride content of well waters in the municipality in view of the increasing industrial activities going on in the city and heavy reliance on well water for domestic purposes and the widespread use of consumer products containing fluoride.

  4. Fluoride geochemistry of thermal waters in Yellowstone National Park: I. Aqueous fluoride speciation

    Science.gov (United States)

    Deng, Y.; Nordstrom, D.K.; Blaine, McCleskey R.

    2011-01-01

    Thermal water samples from Yellowstone National Park (YNP) have a wide range of pH (1-10), temperature, and high concentrations of fluoride (up to 50mg/l). High fluoride concentrations are found in waters with field pH higher than 6 (except those in Crater Hills) and temperatures higher than 50??C based on data from more than 750 water samples covering most thermal areas in YNP from 1975 to 2008. In this study, more than 140 water samples from YNP collected in 2006-2009 were analyzed for free-fluoride activity by ion-selective electrode (ISE) method as an independent check on the reliability of fluoride speciation calculations. The free to total fluoride concentration ratio ranged from 99% at high pH. The wide range in fluoride activity can be explained by strong complexing with H+ and Al3+ under acidic conditions and lack of complexing under basic conditions. Differences between the free-fluoride activities calculated with the WATEQ4F code and those measured by ISE were within 0.3-30% for more than 90% of samples at or above 10-6 molar, providing corroboration for chemical speciation models for a wide range of pH and chemistry of YNP thermal waters. Calculated speciation results show that free fluoride, F-, and major complexes (HF(aq)0, AlF2+, AlF2+ and AlF30) account for more than 95% of total fluoride. Occasionally, some complex species like AlF4-, FeF2+, FeF2+, MgF+ and BF2(OH)2- may comprise 1-10% when the concentrations of the appropriate components are high. According to the simulation results by PHREEQC and calculated results, the ratio of main fluoride species to total fluoride varies as a function of pH and the concentrations and ratios of F and Al. ?? 2011.

  5. Application Of Vacuum Salt Distillation Technology For The Removal Of Fluoride

    International Nuclear Information System (INIS)

    concerned with the removal of the halide ions associated with plutonium trifluoride (PuF3), plutonium tetrafluoride (PuF4), calcium fluoride (CaF2), and calcium chloride (CaCl2). This report discusses non-radioactive testing of small-scale and pilot-scale systems and radioactive testing of a small-scale system. Experiments focused on demonstrating the chemistry for halide removal and addressing the primary engineering questions associated with a change in the process chemistry.

  6. Fluorine uptake into the human enamel surface from fluoride-containing sealing materials during cariogenic pH cycling

    International Nuclear Information System (INIS)

    To prevent the formation of caries and reduce dentin hypersensitivity, sealing materials, either with or without fluoride, are generally applied on the tooth in clinical practice. Application of fluoride-free sealing materials results in the formation of an acid-resistant layer on the tooth surface. On the other hand, fluoride-containing sealing materials might not only form an acid-resistant layer but could possibly further provide fluoride to enhance remineralization and reduce demineralization. In this study, the demineralization prevention ability and fluorine uptake rate in human enamel of fluoride-containing sealing materials [“MS coats F” (MSF)] and fluoride-free sealing materials (“hybrid coats 2” [HI]) were evaluated using an automatic pH cycling system. Each material was applied to the original tooth surface, the cut surfaces were covered with sticky wax, and the automatic pH-cycling system simulated daily acid changes (pH 6.8–4.5) occurring in the oral cavity for 4 weeks. Caries progression was analyzed using transverse microradiography (TMR) taken pre and post the 4 weeks of pH cycling. The fluorine and calcium distributions in the carious lesion in each specimen were evaluated using the proton-induced gamma emission (PIGE) and proton-induced X-ray (PIXE) techniques, respectively. TMR analysis showed that both MSF and HI had a caries-preventing effect after 4 weeks of pH cycling. PIGE/PIXE analysis demonstrated that only MSF resulted in fluoride uptake in the enamel surface. Therefore, MSF can help to form an acid-resistant layer and provide fluoride to the enamel surface. The presence of fluoride on the enamel surface suggested that MSF could prevent demineralization, even if the acid-resistant layer was removed, in clinical settings. The data obtained using the PIGE and PIXE techniques are useful for understanding the benefits of the use of a fluoride-containing sealing material for preventing caries

  7. Fluorine uptake into the human enamel surface from fluoride-containing sealing materials during cariogenic pH cycling

    Energy Technology Data Exchange (ETDEWEB)

    Yasuhiro, Matsuda, E-mail: matsuda@den.hokudai.ac.jp [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan); Katsushi, Okuyama [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan); Hiroko, Yamamoto [Graduate School of Dentistry, Osaka University (Japan); Hisanori, Komatsu [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan); Masashi, Koka; Takahiro, Sato [Takasaki Advanced Radiation Research Institute, JAEA (Japan); Naoki, Hashimoto; Saiko, Oki; Chiharu, Kawamoto; Hidehiko, Sano [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan)

    2015-04-01

    To prevent the formation of caries and reduce dentin hypersensitivity, sealing materials, either with or without fluoride, are generally applied on the tooth in clinical practice. Application of fluoride-free sealing materials results in the formation of an acid-resistant layer on the tooth surface. On the other hand, fluoride-containing sealing materials might not only form an acid-resistant layer but could possibly further provide fluoride to enhance remineralization and reduce demineralization. In this study, the demineralization prevention ability and fluorine uptake rate in human enamel of fluoride-containing sealing materials [“MS coats F” (MSF)] and fluoride-free sealing materials (“hybrid coats 2” [HI]) were evaluated using an automatic pH cycling system. Each material was applied to the original tooth surface, the cut surfaces were covered with sticky wax, and the automatic pH-cycling system simulated daily acid changes (pH 6.8–4.5) occurring in the oral cavity for 4 weeks. Caries progression was analyzed using transverse microradiography (TMR) taken pre and post the 4 weeks of pH cycling. The fluorine and calcium distributions in the carious lesion in each specimen were evaluated using the proton-induced gamma emission (PIGE) and proton-induced X-ray (PIXE) techniques, respectively. TMR analysis showed that both MSF and HI had a caries-preventing effect after 4 weeks of pH cycling. PIGE/PIXE analysis demonstrated that only MSF resulted in fluoride uptake in the enamel surface. Therefore, MSF can help to form an acid-resistant layer and provide fluoride to the enamel surface. The presence of fluoride on the enamel surface suggested that MSF could prevent demineralization, even if the acid-resistant layer was removed, in clinical settings. The data obtained using the PIGE and PIXE techniques are useful for understanding the benefits of the use of a fluoride-containing sealing material for preventing caries.

  8. Voriconazole Enhances the Osteogenic Activity of Human Osteoblasts In Vitro through a Fluoride-Independent Mechanism.

    Science.gov (United States)

    Allen, Kahtonna C; Sanchez, Carlos J; Niece, Krista L; Wenke, Joseph C; Akers, Kevin S

    2015-12-01

    Periostitis, which is characterized by bony pain and diffuse periosteal ossification, has been increasingly reported with prolonged clinical use of voriconazole. While resolution of clinical symptoms following discontinuation of therapy suggests a causative role for voriconazole, the biological mechanisms contributing to voriconazole-induced periostitis are unknown. To elucidate potential mechanisms, we exposed human osteoblasts in vitro to voriconazole or fluconazole at 15 or 200 μg/ml (reflecting systemic or local administration, respectively), under nonosteogenic or osteogenic conditions, for 1, 3, or 7 days and evaluated the effects on cell proliferation (reflected by total cellular DNA) and osteogenic differentiation (reflected by alkaline phosphatase activity, calcium accumulation, and expression of genes involved in osteogenic differentiation). Release of free fluoride, vascular endothelial growth factor (VEGF), and platelet-derived growth factor (PDGF) was also measured in cell supernatants of osteoblasts exposed to triazoles, with an ion-selective electrode (for free fluoride) and enzyme-linked immunosorbent assays (ELISAs) (for VEGF and PDGF). Voriconazole but not fluconazole significantly enhanced the proliferation and differentiation of osteoblasts. In contrast to clinical observations, no increases in free fluoride levels were detected following exposure to either voriconazole or fluconazole; however, significant increases in the expression of VEGF and PDGF by osteoblasts were observed following exposure to voriconazole. Our results demonstrate that voriconazole can induce osteoblast proliferation and enhance osteogenic activity in vitro. Importantly, and in contrast to the previously proposed mechanism of fluoride-stimulated osteogenesis, our findings suggest that voriconazole-induced periostitis may also occur through fluoride-independent mechanisms that enhance the expression of cytokines that can augment osteoblastic activity. PMID:26324277

  9. Efficacy of silver diamine fluoride as an antibacterial as well as antiplaque agent compared to fluoride varnish and acidulated phosphate fluoride gel: An in vivo study

    OpenAIRE

    Shalin Shah; Vijay Bhaskar; Karthik Venkataraghavan; Prashant Choudhary; M Ganesh; Krishna Trivedi

    2013-01-01

    Background: Silver diamine fluoride (SDF) is already proven as an antibacterial agent in vitro. Present study was formulated to compare the efficacy of SDF as an antibacterial as well as antiplaque agent in vivo with fluoride varnish and acidulated phosphate fluoride (APF) gel. Study Design: Total 123 children (male = 82, female = 41) were included in the study for a period of 18 months. Children were divided into three different groups-Group 1: SDF; Group 2: fluoride varnish; and Group 3...

  10. Chemisorption of uranium hexa-fluoride on sodium fluoride pellets

    International Nuclear Information System (INIS)

    This paper comprises kinetics of chemical reaction or rather chemisorption of uranium hexafluoride gas on sodium fluoride pellets. The chemisorption is essentially irreversible at room temperature, while the process reverses at high temperature above 280 deg C. This chemisorption process was experimentally conducted in static condition at room temperature and its kinetics was studied. In the experiments, practically pure UF6 was used and the effects of gas pressure and weight of NaF pellets, were studied. In this heterogenous reaction, in which diffusion through ash layer is followed by chemical reaction, the reaction part is instantaneous and is first order with respect to gas concentration. Since the process of chemisorption is not only pure chemical reaction but also gas diffusion through ash layer, the rate constant depreciates with the percentage loading of UF6 on NaF pellets. The kinetic equation for the above process has been established for a particular size of NaF pellets and pellet porosity. (author)

  11. Daily Fluoride Intake from Iranian Green Tea: Evaluation of Various Flavorings on Fluoride Release.

    Science.gov (United States)

    Maleki, Afshin; Daraei, Hiua; Mohammadi, Elham; Zandi, Shiva; Teymouri, Pari; Mahvi, Amir Hossien; Gharibi, Fardin

    2016-01-01

    With increased awareness of the health benefits of the compounds in green tea, especially polyphenols, its consumption is rising. The main purpose of this study is to determine the effect of different additives on the released fluoride into tea liquor and also daily fluoride intake. The concentrations of fluoride, nitrate, sulfate, and chloride were measured in 15 different flavored green teas (Refah-Lahijan). The fluoride and other anion concentrations were measured by ion chromatography method. The data were analyzed with Statistical Package for the Social Sciences version 16.0. The results showed that the minimum and maximum concentrations of fluoride in the green tea infusions were 0.162 mg/L (cinnamon-flavored green tea) and 3.29 mg/L (bagged peach-flavored green tea), respectively. The mean concentration of fluoride in the green tea leaves was 52 mg/kg, and approximately 89% of the fluoride was released from the green tea leaves into the infusions after brewing. The fluoride concentrations varied significantly among the examined green teas (P 0.05). Finally, drinking of the studied green teas cannot make a significant contribution to the daily dietary intake of F for consumers. PMID:27042093

  12. Daily Fluoride Intake from Iranian Green Tea: Evaluation of Various Flavorings on Fluoride Release

    Science.gov (United States)

    Maleki, Afshin; Daraei, Hiua; Mohammadi, Elham; Zandi, Shiva; Teymouri, Pari; Mahvi, Amir Hossien; Gharibi, Fardin

    2016-01-01

    With increased awareness of the health benefits of the compounds in green tea, especially polyphenols, its consumption is rising. The main purpose of this study is to determine the effect of different additives on the released fluoride into tea liquor and also daily fluoride intake. The concentrations of fluoride, nitrate, sulfate, and chloride were measured in 15 different flavored green teas (Refah-Lahijan). The fluoride and other anion concentrations were measured by ion chromatography method. The data were analyzed with Statistical Package for the Social Sciences version 16.0. The results showed that the minimum and maximum concentrations of fluoride in the green tea infusions were 0.162 mg/L (cinnamon-flavored green tea) and 3.29 mg/L (bagged peach-flavored green tea), respectively. The mean concentration of fluoride in the green tea leaves was 52 mg/kg, and approximately 89% of the fluoride was released from the green tea leaves into the infusions after brewing. The fluoride concentrations varied significantly among the examined green teas (P 0.05). Finally, drinking of the studied green teas cannot make a significant contribution to the daily dietary intake of F for consumers. PMID:27042093

  13. Determination of Fluoride in the Bottled Drinking Waters in Iran

    OpenAIRE

    Amanlou, Massoud; Hosseinpour, Maedeh; Azizian, Homa; Khoshayand, Mohammad Reza; Navabpoor, Mojtaba; Souri, Effat

    2010-01-01

    Fluoride is recognized as an effective agent for dental caries prevention. Generally, the main source of fluoride intake is drinking water. In this study, fluoride content in 18 commercial brands of bottled waters was investigated. Six samples from each batch of 18 Iranian commercial brands of bottled waters were supplied. The fluoride content of samples was analyzed by Fluoride Ion Selective Electrode. The mean ± SD fluoride content of the bottled waters was 0.202 ± 0.00152 mg/L with a range...

  14. A comparative assessment of fluoride concentration available in saliva using daily prescribed topical fluoride agents

    Science.gov (United States)

    Talwar, Manjit; Tewari, Amrit; Chawla, H. S.; Sachdev, Vinod

    2016-01-01

    Objective: To assess the availability of fluoride concentration in saliva following the use of fluoride mouthrinse and dentifrice. Materials and Methods: The experiment was carried out in 7–15 year-old school children of Chandigarh (n = 90). The children were nonfluoride users. Baseline saliva samples were collected. The subjects were exposed to two test agents, i.e., fluoride mouthrinse (0.05%, 225 ppm F) and dentifrice (1000 ppm F) for 7 days and on the day 8, saliva samples were collected over a 20 hrs period. Wash out period of 31/2 months was there before the subjects were exposed to the second test agent. Fluoride in saliva was estimated using fluoride ion-specific electrode. Written informed consent was taken. Statistical Analysis: Kolmogorov–Smirnov test was applied to test the normality of the variables. Mann–Whitney U-test was used to compare the fluoride concentration available in saliva at respective time intervals subsequent to use of the two test agents. Results: Fluoride concentration was elevated in saliva compared to baseline for both the test agents. Fluoride mouthrinse (0.05% sodium fluoride [NaF]) and dentifrice (1000 ppm monofluorophosphate [MFP]) showed a biphasic clearance. Peak in saliva occurred at 15 mins postuse. Night-time use resulted in higher concentration of fluoride in saliva compared to baseline. There was statistically significantly higher fluoride concentration available in saliva for the dentifrice at 5 hrs, 10 hrs, and 20 hrs postuse (P < 0.05). Conclusion: Subsequent to the use of NaF (0.05%) daily mouthrinse and MFP dentifrice (1000 ppm) the fluoride concentration in saliva remained elevated to a level of 0.12 ppm for mouthrinse and 0.14 ppm for dentifrice compared to baseline (0.03 ppm) up to 20 hrs postuse. The therapeutic window though not yet established but suggested is 0.1–1 ppm for prevention of demineralization, indicating that daily use of fluoride mouthrinse and dentifrice provides fluoride concentration in

  15. Calcium in diet

    Science.gov (United States)

    ... best source. Milk and dairy products such as yogurt, cheeses, and buttermilk contain a form of calcium ... the amount of calcium in a dairy product. Yogurt, most cheeses, and buttermilk are excellent sources of ...

  16. Fenoprofen calcium overdose

    Science.gov (United States)

    Fenoprofen calcium is a type of medicine called a nonsteroidal anti-inflammatory drug. It is a prescription pain medicine used to relieve symptoms of arthritis . Fenoprofen calcium overdose occurs when someone takes more than the ...

  17. Calcium channel blocker overdose

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002580.htm Calcium channel blocker overdose To use the sharing features on this page, please enable JavaScript. Calcium channel blockers are a type of medicine used ...

  18. Fenoprofen calcium overdose

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002649.htm Fenoprofen calcium overdose To use the sharing features on this page, please enable JavaScript. Fenoprofen calcium is a type of medicine called a nonsteroidal ...

  19. An in vitro evaluation of the demineralization inhibitory effect of F− varnish and casein phosphopeptide-amorphous calcium phosphate on enamel in young permanent teeth

    OpenAIRE

    Duraisamy, Vinola; Xavier, Ananda; Nayak, Ullal Anand; Reddy, Venugopal; Rao, Arun Prasad

    2015-01-01

    Aims and Objectives: To determine the demineralization inhibitory potential of fluoride varnish and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and to compare and evaluate the additive effect of fluoride varnish + CPP-ACP. Materials and Methods: Ten healthy premolar teeth that were extracted for orthodontic purposes were collected, and each tooth was longitudinally sectioned buccolingually and mesiodistally into four sections. The teeth were then assigned to four different tre...

  20. Calcium and magnesium disorders.

    Science.gov (United States)

    Goff, Jesse P

    2014-07-01

    Hypocalcemia is a clinical disorder that can be life threatening to the cow (milk fever) and predisposes the animal to various other metabolic and infectious disorders. Calcium homeostasis is mediated primarily by parathyroid hormone, which stimulates bone calcium resorption and renal calcium reabsorption. Parathyroid hormone stimulates the production of 1,25-dihydroxyvitamin D to enhance diet calcium absorption. High dietary cation-anion difference interferes with tissue sensitivity to parathyroid hormone. Hypomagnesemia reduces tissue response to parathyroid hormone. PMID:24980727

  1. Calcium and Mitosis

    Science.gov (United States)

    Hepler, P.

    1983-01-01

    Although the mechanism of calcium regulation is not understood, there is evidence that calcium plays a role in mitosis. Experiments conducted show that: (1) the spindle apparatus contains a highly developed membrane system that has many characteristics of sarcoplasmic reticulum of muscle; (2) this membrane system contains calcium; and (3) there are ionic fluxes occurring during mitosis which can be seen by a variety of fluorescence probes. Whether the process of mitosis can be modulated by experimentally modulating calcium is discussed.

  2. Global Measurements of Atmospheric Sulfuryl Fluoride

    Science.gov (United States)

    Mühle, J.; Harth, C. M.; Salameh, P.; Miller, B. R.; Weiss, R. F.; Porter, L. W.; Fraser, P. J.; Greally, B. R.; O'Doherty, S.

    2006-12-01

    Sulfuryl fluoride (SO2F2) is used increasingly as a fumigant, but information about its emissions to the atmosphere is limited. Its atmospheric fate and lifetime are uncertain, with hydrolysis in the basic surface waters of the oceans a likely dominant sink, and its roles as a greenhouse gas and as a sulfur source to the stratosphere are unknown. We present here the first results of two years of high-frequency high-precision in situ observations of sulfuryl fluoride in the AGAGE (Advanced Global Atmospheric Gases Experiment) global measurement program. At La Jolla, California, baseline conditions are rarely achieved, and pollution events of up to 1.7 ppb (the exposure limit is 5 ppm) from nearby structural fumigation are common. At the Mace Head, Ireland, and Cape Grim, Tasmania, AGAGE stations, baseline conditions are observed with mixing ratios at the beginning of 2005 of ~1.0 ppt and ~0.9 ppt, respectively. Measured growth rates at these stations are ~0.06 ppt per year and ~0.04 ppt per year, respectively. Using these preliminary results and assuming no significant emissions in the southern hemisphere, a simple 2-box model can be used to estimate the tropospheric lifetime of sulfuryl fluoride as about one and a half decades, which is substantially longer than previous industry estimates. The corresponding modeled sulfuryl fluoride flux to the troposphere is ~2 x 109 g per year. Based on these initial measurements, the current global warming contribution of sulfuryl fluoride is likely small. Although the lifetime of sulfuryl fluoride is longer than that of carbonyl sulfide, sulfuryl fluoride is likely less important as source of sulfur to the stratosphere, due to its low atmospheric mixing ratio.

  3. Caries inhibition by fluoride-releasing primers.

    Science.gov (United States)

    Kerber, L J; Donly, K J

    1993-10-01

    This study evaluated the caries inhibition of dentin primers with the addition of fluoride. Two standardized Class V preparations were placed in 20 molars, the gingival margin placed below the cementoenamel junction and the occlusal margin placed in enamel. Two dentin primers (Syntac and ScotchPrep) were placed in equal numbers of 20 preparations, according to manufacturer's instructions. Ammonium fluoride (10% by weight) was then added to these primers and they were placed in the remaining 20 preparations, opposing the non-fluoridated primer of the same system. All teeth were then restored with a non-fluoridated resin composite. All teeth were subjected to an artificial caries challenge (pH 4.2) for 5 days. Sections of 100 microns were obtained, photographed under polarized light microscopy, then demineralized areas were quantitated by digitization. Results demonstrated the mean areas (mm2 +/- S.D.) demineralization at 0.25 mm, 0.5 mm and 1.0 mm from the restoration margin to be: Syntac/fluoride (1.44 +/- 0.49, 1.68 +/- 0.54, 3.72 +/- 0.74); Syntac (1.99 +/- 0.58, 1.50 +/- 0.35, 2.98 +/- 1.26); ScotchPrep/fluoride (1.23 +/- 0.68, 1.55 +/- 0.64, 3.08 +/- 1.16); ScotchPrep (1.90 +/- 0.83, 1.71 +/- .038, 3.36 +/- 0.62). A paired t-test indicated primers with fluoride to demonstrate significantly less demineralization 0.25 mm from the restoration margin (P < 0.07). PMID:7880460

  4. Calcium en cardioplegie

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Meijler, F.L.

    1985-01-01

    Coronary perfusion with a calcium-free solution, followed by reperfusion with a calcium containing solution, may result in acute myocardial cell death and in irreversible loss of the e1ectrical and mechanical activity of the heart. This phenomenon is known as the calcium paradox. A number of cardiop

  5. Thermodynamic data-base for metal fluorides

    International Nuclear Information System (INIS)

    This study is aimed at collecting useful data of thermodynamic properties of various metal fluorides. Many thermodynamic data for metal fluorides are needed for the effective development, but no report of data-base was published. Accordingly, the objective of this report is to rearrange systematically the existing thermodynamic data based on metal fluorides and is to use it as basic data for the development of pyrochemical process. The physicochemical properties of various metal fluorides and metals were collected from literature and such existing data base as HSC code, TAPP code, FACT code, JANAF table, NEA data-base, CRC handbook. As major contents of the thermodynamic data-base, the physicochemical properties such as formation energy, viscosity, density, vapor pressure, etc. were collected. Especially, some phase diagrams of eutectic molten fluorides are plotted and thermodynamic data of liquid metals are also compiled. In the future, the technical report is to be used as basic data for the development of the pyrochemical process which is being carried out as a long-term nuclear R and D project

  6. Thermodynamic data-base for metal fluorides

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jae Hyung; Lee, Byung Gik; Kang, Young Ho and others

    2001-05-01

    This study is aimed at collecting useful data of thermodynamic properties of various metal fluorides. Many thermodynamic data for metal fluorides are needed for the effective development, but no report of data-base was published. Accordingly, the objective of this report is to rearrange systematically the existing thermodynamic data based on metal fluorides and is to use it as basic data for the development of pyrochemical process. The physicochemical properties of various metal fluorides and metals were collected from literature and such existing data base as HSC code, TAPP code, FACT code, JANAF table, NEA data-base, CRC handbook. As major contents of the thermodynamic data-base, the physicochemical properties such as formation energy, viscosity, density, vapor pressure, etc. were collected. Especially, some phase diagrams of eutectic molten fluorides are plotted and thermodynamic data of liquid metals are also compiled. In the future, the technical report is to be used as basic data for the development of the pyrochemical process which is being carried out as a long-term nuclear R and D project.

  7. Emissions of fluorides from welding processes.

    Science.gov (United States)

    Szewczyńska, Małgorzata; Pągowska, Emilia; Pyrzyńska, Krystyna

    2015-11-01

    The levels of fluoride airborne particulates emitted from welding processes were investigated. They were sampled with the patented IOM Sampler, developed by J. H. Vincent and D. Mark at the Institute of Occupational Medicine (IOM), personal inhalable sampler for simultaneous collection of the inhalable and respirable size fractions. Ion chromatography with conductometric detection was used for quantitative analysis. The efficiency of fluoride extraction from the cellulose filter of the IOM sampler was examined using the standard sample of urban air particle matter SRM-1648a. The best results for extraction were obtained when water and the anionic surfactant N-Cetyl-N-N-N-trimethylammonium bromide (CTAB) were used in an ultrasonic bath. The limits of detection and quantification for the whole procedure were 8μg/L and 24μg/L, respectively. The linear range of calibration was 0.01-10mg/L, which corresponds to 0.0001-0.1mg of fluorides per m(3) in collection of a 20L air sample. The concentration of fluorides in the respirable fraction of collected air samples was in the range of 0.20-1.82mg/m(3), while the inhalable fraction contained 0.23-1.96mg/m(3) of fluorides during an eight-hour working day in the welding room. PMID:26574102

  8. The kinetics of fluoride uptake by synthetic hydroxyapatite

    Directory of Open Access Journals (Sweden)

    Takudzwa Gomwe

    2012-03-01

    Full Text Available The kinetics of fluoride uptake by synthetic hydroxyapatite from aqueous solution has been studied. Experiments involved exposing 0.1 g of synthetic hydroxyapatite to 5 cm3 of sodium fluoride solution in the concentration range 100-1000 ppm fluoride and determining fluoride concentration at regular time intervals with a fluoride ion-selective electrode. In all cases, uptake was found to follow pseudo-second order kinetics with correlation coefficients of at least 0.998; all systems equilibrated by 24 hours with equilibrium uptake values that varied with the initial fluoride concentration. The kinetic results differ from those previously reported for much lower concentrations of fluoride, but in the present case, the concentrations were of clinical relevance, as they are those used in fluoride-containing dental products. Further work is necessary to determine how well these findings model uptake by natural hydroxyapatite and hence the extent to which they might apply in vivo.

  9. Removing Fluoride Ions with Continously Fed Activated Alumina.

    Science.gov (United States)

    Wu, Yeun C.; Itemaking, Isara Cholapranee

    1979-01-01

    Discussed is the mathematical basis for determining fluoride removal during water treatment with activated alumina. The study indicates that decreasing particle size decreases the pore diffusion effect and increases fluoride removal. (AS)

  10. Promotion of beta-glucan synthase activity in corn microsomal membranes by calcium and protein phosphorylation

    Science.gov (United States)

    Paliyath, G.; Poovaiah, B. W.

    1988-01-01

    Regulation of the activity of beta-glucan synthase was studied using microsomal preparations from corn coleoptiles. The specific activity as measured by the incorporation of glucose from uridine diphospho-D-[U-14C]glucose varied between 5 to 15 pmol (mg protein)-1 min-1. Calcium promoted beta-glucan synthase activity and the promotion was observed at free calcium concentrations as low as 1 micromole. Kinetic analysis of substrate-velocity curve showed an apparent Km of 1.92 x 10(-4) M for UDPG. Calcium increased the Vmax from 5.88 x 10(-7) mol liter-1 min-1 in the absence of calcium to 9.52 x 10(-7) mol liter-1 min-1 and 1.66 x 10(-6) mol liter-1 min-1 in the presence of 0.5 mM and 1 mM calcium, respectively. The Km values remained the same under these conditions. Addition of ATP further increased the activity above the calcium-promoted level. Sodium fluoride, a phosphoprotein phosphatase inhibitor, promoted glucan synthase activity indicating that phosphorylation and dephosphorylation are involved in the regulation of the enzyme activity. Increasing the concentration of sodium fluoride from 0.25 mM to 10 mM increased glucan synthase activity five-fold over the + calcium + ATP control. Phosphorylation of membrane proteins also showed a similar increase under these conditions. Calmodulin, in the presence of calcium and ATP stimulated glucan synthase activity substantially, indicating that calmodulin could be involved in the calcium-dependent phosphorylation and promotion of beta-glucan synthase activity. The role of calcium in mediating auxin action is discussed.

  11. A simple and colorimetric fluoride receptor and its fluoride-responsive organogel

    International Nuclear Information System (INIS)

    In this paper, a new p-nitrophenylhydrozine-based anion receptor 1 containing cholesterol group had been designed and synthesized. It could selectively recognize fluoride among different anions tested with color changes from pale yellow to red for visual detection. Simultaneously, it could gel in cyclohexane, and the gel was also fluoride-responsive. When treated with TBAF (tetra-n-butylammonium fluoride), the gel could undergo gel–sol transition accompanied by color, morphology and surface changes. The binding mechanism had been investigated by UV–vis and 1HNMR (proton nuclear magnetic resonance spectra) titrations. From SEM (scanning electron microscope), SAXS (small-angle X-ray scattering), IR (Infrared Spectroscopy) and CA (contact angle) experiments, it was indicated that the addition of F− could destroy the molecule assembly of host 1 in the gel state, thus resulting in the gel-to-sol transition due to the binding site competition effect. To the best of our knowledge, this was the simplest fluoride-responsive organogel with high selectivity. Highlights: ► A novel kind receptor for selective recognition of fluoride had been designed. ► Its organogel was also fluoride-responsive. ► This is the simplest fluoride-responsive organogel with high selectivity.

  12. Parabens do not increase fluoride uptake by dental enamel

    OpenAIRE

    Vanessa Silva Tramontino; Daniela Labbate; Tabchoury, Cínthia Pereira Machado; Jaime Aparecido CURY

    2010-01-01

    Objective: To evaluate whether methylparaben and propylparaben, which present a similar chemical structure, increase fluoride uptake by demineralized dental enamel when present in buffered solutions. Methods: The study comprised an in vitro experiment using blocks of bovine dental enamel with artificial carious lesions. Enamel blocks were exposed to the following treatment (n=12): fluoride solution (200 ppm fluoride) - control; solution containing fluoride and 13 mM methylparaben; solution co...

  13. FLUORIDE: A REVIEW OF USE AND EFFECTS ON HEALTH

    Science.gov (United States)

    Kanduti, Domen; Sterbenk, Petra; Artnik, Barbara

    2016-01-01

    Introduction: Appropriate oral health care is fundamental for any individual’s health. Dental caries is still one of the major public health problems. The most effective way of caries prevention is the use of fluoride. Aim: The aim of our research was to review the literature about fluoride toxicity and to inform physicians, dentists and public health specialists whether fluoride use is expedient and safe. Methods: Data we used in our review were systematically searched and collected from web pages and documents published from different international institutions. Results: Fluoride occurs naturally in our environment but we consume it in small amounts. Exposure can occur through dietary intake, respiration and fluoride supplements. The most important factor for fluoride presence in alimentation is fluoridated water. Methods, which led to greater fluoride exposure and lowered caries prevalence, are considered to be one of the greatest accomplishments in the 20th century`s public dental health. During pregnancy, the placenta acts as a barrier. The fluoride, therefore, crosses the placenta in low concentrations. Fluoride can be transmitted through the plasma into the mother’s milk; however, the concentration is low. The most important action of fluoride is topical, when it is present in the saliva in the appropriate concentration. The most important effect of fluoride on caries incidence is through its role in the process of remineralization and demineralization of tooth enamel. Acute toxicity can occur after ingesting one or more doses of fluoride over a short time period which then leads to poisoning. Today, poisoning is mainly due to unsupervised ingestion of products for dental and oral hygiene and over-fluoridated water. Conclusion: Even though fluoride can be toxic in extremely high concentrations, it`s topical use is safe. The European Academy of Paediatric Dentistry (EAPD) recommends a preventive topical use of fluoride supplements because of their

  14. Pharmacokinetics of fluoride in toddlers after application of 5% sodium fluoride dental varnish.

    Science.gov (United States)

    Milgrom, Peter; Taves, Donald M; Kim, Amy S; Watson, Gene E; Horst, Jeremy A

    2014-09-01

    The prevalence of dental caries (tooth decay) among preschool children is increasing, driven partially by an earlier age of onset of carious lesions. The American Academy of Pediatrics recommends application of 5% sodium fluoride varnish at intervals increasing with caries risk status, as soon as teeth are present. However, the varnishes are marketed for treatment of tooth sensitivity and are regulated as medical devices rather than approved by the US Food and Drug Administration for prevention of dental caries (tooth decay). The objective of this research is to examine the safety of use in toddlers by characterizing the absorption and distribution profile of a currently marketed fluoride varnish. We measured urinary fluoride for 5 hours after application of fluoride varnish to teeth in 6 toddlers aged 12 to 15 months. Baseline levels were measured on a separate day. The urine was extracted from disposable diapers, measured by rapid diffusion, and extrapolated to plasma levels. The mean estimated plasma fluoride concentration was 13 μg/L (SD, 9 μg/L) during the baseline visit and 21 μg/L (SD, 8 μg/L) during the 5 hours after treatment. Mean estimated peak plasma fluoride after treatment was 57 μg/L (SD, 22 μg/L), and 20 μg/kg (SD, 4 μg/L) was retained on average. Retained fluoride was 253 times lower than the acute toxic dose of 5 mg/kg. Mean plasma fluoride after placement of varnish was within an SD of control levels. Occasional application of fluoride varnish following American Academy of Pediatrics guidance is safe for toddlers. PMID:25136045

  15. Uranyl fluoride luminescence in acidic aqueous solutions

    International Nuclear Information System (INIS)

    Luminescence emission spectra and decay rates are reported for uranyl species in acidic aqueous solutions containing HF or added NaF. The longest luminescence lifetime, 0.269 ± 0.006 ms, was observed from uranyl in 1 M HF + 1 M HClO4 at 296 K and decreased with increasing temperature. Based on a luminescence dynamics model that assumes equilibrium among electronically excited uranyl fluoride species and free fluoride ion, this long lived uranyl luminescence in aqueous solution is attributed primarily to UO2F2. Studies on the effect of added LiNO3 or Na2WO4·2H2O showed relatively weak quenching of uranyl fluoride luminescence which suggests that high sensitivity determination of the UF6 content of WF6 gas should be feasible via uranyl luminescence analysis of hydrolyzed gas samples of impure WF6

  16. Serum calciotropic hormone levels,and dental fluorlsis in Children exposed to different concentrations of fluoride and iodine in drinking water

    Institute of Scientific and Technical Information of China (English)

    BA Yue; ZHANG Ya-wei; ZHU Jiang-yuan; YANG Yue-jin; YU Bo; HUANG Hui; WANG Gang; REN Li-jun; CHENG Xue-min; CUI Liu-xin

    2010-01-01

    Background High fluoride exposure can result in dental fluorosis.Fluoride and iodine are coexistent in the drinking water of areas in China and may affect the prevalence of dental fluorosis and osteogenesis.The aim of this study was to investigate the relationship between serum calciotropic hormone level.and dentaI fluorisis in children exposed to different concentrations of fluoride and iodine in drinking water.Methods A pilot study was conducted in three villages located in the Kaifeng and Tongxu counties of Henan Province,China in 2006.Children aged 8 to 12 years.born and raised in the three villages were recruited.The fluoride levels in the samples of urine from these children were detected by fluoride ion selective electrode.Calcitonin and osteocalcin levels in the serum,and serum calcium were measured by radioimmunassay and flame atomic absorption spectrometry, respectively.Results Fluoride levels in urine were significantly lower in children from control area(CA)as compared with those from the high fluoride & iodine areas(HFIA)and the high fluoride area(HFA)(P<0.05 respectively),and no statistically significant difference was found between the children from HFIA and HFA.Additionally,calcitonin levels in the serum were significantly lower in children from CA and HFA as compared with that from HFIA(P<0.05 respectively),and osteocalcin levels in the serum was lower in children from CA than those from HFIA (P<0.05).No statistically significant difference in serum osteocalcin concentrations was found between children from HFA and HFIA.Conclusion This study provides an evidence that iodine exposure may modify the serum calciotropic hormone levels related to fluorine exposure.

  17. Comparative Evaluation of Fluoride Uptake Rate in the Enamel of Primary Teeth after Application of Two Pediatric Dentifrices

    Directory of Open Access Journals (Sweden)

    B. Malekafzali

    2006-09-01

    Full Text Available Statement of problem: The effectiveness of fluoride dentifrices in reducing dental caries is well documented. However, not all fluoride dentifrices are equally effective Purpose: The objective of this experimental study was to compare fluoride uptake from Pooneh pediatric toothpaste and an ADA-approved pediatric dentifrice, in sound enamel of primary teeth.Materials and Methods: In an in vitro randomized controlled trial, 20 sound primary canines were divided into 2 groups according to the experimental dentifrices. Each tooth was sectioned longitudinally into experimental and control halves. The test groups were treated with dentifrice slurries for 1 hour. All specimens were then suspended in 5ml artificial saliva for 24 hours at 37°C and were etched twice for 30 seconds with a 1ml solution of 0.5M percholoric acid. Fluoride and calcium concentrations were measured by a potentiometer and an atomic absorption spectrophotometer,respectively. The collected data were analyzed using repeated measurement ANOVA and Tukey's test.Results: The mean fluoride concentrations in the Aqua fresh group (4098.44 and 3755.25 ppm in first and both layers respectively were higher than Pooneh (first layer 2420.51 ppm and both layers 2242.73 ppm, and both were higher than the controls (P<0.05. No significant difference was observed between the control groups. Theenamel thickness in Aqua fresh cases was less than the teeth treated with Pooneh (first layer 3.09 vs. 3.85 μm, both layers 4.98 vs. 6.09 μm and both were less than the controls (P<0.05. There was no significant difference between the control groups.Conclusion: Fluoride uptake was lower in Pooneh pediatric toothpaste as compared to the tested ADA-approved dentifrice, but considerably higher than the control group.

  18. 21 CFR 177.2510 - Polyvinylidene fluoride resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyvinylidene fluoride resins. 177.2510 Section... as Components of Articles Intended for Repeated Use § 177.2510 Polyvinylidene fluoride resins. Polyvinylidene fluoride resins may be safely used as articles or components of articles intended for repeated...

  19. Cancer incidence and mortality in workers exposed to fluoride

    DEFF Research Database (Denmark)

    Grandjean, P; Olsen, J H; Jensen, O M; Juel, K

    1992-01-01

    Although a recent bioassay showed increased frequency of bone cancer in rats with high oral intake of fluoride, the data are reported as equivocal evidence of carcinogenicity. In humans, occupational fluoride exposure may cause skeletal fluorosis, and our earlier follow-up of fluoride...

  20. Coprecipitation of iron and silver with barium fluoride

    International Nuclear Information System (INIS)

    Distribution of trace contaminants of iron and silver at coprecipitation of barium fluoride is studied in present work. It is defined that iron almost completely coprecipitated with barium fluoride in wide range of ph 5.5-12. Silver coprecipitated with barium fluoride in ph range 4-7. The value of coprecipitation varies from 94% to 100%.

  1. Plasma processing of fluoride solutions of refractory rare metals

    Energy Technology Data Exchange (ETDEWEB)

    Gutsol, A.F. [Institute of Chemistry and Technology of Less-Common Elements and Raw Materials, Murmanskaya oblast` (Russian Federation)

    1995-09-01

    Features of plasma processing of fluoride solutions of refractory metals were studied. It was shown that pyrohydrolysis of niobium, tantalum, and titanium fluorides occurs in the gas phase, thus providing fine oxide powders. The pyrohydrolysis of low-volatility zirconium fluoride occurs in the solid phase, yielding oxide particles corresponding to the size of initial droplets.

  2. Onderzoek naar de bepaling van fluoride in een doorstroomsysteem

    NARCIS (Netherlands)

    Neele J; Nagtegaal-Wouterse GWM; Reijnders HFR

    1989-01-01

    Een snelle methode voor de bepaling van fluoride in een doorstroomsysteem met potentiometrische detectie en een lage onderste analysegrens is ontwikkeld. De mate waarin fluoride uit fluoride-verbindingen wordt vrijgemaakt door complexvormende stoffen is gevolgd om vast te stellen hoeveel tijd hierv

  3. Reconstructing temporal variation of fluoride uptake in eastern grey kangaroos (Macropus giganteus) from a high-fluoride area by analysis of fluoride distribution in dentine.

    Science.gov (United States)

    Kierdorf, Horst; Rhede, Dieter; Death, Clare; Hufschmid, Jasmin; Kierdorf, Uwe

    2016-04-01

    Trace element profiling in the incrementally formed dentine of mammalian teeth can be applied to reconstruct temporal variation of incorporation of these elements into the tissue. Using an electron microprobe, this study analysed fluoride distribution in dentine of first and third mandibular molars of free-ranging eastern grey kangaroos inhabiting a high-fluoride area, to assess temporal variation in fluoride uptake of the animals. Fluoride content in the early-formed dentine of first molars was significantly lower than in the late-formed dentine of these teeth, and was also lower than in both, the early and the late-formed dentine of third molars. As early dentine formation in M1 takes place prior to weaning, this finding indicates a lower dentinal fluoride uptake during the pre-weaning compared to the post-weaning period. This is hypothetically attributed to the action of a partial barrier to fluoride transfer from blood to milk in lactating females and a low bioavailability of fluoride ingested together with milk. Another factor contributing to lower plasma fluoride levels in juveniles compared to adults is the rapid clearance of fluoride from blood plasma in the former due to their intense skeletal growth. The combined action of these mechanisms is considered to explain why in kangaroos from high-fluoride areas, the (early-formed) first molars are not affected by dental fluorosis while the (later-formed) third and fourth molars regularly exhibit marked to severe fluorotic lesions. PMID:26736058

  4. Calcium absorption and achlorhydria

    International Nuclear Information System (INIS)

    Defective absorption of calcium has been thought to exist in patients with achlorhydria. The author compared absorption of calcium in its carbonate form with that in a pH-adjusted citrate form in a group of 11 fasting patients with achlorhydria and in 9 fasting normal subjects. Fractional calcium absorption was measured by a modified double-isotope procedure with 0.25 g of calcium used as the carrier. Mean calcium absorption (+/- S.D.) in the patients with achlorhydria was 0.452 +/- 0.125 for citrate and 0.042 +/- 0.021 for carbonate (P less than 0.0001). Fractional calcium absorption in the normal subjects was 0.243 +/- 0.049 for citrate and 0.225 +/- 0.108 for carbonate (not significant). Absorption of calcium from carbonate in patients with achlorhydria was significantly lower than in the normal subjects and was lower than absorption from citrate in either group; absorption from citrate in those with achlorhydria was significantly higher than in the normal subjects, as well as higher than absorption from carbonate in either group. Administration of calcium carbonate as part of a normal breakfast resulted in completely normal absorption in the achlorhydric subjects. These results indicate that calcium absorption from carbonate is impaired in achlorhydria under fasting conditions. Since achlorhydria is common in older persons, calcium carbonate may not be the ideal dietary supplement

  5. EXERCISE ENHANCING CALCIUM ABSORPTION MECHANISM

    OpenAIRE

    Muliani

    2013-01-01

    Calcium has important role in many biological processes therefore calcium homeostasis should be maintained. Imbalance in calcium homeostasis would affects the bone metabolism, neuromuscular function, blood coagulation, cell proliferation and signal transduction. Homeostasis of calcium is maintained by three major organs: gastrointestinal tract, bone and kidney. Intestinal calcium absorption is the sole mechanism to supply calcium to the body. Calcium absorption controlled by calcitropic hormo...

  6. Micro-determination of fluoride by means of metallic sodium fusion and using fluoride-sensitive electrode.

    OpenAIRE

    Roy J; Rane S; Ghani A; Chaudhury C

    1993-01-01

    A simple and accurate method to determine the content of fluoride in non-volatile organofluoro compounds or in biological samples has been developed. The method includes the metallic sodium fusion followed by quantitative estimation of fluoride using fluoride-sensitive electrode.

  7. Modeling and optimization of fluoride and cadmium trapping in phosphogypsum using design methodology

    Energy Technology Data Exchange (ETDEWEB)

    Hajem, Besma; Djebali, Kais; M' nif, Adel [Laboratoire de Valorisation des Ressources Naturelles et des Materiaux de Recuperation, Centre National de Recherches en Sciences des Materiaux, Pole Technologique de Borj Cedria, Hammam Lif (Tunisia)

    2010-09-15

    The manufacturing of phosphoric acid from natural calcium phosphate generates a solid residue containing 25-30% humidity. This solid residue (phosphogypsum) generates acidic solution (pH {approx} 2.5) containing several toxic ionic species, that coat its grains. Fluorides and heavy metals such as cadmium are considered the most harmful species contained in the released solution from phosphogypsum. The purpose of this work is to study the trapping of fluorides and cadmium in phosphogypsum as well as effluent neutralization before its discharge into natural recipient. Therefore, calcium carbonate finely ground was added and fully mixed with wet phosphogypsum. A four factors central composite design was used to model and to optimize the operating parameters that govern the process. The studied factors were temperature, reaction time, mass, and grains size of CaCO{sub 3}. Considered responses were pH, F{sup -}, and Cd{sup 2+} concentrations in the released solution after reaction with CaCO{sub 3}. The optimum operating conditions were quite efficient to trap, respectively, 99% Cd{sup 2+} and 97% of F{sup -} with a final pH of 6.66. So an original, easy, simple, and cost effective method to trap some toxic species on phosphogypsum through CaCO{sub 3} addition would likely to be integrated in phosphoric acid manufacturing plant. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  8. Application Of Vacuum Salt Distillation Technology For The Removal Of Fluoride And Chloride From Legacy Fissile Materials

    International Nuclear Information System (INIS)

    Between September 2009 and January 2011, the Savannah River National Laboratory (SRNL) and the Savannah River Site (SRS) HB-Line Facility designed, developed, tested, and successfully deployed a production-scale system for the distillation of sodium chloride (NaCl) and potassium chloride (KCl) from plutonium oxide (PuO2). Subsequent efforts adapted the vacuum salt distillation (VSD) technology for the removal of chloride and fluoride from less-volatile halide salts at the same process temperature and vacuum. Calcium chloride (CaCl2), calcium fluoride (CaF2), and plutonium fluoride (PuF3) were of particular concern. To enable the use of the same operating conditions for the distillation process, SRNL employed in situ exchange reactions to convert the less-volatile halide salts to compounds that facilitated the distillation of halide without removal of plutonium. SRNL demonstrated the removal of halide from CaCl2, CaF2 and PuF3 below 1000 C using VSD technology.

  9. Some electronic and magnetic properties of Fluoride ion in Fluoride structure nanocrystals

    Science.gov (United States)

    Imtani, Ali Nasir

    2012-01-01

    We have investigated the effects of the environment potential around Fluoride ion on some important electronic and magnetic properties such as dipole polarisability, moment of oscillator strengths S(k) and magnetic susceptibility. The theoretical procedure is based on the variational-perturbation theory with two parameter trial functions incorporated in an ionic model. We estimate these properties in four cases for Fluoride ion; free ion, ion under different potentials, ion in the crystals and ion in nanocrystal, CdF2, CaF2, PbF2, SrF2 and BaF2. Our results indicate that these properties vary with ion environments and the free state of Fluoride ion has higher values and there is linearity behaviour of these properties with lattice constant. For Fluoride ion in nanocrystal, we have found that there is an extra parameter that can also affect the dipole polarisability, the number of ions in the structure.

  10. Combining CPP-ACP with fluoride: a synergistic remineralization potential of artificially demineralized enamel or not?

    Science.gov (United States)

    El-Sayad, I. I.; Sakr, A. K.; Badr, Y. A.

    2008-08-01

    Background and objective: Minimal intervention dentistry (MID) calls for early detection and remineralization of initial demineralization. Laser fluorescence is efficient in detecting changes in mineral tooth content. Recaldent is a product of casein phosphopeptide-amorphous calcium phosphate (CPP- ACP) which delivers calcium and phosphate ions to enamel. A new product which also contains fluoride is launched in United States. The remineralizing potential of CPP- ACP per se, or when combined with 0.22% Fl supplied in an oral care gel on artificially demineralised enamel using laser fluorescence was investigated. Methods: Fifteen sound human molars were selected. Mesial surfaces were tested using He-Cd laser beam at 441.5nm with 18mW power as excitation source on a suitable set-up based on Spex 750 M monochromator provided with PMT for detection of collected auto-fluorescence from sound enamel. Mesial surfaces were subjected to demineralization for ten days. The spectra from demineralized enamel were measured. Teeth were then divided according to the remineralizing regimen into three groups: group I recaldent per se, group II recaldent combined with fluoride gel and group III artificial saliva as a positive control. After following these protocols for three weeks, the spectra from remineralized enamel from the three groups were measured. The spectra of enamel auto-fluorescence were recorded and normalized to peak intensity at about 540 nm to compare between spectra from sound, demineralized and remineralized enamel surfaces. Results: A slight red shift was noticed in spectra from demineralized enamel, while a blue shift may occur in remineralized enamel. Group II showed the highest remineralizing potential. Conclusions: Combining fluoride with CPP-ACP had a synergistic effect on enamel remineralization. In addition, laser auto-fluorescence is an accurate technique for assessment of changes in tooth enamel minerals.

  11. Comparative evaluation of fluoride release from PRG-composites and compomer on application of topical fluoride: An in-vitro study

    Directory of Open Access Journals (Sweden)

    Dhull K

    2009-03-01

    Full Text Available Aims and Objective: To determine the fluoride release from Giomer and Compomer, using different topical fluoride regimes, and to compare the amount of fluoride release from giomer with that of compomer. Materials and Method: Forty-eight specimens of each giomer and compomer were divided into four treatment groups, namely, control group, fluoridated dentifrice (500 ppm once daily group, fluoridated dentifrice (500 ppm twice daily group, fluoridated dentifrice (500 ppm once daily + fluoridated mouthwash (225 ppm group. Each specimen was suspended in demineralizing solution for six hours and remineralizing solution for 18 hours. Fluoride release was measured in both the demineralizing solution and remineralizing solution daily for seven days. Total daily fluoride release for each specimen was calculated by adding the amount released in the demineralizing solution to that released in remineralizing solution. Results and Conclusion: The fluoride release (ppm was found to be more in Giomer when compared to Compomer. The fluoride released from Giomer and Compomer was significantly greater in the acidic demineralizing solution than in the neutral remineralizing solution. It was found that increasing fluoride exposure significantly increased fluoride release from the giomer and compomer. It was found that the fluoride release from the subgroups of giomer and compomer was in the following order: fluoridated dentifrice twice daily > fluoridated dentifrice once daily + fluoridated mouthwash > fluoridated dentifrice once daily > control group. It was found that the giomer showed a greater fluoride uptake than the compomer.

  12. Manufacture of high purity low arsenic anhydrous hydrogen fluoride

    International Nuclear Information System (INIS)

    A process for manufacturing anhydrous hydrogen fluoride with reduced levels of arsenic impurity from arsenic contaminated anhydrous hydrogen fluoride is described which comprises: (a) contacting the anhydrous hydrogen fluoride with an effective amount of hydrogen peroxide to oxidize the arsenic impurity in the presence of a catalyst which comprises a catalytic amount of (i) molybdenum or an inorganic molybdenum compound and (ii) a phosphate compound, at a temperature and for a period of time sufficient to oxidize volatile trivalent arsenic impurities in the anhydrous hydrogen fluoride to non-volatile pentavalent arsenic compounds, and (b) distilling the resulting mixture and recovering anhydrous hydrogen fluoride with reduced levels of arsenic impurity

  13. Fluoride: a risk factor for inflammatory bowel disease?

    Science.gov (United States)

    Follin-Arbelet, Benoit; Moum, Bjørn

    2016-09-01

    Although the association between inflammatory bowel disease (IBD) and oral hygiene has been noticed before, there has been little research on prolonged fluoride exposure as a possible risk factor. In the presented cases, exposure to fluoride seems indirectly associated with higher incidence of IBD. Fluoride toxicology and epidemiology documents frequent unspecific chronic gastrointestinal symptoms and intestinal inflammation. Efflux genes that confer resistance to environmental fluoride may select for IBD associated gut microbiota and therefore be involved in the pathogenesis. Together these multidisciplinary results argue for further investigation on the hypothesis of fluoride as a risk factor for IBD. PMID:27199224

  14. Fluoride inhibition of proton-translocating ATPases of oral bacteria.

    OpenAIRE

    Sutton, S V; Bender, G R; Marquis, R E

    1987-01-01

    The ATPases of isolated membranes of lactic acid bacteria were found to be inhibited by fluoride in a complex manner. Among the enzymes tested, that of Streptococcus mutans GS-5 was the most sensitive to fluoride, and the initial rate of hydrolysis of ATP was reduced 50% by approximately 3 mM fluoride. The enzyme of Lactobacillus casei ATCC 4646 was the most resistant, and about 25 mM fluoride was required for 50% inhibition. The response to fluoride appeared to involve reversible, noncompeti...

  15. Oral Fluoride Including Drinking Water in Prevention of Tooth Decay

    OpenAIRE

    Vitoria I

    2015-01-01

    Herein we present a review of the role of oral fluoride in the prevention of tooth decay, together with updated recommendations on fluoride supplements. Fluoridation of public drinking water is still considered effective, but the recommended level of fluoride is now 0.7 mg/L, compared with the previously recommended range of 0.7-1.2 mg/L. Oral fluoride supplements are currently not restricted to the children at high risk for tooth decay, but recommended initiate at 6 months&nbs...

  16. Geochemical appraisal of fluoride-laden groundwater in Suri I and II blocks, Birbhum district, West Bengal

    Science.gov (United States)

    Das, Shreya; Nag, S. K.

    2016-08-01

    The present study has been carried out covering two blocks—Suri I and II in Birbhum district, West Bengal, India. The evaluation focuses on occurrence, distribution and geochemistry in 26 water samples collected from borewells spread across the entire study area homogeneously. Quantitative chemical analysis of groundwater samples collected from the present study area has shown that samples from two locations—Gangta and Dhalla contain fluoride greater than the permissible limit prescribed by WHO during both post-monsoon and pre-monsoon sampling sessions. Significant factor controlling geochemistry of groundwater has been identified to be rock-water interaction processes during both sampling sessions based on the results of Gibb's diagrams. Geochemical modeling studies have revealed that fluorite (CaF2) is, indeed, present as a significant fluoride-bearing mineral in the groundwaters of this study area. Calcite or CaCO3 is one of the most common minerals with which fluorite remains associated, and saturation index calculations have revealed that the calcite-fluorite geochemistry is the dominant factor controlling fluoride concentration in this area during both post- and pre-monsoon. High fluoride waters have also been found to be of `bicarbonate' type showing increase of sodium in water with decrease of calcium.

  17. Dengue and Calcium

    OpenAIRE

    Shivanthan, Mitrakrishnan C; Rajapakse, Senaka

    2014-01-01

    Dengue is potentially fatal unless managed appropriately. No specific treatment is available and the mainstay of treatment is fluid management with careful monitoring, organ support, and correction of metabolic derangement. Evidence with regards to the role of calcium homeostasis in dengue is limited. Low blood calcium levels have been demonstrated in dengue infection and hypocalcemia maybe more pronounced in more severe forms. The cause of hypocalcemia is likely to be multifactorial. Calcium...

  18. Measurements of intracellular calcium

    International Nuclear Information System (INIS)

    Intracellular calcium concentration ([Ca2+]i) has been measured in cultured cells by using Fura-2 load cells and a computer-controlled Perkin Elmer LS-5B spectrofluorometer. Increased [Ca2+]i in cells exposed to extracellular bilirubin was observed both with and without extracellular calcium. However, the increase was considerable larger with extracellular calcium. The enhancement of [Ca2+]i became smaller with decreasing bilirubin/BSA (bovine serum albumine) ratio. 5 refs., 5 figs

  19. Actinide measurements by AMS using fluoride matrices

    Science.gov (United States)

    Cornett, R. J.; Kazi, Z. H.; Zhao, X.-L.; Chartrand, M. G.; Charles, R. J.; Kieser, W. E.

    2015-10-01

    Actinides can be measured by alpha spectroscopy (AS), mass spectroscopy or accelerator mass spectrometry (AMS). We tested a simple method to separate Pu and Am isotopes from the sample matrix using a single extraction chromatography column. The actinides in the column eluent were then measured by AS or AMS using a fluoride target matrix. Pu and Am were coprecipitated with NdF3. The strongest AMS beams of Pu and Am were produced when there was a large excess of fluoride donor atoms in the target and the NdF3 precipitates were diluted about 6-8 fold with PbF2. The measured concentrations of 239,240Pu and 241Am agreed with the concentrations in standards of known activity and with two IAEA certified reference materials. Measurements of 239,240Pu and 241Am made at A.E. Lalonde AMS Laboratory agree, within their statistical uncertainty, with independent measurements made using the IsoTrace AMS system. This work demonstrated that fluoride targets can produce reliable beams of actinide anions and that the measurement of actinides using fluorides agree with published values in certified reference materials.

  20. THE DEVELOPMENT OF AN INDIGENOUS FLUORIDE FILTER

    Science.gov (United States)

    Given that an essential component of the design is that it can be adapted for use throughout the world, the potential media investigated are those available in the regions containing fluoride contaminated groundwater. From the literature, wood charcoal, bone char, laterite and...

  1. Total Fluoride Intake by Children from a Tropical Brazilian City.

    Science.gov (United States)

    Lima, Carolina V; Cury, Jaime A; Vale, Glauber C; Lima, Marina D M; Moura, Lúcia de Fátima A D; Moura, Marcoeli Silva de

    2015-01-01

    The main sources of fluoride intake by children are fluoridated water and toothpaste. Little has been studied regarding fluoride intake from these sources in regions with tropical climates and high temperatures throughout the year. This study aimed to determine the amount of fluoride ingested from diet and tooth brushing by children who live in a city with a tropical climate. Sixty-seven children from Teresina, Piauí, Brazil, took part in this study. The city's water supply was optimally fluoridated. The duplicate-diet method was used to determine the fluoride intake from diet. The intake of fluoride from dentifrice was determined by subtracting the amount of fluoride placed on the toothbrush and that recovered after brushing. The concentration of fluoride was measured using an ion-specific electrode and is expressed as milligrams/kilogram of body weight/day. The mean (±SD) total amount was 0.071 ± 0.036 mg F/kg body weight/day, and the relative contributions of diet and toothpaste were 0.025 ± 0.010 and 0.046 ± 0.035, respectively. The factors associated with fluoride intake from toothpaste were: use of children's toothpaste (p = 0.003), use of large amounts of toothpaste (p fluoride ingested by most children who live in a Brazilian city with a tropical climate is considered safe in terms of the risk of dental fluorosis. PMID:26655142

  2. Estimated Fluoride Doses from Toothpastes Should be Based on Total Soluble Fluoride

    Directory of Open Access Journals (Sweden)

    Jaime A. Cury

    2013-11-01

    Full Text Available The fluoride dose ingested by young children may be overestimated if based on levels of total fluoride (TF rather than levels of bioavailable fluoride (total soluble fluoride—TSF in toothpaste. The aim of the present study was to compare doses of fluoride intake based on TF and TSF. Fluoride intake in 158 Brazilian children aged three and four years was determined after tooth brushing with their usual toothpaste (either family toothpaste (n = 80 or children’s toothpaste (n = 78. The estimated dose (mg F/day/Kg of body weight of TF or TSF ingested was calculated from the chemical analysis of the toothpastes. Although the ingested dose of TF from the family toothpastes was higher than that from the children’s toothpastes (0.074 ± 0.007 and 0.039 ± 0.003 mg F/day/Kg, respectively; p 0.05. The fluoride dose ingested by children from toothpastes may be overestimated if based on the TF of the product. This finding suggests that the ingested dose should be calculated based on TSF. Dose of TSF ingested by children is similar whether family or children’s toothpaste is used.

  3. Estimation of atmospheric fluoride by limed filter papers

    International Nuclear Information System (INIS)

    The limed filter paper method of static sampling of atmospheric fluoride is reviewed in this report. Use of the technique, in conjunction with precise measurement of the absorbed fluoride and calibration with dynamic air sampling techniques, to estimate atmospheric fluoride levels, is considered to give only qualitative data (± 50%). The limed filter paper method is site specific due to variations in meteorological conditions. Its main value is to indicate seasonal and annual trends in fluoride exposure of vegetation. Subject to these considerations, the lower and upper limits of atmospheric fluoride exposure and the applicability to atmospheric fluoride estimation under routine or emergency fluoride release conditions are discussed, with special emphasis on the limiting factors

  4. A study of fluoride groundwater occurrence in Nathenje, Lilongwe, Malawi

    Science.gov (United States)

    Msonda, K. W. M.; Masamba, W. R. L.; Fabiano, E.

    A study was carried out to determine fluoride concentration in groundwaters of Nathenje area situated in Lilongwe District in the central region of Malawi. Water samples were collected from 176 boreholes and shallow wells during different months in 2001 and 2002. Samples were then analysed for fluoride by using a fluoride electrode and an ion selective meter. The results showed that fluoride concentrations for the rainy season varied from part of Nathenje had high fluoride concentration of between 2 and 7.02 mg/l and these high fluoride values seemed to extend eastwards beyond the boundary of the study area. However, the southern and western parts had dental fluorosis in areas where the fluoride concentration was high.

  5. FLUORIDE CONTENT OF COMMERCIALLY AVAILABLE SOY MILK PRODUCTS IN THAILAND.

    Science.gov (United States)

    Rirattanapong, Opas; Rirattanapong, Praphasri

    2016-01-01

    Abstract. In Thailand, the consumption of soy milk products is common but there is limited data about their fluoride content. The purpose of this study was to es- timate the fluoride content of soy milk products available in Thailand. Fluoride content was determined for 76 brands of soy milk using a F-ion-specific electrode. The fluoride concentrations ranged from 0.01 to 3.78 μg/ml. The fluoride content was not related to sugar content, soy bean content or the sterilization process. Among 3 brands of soy milk containing tea powder extract, the fluoride content was high (1.25 to 3.78 μg/ml). Most brands of soy milk tested in our study had fluoride content below the optimal daily intake but brands containing tea powder extract if consumed by children may increase their risk for fluorosis. PMID:27086437

  6. Separative recovery with lime of phosphate and fluoride from an acidic effluent containing H3PO4, HF and/or H2SiF6.

    Science.gov (United States)

    Gouider, Mbarka; Feki, Mongi; Sayadi, Sami

    2009-10-30

    formation, leading to CaF2 precipitate. Calcium fluoride and calcium phosphate based-by-products resulting from the two-step treatment process can be used as raw materials in several industrial sectors, such as ceramic and phosphate fertilizer industries. PMID:19524365

  7. Water fluoridation in 40 Brazilian cities: 7 year analysis

    Directory of Open Access Journals (Sweden)

    Suzely Adas Saliba MOIMAZ

    2013-01-01

    Full Text Available Objectives Fluoride levels in the public water supplies of 40 Brazilian cities were analyzed and classified on the basis of risk/benefit balance. Material and Methods Samples were collected monthly over a seven-year period from three sites for each water supply source. The samples were analyzed in duplicate in the laboratory of the Center for Research in Public Health - UNESP using an ion analyzer coupled to a fluoride-specific electrode. Results A total of 19,533 samples were analyzed, of which 18,847 were artificially fluoridated and 686 were not artificially fluoridated. In samples from cities performing water fluoridation, 51.57% (n=9,720 had fluoride levels in the range of 0.55 to 0.84 mg F/L; 30.53% (n=5,754 were below 0.55 mg F/L and 17.90% (n=3,373 were above 0.84 mg F/L (maximum concentration=6.96 mg F/L. Most of the cities performing fluoridation that had a majority of samples with fluoride levels above the recommended parameter had deep wells and more than one source of water supply. There was some variability in the fluoride levels of samples from the same site and between collection sites in the same city. Conclusions The majority of samples from cities performing fluoridation had fluoride levels within the range that provides the best combination of risks and benefits, minimizing the risk of dental fluorosis while preventing dental caries. The conduction of studies about water distribution systems is suggested in cities with high natural fluoride concentrations in order to optimize the use of natural fluoride for fluoridation costs and avoid the risk of dental fluorosis.

  8. Effects of fluoridated milk on root dentin remineralization.

    Directory of Open Access Journals (Sweden)

    Wolfgang H Arnold

    Full Text Available The prevalence of root caries is increasing with greater life expectancy and number of retained teeth. Therefore, new preventive strategies should be developed to reduce the prevalence of root caries. The aim of this study was to investigate the effects of fluoridated milk on the remineralization of root dentin and to compare these effects to those of sodium fluoride (NaF application without milk.Thirty extracted human molars were divided into 6 groups, and the root cementum was removed from each tooth. The dentin surface was demineralized and then incubated with one of the following six solutions: Sodium chloride NaCl, artificial saliva, milk, milk+2.5 ppm fluoride, milk+10 ppm fluoride and artificial saliva+10 ppm fluoride. Serial sections were cut through the lesions and investigated with polarized light microscopy and quantitative morphometry, scanning electron microscopy (SEM and energy-dispersive X-ray spectroscopy (EDS. The data were statistically evaluated using a one-way ANOVA for multiple comparisons.The depth of the lesion decreased with increasing fluoride concentration and was the smallest after incubation with artificial saliva+10 ppm fluoride. SEM analysis revealed a clearly demarcated superficial remineralized zone after incubation with milk+2.5 ppm fluoride, milk+10 ppm fluoride and artificial saliva+10 ppm fluoride. Ca content in this zone increased with increasing fluoride content and was highest after artificial saliva+10 ppm fluoride incubation. In the artificial saliva+10 ppm fluoride group, an additional crystalline layer was present on top of the lesion that contained elevated levels of F and Ca.Incubation of root dentin with fluoridated milk showed a clear effect on root dentin remineralization, and incubation with NaF dissolved in artificial saliva demonstrated a stronger effect.

  9. Fluoride uptake into the developing enamel and dentine of sheep incisors following daily ingestion of fluoridated milk or water

    International Nuclear Information System (INIS)

    The caries preventive action of fluoride is common knowledge, although some of the mechanisms involved remain equivocal. At present, raised local levels of fluoride at, or in, the surface of tooth enamel is the most commonly accepted explanation of the anti-cariogenic action of fluoride. However, fluoride incorporated as fluorapatite into the tooth during its formation remains a possible alternative or complementary anti-cariogenic mechanism. If so, regular ingestion of fluoride during tooth formation is beneficial. Although use of fluoridated water is the preferred method in public health programmes, access to suitable potable water is required, and often this in not feasible. Fresh, preserved, or dried cow's milk products are widely used as nutritional and dietary items in most populations, particularly for young children. Milk is a practical, controllable means for regular delivery of fluoride. Processing of milk is commonly centralised and uses standardised conditions, allowing easy supplementation of fluoride for distribution to communities. The purpose of this study was to resolve the question of availability of fluoride ingested in milk compared with fluoride ingested in water by measuring fluoride deposition in the developing permanent incisors of young sheep. Incisors were analysed using a proton microprobe. (author). 18 refs., 1 tabs., 3 figs

  10. Water Fluoridation: A Critical Review of the Physiological Effects of Ingested Fluoride as a Public Health Intervention

    Directory of Open Access Journals (Sweden)

    Stephen Peckham

    2014-01-01

    Full Text Available Fluorine is the world’s 13th most abundant element and constitutes 0.08% of the Earth crust. It has the highest electronegativity of all elements. Fluoride is widely distributed in the environment, occurring in the air, soils, rocks, and water. Although fluoride is used industrially in a fluorine compound, the manufacture of ceramics, pesticides, aerosol propellants, refrigerants, glassware, and Teflon cookware, it is a generally unwanted byproduct of aluminium, fertilizer, and iron ore manufacture. The medicinal use of fluorides for the prevention of dental caries began in January 1945 when community water supplies in Grand Rapids, United States, were fluoridated to a level of 1 ppm as a dental caries prevention measure. However, water fluoridation remains a controversial public health measure. This paper reviews the human health effects of fluoride. The authors conclude that available evidence suggests that fluoride has a potential to cause major adverse human health problems, while having only a modest dental caries prevention effect. As part of efforts to reduce hazardous fluoride ingestion, the practice of artificial water fluoridation should be reconsidered globally, while industrial safety measures need to be tightened in order to reduce unethical discharge of fluoride compounds into the environment. Public health approaches for global dental caries reduction that do not involve systemic ingestion of fluoride are urgently needed.

  11. Calcium D-saccharate

    DEFF Research Database (Denmark)

    Garcia, André Castilho; Hedegaard, Martina Vavrusova; Skibsted, Leif Horsfelt

    2016-01-01

    Molar conductivity of saturated aqueous solutions of calcium d-saccharate, used as a stabilizer of beverages fortified with calcium d-gluconate, increases strongly upon dilution, indicating complex formation between calcium and d-saccharate ions, for which, at 25 °C, Kassoc = 1032 ± 80, ΔHassoc......° = -34 ± 6 kJ mol-1, and ΔSassoc° = -55 ± 9 J mol-1 K-1, were determined electrochemically. Calcium d-saccharate is sparingly soluble, with a solubility product, Ksp, of (6.17 ± 0.32) × 10-7 at 25 °C, only moderately increasing with the temperature: ΔHsol° = 48 ± 2 kJ mol-1, and ΔSassoc° = 42 ± 7 J mol-1...... K-1. Equilibria in supersaturated solutions of calcium d-saccharate seem only to adjust slowly, as seen from calcium activity measurements in calcium d-saccharate solutions made supersaturated by cooling. Solutions formed by isothermal dissolution of calcium d-gluconate in aqueous potassium d...

  12. Experimental research on combustion fluorine retention using calcium-based sorbets during coal combustion (Ⅰ)

    Institute of Scientific and Technical Information of China (English)

    QI Qing-jie; LIN Zhi-yan; LIU Jian-zhong; WU Xian; ZHOU Jun-hu; CEN Ke-fa

    2008-01-01

    In order to provide experimental guide to commercial use of fluorine pollution control during coal combustion, with fluorine pollution control during coal combustion in mind, this paper proposed the theory of combustion fluorine retention technology. Feasibility of fluorine retention reaction with calcium-based fluorine retention agent was analyzed through thermo-dynamic calculation during coal combustion. By simulating the restraining and retention effects and influential factors of calcium-based sorbets on vaporized fluoride during experimental combustion using fixed bed tube furnace, the paper systematically explored the influential law of such factors as combustion temperature, retention time, and added quantities of calcium-based sorbets on effects of fluorine retention. The research result shows that adding calcium-based fluorine retention agent in coal combustion has double effects of fluorine retention and sulfur retention, it lays an experimental foundation for commercial test of combustion fluorine retention.

  13. Protective potential of casein phosphopeptide amorphous calcium phosphate containing paste on enamel surfaces

    OpenAIRE

    Padmini Somasundaram; Vimala, N; Lalita Gauri Mandke

    2013-01-01

    Background: Dental caries remains the most common dental disease facing mankind. Prevention of initiation and interruption in progression of early lesions are the desirable modes of caries management. There is a scope for agents, which may be used to enhance anti - caries activity. This need has redirected research to develop novel preventive agents that can act as an adjunct to fluoride or independent of it. Casein Phosphopeptide - Amorphous Calcium Phosphate (CPP-ACP) is one such agent that...

  14. Ability of Pit and Fissure Sealant-containing Amorphous Calcium Phosphate to inhibit Enamel Demineralization

    OpenAIRE

    Zawaideh, Feda I; Owais, Arwa I; Kawaja, Wasan

    2016-01-01

    ABSTRACT Aim: To evaluate the effect of amorphous calcium phosphate (ACP)-containing pit and fissure sealant on inhibition of enamel demineralization in vitro. Materials and methods: Enamel specimens (n = 75) were prepared using freshly extracted noncarious human third molars. Box-shaped cavities (8 × 2 × 2 mm) on the buccal or lingual surfaces were prepared and restored with resin-based sealant (Concise™), ACP-containing sealant (Aegis®) or fluoride-containing sealant (Conseal-F™). The sampl...

  15. Serum Calcium Level in Hypertension

    OpenAIRE

    Hazari, Mohammed Abdul Hannan; Arifuddin, Mehnaaz Sameera; Muzzakar, Syed; Reddy, Vontela Devender

    2012-01-01

    Background: The alterations in extracellular calcium level may influence intracellular calcium level and possibly play a role in the pathogenesis of essential hypertension. Aim: The purpose was to find out the association between serum calcium levels and hypertension; and to compare the serum calcium levels between normotensive controls, hypertensive subjects on calcium channel blockers, and hypertensive subjects on antihypertensive medication other than calcium channel blockers. Materials an...

  16. Effective use of fluorides for the prevention of dental caries in the 21st century

    DEFF Research Database (Denmark)

    Petersen, Poul Erik; Lennon, Michael A

    2004-01-01

    , due to changing living conditions and dietary habits, and inadequate exposure to fluorides. Research on the oral health effects of fluoride started around 100 years ago; the focus has been on the link between water and fluorides and dental caries and fluorosis, topical fluoride applications, fluoride...... toothpastes, and salt and milk fluoridation. Most recently, efforts have been made to summarize the extensive database through systematic reviews. Such reviews concluded that water fluoridation and use of fluoride toothpastes and mouthrinses significantly reduce the prevalence of dental caries. WHO recommends...... fluoridation schemes may be considered for prevention of dental caries....

  17. Peran kalsium sebagai prevensi terjadinya hipoplasia enamel (The role of calcium on enamel hypoplasia prevention

    Directory of Open Access Journals (Sweden)

    Soegeng Wahluyo

    2013-09-01

    Full Text Available Background: Fluoride is a trace element found in many natural and commonly consumed by humans in the form of fluoride salts such as Sodium Fluoride (NaF. The impacts that are most often caused by the intake of fluoride is a damage of enamel tooth/enamel hypoplasi or fluorosis. The manifestations of these effects are defects in teeth with whitish colour, brown to black colour effected on the aesthetic. So that the prevention of fluorosis is required. Purpose: The aim of this study was to analyze the effect of calcium as prevention against tooth enamel fluorosis in Wistar rats caused by exposure to fluoride through indicators of Amelogenin, Calbindin- 28kDa protein expression, the matrix of tooth enamel density and distance between ameloblast cell. Methods: This was an experimental studies, post-test only control group design. This study used three groups of rats. Group 1 (Control was induced by sterile destilled water, group 2 (treatment 1 was induced by fluoride and group 3 (treatment 2 was induced by combination of fluoride and calcium. Each induction was done through sonde for 28 days. results: The results showed that the induction of fluoride causes the increased expression of Amelogenin protein; decreased expression of Calbindin-28kDa protein; a decrease in the density of the enamel matrix and widen the distance between cells ameloblast, while the result of the combination induced by fluoride and calcium showed increased protein expression of Calbindin-28kDa and increased density of the enamel matrix. Conclusion: Calcium can be used as an alternative preventive against the occurrence of enamel hypoplasia due to exposure of fluoride in Wistar rats.latar belakang: Fluorida adalah salah satu trace element yang ada dialam dan sering dikonsumsi manusia dalam bentuk garam fluorida yaitu sodium fluoride (NaF. Paparan fluorida biasanya berkaitan dengan asupan fluorida yang dapat membahayakan enamel gigi yaitu terjadinya hipoplasia enamel atau

  18. Fluoride content of clay minerals and argillaceous earth materials

    Science.gov (United States)

    Thomas, J., Jr.; Glass, H.D.; White, W.A.; Trandel, R.M.

    1977-01-01

    A reliable method, utilizing a fluoride ion-selective electrode, is described for the determination of fluoride in clays and shales. Interference by aluminum and iron is minimal. The reproducibility of the method is about ??5% at different levels of fluoride concentration. Data are presented for various clay minerals and for the clays and shales. Fluoride values range from 44 ppm (0.0044%) for nontronite from Colfax, WA, to 51,800 ppm (5.18%) for hectorite from Hector, CA. In general, clays formed under hydrothermal conditions are relatively high in fluoride content, provided the hydrothermal waters are high in fluoride content. Besides hectorite, dickite from Ouray, CO, was found to contain more than 50 times as much fluoride (6700 ppm) as highly crystalline geode kaolinite (125 ppm). The clay stratum immediately overlying a fluorite mineralized zone in southern Illinois was found to have a higher fluoride content than the same stratum in a nonmineralized zone approximately 1 mile away. Nonmarine shales in contact with Australian coals were found to be lower in fluoride content than were marine shales in contact with Illinois coals. It is believed that, in certain instances, peak shifts on DTA curves of similar clay minerals are the result of significant differences in their fluoride content. ?? 1977.

  19. Community water fluoridation and caries prevention: a critical review.

    Science.gov (United States)

    Pizzo, Giuseppe; Piscopo, Maria R; Pizzo, Ignazio; Giuliana, Giovanna

    2007-09-01

    The aim of this paper was to critically review the current role of community water fluoridation in preventing dental caries. Original articles and reviews published in English language from January 2001 to June 2006 were selected through MEDLINE database. Other sources were taken from the references of the selected papers. For the past 50 years community water fluoridation has been considered the milestone of caries prevention and as one of the major public health measures of the 20th century. However, it is now accepted that the primary cariostatic action of fluoride occurs after tooth eruption. Moreover, the caries reduction directly attributable to water fluoridation have declined in the last decades as the use of topical fluoride had become more widespread, whereas enamel fluorosis has been reported as an emerging problem in fluoridated areas. Several studies conducted in fluoridated and nonfluoridated communities suggested that this method of delivering fluoride may be unnecessary for caries prevention, particularly in the industrialized countries where the caries level has became low. Although water fluoridation may still be a relevant public health measure in poor and disadvantaged populations, the use of topical fluoride offers an optimal opportunity to prevent caries among people living in both industrialized and developing countries. PMID:17333303

  20. Parabens do not increase fluoride uptake by dental enamel

    Directory of Open Access Journals (Sweden)

    Vanessa Silva Tramontino

    2010-04-01

    Full Text Available Objective: To evaluate whether methylparaben and propylparaben, which present a similar chemical structure, increase fluoride uptake by demineralized dental enamel when present in buffered solutions. Methods: The study comprised an in vitro experiment using blocks of bovine dental enamel with artificial carious lesions. Enamel blocks were exposed to the following treatment (n=12: fluoride solution (200 ppm fluoride - control; solution containing fluoride and 13 mM methylparaben; solution containing fluoride and 13 mM propylparaben in 35% propylene glycol; solution containing fluoride in 35% propylene glycol. All solutions were buffered (0.01 M cacodilate and the pH was adjusted to 6.27. The blocks were exposed to the treatment solutions in the proportion of 2 ml per mm2 of exposed enamel area and fluoride formed was estimated after removing an enamel layer by acid etching. Fluoride extracted was determined by ion specific electrode and the amount of enamel removed was estimated by phosphorus analysis. ANOVA followed by Tukey’s test were used for statistical analysis, with significance level at 5%. Results: The dental blocks of treatment groups containing both parabens and the control group presented similar fluoride concentration in enamel and no statistical difference was observed among them (p>0.05. The dental blocks of treatment group containing fluoride and propylene glycol showed the lowest value of fluoride present in enamel, which was significantly different from the control and fluoride and methylparaben groups (p<0.05. Conclusion: Methyl and propylparaben in a buffered solution do not enhance fluoride uptake by demineralized dental enamel.

  1. Urinary fluoride concentration as an estimator of welding fume exposure from basic electrodes.

    OpenAIRE

    Sjörgren, B; Hedström, L; Lindstedt, G.

    1984-01-01

    Urinary fluoride concentrations have been measured in electric arc welders using basic electrodes. The fluoride concentration and the total welding fume concentration in air showed a linear relation with postshift urinary fluoride concentration. The measured concentrations were below internationally recommended postshift urinary fluoride concentrations believed to cause fluorosis. Biological monitoring by postshift urinary fluoride measurements is evaluated for the prediction of total welding...

  2. Anticaries effect of dentifrices with calcium citrate and sodium trimetaphosphate

    Directory of Open Access Journals (Sweden)

    Alberto Carlos Botazzo Delbem

    2012-02-01

    Full Text Available Because of the growing concerns regarding fluoride ingestion by young children and dental fluorosis, it is necessary to develop new dentifrices. OBJECTIVE: The aim of this study was to evaluate the effect of dentifrices with calcium citrate (Cacit and sodium trimetaphosphate (TMP on enamel demineralization. MATERIAL AND METHODS: Enamel blocks (n=70, previously selected through surface hardness analysis, were submitted to daily treatment with dentifrices diluted in artificial saliva and to a pH-cycling model. The fluoride concentration in dentifrices was 0, 250, 450, 550, 1,000 and 1,100 µg F/g. CrestTM was used as a positive control (1,100 mg F/g. Cacit (0.25% and TMP (0.25% were added to dentifrices with 450 and 1,000 µg F/g. Surface hardness was measured again and integrated loss of subsurface hardness and fluoride concentration in enamel were calculated. Parametric and correlation tests were used to determine difference (p0.05. CONCLUSIONS: Dentifrices with 450 and 1,000 µg F/g, Cacit and TMP were as effective as a gold standard one.

  3. Characterization of transport of calcium by microsomal membranes from roots maize

    Energy Technology Data Exchange (ETDEWEB)

    Vaughan, M.A.

    1985-01-01

    This study investigates calcium transport by membranes of roots of maize isolated by differential centrifugation. The preparation was determined to be enriched in plasma membrane using market enzyme and electron microscopy. Using the /sup 45/Ca filtration technique and liquid scintillation counting, vesicular calcium uptake was shown to be stimulated by added calmodulin and specific for and dependent on ATP. Conditions for maximal calcium accumulation were found to be 30 min incubation in the presence of 5 mM ATP, 5 mM MgCl/sub 2/, 50 ..mu..M CaCl/sub 2/, at 23/sup 0/C, and at pH 6.5. Calcium uptake was inhibited by the ionophores A23187, X-537A, and ionomycin. Sodium fluoride, ruthenium red, and p-chloromercuribenzoate completely inhibited transport: diamide and vanadate produced slight inhibition; caffeine, caffeic acid, oligomycin, and ouabain produced little or no inhibition. Chlorpromazine, W7, trifluoperazine, and R 24 571 inhibit calcium uptake irrespective of added calmodulin, while W5 showed little effect on uptake. Verapamil, nifedipine, cinnarizine, flunarizine, lidoflazine, and diltiazem decreased calcium uptake by 17%-50%. Electron microscopic localization of calcium by pyroantimonate showed vesicles incubated with calmodulin and ATP showed the greatest amount of precipitate. These results suggest that these vesicles accumulate calcium in an ATP-dependent, calmodulin-stimulated manner.

  4. HYPERTHERMIA, INTRACELLULAR FREE CALCIUM AND CALCIUM IONOPHORES

    NARCIS (Netherlands)

    STEGE, GJJ; WIERENGA, PK; KAMPINGA, HH; KONINGS, AWT

    1993-01-01

    It is shown that heat-induced increase of intracellular calcium does not correlate with hyperthermic cell killing. Six different cell lines were investigated; in four (EAT, HeLa S3, L5178Y-R and L5178Y-S) heat treatments killing 90% of the cells did not affect the levels of intracellular free calciu

  5. Fluorine analysis of human dentin surrounding resin composite after fluoride application by μ-PIGE/PIXE analysis

    International Nuclear Information System (INIS)

    The use of fluoride for the prevention of caries is based on the transformation of hydroxylapatite to fluoroapatite in the presence of fluoride ions, thereby strengthening tooth structure. Adhesion of dentin and resin composite (tooth-colored restoration material) requires a dentin bonding system, since resin composite is not able to adhere to dentin directly. Demineralization of dentin by acid etching is an important step in the dentin bonding system, however, demineralization also introduces weaknesses in tooth structure. If the demineralized dentin could be strengthened by the application of fluoride, then the dentin-resin composite bond strength might also improve. To test this hypothesis, the present study evaluated the influence of fluoride applications on the strength of the dentin-resin composite bond by (1) tensile strength testing analyses, (2) SEM analyses of tooth structure, and (3) detection of calcium (Ca) and fluorine (F) distribution patterns by micro proton-induced X-ray emission (μ-PIXE) and micro proton-induced gamma-ray emission (μ-PIGE) analyses conducted at the Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) at the Takasaki Advanced Radiation Research Institute (TARRI). In this study, the dentin in extracted human molars was exposed by grinding and the dentin was etched with 35% phosphoric acid. Fluoride was applied at two concentrations, 0.022% (100 ppm F) and 2.21% (10,000 ppm F) NaF solution, for two time periods, 30 and 60 s, prior to bonding the resin composite with the treated dentin. Controls were prepared in the same manner, but without the fluoride application. Bond strength was measured with a micro-tensile testing unit, and the fluorine and calcium distributions at the interface between dentin and resin composite were detected by μ-PIGE and μ-PIXE analysis, respectively. Results indicate that the 10,000 ppm F applications resulted in higher bond strengths than observed in either the 100 ppm F applications or

  6. Fluorine analysis of human dentin surrounding resin composite after fluoride application by μ-PIGE/PIXE analysis

    Science.gov (United States)

    Okuyama, Katsushi; Komatsu, Hisanori; Yamamoto, Hiroko; Pereira, Patricia N. R.; Bedran-Russo, Ana K.; Nomachi, Masaharu; Sato, Takahiro; Sano, Hidehiko

    2011-10-01

    The use of fluoride for the prevention of caries is based on the transformation of hydroxylapatite to fluoroapatite in the presence of fluoride ions, thereby strengthening tooth structure. Adhesion of dentin and resin composite (tooth-colored restoration material) requires a dentin bonding system, since resin composite is not able to adhere to dentin directly. Demineralization of dentin by acid etching is an important step in the dentin bonding system, however, demineralization also introduces weaknesses in tooth structure. If the demineralized dentin could be strengthened by the application of fluoride, then the dentin-resin composite bond strength might also improve. To test this hypothesis, the present study evaluated the influence of fluoride applications on the strength of the dentin-resin composite bond by (1) tensile strength testing analyses, (2) SEM analyses of tooth structure, and (3) detection of calcium (Ca) and fluorine (F) distribution patterns by micro proton-induced X-ray emission (μ-PIXE) and micro proton-induced gamma-ray emission (μ-PIGE) analyses conducted at the Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) at the Takasaki Advanced Radiation Research Institute (TARRI). In this study, the dentin in extracted human molars was exposed by grinding and the dentin was etched with 35% phosphoric acid. Fluoride was applied at two concentrations, 0.022% (100 ppm F) and 2.21% (10,000 ppm F) NaF solution, for two time periods, 30 and 60 s, prior to bonding the resin composite with the treated dentin. Controls were prepared in the same manner, but without the fluoride application. Bond strength was measured with a micro-tensile testing unit, and the fluorine and calcium distributions at the interface between dentin and resin composite were detected by μ-PIGE and μ-PIXE analysis, respectively. Results indicate that the 10,000 ppm F applications resulted in higher bond strengths than observed in either the 100 ppm F applications or

  7. Fluorine analysis of human dentin surrounding resin composite after fluoride application by {mu}-PIGE/PIXE analysis

    Energy Technology Data Exchange (ETDEWEB)

    Okuyama, Katsushi, E-mail: katsu@den.hokudai.ac.jp [Graduate School of Dental Medicine, Hokkaido University, Department of Restorative Dentistry, Kita-13, Nishi-7, Kita-ku, Hokkaido, Sapporo 060-8586 (Japan) and School of Dentistry, University of North Carolina, Department of Operative Dentistry, 302 Brauer, CB 7450, Chapel Hill, NC 27599-7450 (United States); Komatsu, Hisanori [Graduate School of Dental Medicine, Hokkaido University, Department of Restorative Dentistry, Kita-13, Nishi-7, Kita-ku, Hokkaido, Sapporo 060-8586 (Japan); Yamamoto, Hiroko [Graduate School of Dentistry, Osaka University, 1-8 Yamada-Oka, Osaka, Suita 565-0871 (Japan); Pereira, Patricia N.R. [School of Dentistry, University of North Carolina, Department of Operative Dentistry, 302 Brauer, CB 7450, Chapel Hill, NC 27599-7450 (United States); Bedran-Russo, Ana K. [University of Illinois at Chicago, College of Dentistry, Department of Restorative Dentistry, 801 S. Paulina St., Chicago, IL 60612 (United States); Nomachi, Masaharu [Graduate School of Science, Osaka University, 1-1 Machikaneyama, Osaka, Toyonaka 560-0043 (Japan); Sato, Takahiro [TARRI, JAEA, Advanced Radiation Technology, 1233 Watanuki-machi, Gunma, Takasaki 370-1292 (Japan); Sano, Hidehiko [Graduate School of Dental Medicine, Hokkaido University, Department of Restorative Dentistry, Kita-13, Nishi-7, Kita-ku, Hokkaido, Sapporo 060-8586 (Japan)

    2011-10-15

    The use of fluoride for the prevention of caries is based on the transformation of hydroxylapatite to fluoroapatite in the presence of fluoride ions, thereby strengthening tooth structure. Adhesion of dentin and resin composite (tooth-colored restoration material) requires a dentin bonding system, since resin composite is not able to adhere to dentin directly. Demineralization of dentin by acid etching is an important step in the dentin bonding system, however, demineralization also introduces weaknesses in tooth structure. If the demineralized dentin could be strengthened by the application of fluoride, then the dentin-resin composite bond strength might also improve. To test this hypothesis, the present study evaluated the influence of fluoride applications on the strength of the dentin-resin composite bond by (1) tensile strength testing analyses, (2) SEM analyses of tooth structure, and (3) detection of calcium (Ca) and fluorine (F) distribution patterns by micro proton-induced X-ray emission ({mu}-PIXE) and micro proton-induced gamma-ray emission ({mu}-PIGE) analyses conducted at the Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) at the Takasaki Advanced Radiation Research Institute (TARRI). In this study, the dentin in extracted human molars was exposed by grinding and the dentin was etched with 35% phosphoric acid. Fluoride was applied at two concentrations, 0.022% (100 ppm F) and 2.21% (10,000 ppm F) NaF solution, for two time periods, 30 and 60 s, prior to bonding the resin composite with the treated dentin. Controls were prepared in the same manner, but without the fluoride application. Bond strength was measured with a micro-tensile testing unit, and the fluorine and calcium distributions at the interface between dentin and resin composite were detected by {mu}-PIGE and {mu}-PIXE analysis, respectively. Results indicate that the 10,000 ppm F applications resulted in higher bond strengths than observed in either the 100 ppm F

  8. Single application of casein phosphopeptide-amorphous calcium phosphate paste-based paste prevents in vitro erosive wear

    OpenAIRE

    Daniela Silva Barroso de Oliveira; Gabriela Cristina Santin; Heitor Marques Honorio; Daniela Rios; Patricia Hernandes Gaton; Léa Assed Bezerra da Silva; Fabio Lourenco Romano; Raquel Assed Bezerra da Silva

    2016-01-01

    Aim: The purpose of this study was to evaluate, in vitro, the effect of a single application of a casein phosphopeptide-amorphous calcium phosphate paste (CPP-ACP) in comparison with a fluoride varnish, in enamel of bovine teeth, after erosive challenge using cola soft drink. Materials and Methods: Forty-five enamel specimens were obtained from bovine teeth, selected according to the surface hardness and randomly divided into three groups: G1 - Fluoride varnish, G2 - CPP-ACP-based paste, and ...

  9. Analysis of differentially expressed genes between fluoride-sensitive and fluoride-endurable individuals in midgut of silkworm, Bombyx mori.

    Science.gov (United States)

    Qian, Heying; Li, Gang; He, Qingling; Zhang, Huaguang; Xu, Anying

    2016-08-15

    Fluoride tolerance is an economically important trait of silkworm. Near-isogenic lines (NILs) of the dominant endurance to fluoride (Def) gene in Bombyx mori has been constructed before. Here, we analyzed the gene expression profiles of midgut of fluoride-sensitive and fluoride-endurable individuals of Def NILs by using high-throughput Illumina sequencing technology and bioinformatics tools, and identified differentially expressed genes between these individuals. A total of 3,612,399 and 3,567,631 clean tags for the libraries of fluoride-endurable and fluoride-sensitive individuals were obtained, which corresponded to 32,933 and 43,976 distinct clean tags, respectively. Analysis of differentially expressed genes indicates that 241 genes are differentially expressed between the two libraries. Among the 241 genes, 30 are up-regulated and 211 are down-regulated in fluoride-endurable individuals. Pathway enrichment analysis demonstrates that genes related to ribosomes, pancreatic secretion, steroid biosynthesis, glutathione metabolism, steroid biosynthesis, and glycerolipid metabolism are down-regulated in fluoride-endurable individuals. qRT-PCR was conducted to confirm the results of the DGE. The present study analyzed differential expression of related genes and tried to find out whether the crucial genes were related to fluoride detoxification which might elucidate fluoride effect and provide a new way in the fluorosis research. PMID:27106117

  10. Revisiting the thermochemistry of chlorine fluorides

    CERN Document Server

    Sánchez, H R

    2016-01-01

    In this work, accurate calculations of standard enthalpies of formation of chlorine fluorides (ClF$_n$, n=1--7; Cl$_2$F and Cl$_3$F$_2$) were performed through the isodesmic reactions scheme. It is argued that, for many chlorine fluorides, the gold standard method of quantum chemistry (CCSD(T)) is not capable to predict enthalpy values nearing chemical accuracy if atomization scheme is used. This is underpinned by a thorough analysis of total atomization energy results and the inspection of multireference features of these compounds. Other thermodynamic quantities were also calculated at different temperatures. In order to complement the energetic description, elimination curves were studied through density functional theory as a computationally affordable alternative to highly correlated wave function-based methods.

  11. Plutonium oxide obtainment from a plutonium fluoride

    International Nuclear Information System (INIS)

    The need to recover the Pu existing in the Alpha Facility for the experimental fabrication of mixed oxides fuel elements (U,Pu)O2, its recovery has been set up from the F4Pu available at the laboratory. To fulfill the strict specifications on fluorides in nuclear fuels, it was necessary to precisely adjust the purification phase. This paper describes the chemical process for the PuO2 obtainment from F4Pu. F4Pu was dissolved in nitric acid, adding aluminium nitrate. The concentration in the medium decreases due to the complexes formation with fluorides and this allows the full dissolution of the salt. Pu separation was carried out by the treatment with RESINE DOWEX in columns. After purification with successive washes in NO3H7M, Pu elution retained in the column was performed. Finally, it precipitated as Pu IV oxalate and PuO2 was obtained by calcination at 700 deg C. (Author)

  12. Fluoridation and tooth wear in Irish adults.

    LENUS (Irish Health Repository)

    Burke, F M

    2010-10-01

    The aim of this study was to determine the prevalence of tooth wear in adults in Ireland and its relationship with water fluoridation. The National Survey of Adult Oral Health was conducted in 2000\\/2001. Tooth wear was determined using a partial mouth examination assessing the upper and lower anterior teeth. A total of 2456 subjects were examined. In this survey, increasing levels and severity of tooth wear were associated with ageing. Men were more affected by tooth wear and were more likely to be affected by severe tooth wear than women. It was found that age, and gender were significant predictors of tooth wear (P < 0.01). Overall, there was no significant relationship between fluoridation and tooth wear in this study.

  13. The hydride fluoride crystal structure database, HFD

    Energy Technology Data Exchange (ETDEWEB)

    Gingl, F.; Gelato, L.; Yvon, K. [Geneva Univ. (Switzerland). Lab. Crystallographie aux Rayons X

    1997-05-20

    HFD is a new data base containing crystal structure information on more than one thousand metal hydrides and fluorides. It includes space group, cell parameters, standardized atom positions, site occupancies and references. The compilation is critical as only refined crystal structures are considered and the data are checked for internal consistency. It is comprehensive as structural information is extracted from all major scientific journals, and it is continuously updated. HFD can be searched according to various criteria such as symmetry, chemical elements, composition etc. The primary motivation for creating HFD was to predict new metal hydrides and to study their structural analogies with metal fluorides. However, HFD can also be used for other applications such as the simulation of diffraction patterns and the drawing of crystal structures. (orig.) 13 refs.

  14. Fluoride solid electrolytes containing rare earth elements

    Institute of Scientific and Technical Information of China (English)

    Viera Trnovcová; Pavel P. Fedorov; Ivan Furár

    2008-01-01

    Relations between the structure, ionic conductivity and dielectric properties of fluoride systems of different structures containing rare earth elements were presented. Superionic conductivities, by fluoride ions, of fluorite-structured (MF2-REF3, M=Ba, Pb, RE=La-Lu, Sc, Y), orthorhombic (REF3, RE=Tb-Er,Y), tysonite-structured (REF3-MF2, RE=La-Nd, M=Sr), monoclinic (BaRE2F8, RE=Ho-Yb, Y) fluoride single crystals and eutectic composites (LiF-REF3, RE=La-Gd,Y) were compared. Anisotropy of electrical properties of crystals with a lower symmetry was explained by modeling optimum ionic paths. For explanation of concentration dependences of fast ionic conductivity, models of aggregation of defects into clusters were proposed. In fluorite-structured crystals, the highest ionic conductivity was found for PbF2: 7 mol% ScF3 (at 500 K, σ500=0.13 S/cm). In tysonite-structured crystals, the highest ionic conductivity was found for LaF3: 3 mol% SrF2 (σ500=2.4×10-2 S/cm). Different types of coordination polyhedrons and their different linking in orthorhombic and tysonite structure explained large differences between conductivities in both structures. Eutectic systems, prepared as directionally solidified composites, enabled to study some orthorhombic fluoride phases (GdF3, SmF3), which cannot be prepared as single crystals. An influence of the orthorhombic-tysonite phase transition on the ionic conductivity was shown.

  15. Health protection: Fluoridation and dental health.

    OpenAIRE

    1983-01-01

    Tooth decay, which affects 95 percent of Americans, is our most common health problem, costing an estimated +2 billion yearly for treatment. By the time children reach 17 years of age, 94 percent have experienced caries and 36 percent have lost one or more permanent teeth due to caries. Dental disease prevention embodies the spectrum of many activities from the fluoridation of community and school water supplies to the dental health education of the child and adult. At this stage of our knowl...

  16. Delivery Challenges for Fluoride, Chlorhexidine and Xylitol

    OpenAIRE

    Featherstone, John DB

    2006-01-01

    The progression or reversal of dental caries is determined by the balance between pathological and protective factors. It is well established that a) fluoride inhibits demineralization and enhances remineralization, b) chlorhexidine reduces the cariogenic bacterial challenge, and c) xylitol is non-cariogenic and has antibacterial properties. The challenge that we face is how best to deliver these anti-caries entities at true therapeutic levels, over time, to favorably tip the caries balance. ...

  17. Effect of fluoride toothpastes on enamel demineralization

    Directory of Open Access Journals (Sweden)

    Gintner Zeno

    2006-06-01

    Full Text Available Abstract Background It was the aim of this study to investigate the effect of four different toothpastes with differing fluoride compounds on enamel remineralization. Methods A 3 × 3 mm window on the enamel surface of 90 human premolars was demineralized in a hydroxyethylcellulose solution at pH 4.8. The teeth were divided into 6 groups and the lower half of the window was covered with varnish serving as control. The teeth were immersed in a toothpaste slurry containing: placebo tooth paste (group 1; remineralization solution (group 2; Elmex Anticaries (group 3; Elmex Sensitive (group 4; Blend-a-med Complete (group 5 and Colgate GRF (group 6. Ten teeth of each group were used for the determination of the F- content in the superficial enamel layer and acid solubility of enamel expressed in soluble phosphorus. Of 6 teeth of each group serial sections were cut and investigated with polarization light microscopy (PLM and quantitative energy dispersive X-ray analysis (EDX. Results The PLM results showed an increased remineralization of the lesion body in the Elmex Anticaries, Elmex Sensitive and Colgate GRF group but not in the Blend-a-med group. A statistically significant higher Ca content was found in the Elmex Anticaries group. The fluoride content in the superficial enamel layer was significantly increased in both Elmex groups and the Blend-a-med group. Phosphorus solubility was significantly decreased in both Elmex groups and the Blend-a-med group. Conclusion It can be concluded that amine fluoride compounds in toothpastes result in a clearly marked remineralization of caries like enamel lesions followed by sodium fluoride and sodium monofluorophosphate formulations.

  18. Necessity to review the Brazilian regulation about fluoride toothpastes

    Science.gov (United States)

    Cury, Jaime Aparecido; Caldarelli, Pablo Guilherme; Tenuta, Livia Maria Andaló

    2015-01-01

    The aim of this study was to evaluate the adequacy of the Brazilian legislation about fluoride toothpaste. A search was conducted in LILACS, Medline and SciELO databases about the fluoride concentration found in Brazilians toothpastes, using descriptors on health. Publications since 1981 have shown that some Brazilian toothpastes are not able to maintain, during their expiration time, a minimum of 1,000 ppm F of soluble fluoride in the formulation. However, the Brazilian regulation (ANVISA, Resolution 79, August 28, 2000) only sets the maximum total fluoride (0.15%; 1,500 ppm F) that a toothpaste may contain but not the minimum concentration of soluble fluoride that it should contain to have anticaries potential, which according to systematic reviews should be 1,000 ppm F. Therefore, the Brazilian regulation on fluoride toothpastes needs to be revised to assure the efficacy of those products for caries control. PMID:26487295

  19. [Problems of fluoride dosing to infants for dental fluorosis prevention].

    Science.gov (United States)

    Davydov, B N; Borinskaia, E Iu; Kushnir, S M; Borinskiĭ, Iu N; Beliaev, V V

    2011-01-01

    Fluoride content in drinking water, breast milk, cow milk, additional food for newborns prepared with water containing different amount of fluoride was determined. Fluoride excretion in urine since the first days of birth and up to 4 months of postnatal development was investigated in breast and artificially fed infants. When a neonate was fed with breast milk, fluoride was received in the amount no more than 20 mkg/day. The additional food contained fluoride which water mainly had. Water with high level of fluorine increased its content in the additional food up to the values not comparable to those in breast milk that presented danger of dental fluorosis development. Data on fluorine content in drinking water were absolutely necessary to calculate daily fluorides consumption by infants and to prevent dental fluorosis. PMID:21378727

  20. The effective use of fluorides in public health

    DEFF Research Database (Denmark)

    Jones, Sheila; Burt, Brian A; Petersen, Poul Erik;

    2005-01-01

    , systematic reviews summarizing these extensive databases have indicated that water fluoridation and fluoride toothpastes both substantially reduce the prevalence and incidence of dental caries. We present four case studies that illustrate the use of fluoride in modern public health practice, focusing on......Dental caries remain a public health problem for many developing countries and for underprivileged populations in developed countries. This paper outlines the historical development of public health approaches to the use of fluoride and comments on their effectiveness. Early research and...... development was concerned with waterborne fluorides, both naturally occurring and added, and their effects on the prevalence and incidence of dental caries and dental fluorosis. In the latter half of the 20th century, the focus of research was on fluoride toothpastes and mouth rinses. More recently...

  1. High Fluoride Dentifrices for Elderly and Vulnerable Adults

    DEFF Research Database (Denmark)

    Ekstrand, Kim Rud

    The primary aim of this work is to present the available evidence that toothpastes containing >1,500 ppm fluoride (2,500-2,800 and 5,000 ppm F) provide an additional caries preventive effect on root caries lesions in elderly patients compared to traditional dentifrices (1,000-1,450 ppm F). The...... secondary aim of this paper is to discuss why high fluoride dentifrices in general should perform better than traditional F-containing toothpaste. When examining the few studies that have considered the preventive benefits of high fluoride products on root caries the relative risk appears to be around 0.......5, and the risk can thus be halved by exchanging traditional F-containing toothpaste for toothpaste containing 5,000 ppm F. There is reasonable evidence that high fluoride dentifrices significantly increase the fluoride concentration in saliva during the day and the fluoride concentration in plaque...

  2. Necessity to review the Brazilian regulation about fluoride toothpastes

    Directory of Open Access Journals (Sweden)

    Jaime Aparecido Cury

    2015-01-01

    Full Text Available The aim of this study was to evaluate the adequacy of the Brazilian legislation about fluoride toothpaste. A search was conducted in LILACS, Medline and SciELO databases about the fluoride concentration found in Brazilians toothpastes, using descriptors on health. Publications since 1981 have shown that some Brazilian toothpastes are not able to maintain, during their expiration time, a minimum of 1,000 ppm F of soluble fluoride in the formulation. However, the Brazilian regulation (ANVISA, Resolution 79, August 28, 2000 only sets the maximum total fluoride (0.15%; 1,500 ppm F that a toothpaste may contain but not the minimum concentration of soluble fluoride that it should contain to have anticaries potential, which according to systematic reviews should be 1,000 ppm F. Therefore, the Brazilian regulation on fluoride toothpastes needs to be revised to assure the efficacy of those products for caries control.

  3. Adsorption of Fluoride Ion by Inorganic Cerium Based Adsorbent

    Institute of Scientific and Technical Information of China (English)

    Jiao Zhongzhi(焦中志); Chen Zhonglin; Yang Min; Zhang Yu; Li Guibai

    2004-01-01

    Excess of fluoride in drinking water is harmful to human health, the concentration of F- ions must be maintained in the range of 0.5 to 1.5 mg/L. An inorganic cerium based adsorbent (CTA) is developed on the basis of research of adsorption of fluoride on cerium oxide hydrate. Some adsorption of fluoride by CTA adsorbent experiments were carried out, and results showed that CTA adsorbent has a quick adsorption speed and a large adsorption capacity. Adsorption follows Freundlich isotherm, and low pH value helps fluoride removal. Some physical-chemical characteristics of CTA adsorbent were experimented, fluoride removal mechanism was explored, and results showed that hydroxyl group of CTA adsorbent played an important role in the fluoride removal.

  4. Distribution of fluoride in ground water of West Virginia

    Science.gov (United States)

    Mathes, M.V.; Waldron, M.C.

    1993-01-01

    This report describes the results of a study by the U.S. Geological Survey, in cooperation with the West Virginia Geological and Economic Survey, to evaluate the distribution of fluoride in ground water of West Virginia. Fluoride is a natural chemical constituent in domestic and public water supplies in West Virginia. Fluoride concentrations of about 1.0 milligram per liter in drinking water are beneficial to dental health. Concentrations greater than 2.0 milligrams per liter, however, could harm teeth and bones. Fluoride concentra- tions in ground water of West Virginia range from less than 0.1 to 12 milligrams per liter. Fluoride concentrations that exceed 2.0 milligrams per liter are found in wells drilled to all depths, wells drilled in all topographic settings, and wells drilled into most geologic units. Most fluoride concentrations that exceed 2.0 milligrams per liter are located at sites clustered in the northwestern part of the State.

  5. Bone scintigraphy in fluoride treated osteoporosis

    International Nuclear Information System (INIS)

    Quantitative bone scintigraphy was performed on 23 white females with post-menopausal osteoporosis and vertebral compression fractures. These patients were then entered into a randomized, double-blind clinical trial or sodium fluoride therapy (NaF=14, placebo=9) which included repeat bone scintigraphy every six months. Scintigraphic images were acquired for 500K counts per image over the total body with computer acquisition over the posterior thoracic and lumbar spine. Images were obtained on a wide field-of-view gamma camera two hours after injecting 15 mCi of Tc-99m MDP. Data analysis showed a significant reduction in the activity ratio of abnormal vertebral body to normal vertebral body in those patients treated with sodium fluoride (paired t-test p=0.0095). No significant change was observed in the control group of (p=0.142). These results suggest that sodium fluoride therapy promotes more rapid healing of osteoporotic vertebral fractures. They also demonstrate the utility of serial quantitative bone scintigraphy in assessing osteoporotic patients with vertebral compression fractures

  6. The electric field gradient in fluorides

    International Nuclear Information System (INIS)

    The electric quadrupole hyperfine interaction was investigated for various fluorides by the time-differential observation of the perturbed γ angular correlation and the Kern-Hanle effect of the 197 keV radiation of the 5/2+ level in 19F. This level was excited by inelastic proton scattering. The dependence of the quadrupole coupling constant from the chemical bond of the atom to its ligands was measured in fluorides of two-valid transition elements and in pureley covalent molecules, as (CF2)sub(n) or SF6. The influence of radiation-induced defects in nonmetals was investigated for cubic fluorides between 80 K and 1050 K. For CaF2 two different field gradients are obtained with coupling constants between 27 MHz and 3 MHz. By measurements of the angular distribution for CaF2/PrF3 mixed crystals which contain a variable concentration of F- interstitials was shown that the appearance of the 3 MHz frequency is correlated with the concentration of F- interstitials in CaF2. (BHO)

  7. Biological effects data: Fluoride and sulfur dioxide

    Energy Technology Data Exchange (ETDEWEB)

    McMechan, K.J. (ed.); Holton, R.L.; Ulbricht, R.J.; Morgan , J.B.

    1975-04-01

    The Alumax Pacific Aluminum Corporation has proposed construction of an aluminum reduction facility near Youngs Bay at Warrenton, Oregon. This report comprises one part of the final report to Alumax on a research project entitled, Physical, Chemical and Biological Studies of Youngs Bay.'' It presents data pertaining to the potential biological effects of fluoride and sulfur dioxide, two potentially hazardous plant-stack emissions, on selected aquatic species of the area. Companion volumes provide a description of the physical characteristics the geochemistry, and the aquatic animals present in Youngs Bay and adjacent ecosystems. An introductory volume provides general information and maps of the area, and summarizes the conclusions of all four studies. The data from the two phases of the experimental program are included in this report: lethal studies on the effects of selected levels of fluoride and sulfur dioxide on the survival rate of eleven Youngs Bay faunal species from four phyla, and sublethal studies on the effects of fluoride and sulfur dioxide on the rate of primary production of phytoplankton. 44 refs., 18 figs., 38 tabs.

  8. Comparison of the Effect of Fluoride and Non-fluoride Dentifriceson Enamel Demineralization and Remineralization in Vitro%含氟牙膏对釉质脱矿影响的体外研究

    Institute of Scientific and Technical Information of China (English)

    陈舟; 罗宗莲; 杨松

    2001-01-01

    目的:探讨国内常见市售含氟牙膏对完整釉质及脱矿釉质的作用。方法:测定市售的3种含氟牙膏的氟含量,并选取釉质完好的牛牙及人工龋脱矿的牛牙,用3种含氟牙膏和不含氟牙膏刷洗釉面后,乳酸处理1 min,用原子吸收光谱仪测定溶出的钙量。结果:含氟牙膏组和不含氟牙膏组均能使完整釉质的溶钙量明显降低,与空白对照组相比差异有显著性;含氟牙膏组和不含氟牙膏组均能使人工龋脱矿釉质的溶钙量明显下降,并且两组间有显著性差异。结论:含氟牙膏可以增强完整釉质及人工龋脱矿釉质的抗酸溶钙能力,且效果与其氟浓度相关,氟浓度为52.63 μmol/L时可显著提高牙齿抗酸力。%Objective: The purpose of the experiment is to investigate the effect of fluoride dentifrices in China on the intact and artificial caries-like bovine enamels. Methods: The artificial caries-like lesions were created by dipping the teeth into an acid buffered solution. Both the bovine intact enamels and the artificial caries-like enamels were assigned tooth brushing 20 times every half an hour with 3 kinds of fluoride dentifrices and one kind of non-fluoride dentifrices respectively. The amount of calcium dissolved by lactic acid was determined as the susceptibility of demineralization by atomic adsorption spectrometry (AAS). Results: The group treated with fluoride dentifrice showed significantly less demineralization than the non-fluoride group (P<0.02). The effect of inhibition of acid solubility in artificial caries-like enamel after tooth brushing is significantly greater than that in intact enamel. Conclusion: Fluoride dentifrices in this experiment can prevent both intact enamel and artificial caries-like enamel from acid solubility after tooth brushing, and it seems that the effect of the fluoride dentifrices on the redemineralization is greater than the reduction of enamel solubility.

  9. Studies on fluoride complexing of hexavalent actinides using a fluoride ion selective electrode

    International Nuclear Information System (INIS)

    Complex formation between actinide(VI) and fluoride ions in aqueous solutions was investigated using a fluoride ion selective electrode (F-ISE). As fairly high acidity used to suppress hydrolysis of the actinide(VI) ions, significant liquid junction potentials (Esub(j)) existed in the system. An iterative procedure was developed for computing free hydrogen ion concentration [Hsup(+)] as it colud not be measured directly, using data obtained with F-ISE. Esub(j) values were estimated from known [Hsup(+)] and the stability constants of fluoride complexes of actinide(VI) ions were calculated following King and Gallagher's method using a computer program. The stability constants were found to follow the order U(VI)>Np(VI)>Pu(VI). (author)

  10. Use of professionally administered topical fluorides in Asia

    OpenAIRE

    Tenuta, LMA; Fox, CH; Lo, ECM

    2012-01-01

    Professionally applied topical fluoride varnish, gel, and solution have been shown to be effective in preventing and in arresting dental caries. Their use in different countries in Asia varies greatly and may not correlate with the dental caries situation of the populations in the countries. In the higher-income countries, use of fluoride varnish and gel is common among dental professionals. In contrast, the use of professionally administered topical fluorides is not common in the lower-incom...

  11. The status of community water fluoridation in the United States.

    OpenAIRE

    Easley, M W

    1990-01-01

    Community water fluoridation has served the American public extremely well as the cornerstone of dental caries prevention activities for 45 years. The dental and general health benefits associated with the ingestion of water-borne fluorides have been well known by researchers for an even longer period. Continued research has repeatedly confirmed the safety, effectiveness, and efficiency of community water fluoridation in preventing dental caries for Americans regardless of age, race, ethnicit...

  12. Neuronal calcium sparks and intracellular calcium “noise”

    OpenAIRE

    Melamed-Book, Naomi; Kachalsky, Sylvia G.; Kaiserman, Igor; Rahamimoff, Rami

    1999-01-01

    Intracellular calcium ions are involved in many forms of cellular function. To accommodate so many control functions, a complex spatiotemporal organization of calcium signaling has developed. In both excitable and nonexcitable cells, calcium signaling was found to fluctuate. Sudden localized increases in the intracellular calcium concentration—or calcium sparks—were found in heart, striated and smooth muscle, Xenopus Laevis oocytes, and HeLa and P12 cells. In the nervous system, intracellular...

  13. Sodium fluoride influences the expression of keratins in cultured keratinocytes

    OpenAIRE

    Prado, Euridice; Wurtz, Tilmann; Ferbus, Didier; Shabana, El-Hassan; FOREST, Nadine; Berdal, Ariane

    2010-01-01

    Epithelia in lung, skin, and kidney are often exposed to fluoride, and tissue damage in lung and kidney due to fluoride is well documented. Nevertheless, the biological effects of fluoride on epithelia are poorly investigated. In the present study, we report effects of sodium fluoride (NaF) on the differentiation of a human epithelial cell line, HaCaT. These cells may serve as a keratinocyte model, because they express a wide spectrum of keratins (Ks), and they associate into stratified tissu...

  14. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

    Risnes, H.; Fjellerup, Jan Søren; Henriksen, Ulrik Birk;

    2003-01-01

    The present work focuses on the influence of calcium addition in gasification. The inorganic¿organic element interaction as well as the detailed inorganic¿inorganic elements interaction has been studied. The effect of calcium addition as calcium sugar/molasses solutions to straw significantly...... affected the ash chemistry and the ash sintering tendency but much less the char reactivity. Thermo balance test are made and high-temperature X-ray diffraction measurements are performed, the experimental results indicate that with calcium addition major inorganic¿inorganic reactions take place very late...... calcium binds silicon primarily as calcium silicates and less as potassium calcium silicates....

  15. Total Fluoride Intake and Urinary Excretion in German Children Aged 3–6 Years

    OpenAIRE

    Haftenberger, Marjolein; Viergutz, Gabriele; Neumeister, Volker; Hetzer, Gisela

    2014-01-01

    There have only been few investigations comparing total fluoride intake and the fluoride proportion excreted in urine in pre–school children. In addition, the results of available studies are conflicting. Total fluoride intake was assessed in 11 healthy children aged 3–6 years on 2 consecutive days and urinary fluoride excretion was determined. The duplicate–diet approach was used for the assessment of fluoride intake from solid and liquid foods. Fluoride intake from toothbrushing was calcula...

  16. Effect of exercise on fluoride metabolism in adult humans: a pilot study

    OpenAIRE

    Fatemeh V. Zohoori; Alison Innerd; Azevedo, Liane B; Whitford, Gary M.; Anne Maguire

    2015-01-01

    An understanding of all aspects of fluoride metabolism is critical to identify its biological effects and avoid fluoride toxicity in humans. Fluoride metabolism and subsequently its body retention may be affected by physiological responses to acute exercise. This pilot study investigated the effect of exercise on plasma fluoride concentration, urinary fluoride excretion and fluoride renal clearance following no exercise and three exercise intensity conditions in nine healthy adults after taki...

  17. Calcium binding by dietary fibre

    International Nuclear Information System (INIS)

    Dietary fibre from plants low in phytate bound calcium in proportion to its uronic-acid content. This binding by the non-cellulosic fraction of fibre reduces the availability of calcium for small-intestinal absorption, but the colonic microbial digestion of uronic acids liberates the calcium. Thus the ability to maintain calcium balance on high-fibre diets may depend on the adaptive capacity on the colon for calcium. (author)

  18. [Calcium suppletion for patients who use gastric acid inhibitors: calcium citrate or calcium carbonate?].

    NARCIS (Netherlands)

    Jonge, H.J. de; Gans, R.O.; Huls, G.A.

    2012-01-01

    Various calcium supplements are available for patients who have an indication for calcium suppletion. American guidelines and UpToDate recommend prescribing calcium citrate to patients who use antacids The rationale for this advice is that water-insoluble calcium carbonate needs acid for adequate ab

  19. Scientific Opinion on Dietary Reference Values for fluoride

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA

    2013-08-01

    Full Text Available Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies (NDA derived Dietary Reference Values (DRVs for fluoride, which are provided as Adequate Intake (AI from all sources, including non-dietary sources. Fluoride is not an essential nutrient. Therefore, no Average Requirement for the performance of essential physiological functions can be defined. Nevertheless, the Panel considered that the setting of an AI is appropriate because of the beneficial effects of dietary fluoride on prevention of dental caries. The AI is based on epidemiological studies (performed before the 1970s showing an inverse relationship between the fluoride concentration of water and caries prevalence. As the basis for defining the AI, estimates of mean fluoride intakes of children via diet and drinking water with fluoride concentrations at which the caries preventive effect approached its maximum whilst the risk of dental fluorosis approached its minimum were chosen. Except for one confirmatory longitudinal study in US children, more recent studies were not taken into account as they did not provide information on total dietary fluoride intake, were potentially confounded by the use of fluoride-containing dental hygiene products, and did not permit a conclusion to be drawn on a dose-response relationship between fluoride intake and caries risk. The AI of fluoride from all sources (including non-dietary sources is 0.05 mg/kg body weight per day for both children and adults, including pregnant and lactating women. For pregnant and lactating women, the AI is based on the body weight before pregnancy and lactation. Reliable and representative data on the total fluoride intake of the European population are not available.

  20. Calcium in plant cells

    Directory of Open Access Journals (Sweden)

    V. V. Schwartau

    2014-04-01

    Full Text Available The paper gives the review on the role of calcium in many physiological processes of plant organisms, including growth and development, protection from pathogenic influences, response to changing environmental factors, and many other aspects of plant physiology. Initial intake of calcium ions is carried out by Ca2+-channels of plasma membrane and they are further transported by the xylem owing to auxins’ attractive ability. The level of intake and selectivity of calcium transport to ove-ground parts of the plant is controlled by a symplast. Ca2+enters to the cytoplasm of endoderm cells through calcium channels on the cortical side of Kaspary bands, and is redistributed inside the stele by the symplast, with the use of Ca2+-АТPases and Ca2+/Н+-antiports. Owing to regulated expression and activity of these calcium transporters, calclum can be selectively delivered to the xylem. Important role in supporting calcium homeostasis is given to the vacuole which is the largest depo of calcium. Regulated quantity of calcium movement through the tonoplast is provided by a number of potential-, ligand-gated active transporters and channels, like Ca2+-ATPase and Ca2+/H+ exchanger. They are actively involved in the inactivation of the calcium signal by pumping Ca2+ to the depo of cells. Calcium ATPases are high affinity pumps that efficiently transfer calcium ions against the concentration gradient in their presence in the solution in nanomolar concentrations. Calcium exchangers are low affinity, high capacity Ca2+ transporters that are effectively transporting calcium after raising its concentration in the cell cytosol through the use of protons gradients. Maintaining constant concentration and participation in the response to stimuli of different types also involves EPR, plastids, mitochondria, and cell wall. Calcium binding proteins contain several conserved sequences that provide sensitivity to changes in the concentration of Ca2+ and when you

  1. Irradiation effects on microhardness of fluoridated and non-fluoridated bovine dentin

    International Nuclear Information System (INIS)

    The objective of this study was to evaluate the effects of irradiation on microhardness of dentin. Dentin blocks from the cervical region of bovine incisors were treated as follows: 1) no irradiation; 2) irradiation of specimens up to 60 Gy (2Gy/day, 5 days/week); 3) no irradiation, but fluoridation of specimens for 5 min/d; 4) irradiation of specimens and daily fluoridation. Knoop hardness number (KHN) of the control specimens was 62.63±14.75 (mean±SD). This was significantly different from the irradiated dentin samples (8.74±2.59 KHN). Hardness of the fluoridated dentin specimens was 11.19±1.95 KHN in the non-irradiated group and 10.03±2.75 KHN in the irradiated groups, respectively. Within the limitations of an in vitro study, it is concluded that dentin is severely affected by irradiation. This could be an explanation for the frequently observed side-effects of irradiation like loss of enamel, gap formation at the amelodentinal junction, and caries of the cervical region. Fluoridation with acidic gels decereases microhardness of dentin surface, and does not prevent softening due to radiation, when saliva is absent. (au)

  2. Synthesis and characterization of ruthenium fluorides and oxide fluorides with high oxidation states

    International Nuclear Information System (INIS)

    The synthesis of ruthenium fluorides and oxide fluorides with high oxidation states was attempted from dioxide RuO2 and tetroxide RuO4. Three fluorinating agents were used: fluorine, chlorine trifluoride and krypton difluoride. The reactions were achieved in anhydrous hydrogen fluoride at room temperature. Thus, the reaction of RuO4 with CIF3 enabled us to prepare chloryl hexafluororuthenate (V), CIO2+ RuF6-, a new compound well identified by vibrational spectroscopy (infra-red and Raman), the structure of which was determined. The reaction of KrF2 with RuO4 gave the oxide tetrafluoride RuOF4, the previously published syntheses and properties of which were not in agreement with each other. This compound was definitely characterized here by chemical analysis, infra-red spectroscopy and X-ray powder diffraction. The product of thermal decomposition (700C) of RuOF4 is presumably RuF4 since only oxygen is liberated during this decomposition. At last, the reaction of KrF2 with RuO2 probably leads to the formation of the new oxide fluoride RuO2F4. Indeed, no oxygen is given off during this reaction, the chemical analysis of the red-orange coloured solid residue is almost in agreement with the one proposed and its infra-red absorption spectrum indicates the presence of ruthenium-oxygen and ruthenium-terminal and bridging fluorine bonds

  3. Synthesis and characterization of ruthenium fluorides and oxide fluorides with high oxidation states

    International Nuclear Information System (INIS)

    The synthesis of ruthenium fluorides and oxide fluorides with high oxidation states was attempted from dioxide RuO2 and tetroxide RuO4. Three fluorinating agents were used: fluorine, chlorine trifluoride and krypton difluoride. The reactions were achieved in anhydrous hydrogen fluoride at room temperature. Thus, the reaction of RuO4 with CIF3 enabled us to prepare chloryl hexafluororuthenate (V), ClO2+ RuF6-, a new compound well idendified by vibrational spectroscopy (infra-red and Raman), the structure of which was determined. The reaction of KrF2 with RuO4 gave the oxide tetrafluoride RuOF4, the previously published syntheses and properties of which were not in agreement with each other. This compound was definitely characterized here by chemical analysis, infra-red spectroscopy and X-ray powder diffraction. The product of thermal decomposition (700C) of RuOF4 is presumably RuF4 since only oxygen is liberated during this decomposition. At last, the reaction of KrF2 with RuO2 probably leads to the formation of the new oxide fluoride RuO2F4. Indeed, no oxygen is given off during this reaction, the chemical analysis of the red-orange coloured solid residue is almost in agreement with the one proposed and its infra-red absorption spectrum indicates the presence of ruthenium-oxygen and ruthenium-terminal and bridging fluorine bonds

  4. Method for decontamination of nickel-fluoride-coated nickel containing actinide-metal fluorides

    Science.gov (United States)

    Windt, N.F.; Williams, J.L.

    In one aspect, the invention comprises contacting nickel-fluoride-coated nickel with gaseous ammonia at a temperature effecting nickel-catalyzed dissociation thereof and effecting hydrogen-reduction of the nickel fluoride. The resulting nickel is heated to form a melt and a slag and to effect transfer of actinide metals from the melt into the slag. The melt and slag are then separated. In another aspect, nickel contianing nickel oxide and actinide metals is contacted with ammonia at a temperature effecting nickel-catalyzed dissociation to effect conversion of the nickel oxide to the metal. The resulting nickel is then melted and separated as described. In another aspect nickel-fluoride-coated nickel containing actinide-metal fluorides is contacted with both steam and ammonia. The resulting nickel then is melted and separated as described. The invention is characterized by higher nickel recovery, efficient use of ammonia, a substantial decrease in slag formation and fuming, and a valuable increase in the service life of the furnace liners used for melting.

  5. CAN FLUORIDATION AFFECT LEAD (II) IN POTABLE WATER? HEXAFLUOROSILICATE AND FLUORIDE EQUILIBRIA IN AQUEOUS SOLUTION

    Science.gov (United States)

    Recent reports have attempted to show that fluoridating potable water is linked to increased levels of lead(II) in the blood. We examine these claims in light of the established science and critically evaluate their significance. The completeness of hexafluorosilicate hydrolysi...

  6. Effects of fluoride on proliferation and mineralization in periodontal ligament cells in vitro.

    Science.gov (United States)

    Li, K Q; Jia, S S; Ma, M; Shen, H Z; Xu, L; Liu, G P; Huang, S Y; Zhang, D S

    2016-07-11

    Fluoride, which is often added to toothpaste or mouthwash in order to protect teeth from decay, may be a novel therapeutic approach for acceleration of periodontal regeneration. Therefore, we investigated the effects of fluoride on proliferation and mineralization in human periodontal ligament cells in vitro. The periodontal ligament cells were stimulated with various concentrations of NaF added into osteogenic inductive medium. Immunohistochemistry of cell identification, cell proliferation, alkaline phosphatase (ALP) activity assay, Alizarin red S staining and quantitative real-time-polymerase chain reaction (RT-PCR) were performed. Moderate concentrations of NaF (50-500 μmol/L) had pro-proliferation effects, while 500 μmol/L had the best effects. ALP activity and calcium content were significantly enhanced by 10 μmol/L NaF with osteogenic inductive medium. Quantitative RT-PCR data varied in genes as a result of different NaF concentrations and treatment periods. We conclude that moderate concentrations of NaF can stimulate proliferation and mineralization in periodontal ligament cells. These in vitro findings may provide a novel therapeutic approach for acceleration of periodontal regeneration by addition of suitable concentrations of NaF into the medication for periodontitis treatment, i.e., into periodontal packs and tissue patches. PMID:27409336

  7. Preparation of fluoride substituted apatite cements as the building blocks for tooth enamel restoration

    Science.gov (United States)

    Wei, Jie; Wang, Jiecheng; Liu, Xiaochen; Ma, Jian; Liu, Changsheng; Fang, Jing; Wei, Shicheng

    2011-06-01

    Fluoride substituted apatite cement (fs-AC) was synthesized by using the cement powders of tetracalcium phosphate (TTCP) and sodium fluoride (NaF), and the cement powders were mixed with diluted phosphoric acid (H 3PO 4) as cement liquid to form fs-AC paste. The fs-AC paste could be directly filled into the carious cavities to repair damaged dental enamel. The results indicated that the fs-AC paste was changed into fluorapatite crystals with the atom molar ratio for calcium to phosphorus of 1.66 and the F ion amount of 3 wt% after self-hardening for 2 days. The solubility of fs-AC in Tris-HCl solution (pH 6) was slightly lower than hydroxyapatite cement (HAC) that was similar to the apatite in enamel, indicating the fs-AC was much insensitive to the weakly acidic solution than the apatite in enamel. The fs-AC was tightly combined with the enamel surface because of the chemical reaction between the fs-AC and the apatite in enamel after the caries cavities was filled with fs-AC. The extracts of fs-AC caused no cytotoxicity on L929 cells, which satisfied the relevant criterion on dental biomaterials, revealing good cytocompatibility. The fs-AC had potential prospect for the reconstitution of carious lesion of dental enamel.

  8. Preparation of fluoride substituted apatite cements as the building blocks for tooth enamel restoration

    Energy Technology Data Exchange (ETDEWEB)

    Wei Jie [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Inter-disciplinary Studies, Peking University, Beijing 100871 (China); Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Wang Jiecheng; Liu Xiaochen [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Inter-disciplinary Studies, Peking University, Beijing 100871 (China); Ma Jian [Hospital of Stomatology, Tongji University, Shanghai 200072 (China); Liu Changsheng [Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Fang Jing, E-mail: biomater2006@yahoo.com.cn [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Inter-disciplinary Studies, Peking University, Beijing 100871 (China); Wei Shicheng, E-mail: nic7505@263.net [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Inter-disciplinary Studies, Peking University, Beijing 100871 (China) and School and Hospital of Stomatology, Peking University, Beijing 100081 (China)

    2011-06-15

    Fluoride substituted apatite cement (fs-AC) was synthesized by using the cement powders of tetracalcium phosphate (TTCP) and sodium fluoride (NaF), and the cement powders were mixed with diluted phosphoric acid (H{sub 3}PO{sub 4}) as cement liquid to form fs-AC paste. The fs-AC paste could be directly filled into the carious cavities to repair damaged dental enamel. The results indicated that the fs-AC paste was changed into fluorapatite crystals with the atom molar ratio for calcium to phosphorus of 1.66 and the F ion amount of 3 wt% after self-hardening for 2 days. The solubility of fs-AC in Tris-HCl solution (pH 6) was slightly lower than hydroxyapatite cement (HAC) that was similar to the apatite in enamel, indicating the fs-AC was much insensitive to the weakly acidic solution than the apatite in enamel. The fs-AC was tightly combined with the enamel surface because of the chemical reaction between the fs-AC and the apatite in enamel after the caries cavities was filled with fs-AC. The extracts of fs-AC caused no cytotoxicity on L929 cells, which satisfied the relevant criterion on dental biomaterials, revealing good cytocompatibility. The fs-AC had potential prospect for the reconstitution of carious lesion of dental enamel.

  9. Preparation of fluoride substituted apatite cements as the building blocks for tooth enamel restoration

    International Nuclear Information System (INIS)

    Fluoride substituted apatite cement (fs-AC) was synthesized by using the cement powders of tetracalcium phosphate (TTCP) and sodium fluoride (NaF), and the cement powders were mixed with diluted phosphoric acid (H3PO4) as cement liquid to form fs-AC paste. The fs-AC paste could be directly filled into the carious cavities to repair damaged dental enamel. The results indicated that the fs-AC paste was changed into fluorapatite crystals with the atom molar ratio for calcium to phosphorus of 1.66 and the F ion amount of 3 wt% after self-hardening for 2 days. The solubility of fs-AC in Tris-HCl solution (pH 6) was slightly lower than hydroxyapatite cement (HAC) that was similar to the apatite in enamel, indicating the fs-AC was much insensitive to the weakly acidic solution than the apatite in enamel. The fs-AC was tightly combined with the enamel surface because of the chemical reaction between the fs-AC and the apatite in enamel after the caries cavities was filled with fs-AC. The extracts of fs-AC caused no cytotoxicity on L929 cells, which satisfied the relevant criterion on dental biomaterials, revealing good cytocompatibility. The fs-AC had potential prospect for the reconstitution of carious lesion of dental enamel.

  10. Optical restoration of irradiated lead fluoride crystals

    International Nuclear Information System (INIS)

    Due to its relatively high resistance to high radiation, lead fluoride (PbF2) crystals are becoming an increasingly popular material of choice for electromagnetic calorimetry, such as for experiments requiring the measurement of high-energy photons in Hall A of Jefferson Lab. For our studies we irradiated the PbF2 crystals using an electron linear accelerator (LINAC) followed by exposing the crystals to blue light so as to restore the nominal optical properties. This technique of optical bleaching with blue light affords an efficient and low-cost means for reversing the deleterious effects of optical transmission loss in radiation-damaged lead fluoride crystals. Whereas earlier experiments irradiated the PbF2 samples with 1.1 and 1.3 MeV γs from 60Co, we used pulsed beams of energetic electrons from the tunable 25-MeV LINAC at Idaho Accelerator Center of Idaho State University in Pocatello, Idaho. A 20-MeV beam of electrons was targeted onto four separate 19 cm length samples of lead fluoride over periods of 1, 2, and 4 hours yielding doses between 7 kGy and 35 kGy. Samples were then bleached with blue light of wavelength 410 - 450 nm for periods between 19.5 and 24 hours. We performed this process twice - radiation, bleaching, radiation, and then followed by bleaching again - for each of these four PbF2 samples. We shall discuss the efficacy of blue light curing on samples that have undergone two cycles of electron irradiation and optical bleaching

  11. Optical restoration of irradiated lead fluoride crystals

    International Nuclear Information System (INIS)

    Due to its relatively high resistance to high radiation, lead fluoride (PbF2) crystals are becoming an increasingly popular material of choice for electromagnetic calorimetry, such as for experiments requiring the measurement of high-energy photons in Hall A of Jefferson Lab. For our studies we irradiated the PbF2 crystals using an electron linear accelerator (LINAC) followed by exposing the crystals to blue light so as to restore the nominal optical properties. This technique of optical bleaching with blue light affords an efficient and low-cost means for reversing the deleterious effects of optical transmission loss in radiation-damaged lead fluoride crystals. Whereas earlier experiments irradiated the PbF2 samples with 1.1 and 1.3 MeV γs from 60Co, we used pulsed beams of energetic electrons from the tunable 25-MeV LINAC at Idaho Accelerator Center of Idaho State University in Pocatello, Idaho. A 20-MeV beam of electrons was targeted onto four separate 19 cm length samples of lead fluoride over periods of 1, 2, and 4 hours yielding doses between 7 kGy and 35 kGy. Samples were then bleached with blue light of wavelength 410 - 450 nm for periods between 19.5 and 24 hours. We performed this process twice - radiation, bleaching, radiation, and then followed by bleaching again - for each of these four PbF2 samples. We shall discuss the efficacy of blue light curing on samples that have undergone two cycles of electron irradiation and optical bleaching. (author)

  12. Optical Restoration of Lead Fluoride Crystals

    International Nuclear Information System (INIS)

    Due to its relatively high resistance to high radiation, lead fluoride (PbF2) crystals are becoming an increasingly popular material of choice for electromagnetic calorimetry, such as for experiments requiring the measurement of high-energy photons in Hall A of Jefferson Lab. For our studies we irradiated the PbF2 crystals using an electron linear accelerator (LINAC) followed by exposing the crystals to blue light so as to restore the nominal optical properties. This technique of optical bleaching with blue light affords an efficient and low-cost means for reversing the deleterious effects of optical transmission loss in radiation-damaged lead fluoride crystals. Whereas earlier experiments irradiated the PbF2 samples with 1.1 and 1.3 MeV gammas from 60Co, we used pulsed beams of energetic electrons from the tunable 25-MeV LINAC at Idaho Accelerator Center of Idaho State University in Pocatello, Idaho. A 20-MeV beam of electrons was targeted onto four separate 19 cm length samples of lead fluoride over periods of 1, 2, and 4 hours yielding doses between 7 kGy and 35 kGy. Samples were then bleached with blue light of wavelength 410-450 nm for periods between 19.5 and 24 hours. We performed this process twice - radiation, bleaching, radiation, and then followed by bleaching again - for each of these four PbF2 samples. We shall discuss the efficacy of blue light curing on samples that have undergone two cycles of electron irradiation and optical bleaching.

  13. Methods of controlling hydrogen fluoride pressure during chemical fabrication processes

    Science.gov (United States)

    Solovyov, Vyacheslav; Wiesmann, Harold

    2009-11-24

    The present invention is a method for producing a crystalline end-product. The method comprising exposing a fluoride-containing precursor to a hydrogen fluoride absorber under conditions suitable for the conversion of the precursor into the crystalline end-product.

  14. Fluoride and children's intelligence: a meta-analysis.

    Science.gov (United States)

    Tang, Qin-Qing; Du, Jun; Ma, Heng-Hui; Jiang, Shao-Jun; Zhou, Xiao-Jun

    2008-01-01

    This paper presents a systematic review of the literature concerning fluoride that was carried out to investigate whether fluoride exposure increases the risk of low intelligence quotient (IQ) in China over the past 20 years. MEDLINE, SCI, and CNKI search were organized for all documents published, in English and Chinese, between 1988 and 2008 using the following keywords: fluorosis, fluoride, intelligence, and IQ. Further search was undertaken in the website www.fluorideresearch.org because this is a professional website concerning research on fluoride. Sixteen case-control studies that assessed the development of low IQ in children who had been exposed to fluoride earlier in their life were included in this review. A qualitative review of the studies found a consistent and strong association between the exposure to fluoride and low IQ. The meta-analyses of the case-control studies estimated that the odds ratio of IQ in endemic fluoride areas compared with nonfluoride areas or slight fluoride areas. The summarized weighted mean difference is -4.97 (95%confidence interval [CI] = -5.58 to -4.36; p < 0.01) using a fixed-effect model and -5.03 (95%CI = -6.51 to 3.55; p < 0.01) using a random-effect model, which means that children who live in a fluorosis area have five times higher odds of developing low IQ than those who live in a nonfluorosis area or a slight fluorosis area. PMID:18695947

  15. Fluoride uptake from restorative dental materials by human enamel

    International Nuclear Information System (INIS)

    The purpose of the study was to determine the uptake in vitro of fluoride from restorative materials by tooth enamel and whether prior etching of the enamel causes a change of uptake. The outermost layer of the labial surface of extracted canines was removed by grinding and the enamel was covered with five different fluoride-containing materials ; a silicate, a composite resin, an amalgam, a silicophosphate, and a polycarboxylate luting cement. The material was either removed immediately or after storing the tooth in distilled water. The fluoride content was determined using a sensitive physical method based on the 19F (p, αγ) 16O reaction. In addition, the fluoride content of enamel after etching for different periods of time and of etched enamel which had been in contact with silicate cement was determined. The mean fluoride content of uncovered interior enamel was 226 parts 106. All materials, except the composite, increased clearly the fluoride content of the underlying enamel. Etching of interior enamel also increased the fluoride values. No difference could be shown in fluoride uptake from silicate and composite resin between etched and unetched enamel. (author)

  16. Computational investigation of the role of fluoride in Tamao oxidations

    DEFF Research Database (Denmark)

    Mader, Mary M.; Norrby, Per-Ola

    2002-01-01

    The Tamao oxidation of alkoxysilanes was investigated computationally to determine the role of fluoride. a key additive. in this reaction. A sequence of fluoride equilibria as well as possible transition states. mediated by basic and neutral peroxide, respectively, were examined, and a potential...

  17. Fluoride Analysis. Training Module 5.200.2.77.

    Science.gov (United States)

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with fluoride analysis procedures. Included are objectives, an instructor guide, student handouts, and a list of reference material. This module considers the determination of fluoride in water supplies using the SPANDS and electrode…

  18. Fluoride inhibits the response of bone cells to mechanical loading

    NARCIS (Netherlands)

    H.M.E. Willems; E.G.H.M. van den Heuvel; S. Castelein; J. Keverling Buisman; A.L.J.J. Bronckers; A.D. Bakker; J. Klein-Nulend

    2011-01-01

    The response of bone cells to mechanical loading is mediated by the cytoskeleton. Since the bone anabolic agent fluoride disrupts the cytoskeleton, we investigated whether fluoride affects the response of bone cells to mechanical loading, and whether this is cytoskeleton mediated. The mechano-respon

  19. Calculation of vapor pressure of fission product fluorides and oxyfluorides

    International Nuclear Information System (INIS)

    The equilibrium diagrams of the condensed phases - solid and liquid - and vapor phase are collected for the principal fluorides and oxyfluorides of fission product elements (atomic number from 30 to 66). These diagrams are used more particularly in fuel reprocessing by fluoride volatility process. Calculations and curves (vapor pressure in function of temperature) are processed using a computer program given in this report

  20. Electrorecovery of tantalum in molten fluorides

    International Nuclear Information System (INIS)

    Considering the privileged situation of Brazil as a productor of tantaliferous minerals, the authors have in view the development of a technology for production of metallic tantalum via molten salts electrolysis; this has the advantage of improving the aggregate value of exportation products, additionally to tantalum oxide and tantalum concentrates. Having in view the preliminary determintion of better conditions of temperature, electrolyte composition and current density for this process, electrolysis were conducted with a solvent composed of an eutetic mixture of lithium, sodium and potassium fluoride for dipotassium fluotantalate and occasionally for tantalum oxide. Current efficiencies as high as 83% were obtained in favoured conditions. (author)

  1. LUMINESCENCE IN POTENTIAL FLUORIDE GLASS LASERS

    OpenAIRE

    Jørgensen, C.

    1987-01-01

    Fluoride glasses of the zirconium barium lanthanide type (invented Rennes, 1975) and lead gallium zinc (or manganese) type (invented Le Mans, 1979) show luminescence of lanthanide J-Levels situated at least 2000 cm-1 above the closest lower level (this limit is a few times larger in most other materials). Not only is the non-radiative de-excitation as weak as incrystalline LaF3 (studied by Weber) but energy transfer between neodymium and ytterbium (III), or from manganese (II), and to some ex...

  2. Fluoride microresonators for mid-IR applications

    CERN Document Server

    Grudinin, Ivan S; Yu, Nan

    2016-01-01

    We study crystalline fluoride microresonators for mid-infrared applications. Whispering gallery mode resonators were fabricated with BaF$_2$, CaF$_2$ and MgF$_2$ crystals. The quality factors were measured at wavelengths of 1.56 {\\mu}m and 4.58 {\\mu}m. The impacts of fabrication technique, impurities, multiphonon absorption and surface water are investigated. It is found that MgF2 resonators have room temperature Q factor of $8.3\\times 10^6$ at wavelength of 4.58 {\\mu}m, limited by multiphonon absorption.

  3. Role of Fish Oil against Physiological Disturbances in Rats Brain Induced by Sodium Fluoride and/or Gamma Rays

    International Nuclear Information System (INIS)

    The impacts of environmental and occupational exposure to ionizing radiation and to long-term intake of high levels of fluoride have caused health problems and increasingly alarming in recent years. Fish oil omega-3 (polyunsaturated fatty acids essential fatty acids) is found in the highest concentrations in fish oil, claim a plethora of health benefits. The objective of the present study was to evaluate the role of fish oil rich in omega-3 fatty acids on sodium fluoride (NaF) and or gamma (γ) rays in inducing neurological and biochemical disturbances in rat’s brain cerebral hemispheres. The results revealed that whole body exposure to γ- radiation at 6 Gy applied as fractionated doses (1.5 Gy x 4 times) and/or chronic receipt of NaF solution (0.13 mg/Kg/day) for a period of 28 days, significantly increased brain fluoride and calcium content, decreased level of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) and induced brain oxidative stress which led to neurotransmitters dysfunction. Supplementation of treated rats with fish oil, via gavages, at a dose of 400 mg/kg body wt has significantly modulated oxidative stress and neurotransmitters alterations. It could be concluded that EPA and DHA, found in fish oil, could possibly protect brain from damaging free radicals and consequently minimize the severity of brain biochemical disturbances

  4. Synthesis and crystal structures of novel LaOAgS-type alkaline earth – Zinc, manganese, and cadmium fluoride pnictides

    Energy Technology Data Exchange (ETDEWEB)

    Charkin, Dmitri O., E-mail: charkin@inorg.chem.msu.ru; Urmanov, Arthur V.; Plokhikh, Igor V.; Korshunov, Alexander D.; Kuznetsov, Alexey N.; Kazakov, Sergey M.

    2014-02-05

    Highlights: • Sight new alkaline earth – Mn, Zn, Cd fluoride pnictides were prepared. • All new compounds adopt the LaOAgS structure type. • Bond distances in their structures are transferable within 2–3%. • Very close similarities are observed in structural chemistry of LaOAgS- and HfCuSi{sub 2}-type compounds of Mn, Cu, Zn, Ag, and Cd. -- Abstract: Systematic studies of the LaOAgS-type compounds among alkaline earth – Zn/Cd/Mn fluoride pnictides revealed the existence of new representatives SrFMnP, SrFMnAs, SrFMnSb, SrFZnAs, SrFZnSb, BaFZnAs, BaFCdP, and BaFCdAs. Similar to rare-earth oxide compounds and contrary to isolobal chalcogenides of Cu/Ag, not all possible compositions could be realized. No compound of the structure type is formed for calcium; strontium forms fluoride pnictides only with zinc and manganese, while for barium, new representatives are also formed with cadmium. This trend, which possibly has a geometrical origin, is corroborated by quantum chemical calculations. Formation of NdOZnP-type compounds also was not observed suggesting the structure to be characteristic only for rare earth – zinc oxide phosphides.

  5. Fluoride use in Controlling Dental Caries and Fluorosis

    Directory of Open Access Journals (Sweden)

    Gaurav Solanki

    2012-07-01

    Full Text Available Policy were introduced to control fluoride exposure and to reduce the prevalence of fluorosis. The study aimed of describing the prevalence, severity and risk factors for fluorosis, and to describe the trend of fluorosis among Indian children. The study also aimed of exploring the effect of the change in fluoride exposure on dental fluorosis and caries. Establishing an appropriate use of fluoride toothpaste could be successful in reducing fluorosis without a significant increase in caries experience. The use of fluorides for oral health has always involved a balance between the protective benefit against dental caries and the risk of developing fluorosis. The link between fluoride and dental health was established to determining the causes of dental fluorosis or enamel mottling. Fluorosis in Indian children was highly prevalent in the early 1990s.

  6. KINETICS OF SORPTION OF FLUORIDE ON CALCINED MAGNESITE IN BATCH

    DEFF Research Database (Denmark)

    Singano, J. J.; Mashauri, D. A.; Mtalo, F. W.;

    1997-01-01

    on first-order reaction with respect to the concentration of fluoride. The rate constant is directly proportional to the dosage. The model takes into accounts the lag time observed. The kinetical model can be described for any given dosage and initial fluoride concentration in the water. The reaction...... rate parameter, K, varies however slightly for different initial concentrations of fluoride in the water and different dosage of calcined magnesia. These relationships are described separately by two linear equations. It is discussed that the observed lag time is due to the fact that magnesia cannot......A series of sorption of fluoride on calcined magnesite are obtained from thermostatic pH-chemostat and jar test experiments. The fluoride removal is observed not to start instantly, as normal, but after a lag time of up to ½ an hour of contact time. A model for sorption kinetics is developed, based...

  7. Milk fluoridation for the prevention of dental caries

    Directory of Open Access Journals (Sweden)

    Jolán Bánóczy

    2013-11-01

    Full Text Available The aim of this review is to give an overview of 55 years experience of milk fluoridation and draw conclusions about the applicability of the method. Fluoridated milk was first investigated in the early 1950s, almost simultaneously in Switzerland, the USA and Japan. Stimulated by the favourable results obtained from these early studies, the establishment of The Borrow Dental Milk Foundation (subsequently The Borrow Foundation in England gave an excellent opportunity for further research, both clinical and non-clinical, and a productive collaboration with the World Health Organization which began in the early 1980s. Numerous peer-reviewed publications in international journals showed clearly the bioavailability of fluoride in various types of milk. Clinical trials were initiated in the 1980s – some of these can be classed as randomised controlled trials, while most of the clinical studies were community preventive programmes. Conclusion. These evaluations showed clearly that the optimal daily intake of fluoride in milk is effective in preventing dental caries. The amount of fluoride added to milk depends on background fluoride exposure and age of the children: commonly in the range 0.5 to 1.0 mg per day. An advantage of the method is that a precise amount of fluoride can be delivered under controlled conditions. The cost of milk fluoridation programmes is low, about € 2 to 3 per child per year. Fluoridation of milk can be recommended as a caries preventive measure where the fluoride concentration in drinking water is suboptimal, caries experience in children is significant, and there is an existing school milk programme.

  8. Caries prevention through the fluoridation of milk. A review.

    Science.gov (United States)

    Bánóczy, Jolán; Rugg-Gunn, Andrew J

    2007-10-01

    The aim of this review is to give an overview of 50 years experience of milk fluoridation and draw conclusions about the applicability of the method. Fluoridated milk was first investigated in the early 1950s, almost simultaneously in Switzerland, the USA and Japan. Stimulated by the favourable results obtained from these early studies, the establishment of The Borrow Dental Milk Foundation (subsequently The Borrow Foundation) in England gave an excellent opportunity for further research, both clinical and non-clinical, and a productive collaboration with the World Health Organization from the early 1980s onwards. Numerous peer-reviewed publications in international journals showed clearly the bioavailability of fluoride in milk, and increased concentrations of fluoride in saliva, dental plaque, dental enamel and dentine, and urine, after consumption of fluoridated milk. Clinical trials were initiated in the 1980s--some of these can be classed as randomised controlled trials, while most of the clinical studies were community preventive programs. These evaluations showed clearly that the optimal daily intake of fluoride in milk is effective in preventing dental caries. At present, milk fluoridation programs are running continuously in about ten countries of the world. Fluoridation of milk can be recommended as a caries preventive measure where the fluoride concentration in drinking water is suboptimal, caries experience in children is significant, and there is an existing school milk program. The program should aim to provide fluoridated milk for at least 200 days per year and should commence before the children are 4 years of age. PMID:18078140

  9. Fluoride-induced disruption of reproductive hormones in men

    International Nuclear Information System (INIS)

    Fluoride-induced reproductive effects have been reported in experimental models and in humans. However, these effects were found in heavily exposed scenarios. Therefore, in this work our objective was to study reproductive parameters in a population exposed to fluoride at doses of 3-27 mg/day (high-fluoride-exposed group--HFEG). Urinary fluoride levels, semen parameters, and reproductive hormones in serum (LH, FSH, estradiol, prolactin, inhibin-B, free and total testosterone) were measured. Results were compared with a group of individuals exposed to fluoride at lower doses: 2-13 mg/day (low-fluoride-exposed group-LFEG). A significant increase in FSH (P<0.05) and a reduction of inhibin-B, free testosterone, and prolactin in serum (P<0.05) were noticed in the HFEG. When HFEG was compared to LFEG, a decreased sensitivity was found in the FSH response to inhibin-B (P<0.05). A significant negative partial correlation was observed between urinary fluoride and serum levels of inhibin-B (r=-0.333, P=0.028) in LFEG. Furthermore, a significant partial correlation was observed between a chronic exposure index for fluoride and the serum concentrations of inhibin-B (r=-0.163, P=0.037) in HFEG. No abnormalities were found in the semen parameters studied in the present work, neither in the HFEG, nor in the LFEG. The results obtained indicate that a fluoride exposure of 3-27 mg/day induces a subclinical reproductive effect that can be explained by a fluoride-induced toxic effect in both Sertoli cells and gonadotrophs

  10. Gravimetric Determination of Calcium as Calcium Carbonate Hydrate.

    Science.gov (United States)

    Henrickson, Charles H.; Robinson, Paul R.

    1979-01-01

    The gravimetric determination of calcium as calcium carbonate is described. This experiment is suitable for undergraduate quantitative analysis laboratories. It is less expensive than determination of chloride as silver chloride. (BB)

  11. Hydrogen Fluoride in the Local Universe

    Science.gov (United States)

    Monje, Raquel R.; Lis, Dariusz C.; Phillips, Thomas G.

    2015-01-01

    The Herschel Space Observatory has provided a unique opportunity to study hydride molecules with large rotational constant in the interstellar medium (ISM) within the nearby universe. Some of the key results from hydride studies with Herschel, and in particular with the Heterodyne Instrument for the Far-Infrared (HIFI), are the first detection at high spectral resolution of the fundamental J = 1 - 0 rotational transition of hydrogen fluoride (HF) at 1.232 THz, and the discovery of its ubiquitous nature within the ISM of the Milky Way galaxy and nearby galaxies. The remarkable Herschel/ HIFI results suggest, that the HF J = 1 - 0 transition promises to yield an extremely sensitive probe of the diffuse molecular gas along the lines of sight toward background far-infrared continuum sources and, as predicted earlier by chemical models, a valuable surrogate for molecular hydrogen in the nearby and high redshift universe. These and other interesting results on hydrogen fluoride from Herschel observations will be presented, as well as the results from follow-up studies from ground-base facilities on hydride molecules towards luminous lensed high-redshifted galaxies with strong submillimeter continuum.

  12. Polyvinylidene fluoride - a polymer as transducer material

    International Nuclear Information System (INIS)

    Polyvinylidene fluoride or PVDF is a flexible, thin piezo film and long chain semicrystalline polymer containing repeated of CH/sub 2/ - CH/sub 2/. In order to obtain desired piezoelectric properties PVDF is poled by subjecting it to high electric field. In poled PVDF piezoelectric constants have different values for each axis and one constant per axis. PVDF polymer exhibits generator and motor action. Usually 1000 A /sup o/ thick vacuum-deposited aluminum electrodes are formed on both sides of the sheet. Polymer material of PVDF can be used as a sensing element with temperature range of -40 /sup 0/ C to 100 /sup 0/C and a frequency range of 10/sup -3/ to 10/sup -9/ Hz. This paper includes as experimental observation of exciting aluminium open-ended tube at its resonance using PVDF transducer and maintained in this condition using phase lock loop or PLL. The tube is free to resonate when 9-micrometer thin polyvinylidene fluoride transducer is energized. It is observed that a film of such material can easily be used to produced the requisite vibrations in the tube. (author)

  13. Lanthanum fluoride nanoparticles for radiosensitization of tumors

    Science.gov (United States)

    Kudinov, Konstantin; Bekah, Devesh; Cooper, Daniel; Shastry, Sathvik; Hill, Colin; Bradforth, Stephen; Nadeau, Jay

    2016-03-01

    Dense inorganic nanoparticles have recently been identified as promising radiosensitizers. In addition to dose enhancement through increased attenuation of ionizing radiation relative to biological tissue, scintillating nanoparticles can transfer energy to coupled photosensitizers to amplify production of reactive oxygen species, as well as provide UVvisible emission for optical imaging. Lanthanum fluoride is a transparent material that is easily prepared as nanocrystals, and which can provide radioluminescence at a number of wavelengths through simple substitution of lanthanum ions with other luminescent lanthanides. We have prepared lanthanum fluoride nanoparticles doped with cerium, terbium, or both, that have good spectral overlap with chlorine6 or Rose Bengal photosensitizer molecules. We have also developed a strategy for stable conjugation of the photosensitizers to the nanoparticle surface, allowing for high energy transfer efficiencies on a per molecule basis. Additionally, we have succeeded in making our conjugates colloidally stable under physiological conditions. Here we present our latest results, using nanoparticles and nanoparticle-photosensitizer conjugates to demonstrate radiation dose enhancement in B16 melanoma cells. The effects of nanoparticle treatment prior to 250 kVp x-ray irradiation were investigated through clonogenic survival assays and cell cycle analysis. Using a custom apparatus, we have also observed scintillation of the nanoparticles and conjugates under the same conditions that the cell samples are irradiated.

  14. Luminescence in potential fluoride glass lasers

    International Nuclear Information System (INIS)

    Fluoride glasses of the zirconium barium lanthanide type (invented Rennes, 1975) and lead gallium zinc (or manganese) type (invented Le Mans, 1979) show luminescence of lanthanide J-Levels situated at least 2000 cm-1 above the closest lower level (this limit is a few times larger in most other materials). Not only is the non-radiative de-excitation as weaK as in crystalline LaF3 (studied by Weber) but energy transfer between neodymium and ytterbium(III), or from manganese(II), and to some extent from chromium(III), to luminescent J-levels of neodymium(III), erbium(III) and thullium(III) is highly efficient even at low concentrations. One advantage for laser applications is that the lowest quartet state of manganese(II) has a life-time 10 to 15 milliseconds (like in many phosphate glasses and crystalline compounds) allowing energy transfer, extending by huge factors the average life-time of the emitting J-levels. Though the tera-watt lasers (Livermore, California, 1978) inducing deuterium-tritium fusion are silicate glass containing neodymium(III), fluoride glasses should be preferable for many purposes. The evaluation of laser parameters from small-scale experimentation is feasible

  15. CALCIUM SOAP LUBRICANTS

    OpenAIRE

    Alaz, Izer; Tugce, Nefise; Devrim, Balköse

    2014-01-01

    The article studies the properties of calcium stearate (CaSt2) and lubricants produced on its basis. These lubricants were prepared using sodium stearate and calcium chloride by subsidence from aqueous solutions. The CaSt2 and the light fraction of crude oil were mixed together to obtain lubricating substances. The article shows that CaSt2 had the melting temperature of 142.8 C that is higher than the melting temperature of crude oil (128 C). The compositions of obtained lubricants were stu...

  16. CALCIUM-INDUCED SUPRAMOLECULAR STRUCTURES IN THE CALCIUM CASEINATE SYSTEM

    Science.gov (United States)

    The molecular details deciphering the spontaneous calcium-induced protein aggregation process in the calcium caseinate system remain obscure. Understanding this complex process could lead to potential new applications of this important food ingredient. In this work, we studied calcium-induced supra...

  17. Efficacy of casein phosphopeptide-amorphous calcium phosphate to prevent stain absorption on freshly bleached enamel: An in vitro study

    OpenAIRE

    Raghuwar D Singh; Ram, Sabita M; Shetty, Omkar; Chand, Pooran; Yadav, Rakesh

    2010-01-01

    Background: Teeth when subjected to bleaching bring about the desiccation of the enamel, making it more susceptible to stain absorption. While subjecting the freshly bleached enamel surface to various surface treatments of Fluoride and Casein Phosphopeptide - Amorphous Calcium phosphate (CPP-ACP) brought about the reduction in stain absorption, which is assessed in this study. Aims: The study aims to evaluate the tea stain absorption on freshly bleached enamel surface of extracted human teeth...

  18. Fluorine uptake into human enamel around fluoride-containing dental materials during cariogenic pH cycling

    International Nuclear Information System (INIS)

    Using PIGE (Proton Induced Gamma Emission) technique at TARRI (Takasaki Advanced Radiation Research Institute), Japan, we measured fluorine (F) uptake into the tooth enamel around two fluoride-containing materials during caries progression using pH cycling. Class V cavities in extracted human teeth were drilled and filled with fluoride-containing materials (i.e. 'Fuji IX' (FN) and 'UniFil flow with MEGA bond' (UF)) and a non-fluoride-containing material (i.e. 'SOLARE with MEGA bond' (SO)). Three 120 μm longitudinal sections including the filling material were obtained from each tooth. In order to simulate daily acid attack occurring in the oral cavity, the pH cycling (pH 6.8-4.5) was carried out for 1, 3 and 5 weeks, separately. After pH cycling, the caries progression in all specimens was observed using transverse microradiography (TMR). The F and calcium distributions of the specimens were evaluated using PIGE and PIXE techniques. The F distribution of the specimens clearly showed the F uptake from FN into enamel adjacent to the filling material, while the F uptakes from UF and SO were not detected. For UF, the MEGA bond (non-fluoride-containing) between the tooth and UniFil flow interfered with the F absorption into the tooth. For FN, the amount of F uptake into the subsurface enamel increased during pH cycling. The amount of F uptake in 5-week pH cycling had significantly higher value compared to those in 1- and 3-week pH cycling. For UF and SO, there were no significant differences between the different durations of pH cycling. Among fluoride-containing materials, there were some differences in the F uptake with increased pH cycling, which could possibly lead to obtaining difference in clinical performance. The data obtained using PIGE and PIXE techniques were useful in understanding the benefit of fluorine by means of fluoride-containing material for preventing caries.

  19. Fluorine uptake into human enamel around fluoride-containing dental materials during cariogenic pH cycling

    Energy Technology Data Exchange (ETDEWEB)

    Komatsu, H. [Graduate School of Dental Medicine, Hokkaido University, Kita-13, Nishi-7, Kita-ku, Sapporo 060-8586 (Japan)], E-mail: kom@den.hokudai.ac.jp; Yamamoto, H. [Graduate School of Dentistry, Osaka University, 1-8 Yamada-Oka, Suita 565-0871 (Japan); Nomachi, M. [Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043 (Japan); Yasuda, K. [The Wakasa wan Energy Research Center, 64-52-1 Hase, Tsuruga 914-0192 (Japan); Matsuda, Y.; Kinugawa, M.; Kijimura, T.; Sano, H. [Graduate School of Dental Medicine, Hokkaido University, Kita-13, Nishi-7, Kita-ku, Sapporo 060-8586 (Japan); Satou, T.; Oikawa, S.; Kamiya, T. [Advanced Radiation Technology, TARRI, JAEA, 1233 Watanuki-machi, Takasaki 370-1292 (Japan)

    2009-06-15

    Using PIGE (Proton Induced Gamma Emission) technique at TARRI (Takasaki Advanced Radiation Research Institute), Japan, we measured fluorine (F) uptake into the tooth enamel around two fluoride-containing materials during caries progression using pH cycling. Class V cavities in extracted human teeth were drilled and filled with fluoride-containing materials (i.e. 'Fuji IX' (FN) and 'UniFil flow with MEGA bond' (UF)) and a non-fluoride-containing material (i.e. 'SOLARE with MEGA bond' (SO)). Three 120 {mu}m longitudinal sections including the filling material were obtained from each tooth. In order to simulate daily acid attack occurring in the oral cavity, the pH cycling (pH 6.8-4.5) was carried out for 1, 3 and 5 weeks, separately. After pH cycling, the caries progression in all specimens was observed using transverse microradiography (TMR). The F and calcium distributions of the specimens were evaluated using PIGE and PIXE techniques. The F distribution of the specimens clearly showed the F uptake from FN into enamel adjacent to the filling material, while the F uptakes from UF and SO were not detected. For UF, the MEGA bond (non-fluoride-containing) between the tooth and UniFil flow interfered with the F absorption into the tooth. For FN, the amount of F uptake into the subsurface enamel increased during pH cycling. The amount of F uptake in 5-week pH cycling had significantly higher value compared to those in 1- and 3-week pH cycling. For UF and SO, there were no significant differences between the different durations of pH cycling. Among fluoride-containing materials, there were some differences in the F uptake with increased pH cycling, which could possibly lead to obtaining difference in clinical performance. The data obtained using PIGE and PIXE techniques were useful in understanding the benefit of fluorine by means of fluoride-containing material for preventing caries.

  20. A modified fluoride reduction route for the preparation of thorium metal

    International Nuclear Information System (INIS)

    Thorium oxide is one of the most stable oxides known in nature. Commercially, thorium metal is produced by calciothermic reduction of its oxide. The process leads to the production of thorium powders, which if not handled carefully, can often lead to oxygen contamination in the final metal. In this paper, we report an alternative possibility of producing bulk thorium metal by calciothermic reduction of its fluorides. Fluoride being less hygroscopic and having higher boiling and melting point is preferred over the chloride intermediate. The process involves mixing of as prepared ThF4 and 20% excess calcium in a crucible in an argon environment and heating the charge to beyond the melting point of thorium. The heat of reaction during calcium reduction of thorium fluoride is not sufficient to increase the temperature of the reacted mass to above the melting points of the products. This is unlike the common metallothermic reduction process, viz. thermit process, in which both the products, the metal and the slag, melt due to the intense heat of the reaction and separate from each other due to density difference. The slag-metal separation in this process has to be ensured by heating the charge to above the melting point of the higher melting substance, otherwise a mixture of CaF2 and thorium metal would result. The reaction sequence of the process was studied by a visual observation. Besides, liquid thorium being very reactive, a proper choice of crucible material becomes important. In this paper, we describe our experiences on the interaction of liquid thorium with the crucible materials. In this work, we used two kind of crucibles: standard molybdenum crucibles and custom made fully dense yttria crucibles. Yttria crucibles of 25 mm dia and 85 mm length were specially made by Glass and Advanced Materials Division, Materials Group. An alternative route for production of metallic thorium is reported. The advantage in the process is that it can make thorium in bulk form

  1. Influence of Calcium Phosphate and Apatite Containing Products on Enamel Erosion

    Science.gov (United States)

    Kensche, A.; Pötschke, S.; Hannig, C.; Richter, G.; Hoth-Hannig, W.; Hannig, M.

    2016-01-01

    For the purpose of erosion prevention the present study aimed to compare the efficacy of two biomimetic products and a fluoride solution to optimize the protective properties of the pellicle. After 1 min of in situ pellicle formation on bovine enamel slabs, 8 subjects adopted CPP-ACP (GC Tooth Mousse), a mouthwash with hydroxyapatite microclusters (Biorepair), or a fluoride based mouthwash (elmex Kariesschutz) for 1 min each. Afterwards, samples were exposed in the oral cavity for 28 min. Native enamel slabs and slabs exposed to the oral cavity for 30 min without any rinse served as controls. After oral exposure, slabs were incubated in HCl (pH values 2, 2.3, and 3) for 120 s and kinetics of calcium and phosphate release were measured photometrically; representative samples were evaluated by SEM and TEM. The physiological pellicle reduced demineralization at all pH values; the protective effect was enhanced by fluoride. The biomimetic materials also reduced ion release but their effect was less pronounced. SEM indicated no layer formation after use of the different products. However, TEM confirmed the potential accumulation of mineral components at the pellicle surface. The tested products improve the protective properties of the in situ pellicle but not as effectively as fluorides. PMID:27430013

  2. A sensor for calcium uptake

    OpenAIRE

    Collins, Sean; Meyer, Tobias

    2010-01-01

    Mitochondria — the cell’s power plants — increase their energy production in response to calcium signals in the cytoplasm. A regulator of the elusive mitochondrial calcium channel has now been identified.

  3. Children's Bone Health and Calcium

    Science.gov (United States)

    ... Trials Resources and Publications Children's Bone Health and Calcium: Condition Information Skip sharing on social media links ... straight, walk, run, and lead an active life. Calcium is one of the key dietary building blocks ...

  4. Calcium ion channel and epilepsy

    Institute of Scientific and Technical Information of China (English)

    Yudan Lü; Weihong Lin; Dihui Ma

    2006-01-01

    OBJECTIVE: To review the relationship between calcium ion channel and epilepsy for well investigating the pathogenesis of epilepsy and probing into the new therapeutic pathway of epilepsy.DATA SOURCES: A computer-based online research Calcium ion channel and epilepsy related articles published between January 1994 and December 2006 in the CKNI and Wanfang database with the key words of "calcium influxion, epilepsy, calcium-channel blocker". The language was limited to Chinese. At the same time,related articles published between January 1993 and December 2006 in Pubmed were searched for on online with the key words of "calcium influxion, epilepsy" in English.STUDY SELECTION: The materials were selected firstly. Inclusive criteria: ① Studies related to calcium ion channel and the pat1hogenesis of epilepsy. ② Studies on the application of calcium ion channel blocker in the treatment of epilepsy. Exclusive criteria: repetitive or irrelated studies.DATA EXTRACTION: According to the criteria, 123 articles were retrieved and 93 were excluded due to repetitive or irrelated studies. Altogether 30 articles met the inclusive criteria, 11 of them were about the structure and characters of calcium ion channel, 10 about calcium ion channel and the pathogenesis of epilepsy and 9 about calcium blocker and the treatment of epilepsy.DATA SYNTHESIS: Calcium ion channels mainly consist of voltage dependent calcium channel and receptor operated calcium channel. Depolarization caused by voltage gating channel-induced influxion is the pathological basis of epileptic attack, and it is found in many studies that many anti-epileptic drugs have potential and direct effect to rivalizing voltage-dependent calcium ion channel.CONCLUSION: Calcium influxion plays an important role in the seizure of epilepsy. Some calcium antagonists seen commonly are being tried in the clinical therapy of epilepsy that is being explored, not applied in clinical practice. If there are enough evidences to

  5. Synthesis of nanocrystalline mixed metal fluorides in nonaqueous medium

    Indian Academy of Sciences (India)

    Neetu Tyagi; Epsita Ghanti; Nikesh Gupta; N P Lalla; Rajamani Nagarajan

    2009-12-01

    Synthesis of mixed metal fluorides of the general formula, KMF3 (M = Mg, Mn, Co, Ni, Cu and Zn), possessing perovskite structure was investigated in non-aqueous medium. The fluorides were characterized by powder X-ray diffraction, FT–IR spectroscopy, thermal analysis, SEM and TEM. Monophasic cubic phases were obtained for the central metal ions such as Mg, Mn, Co, Ni, and Zn and a tetragonally distorted phase was observed for Cu. The usage of non-aqueous medium is advantageous for the bulk synthesis of these fluorides, since it eliminated the generation and handling of the hazardous HF that has usually been encountered during aqueous preparations. The average crystallite size of the fluorides obtained by this approach was estimated to be in the range of 9–30 nm. SEM micrographs of KZnF3 showed cubic morphology of perovskite phases. TEM studies on KCuF3 confirmed the presence of tetragonal distortion. The fluoride content was determined by titrimetry and found to be nearly stoichiometric. Some of these fluorides were found to be thermally stable up to 225°C in air. These fluorides were employed as fluorinating agents in organic fluorination reactions, thereby suggesting their possible utilization for selective fluorination of aliphatic and aromatic hydrofluorocarbons (HFCs) that are industrially relevant.

  6. Fluoride Levels of Mothers' Breast Milk in Egypt

    Directory of Open Access Journals (Sweden)

    Ghada, Z A Soliman and Tamer M M Saad

    2012-01-01

    Full Text Available Introduction: Fluoride exists naturally in water sources and is derived from fluorine. It is well known that fluoride helps, prevent and even reverse the early stages of tooth decay. Aim: The aim of the present study was to determine the fluoride levels in plasma and breast milk of lactating mothers in Egypt (Cairo and Giza Governorate. Material and Methods: Two hundred healthy lactating mothers aged between 20-40 years old were asked to give plasma and milk samples voluntary. Breast milk samples were directly refrigerated until measurements. The fluoride concentrations of plasma, milk and drinking tap water were assessed using an ion-selective fluoride electrode combined with an ion analyzer. Results: The fluoride levels of plasma, breast milk and drinking tap water samples were 0.0207±0.012, 0.0111±0.0044 ppm, and 0.482±0.117 ppm, respectively. A significant direct correlation between fluoride content in breast milk and drinking tap water was found (r=0.858, p< 0.01.

  7. Solar Imagery - Chromosphere - Calcium

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset consists of full-disk images of the sun in Calcium (Ca) II K wavelength (393.4 nm). Ca II K imagery reveal magnetic structures of the sun from about...

  8. Dielectric relaxation in ytterbium- and lead-doped calcium fluoride crystals

    Science.gov (United States)

    Stef, Marius; Nicoara, Irina; Stef, Florica

    2013-04-01

    YbF3-doped and 1 mol% PbF2 co-doped CaF2 crystals were grown by vertical Bridgman method using a shaped graphite furnace in vacuum. Dielectric spectra and optical absorption spectra were measured in order to study the influence of Pb2+ ions on the charge compensating defects formation. The influence of Pb2+ ions on the various charge compensating defects depend on the YbF3 concentration. For low YbF3 concentrations the influence is stronger than for concentrations higher than 1 mol% YbF3. Dielectric relaxation in double doped (Yb,Pb):CaF2 crystals in order the study the charge compensating defects formation was not reported before.

  9. Ultraviolet Laser Induced Photochromic Centers in Cerium Doped Calcium-Fluoride

    Science.gov (United States)

    Pogatshnik, Gerald Joseph

    The optical excitation of the lowest 4f to 5d transition in Ce('3+):CaF(,2) using the 308 nm output of a XeCl excimer laser results in a strong coloration of the sample. The centers created by the UV laser irradiation were identified, using low temperature absorption spectroscopy, and were found to be divalent cerium ions at cubic sites in the crystal. The system exhibits photochromic properties in that the crystal can be returned to the original transparent state by illuminating it with light which is absorbed by the divalent cerium ions. The creation process for these photochromic centers involves a resonant two-photon transition from the 4f ground state of the cerium ion to the conduction band of the CaF(,2) host. The lowest 5d level of the cerium ion serves as the real intermediate state for this transition. The photoionized electron can be trapped by another trivalent cerium ion at a site of cubic symmetry. These impurity sites with O(,h) symmetry result when the charge compensator associated with the rare earth ion is somewhat removed from the cerium ion site. The charge compensator is needed to maintain charge neutrality in the crystal when a trivalent rare earth is substituted for a Ca ion in the host lattice. The absence of a local charge compensator at a Ce('3+) site with O(,h) symmetry, provides a net positive Coulombic potential, which aids in the trapping of electrons from the conduction band. The capture of an electron by a cerium ion at cubic site, changes the valence state of the ion to Ce('2+). The presence of divalent cerium, with its broad absorption bands in the visible region of the spectrum, accounts for the coloration of the crystal after illumination with UV laser light. A model for the production of the photochromic centers, based on a rate equation is presented. This model reflects the two-photon nature of the photoionization process, as well as the optical bleaching characteristics of the photochromic center, and accurately reproduces the experimental results.

  10. Seawater intrusion and behaviour of dissolved boron, fluoride, calcium, magnesium and nutrients in Vashisti Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Zingde, M.D.; Ram, A.; Sharma, P.; Abidi, S.A.H.

    Behaviour of dissolved B, F, Ca, Mg and nutrients in partially stratified estuary of Vashiti River, Karnataka, India has been studied under stable conditions of riverine flow. The dominance of Mg over Ca concentration in river water resulted...

  11. Optical absorption and thermoluminescence in calcium fluoride doped with manganese and cerium

    International Nuclear Information System (INIS)

    Optical absorption curves of CaF2 singly doped with Mn or Ce, and doubly doped with both Mn and Ce, show complex arrays of absorption bands after irradiation. In the Mn-only doped samples the absorption can be clearly related to Mn, whereas various forms of Ce centre dominate the radiation-induced absorption in the Ce-doped samples. However, in the doubly doped specimens only the Ce related absorptions can be seen. From these observations, along with thermal and optical bleaching measurements, we suggest that the Mn-related centres are Mn/F centre complexes. These are believed to be the centres responsible for the TL in dosimetry grade CaF2:Mn. Possible mechanisms for the TL production process are discussed. (author)

  12. Crystal growth and scintillation properties of Ce-doped sodium calcium lutetium complex fluoride

    Czech Academy of Sciences Publication Activity Database

    Wakahara, S.; Furuya, Y.; Yanagida, T.; Yokota, Y.; Pejchal, Jan; Sugiyama, M.; Kawaguchi, N.; Totsuka, D.; Yoshikawa, A.

    2012-01-01

    Roč. 34, č. 4 (2012), s. 729-732. ISSN 0925-3467 Institutional research plan: CEZ:AV0Z10100521 Keywords : scintillator * micro-pulling-down method * single crystal * gamma-ray stopping power Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.918, year: 2012

  13. Photo-transfer of Tl grade natural calcium fluoride by induced ultra-violet irradiation

    International Nuclear Information System (INIS)

    Natural CaF2 shows four main glow peaks. The third one (P3) at 453 K is considered as the dosimetry peak. By deconvolution (CGCD) technique this peak could be analysed into 3 simple overlapping peaks at 440, 455 and 482 K. The kinetic parameters of these peaks have been calculated, like its activation energy (E), frequency factor (s), mean life time (τ) and the resonance escape probability (P). The chemical composition of CaF2 has been analysed specially the major elements as well as the trace elements. The photo-transfer phenomenon has been studied in some details. This transfer due to P3 with UV exposure increase with increasing time till 120 seconds then shows saturation. The rate of photo-transfer is increased by increasing the pre-gamma exposure. From the experimental results and theoretical calculations, it could be evaluated that the first part of P3 will be decayed after 5.05 years while the last part of the same peak could be disappear after 88.73 years when the irradiated Tl material is stored at 25 degree C.

  14. The role of casein phosphopeptide-amorphous calcium phosphate products in remineralization of incipient enamel lesions and its substantivity

    Directory of Open Access Journals (Sweden)

    Abhay Taranath

    2014-02-01

    Full Text Available Objective: Milk derived calcium, phosphate and casein were known to be anti-cariogenic but in the modern era of early interception of caries the agents like casien phosphopeptide-amorphous calcium phosphate (CPP-ACP derived from milk are known to also repair early lesions. This in vitro study was designed to evaluate the remineralizing potential of CPP-ACP and CPP-amorphous calcium phosphate fluoride (ACPF on smooth surface carious lesions of the enamel and its substantivity following demineralization. Methods: Sixty caries free molar and premolars included in the study were sectioned and assigned to two experimental groups in which samples were remineralized with CPP-ACP or CPP-ACPF. The remineralization caused by CPP-ACP was evaluated using laser fluorescence device. Samples were then demineralized to evaluate the substantivity of remineralization. Results: CPP-ACPF and CPP-ACP showed significantly higher remineralization than baseline levels. On the other hand, CPP-ACPF showed significantly less demineralization than CPP-ACP. Conclusion: The remineralization produced by CPP-ACPF is more stable to further demineralization probably attributed to presence of fluoride. Addition of fluoride was shown to be protective from subsequent demineralization challenges. [J Exp Integr Med 2014; 4(1.000: 67-70

  15. Impregnating Coal With Calcium Carbonate

    Science.gov (United States)

    Sharma, Pramod K.; Voecks, Gerald E.; Gavalas, George R.

    1991-01-01

    Relatively inexpensive process proposed for impregnating coal with calcium carbonate to increase rates of gasification and combustion of coal and to reduce emission of sulfur by trapping sulfur in calcium sulfide. Process involves aqueous-phase reactions between carbon dioxide (contained within pore network of coal) and calcium acetate. Coal impregnated with CO2 by exposing it to CO2 at high pressure.

  16. Acidosis and Urinary Calcium Excretion

    DEFF Research Database (Denmark)

    Alexander, R Todd; Cordat, Emmanuelle; Chambrey, Régine;

    2016-01-01

    Metabolic acidosis is associated with increased urinary calcium excretion and related sequelae, including nephrocalcinosis and nephrolithiasis. The increased urinary calcium excretion induced by metabolic acidosis predominantly results from increased mobilization of calcium out of bone and...... renal tubule and then discuss why not all gene defects that cause renal tubular acidosis are associated with hypercalciuria and nephrocalcinosis....

  17. Amelioration of Fluoride Toxicity with the Use of Indigenous Inputs

    Directory of Open Access Journals (Sweden)

    Maitra A.

    2013-08-01

    Full Text Available An assessment was undertaken to study the efficacy of bacterial consortia isolated from different sources viz. rhizosphere of rice plant, oil spill sites of a petrol pump and from the sludge of a pharmaceutical waste water drain against the impact of fluoride. The experiments were conducted with two crops. In this mung bean experiment Vigna radiata was selected as a test crop. The seeds were sown in the field with bacterial consortia, compost and reduced dose (25% less nitrogen than recommended dose of chemical fertilizer. After 30days of seed sowing (DAS, plants were collected from the field and dipped into the sodium fluoride solution with different concentrations for 48 hours. Thereafter, the impact of fluoride on chlorophyll, sugar, proline and relative water content (% were evaluated. Scanning electron microscopy (SEM of the stem section was performed. SEM studies revealed that anatomical structure deformed with 1.5 mg/l sodium fluoride solution. It was observed that such treatment combination during the sowing of crops leads to combat the impact of lower doses of sodium fluoride (0.2 mg/l. Another experiment was also conducted within plastic pots with and without bacterial consortia isolated from rhizosphere of rice plant and oil spilled soil of petrol pump with the same field soil. Each pot was filled with 5 kg of soil + 2lt of water (on the basis of soil saturation. Oryza sativa seedlings were transplanted with different strength of sodium fluoride solution (25 mgNaF/kg, 50 mgNaF/kg, 100 mgNaF/kg and 500mgNaF/kg within the above pots. In second experiment, rice plants dried in all pots after 500 mgNaF/kg concentration of sodium fluoride. In this pot experiment bacterial strain are capable of reducing fluoride content in soil as noted by measuring fluoride in the pot soil after the experiment.

  18. Fluoride and lead adsorption on carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    WANG Shuguang; LI Yanhui

    2004-01-01

    The properties and applications of CNT have been studied extensively since Iijima discovered them in 1991[1,2]. They have exceptional mechanical properties and unique electrical property, highly chemical stability and large specific surface area. Thus far, they have widely potential applications in many fields. They can be used as reinforcing materials in composites[3], field emissions[4], hydrogen storage[5], nanoelectronic components[6], catalyst supports[7], adsorption material and so on. However, the study on the potential application of CNT, environmental protection field in particular, was hardly begun.Long[8] et al. reported that CNT had a significantly higher dioxin removal efficiency than that of activated carbon. The Langmuir adsorption constant is 2.7 × 1052, 1.3 × 1018 respectively. The results indicated that CNT is potential candidate for the removal of micro-organic pollutants. However, the reports on the CNT used as fluoride and heavy metal adsorbent are seldom.In this paper, A novel material, alumina supported on carbon nanotubes (Al2O3/CNT), was prepared from carbon nanotubes and Al(NO3)3. X-ray diffraction (XRD) spectra demonstrate that alumina is amorphous, and scanning electron microscope (SEM) images show that CNT and alumina are homogeneously mixed. Furthermore, the fluoride adsorption behavior on the surface of Al2O3/CNT has been investigated and compared with other adsorbents. The results indicate that Al2O3/CNT has a high adsorption capacity, with a saturation adsorption capacity of 39.4 mg/g. It is also found that the adsorption capacity of Al2O3/CNT is 3.0~4.5 times that of γ-Al2O3while almost equal to that of IRA-410 polymeric resin at 25 ℃. The adsorption isotherms of fluoride on Al2O3/CNT is fit the Freundlich equation well, optimal pH ranging from 5.0 to 9.0.Also in this paper, a novel material, modified carbon nanotubes (CNT), was prepared from carbon nanotubes and HNO3 under boiling condition. Infrared spectroscopy (IR

  19. Pharmacokinetics of Fluoride in Toddlers After Application of 5% Sodium Fluoride Dental Varnish

    OpenAIRE

    Milgrom, Peter; Taves, Donald M.; Kim, Amy S.; Watson, Gene E; Jeremy A Horst

    2014-01-01

    The prevalence of dental caries (tooth decay) among preschool children is increasing, driven partially by an earlier age of onset of carious lesions. The American Academy of Pediatrics recommends application of 5% sodium fluoride varnish at intervals increasing with caries risk status, as soon as teeth are present. However, the varnishes are marketed for treatment of tooth sensitivity and are regulated as medical devices rather than approved by the US Food and Drug Administration for preventi...

  20. Separation of volatile fluorides by selective desorption from granular inorganic fluorides

    International Nuclear Information System (INIS)

    Problems posed by the theory of gas mixtures separation by the method of selective desorption of components as applied to purification of uranium hexafluoride from some volatile impurity fluorides, i.e. WF6, MoF6, HF, are stated. Examples of calculation of WF6 - MoF6 mixture separation factor, as well as of composition of MoF6 stripping, depending on the composition of the initial WF6 - MoF6 mixture, are provided

  1. Fluorine-fixing efficiency on calcium-based briquette: pilot experiment, demonstration and promotion

    Institute of Scientific and Technical Information of China (English)

    YANG Jiao-lan; CHEN Dong-qing; LI Shu-min; YUE Yin-ling; JIN Xin; ZHAO Bing-cheng; YING Bo

    2010-01-01

    Background The fluorosis derived from coal burning is a very serious problem in China. By using fluorine-fixing technology during coal burning we are able to reduce the release of fluorides in coal at the source in order to reduce pollution to the surrounding environment by coal burning pollutants as well as decrease the intake and accumulating amounts of fluorine in the human body. The aim of this study was to conduct a pilot experiment on calcium-based fluorine-fixing material efficiency during coal burning to demonstrate and promote the technology based on laboratory research.Methods A proper amount of calcium-based fluorine sorbent was added into high-fluorine coal to form briquettes so that the fluorine in high-fluorine coal can be fixed in coal slag and its release into atmosphere reduced. We determined figures on various components in briquettes and fluorine in coal slag as well as the concentrations of indoor air pollutants, including fluoride, sulfur dioxide and respirable particulate matter (RPM), and evaluated the fluorine-fixing efficiency of calcium-based fluorine sorbents and the levels of indoor air pollutants.Results Pilot experiments on fluorine-fixing efficiency during coal burning as well as its demonstration and promotion were carried out separately in Guiding and Longli Counties of Guizhou Province, two areas with coal burning fluorosis problems. If the calcium-based fluorine sorbent mixed coal was made into honeycomb briquettes the average fluorine-fixing ratio in the pilot experiment was 71.8%. If the burning calcium-based fluorine-fixing bitumite was made into a coalball, the average of fluorine-fixing ratio was 77.3%. The concentration of fluoride, sulfur dioxide and PM10 of indoor air were decreased significantly. There was a 10% increase in the cost of briquettes due to the addition of calcium-based fluorine sorbent.Conclusions The preparation process of calcium-based fluorine-fixing briquette is simple yet highly flammable and it is

  2. Fluoride reactions with dental enamel following different forms of fluoride supply

    International Nuclear Information System (INIS)

    The reactions with dental enamel of NaF as tablets dissolved in different beverages or supplied with NaCl, simulating domestic salt fluoridation, were studied in tests with enamel surfaces and enamel powder. It was confirmed that powdered enamel can react quite differently from enamel surfaces under certain conditions. Enamel surfaces took up much more fluoride (F) from orange juice than from water or milk, and neither the low pH nor the citrate content of the juice increased the formation of unstable CaF2 in the enamel, as judged from a KOH leaching test. The F uptake by enamel surfaces from 0.25 mM NaF in 175 mM NaCl, corresponding to a dish prepared with salt containing 500 parts/106 F, was about 80 percent greater than from the same NaF concentration in water. This NaCl concentration did not increase the formation of CaF2 in the enamel, as judged from the KOH test, while 350 mM NaCl caused a moderate increase. The investigations support the administration of NaF tablets with orange juice and the plans for domestic salt fluoridation. (author)

  3. Determination of fluoride with thorium nitrate by catalytic titration

    International Nuclear Information System (INIS)

    Amperometry, constant-current potentiometry and spectrophotometry were used to follow the course of catalytic titrations of fluoride and silicofluoride with thorium nitrate. The hydrogen peroxide-iodide system was used as the indicator reaction. Titrations were performed in 50% ethanolic acetate buffer, pH 3.6. Amounts of 3.70 to 6.85 mg of ammonium fluoride, 5.53 to 10.79 mg of potassium fluoride and 4.34 to 8.41 mg of sodium silicofluoride were determined with a maximum average deviation of 0.9%. The results obtained are in good agreement with those of comparable methods. (author)

  4. Spectrophotometric determination of fluorides in water with Hach equipment

    International Nuclear Information System (INIS)

    The spectrophotometric method for the determination of the fluoride ion in water, demineralized water, raw waters, laundry waters and waters treated with ion exchange resins , using the technique and the SPADNS coloring indicated in the operation manual of the Hach equipment is described. This method covers the determination of the fluoride ion in the range from 0 to 2 mg/l on 25 ml. of radioactive base sample. These limits can be variable if the size of the used aliquot one is changed for the final determination of the fluoride ion. (Author)

  5. Nitrogen Trifluoride-Based Fluoride- Volatility Separations Process: Initial Studies

    Energy Technology Data Exchange (ETDEWEB)

    McNamara, Bruce K.; Scheele, Randall D.; Casella, Andrew M.; Kozelisky, Anne E.

    2011-09-28

    This document describes the results of our investigations on the potential use of nitrogen trifluoride as the fluorinating and oxidizing agent in fluoride volatility-based used nuclear fuel reprocessing. The conceptual process uses differences in reaction temperatures between nitrogen trifluoride and fuel constituents that produce volatile fluorides to achieve separations and recover valuable constituents. We provide results from our thermodynamic evaluations, thermo-analytical experiments, kinetic models, and provide a preliminary process flowsheet. The evaluations found that nitrogen trifluoride can effectively produce volatile fluorides at different temperatures dependent on the fuel constituent.

  6. Graphene Fluoride: A Stable Stoichiometric Graphene Derivative and its Chemical Conversion to Graphene

    OpenAIRE

    Zbořil, Radek; Karlický, František; Bourlinos, Athanasios B.; Steriotis, Theodore A.; Athanasios K. Stubos; Georgakilas, Vasilios; Šafářová, Klára; Jančík, Dalibor; Trapalis, Christos; Otyepka, Michal

    2010-01-01

    Stoichoimetric graphene fluoride monolayers are obtained in a single step by the liquid-phase exfoliation of graphite fluoride with sulfolane. Comparative quantum-mechanical calculations reveal that graphene fluoride is the most thermodynamically stable of five studied hypothetical graphene derivatives; graphane, graphene fluoride, bromide, chloride, and iodide. The graphene fluoride is transformed into graphene via graphene iodide, a spontaneously decomposing intermediate. The calculated ban...

  7. Solubility of fluorides of alkaline earth metals and some rare earths in anhydrous trifluoroacetic acid

    International Nuclear Information System (INIS)

    Solubility of fluorides of alkaline earth and some rare earth metals in anhydrous trifluoroacetic acid is studied. For each type of fluoride solubility depends on the ionic radius of the cation. Solubility of fluorides of alkaline earth metals grows from magnesium to barium. All the fluorides in anhydrous trifluoroacetic acid form solvates. Solvates of strontium and scandium fluorides are shown to decompose at 110 and 150 deg C respectively

  8. Evaluation of efficacy caries prevent of stabilized fluoride dentifrices in students of medical university

    OpenAIRE

    Марченко, Наталья Сергеевна; Політун, Антоніна Михайлівна; Терешина, Тетяна Петрівна

    2015-01-01

    Conducted laboratory and clinical evaluation of the efficacy of  stabilized fluoride dentifrice compared to without fluoride dentifrice, for the prevention of dental caries in students. Indexes stability of fluoride in dentifrice containing fluoride , concentration and  prolonged action ionized fluoride in saliva for the prevention of dental caries.Methods: Clinical and laboratory testing of dentifrice in vivo and in vitro research.Results: In clinical and laboratory testing of caries prevent...

  9. Change in fluoride content of Maltese tapwaters : implications for oral health

    OpenAIRE

    Vella, Alfred J.; Borg, Vincent

    1989-01-01

    Dietary intake of fluoride is believed to be largely derived from drinking water. In Malta, tap water presently contains less fluoride than is found in naturally occurring ground water obtained from aquifers. Over 55% of water production comes from reverse osmosis and such water is practically fluoride-free. Before the introduction of reverse osmosis water into the water budget, fluoride levels measured from 10 different tap waters averaged 0.51 ppm F-. Now, fluoride content measured from 19 ...

  10. Determination of fluoride content in toothpaste using spectrophotometry

    Directory of Open Access Journals (Sweden)

    Susanti Pudji Hastuti

    2013-09-01

    Full Text Available Background: Intake excessive fluoride in children’s teeth are generally marked with white and brown patches. Excessive fluoride of more than 4.0 mg/L can cause a person suffering from poisoning, fragility of the bones (osteoporosis, liver and kidney damage. Knowledge about the spectrophotometry for determination method of fluoride content in commercially available toothpaste is very few. Purpose: The purposes of study were to examine the suitable method for fluoride extraction and to determine out the accuracy, precision, linearity, and stability of the measurement method of fluoride content in toothpaste. Methods: The suitable F extraction method was determined by the comparison among 3 methods of extraction; e.g. the dried samples were immersed in (1 distilled water, (2 96% HCl, and (3 96% HNO3; and the validation methods of measurement were the maximum wavelength, standart curve, accuracy test, precision test, and stability test. Results: Result showed that the fluoride extraction by using the concentrated HNO3 was found to have the highest levels of fluoride, followed by hydrochloric acid dissolution (HCl and distilled water, while the method of validation showed that SPADNS revealed the acceptable accuracy. Precision has the RSD ≤ 2.00%. Furthermore the stability test result showed that the measurement of fluoride less than 2 hours was still reliable. Conclusion: The study suggested that the best result of fluoride extraction from toothpaste could be gained by using concentrate HNO3, and the spectrophotometer (UV-Vis Mini Shimadzu U-1240 and SPADNS have the acceptable accuracy.Latar Belakang: Pemasukan fluoride yang berlebihan pada gigi anak ditandai dengan bercak putih dan coklat. Fluoride lebih dari 4.0 mg / L dapat menyebabkan seseorang menderita keracunan , kerapuhan tulang (osteoporosis, kerusakan hati dan ginjal. Pengetahuan tentang spektrofotometri untuk metode penentuan kadar fluoride dalam pasta gigi yang tersedia secara

  11. Cerium fluoride crystals for calorimetry at LHC

    International Nuclear Information System (INIS)

    High-resolution homogeneous calorimetry is fully justified for part of the physics program at the Large Hadron Collider (LHC). The main design features of proposed CeF3 crystals for calorimetry for LHC are discussed. The severe constraints LHC imposes on detectors make the use of 'classical' crystals impossible. Therefore, a large R and D effort has been undertaken by the 'Crystal Clear' collaboration in order to find new, dense, fast and radiation hard crystals. A good candidate, cerium fluoride, has been identified and studied. It is interesting at this stage to review the specifications of scintillators for LHC and to see how well available data on CeF3 luminescence, decay time, light yield, optical transmission and resistance to radiation meet them. Milestones to reach before starting a large scale crystal production in view of the eventual construction of a calorimeter, are also discussed. (author) 15 refs., 15 figs., 1 tab

  12. Further results on cerium fluoride crystals

    International Nuclear Information System (INIS)

    A systematic investigation of the properties of cerium fluoride monocrystals has been performed by the 'Crystal Clear' collaboration in view of a possible use of such crystals for the construction of high precision electromagnetic calorimeters for the future generation of high luminosity accelerators. A large sample of different crystals grown by several producers has been studied. The spectroscopic characteristics, the transmission, luminescence and excitation spectra and the decay time curves are analysed. The light yield of the different crystals is measured with photomultipliers and Si photodiodes and compared to reference standards like BGO and NaI(Tl). The radiation damage behaviour is then presented for γ and neutron irradiations, at different doses and dose rates, including thermal and optical bleaching. (orig.)

  13. Further results on cerium fluoride crystals

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, S.; Auffray, E.; Aziz, T.; Baccaro, S.; Banerjee, S.; Bareyre, P.; Barone, L.E.; Borgia, B.; Boutet, D.; Burq, J.P.; Chemarin, M.; Chipaux, R.; Dafinei, I.; D' Atanasio, P.; De Notaristefani, F.; Dezillie, B.; Dujardin, C.; Dutta, S.; Faure, J.L.; Fay, J.; Ferrere, D.; Francescangeli, O.; Fuchs, B.A.; Ganguli, S.N.; Gillespie, G.; Goyot, M.; Gupta, S.K.; Gurtu, A.; Heck, J.; Herve, A.; Hillemanns, H.; Holdener, F.; Ille, B.; Joensson, L.; Kierstead, J.; Krenz, W.; Kway, W.; Le Goff, J.M.; Lebeau, M.; Lebrun, P.; Lecoq, P.; Lemoigne, Y.; Loomis, G.; Lubelsmeyer, K.; Madjar, N.; Majni, G.; El Mamouni, H.; Mangla, S.; Mares, J.A.; Martin, J.P.; Mattioli, M.; Mauger, G.J.; Mazumdar, K.; Mengucci, P.; Merlo, J.P.; Moine, B.; Nikl, N.; Pansart, J.P.; Pedrini, C.; Poinsignon, J.; Polak, K.; Raghavan, R.; Rebourgeard, P.; Rinaldi, D.; Rosa, J.; Rosowsky, A.; Sahuc, P.; Samsonov, V.; Sarkar, S.; Schegelski, V.; Schmitz, D.; Schneegans, M.; Seliverstov, D.; Stoll, S.; Sudhakar, K.; Sven; Crystal Clear Collaboration

    1993-08-15

    A systematic investigation of the properties of cerium fluoride monocrystals has been performed by the 'Crystal Clear' collaboration in view of a possible use of such crystals for the construction of high precision electromagnetic calorimeters for the future generation of high luminosity accelerators. A large sample of different crystals grown by several producers has been studied. The spectroscopic characteristics, the transmission, luminescence and excitation spectra and the decay time curves are analysed. The light yield of the different crystals is measured with photomultipliers and Si photodiodes and compared to reference standards like BGO and NaI(Tl). The radiation damage behaviour is then presented for [gamma] and neutron irradiations, at different doses and dose rates, including thermal and optical bleaching. (orig.)

  14. Chemical etching of polyvinylidene fluoride films

    International Nuclear Information System (INIS)

    The chemical etching of two types of polyvinylidene fluoride (PVDF) film irradiated with heavy ions was studied. Several etchants have been investigated in this work. It was found that for a solution of KOH+KMnO4 the radial etch rate (RER) is larger than for solutions used by other authors. This new solution for etching PVDF is used both for microfilter and for track detector purposes. Even alphas from a thick uranium foil register in solef PVDF by using this solution. As expected the RER for alphas is considerably lower than that for heavy ions. The diameter of the sandglass shaped pores at the surface of the film as a function of the etching time for various concentrations of KMnO4 and KOH and at different temperatures was measured. (author)

  15. Fluoridated toothpaste: usage and ingestion of fluoride by 4- to 6-yr-old children in England.

    Science.gov (United States)

    Zohoori, Fatemeh V; Duckworth, Ralph M; Omid, Narges; O'Hare, William T; Maguire, Anne

    2012-10-01

    Fluoridated toothpaste is effective for dental caries control, yet may be a risk factor for dental fluorosis. This study aimed to quantify fluoride ingestion from toothpaste by children and to investigate the effects of age, gender, and social class on the amount of fluoride ingested per toothbrushing session. Sixty-one children, 4-6 yr of age, were recruited: 38 were from low socio-economic (LSE) areas of Newcastle, UK, and 23 were from high socio-economic (HSE) areas of Newcastle, UK. All expectorated saliva, rinse water (if used), and residual toothpaste were collected after brushing at home and were analysed for fluoride. Of the children, 74% and 69% from HSE and LSE areas, respectively, claimed that they brushed twice per day. The mean (SD) weight of toothpaste dispensed was 0.67 (0.36) g. The mean (SD) amount of fluoride ingested per toothbrushing session and per day was 17.0 (14.7) and 29.3 (32.8) μg kg(-1) of body weight, respectively. Daily fluoride intake per kilogram of body weight did not differ significantly between children from LSE and HSE areas. Fluoride intake per toothbrushing session was significantly influenced by weight of toothpaste, its fluoride concentration, and the child's age. Whilst the average amount of toothpaste used per toothbrushing session was more than twice the recommended amount (of 0.25 g), only one child had a daily fluoride intake that exceeded the tolerable upper intake level of 0.1 mg kg(-1) of body weight for this age group. PMID:22984999

  16. Using High Fluoride Concentration Products in Public Policy: A Rapid Review of Current Guidelines for High Fluoride Concentration Products.

    Science.gov (United States)

    Douglas, Gail V A; Ramsdale, Martin P; Vinall-Collier, Karen; Csikar, Julia I

    2016-01-01

    Despite improvements in dental caries levels since the widespread introduction of fluoride toothpastes, it is still a disease which is considered to be a priority in many countries around the world. Individuals at higher risk of caries can be targeted with products with a high fluoride concentration to help reduce the amount and severity of the disease. This paper compares guidance from around the world on the use of products with a high fluoride concentration and gives examples of how guidance has been translated into activity in primary care dental practice. A rapid review of electronic databases was conducted to identify the volume and variation of guidance from national or professional bodies on the use of products with a high fluoride concentration. Fifteen guidelines published within the past 10 years and in English were identified and compared. The majority of these guidelines included recommendations for fluoride varnish use as well as for fluoride gels, while a smaller number offered guidance on high fluoride strength toothpaste and other vehicles. Whilst there was good consistency in recommendations for fluoride varnish in particular, there was sometimes a lack of detail in other areas of recommendation for other vehicles with a high fluoride concentration. There are good examples within the UK, such as the Childsmile project and Delivering Better Oral Health, which highlight that the provision of evidence-based guidance can be influential in directing scarce resources towards oral health improvements. Policy can be influenced by evidence-based national recommendations and used to help encourage dental professionals and commissioners and third-party payers to adopt higher levels of practices aimed at oral health improvement. PMID:27100106

  17. Structural characterization of pure and doped calcium phosphate bioceramics prepared by simple solid state method

    International Nuclear Information System (INIS)

    Calcium Phosphate based bioceramic materials, in pure and doped forms have been successfully synthesized from egg shells by using solid-state method for the first time. Considering the diverse role of zinc and fluoride in biological functions, these two ions were chosen to develop the substituted bioceramic materials. Structural characterizations of these developed bioceramics were performed by using FTIR, XRD, SEM and EDS techniques. The results revealed that the fluoride doped apatite was formed in single phase containing hydroxyapatite while pure and Zinc doped apatites contained -TCP with hydroxyapatite. Experimental results and the crystallographic parameters matched well with the literature values indicating that the present experimental protocol favoured the formation of the desired bioceramics. However, to synthesize the (Ca (PO)) based bioceramic materials, such a simple solid-state approach would obviously be very helpful, not only in making the process economically feasible, but also in creating an effective material recycling technology for waste-management. (author)

  18. Treatment of post-orthodontic white spot lesions with casein phosphopeptide-stabilised amorphous calcium phosphate

    DEFF Research Database (Denmark)

    Bröchner, Ann; Christensen, Carsten; Kristensen, Bjarne;

    2010-01-01

    This study aims to investigate the effect of topical applications of 10% casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on white spot lesions (WSL) detected after treatment with fixed orthodontic appliances. Sixty healthy adolescents with >/=1 clinically visible WSL at debonding were...... recruited and randomly allocated to a randomised controlled trial with two parallel groups. The intervention group was instructed to topically apply a CPP-ACP -containing agent (Tooth Mousse, GC Europe) once daily and the subjects of the control group brushed their teeth with standard fluoride toothpaste...... included in the final evaluation. A statistically significant (p <0.05) regression of the WSL was disclosed in both study groups compared to baseline, but there was no difference between the groups. The mean area of the lesions decreased by 58% in the CPP-ACP group and 26% in the fluoride group (p = 0...

  19. Fruit Calcium: Transport and Physiology

    Science.gov (United States)

    Hocking, Bradleigh; Tyerman, Stephen D.; Burton, Rachel A.; Gilliham, Matthew

    2016-01-01

    Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium

  20. Fruit Calcium: Transport and Physiology.

    Science.gov (United States)

    Hocking, Bradleigh; Tyerman, Stephen D; Burton, Rachel A; Gilliham, Matthew

    2016-01-01

    Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium

  1. Preparation and Characterization of Rare Earth Doped Fluoride Nanoparticles

    Directory of Open Access Journals (Sweden)

    Timothy A. DeVol

    2010-03-01

    Full Text Available This paper reviews the synthesis, structure and applications of metal fluoride nanoparticles, with particular focus on rare earth (RE doped fluoride nanoparticles obtained by our research group. Nanoparticles were produced by precipitation methods using the ligand ammonium di-n-octadecyldithiophosphate (ADDP that allows the growth of shells around a core particle while simultaneously avoiding particle aggregation. Nanoparticles were characterized on their structure, morphology, and luminescent properties. We discuss the synthesis, properties, and application of heavy metal fluorides; specifically LaF3:RE and PbF2, and group IIA fluorides. Particular attention is given to the synthesis of core/shell nanoparticles, including selectively RE-doped LaF3/LaF3, and CaF2/CaF2 core/(multi-shell nanoparticles, and the CaF2-LaF3 system.

  2. Redox condition in molten fluoride salts Definition and control

    International Nuclear Information System (INIS)

    The loosely-used term 'redox condition' as applied to molten fluoride salts such as flibe is defined quantitatively as the fluorine potential. Several methods of controlling the property of the melt are discussed

  3. Physical and chemical properties of volatile ruthenium fluorides

    International Nuclear Information System (INIS)

    Available data are compiled published before 1977 on the preparation and the physical and chemical properties of ruthenium hexafluoride, ruthenium oxide tetrafluoride, ruthenium pentafluoride and ruthenium octa-fluoride. (author)

  4. Calcium and calcitonin responses to calcium infusion in type I diabetes mellitus.

    OpenAIRE

    Amado, J. A.; C. Gomez; Obaya, S.; Otero, M; Gonzalez-Macias, J

    1987-01-01

    We studied calcium and calcium and calcitonin responses to intravenous calcium infusion (3 mg of elemental calcium/kg of body weight in 10 minutes) in 21 type I diabetic males and 17 age-matched normal males. Baseline total calcium, parathyroid hormone and calcitonin levels were normal in the diabetic group, but ionized calcium was lowered. Cortical bone status and osteocalcin levels were normal, suggesting a normal osteoblastic function. Total calcium and ionized calcium responses to calcium...

  5. Efficacy of silver diamine fluoride as an antibacterial as well as antiplaque agent compared to fluoride varnish and acidulated phosphate fluoride gel: An in vivo study

    Directory of Open Access Journals (Sweden)

    Shalin Shah

    2013-01-01

    Full Text Available Background: Silver diamine fluoride (SDF is already proven as an antibacterial agent in vitro. Present study was formulated to compare the efficacy of SDF as an antibacterial as well as antiplaque agent in vivo with fluoride varnish and acidulated phosphate fluoride (APF gel. Study Design: Total 123 children (male = 82, female = 41 were included in the study for a period of 18 months. Children were divided into three different groups-Group 1: SDF; Group 2: fluoride varnish; and Group 3: APF gel. All subjects were evaluated via plaque score at 6 th , 12 th , and 18 th months as well as Streptococcus mutans counts in saliva at 72 h, 6 th , 12 th , and 18 th months of follow-up. Results: Significant reduction was found in plaque score as well as S. mutans counts irrespective of group division. On intergroup comparison, no statistically significant difference was found in plaque score, but significant reduction in S. mutans counts was found in Group 1 as compared with Groups 2 and 3, while no significant difference was found between Groups 2 and 3. Conclusion: In vivo application of SDF on enamel significantly decreases S. mutans counts as compared to fluoride varnish and APF gel.

  6. DISTILLATION OF CALCIUM

    Science.gov (United States)

    Barton, J.

    1954-07-27

    This invention relates to an improvement in the process for the purification of caicium or magnesium containing an alkali metal as impurity, which comprises distiiling a batch of the mixture in two stages, the first stage distillation being carried out in the presence of an inert gas at an absolute pressure substantially greater than the vapor pressure of calcium or maguesium at the temperature of distillation, but less than the vaper pressure at that temperature of the alkali metal impurity so that only the alkali metal is vaporized and condensed on a condensing surface. A second stage distilso that substantially only the calcium or magnesium distills under its own vapor pressure only and condenses in solid form on a lower condensing surface.

  7. Preparation and Characterization of Rare Earth Doped Fluoride Nanoparticles

    OpenAIRE

    DeVol, Timothy A.; Basak Yazgan-Kukouz; Baris Kokuoz; DiMaio, Jeffrey R.; Kevin B. Sprinkle; James, Tiffany L.; Kucera, Courtney J.; Jacobsohn, Luiz G.; John Ballato

    2010-01-01

    This paper reviews the synthesis, structure and applications of metal fluoride nanoparticles, with particular focus on rare earth (RE) doped fluoride nanoparticles obtained by our research group. Nanoparticles were produced by precipitation methods using the ligand ammonium di-n-octadecyldithiophosphate (ADDP) that allows the growth of shells around a core particle while simultaneously avoiding particle aggregation. Nanoparticles were characterized on their structure, morphology, and luminesc...

  8. Corrosion behavior of zirconia in acidulated phosphate fluoride

    OpenAIRE

    Anie Thomas; Sathyanarayanan Sridhar; Shant Aghyarian; Pilanda Watkins-curry; Chan, Julia Y.; Alessandro Pozzi; Danieli C. Rodrigues

    2016-01-01

    ABSTRACT Objective The corrosion behavior of zirconia in acidulated phosphate fluoride (APF) representing acidic environments and fluoride treatments was studied. Material and Methods Zirconia rods were immersed in 1.23% and 0.123% APF solutions and maintained at 37°C for determined periods of time. Surfaces of all specimens were imaged using digital microscopy and scanning electron microscopy (SEM). Sample mass and dimensions were measured for mass loss determination. Samples were charac...

  9. Corrosion behavior of zirconia in acidulated phosphate fluoride

    OpenAIRE

    Thomas, Anie; Sridhar, Sathyanarayanan; Aghyarian, Shant; Watkins-Curry, Pilanda; Chan, Julia Y.; Pozzi, Alessandro; Danieli C. Rodrigues

    2016-01-01

    ABSTRACT Objective The corrosion behavior of zirconia in acidulated phosphate fluoride (APF) representing acidic environments and fluoride treatments was studied. Material and Methods Zirconia rods were immersed in 1.23% and 0.123% APF solutions and maintained at 37°C for determined periods of time. Surfaces of all specimens were imaged using digital microscopy and scanning electron microscopy (SEM). Sample mass and dimensions were measured for mass loss determination. Samples were characteri...

  10. Fluoride Consumption and Its Impact on Oral Health

    OpenAIRE

    Luis Fernando Jacinto-Alemán; Javier de la Fuente-Hernández; María Dolores Jiménez-Farfán; Juan Carlos Hernández-Guerrero; Lilia Adriana Juárez-López

    2011-01-01

    Objective. The purpose of this study was to evaluate caries and dental fluorosis among Mexican preschoolers and school-aged children in a non-endemic zone for fluorosis and to measure its biological indicators. Methods. DMFT, DMFS, dmft, dmfs, and CDI indexes were applied. Fluoride urinary excretion and fluoride concentrations in home water, table salt, bottled water, bottled drinks, and toothpaste were determined. Results. Schoolchildren presented fluorosis (CDI = 0.96) and dental caries (DM...

  11. Scientific Opinion on Dietary Reference Values for fluoride

    OpenAIRE

    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA)

    2013-01-01

    Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies (NDA) derived Dietary Reference Values (DRVs) for fluoride, which are provided as Adequate Intake (AI) from all sources, including non-dietary sources. Fluoride is not an essential nutrient. Therefore, no Average Requirement for the performance of essential physiological functions can be defined. Nevertheless, the Panel considered that the setting of an AI is appropriate because of the be...

  12. Thermodynamic investigation of fluoride salts for nuclear energy production

    OpenAIRE

    Beilmann, Markus

    2013-01-01

    In this work thermodynamic properties of molten fluoride salts and salt mixtures are investigated. Fluoride salts have advantageous properties to be used in energy producing systems based on the conversion from heat to energy like i.e in Molten Salt Reactors. For this purpose it is very important to have detailed information about the heat capacity of the pure salts and salt mixtures. To get a better understanding about the heat capacity in mixtures drop calorimetry measurements of mixture...

  13. The economic value of Quebec’s water fluoridation program

    OpenAIRE

    Tchouaket, Eric; Brousselle, Astrid; Fansi, Alvine; Dionne, Pierre Alexandre; Bertrand, Elise; Fortin, Christian

    2013-01-01

    Aim Dental caries is a major public health problem worldwide, with very significant deleterious consequences for many people. The available data are alarming in Canada and the province of Quebec. The water fluoridation program has been shown to be the most effective means of preventing caries and reducing oral health inequalities. This article analyzes the cost-effectiveness of Quebec’s water fluoridation program to provide decision-makers with economic information for assessing its usefulnes...

  14. Polyvinylidene fluoride based nanocomposites for the development of energy systems

    OpenAIRE

    Pereira, J. Nunes

    2013-01-01

    The economic and environmental costs of current energy resources created the need to develop new methods to generate and store energy. In this sense, the development of polymer materials led to the emergence of a new generation of porous polymers for energy applications, which are typically described as “energy polymers”. The specific properties of poly(vinylidene fluoride) (PVDF) and its copolymer poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)), such as high diele...

  15. Quality of our groundwater resources: arsenic and fluoride

    Science.gov (United States)

    Nordstrom, D. Kirk

    2011-01-01

    Groundwater often contains arsenic or fluoride concentrations too high for drinking or cooking. These constituents, often naturally occurring, are not easy to remove. The right combination of natural or manmade conditions can lead to elevated arsenic or fluoride which includes continental source rocks, high alkalinity and pH, reducing conditions for arsenic, high phosphate, high temperature and high silica. Agencies responsible for safe drinking water should be aware of these conditions, be prepared to monitor, and treat if necessary.

  16. Polyacrylamide supported SPADNS-zirconium resin for fluoride removal

    International Nuclear Information System (INIS)

    Fluoride contamination of groundwater, both anthropogenic and natural, is a major problem worldwide. In the present work a new adsorbent has been prepared by incorporating SPADNS (trisodium 2-parasulfophenylazo-1,8-dihydroxy-3,6-napthalenedisulfonate salt) into the acrylamide matrix. SPADNS was selected because it has strong complexating ability towards zirconium. The substrate was conditioned for selective fluoride ion sorption by forming zirconium complex with SPADNS. The adsorbent was characterized using FTlR and EDXRF analysis

  17. Electrochemistry of silicon in chloro-fluoride and carbonate melts

    Directory of Open Access Journals (Sweden)

    Devyatkin S.V.

    2003-01-01

    Full Text Available The electrochemical behavior of K2SiF6 in chloro-fluoride melts and that of SiO2 in carbonate melts has been studied. Silicon, titanium silicides, boron silicide and ternary compounds Ti-Si-B have been deposited from chloro-fluoride melts. Only SiC was deposited from carbonate-silica melts under carbon dioxide atmosphere (that is, excessive pressure of CO2.

  18. Fluoride-assisted synthesis of bimodal microporous SSZ-13 zeolite.

    Science.gov (United States)

    Zhu, Xiaochun; Kosinov, Nikolay; Hofmann, Jan P; Mezari, Brahim; Qian, Qingyun; Rohling, Roderigh; Weckhuysen, Bert M; Ruiz-Martínez, Javier; Hensen, Emiel J M

    2016-02-21

    The presence of small amount of fluoride in alkaline hydrothermal synthesis of SSZ-13 zeolite yields bimodal microporous particles with substantially improved performance in the methanol-to-olefins (MTO) reaction. Hydrocarbon uptake measurements and fluorescence microspectroscopy of spent catalysts demonstrate enhanced diffusion through micropores at the grain boundaries of nanocrystals running through the zeolite particles. Fluoride-assisted SSZ-13 synthesis is a cheap and scalable approach to optimize the performance of MTO zeolite catalysts. PMID:26810114

  19. Fluoride levels in commercial dentifrices and drinking Water in Algeria

    OpenAIRE

    MERGHACHE, D.; BELLOUT, B.; MERGHACHE, S.; BOUCHERIT-ATMANI, Z.

    2011-01-01

    More and more scientific evidence show that fluorides have a cariostatic action to the plaque-saliva-tooth interface during cariogenous dissolution. Fluorides slow down demineralization and enhance remineralization. Their action is optimal, in the oral environment, when used at low concentrations on a continuous basis. The use of the fluorinated toothpastes during brushing of the teeth is a simple, rational method of daily topics application of fluorine, largely used in the context of prevent...

  20. Fluoride Concentration in Drinking Water Resources; North of Iran

    Directory of Open Access Journals (Sweden)

    Amouei A.I. PhD,

    2016-03-01

    Full Text Available Aims Fluoride is one of the anions present in soil and water, and determining its level in drinking water is vital for preventing dental and bone diseases in societies. This research aimed to determine fluoride concentrations in drinking water sources of rural and urban areas of Babol City, Iran. Instrument & Methods This descriptive cross-sectional study was conducted in Babol City, Iran, in 2014. 384 water samples were taken from 43 wells and 3 springs in the rural areas, and from 20 wells, 3 water reservoirs, and the water distribution system in the urban areas. Fluoride concentrations of water samples were measured with a model DR2000 spectrophotometer using the standard SPADNS method. Data were entered to SPSS 16 software and were analyzed by ANOVA test. Findings The mean fluoride concentrations in the water samples of the deep wells were higher compared to those of the springs (p=0.01. The mean fluoride concentrations in the plains areas were higher compared to the mountainous regions (p=0.02. The mean fluoride concentrations in the wells of the urban areas, in the urban reservoirs, and in the urban water distribution system were 0.40±0.14, 0.39±0.15, and 0.40±0.15mg/l, respectively (p=0.07. Fluoride concentrations in water in urban areas during various seasons varied from 0.31 to 0.45mg/l (p=0.06. Conclusion Fluoride concentrations in all drinking water sources in urban and rural areas of Babol are less than the ranges recommended by WHO and Iranian national standards.

  1. EXPERIMENTAL STUDY AND NUMERICAL SIMULATION OF FLUORIDE IN SAND

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong-mei; SU Bao-yu

    2006-01-01

    The transport and transformation of fluoride in sand were studied by using soil tank test under the condition of saturated water in this article. Based on the analysis of the laboratory experiments, the rules of fluorine transportation and transformation were simulated in sand by solving the advection-diffusion equation. Through comparison between computed results and observed data , it is shown that the established model and determined parameters could be used to simulate the fluoride transport in sand.

  2. Models of calcium signalling

    CERN Document Server

    Dupont, Geneviève; Kirk, Vivien; Sneyd, James

    2016-01-01

    This book discusses the ways in which mathematical, computational, and modelling methods can be used to help understand the dynamics of intracellular calcium. The concentration of free intracellular calcium is vital for controlling a wide range of cellular processes, and is thus of great physiological importance. However, because of the complex ways in which the calcium concentration varies, it is also of great mathematical interest.This book presents the general modelling theory as well as a large number of specific case examples, to show how mathematical modelling can interact with experimental approaches, in an interdisciplinary and multifaceted approach to the study of an important physiological control mechanism. Geneviève Dupont is FNRS Research Director at the Unit of Theoretical Chronobiology of the Université Libre de Bruxelles;Martin Falcke is head of the Mathematical Cell Physiology group at the Max Delbrück Center for Molecular Medicine, Berlin;Vivien Kirk is an Associate Professor in the Depar...

  3. Fluoride, aluminum, and phosphate kinetics in cryolite workers.

    Science.gov (United States)

    Grandjean, P; Hørder, M; Thomassen, Y

    1990-01-01

    Exposure to cryolite (Na3AlF6) dust may result in skeletal fluorosis. Eight male workers at a cryolite concentrator participated in a 4-day study after 5 days of vacation. Dust exposures were 0.16 to 21.2 mg/m3. Urine was collected before work began and during two 4-hour periods. Preshift urine fluoride concentrations increased during the week. Fluoride concentrations in postshift urine and serum both correlated with the dust exposures. Serum fluoride concentrations decreased with a half-life of 3.3 to 6.9 hours after work. Fluoride clearance was 40.5 to 76.5 mL/min at urinary flow rates of 0.89 to 2.21 mL/min. Serum aluminum concentrations varied without relation to the exposure, but the urinary aluminum excretion correlated with the fluoride levels. Preshift serum-phosphate concentrations increased significantly during the week, possibly indicating changes in mineral metabolism. For monitoring of individual uptake of cryolite dust, serum fluoride measurements are most useful. PMID:2324845

  4. Fluoride and aluminum in teas and tea-based beverages

    Directory of Open Access Journals (Sweden)

    Hayacibara Mitsue Fujimaki

    2004-01-01

    Full Text Available OBJECTIVE: To evaluate fluoride and aluminum concentration in herbal, black, ready-to-drink, and imported teas available in Brazil considering the risks fluoride and aluminum pose to oral and general health, respectively. METHODS: One-hundred and seventy-seven samples of herbal and black tea, 11 types of imported tea and 21 samples of ready-to-drink tea were divided into four groups: I-herbal tea; II-Brazilian black tea (Camellia sinensis; III-imported tea (Camellia sinensis; IV-ready-to-drink tea-based beverages. Fluoride and aluminum were analyzed using ion-selective electrode and atomic absorption, respectively. RESULTS: Fluoride and aluminum levels in herbal teas were very low, but high amounts were found in black and ready-to-drink teas. Aluminum found in all samples analyzed can be considered safe to general health. However, considering 0.07 mg F/kg/day as the upper limit of fluoride intake with regard to undesirable dental fluorosis, some teas exceed the daily intake limit for children. CONCLUSIONS: Brazilian and imported teas made from Camellia sinensis as well as some tea-based beverages are sources of significant amounts of fluoride, and their intake may increase the risk of developing dental fluorosis.

  5. Preparation of mixed rare earths modified chitosan for fluoride adsorption

    Institute of Scientific and Technical Information of China (English)

    梁鹏; 张艺; 汪东风; 徐莹; 罗斓

    2013-01-01

    This paper described the fluoride removal from water using a new adsorbent namely mixed rare earths modified chitosan (CR). Mixed rare earths mainly contained La followed by Ce which was analyzed by inductively coupled plasma mass spectrometry (ICP-MS). La(III)-modified chitosan (CL) was also prepared as control. For the batch technique, the effects of various parameters such as contact time, pH, adsorbent dose, initial fluoride concentration and co-ions on fluoride adsorption were studied. Fourier trans-form infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to characterize adsorbents. It was observed that the fluo-ride adsorption capacity of CR (3.72 mgF-/g) was higher than CL (3.16 mgF-/g) at 2 h. The presence of co-ions such as bicarbonate and carbonate greatly affected the fluoride adsorption from water. Characterization experiments indicated the successful chelation between mixed rare earths and chitosan. The possible fluoride adsorption mechanism of CR was explained by a chemical reaction.

  6. Monitoring of fluoride in water samples using a smartphone.

    Science.gov (United States)

    Levin, Saurabh; Krishnan, Sunderrajan; Rajkumar, Samuel; Halery, Nischal; Balkunde, Pradeep

    2016-05-01

    In several parts of India, groundwater is the only reliable, year round source for drinking water. Prevention of fluorosis, a chronic disease resulting from excess intake of fluoride, requires the screening of all groundwater sources for fluoride in endemic areas. In this paper, the authors present a field deployable colorimetric analyzer based on an inexpensive smartphone embedded with digital camera for taking photograph of the colored solution as well as an easy-fit, and compact sample chamber (Akvo Caddisfly). Phones marketed by different smartphone makers were used. Commercially available zirconium xylenol orange reagent was used for determining fluoride concentration. A software program was developed to use with the phone for recording and analyzing the RGB color of the picture. Linear range for fluoride estimation was 0-2mgl(-1). Around 200 samples, which consisted of laboratory prepared as well as field samples collected from different locations in Karnataka, India, were tested with Akvo Caddisfly. The results showed a significant positive correlation between Ion Selective Electrode (ISE) method and Akvo Caddisfly (Phones A, B and C), with correlation coefficient ranging between 0.9952 and 1.000. In addition, there was no significant difference in the mean fluoride content values between ISE and Phone B and C except for Phone A. Thus the smartphone method is economical and suited for groundwater fluoride analysis in the field. PMID:26874766

  7. Removal of fluoride from water using aluminium containing compounds

    Institute of Scientific and Technical Information of China (English)

    M. Karthikeyan; K. P. Elango

    2009-01-01

    Batch adsorption studies were undertaken to assess the suitability of aluminium titanate (AT) and bismuth aluminate (BA) to remove fluoride ions from water.The effect of pH,dose of adsorbent,contact time,initial concentration,co-ions and temperature on fluoride removal efficiency were studied.The amounts of fluoride ions adsorbed,at 30℃ from 4 mg/L of fluoride ion solution,by AT and BA are 0.85 and 1.55 mg/g,respectively.The experimental data fitted well to the Freundlich and Langmuir isotherms.Thermodynamic parameters such as △H~0,△S~0 and △G~0 indicated that the removal of fluoride ions by AT is exothermic and non-spontaneous while that by BA is endothermic and spontaneous.Furrier transform infrared (FT-IR) analysis and X-ray diffraction (XRD) patterns of the adsorbent before and after adsorption indicated that fluoride ions are chemisorbed by these adsorbents.

  8. Sodium fluoride induces apoptosis in mouse embryonic stem cells through ROS-dependent and caspase- and JNK-mediated pathways

    International Nuclear Information System (INIS)

    Sodium fluoride (NaF) is used as a source of fluoride ions in diverse applications. Fluoride salt is an effective prophylactic for dental caries and is an essential element required for bone health. However, fluoride is known to cause cytotoxicity in a concentration-dependent manner. Further, no information is available on the effects of NaF on mouse embryonic stem cells (mESCs). We investigated the mode of cell death induced by NaF and the mechanisms involved. NaF treatment greater than 1 mM reduced viability and DNA synthesis in mESCs and induced cell cycle arrest in the G2/M phase. The addition of NaF induced cell death mainly by apoptosis rather than necrosis. Catalase (CAT) treatment significantly inhibited the NaF-mediated cell death and also suppressed the NaF-mediated increase in phospho-c-Jun N-terminal kinase (p-JNK) levels. Pre-treatment with SP600125 or z-VAD-fmk significantly attenuated the NaF-mediated reduction in cell viability. In contrast, intracellular free calcium chelator, but not of sodium or calcium ion channel blockers, facilitated NaF-induced toxicity in the cells. A JNK specific inhibitor (SP600125) prevented the NaF-induced increase in growth arrest and the DNA damage-inducible protein 45α. Further, NaF-mediated loss of mitochondrial membrane potential was apparently inhibited by pifithrin-α or CAT inhibitor. These findings suggest that NaF affects viability of mESCs in a concentration-dependent manner, where more than 1 mM NaF causes apoptosis through hydroxyl radical-dependent and caspase- and JNK-mediated pathways. -- Highlights: ► The mode of NaF-induced cell death and the mechanisms involved were examined. ► NaF induced mainly apoptotic death of mouse embryonic stem cells (mESCs). ► NaF induced mitochondrial-mediated and caspase-dependent apoptosis. ► JNK- and p53-mediated pathways are involved in NaF-mediated apoptosis in the cells. ► ROS are the up-stream effector in NaF-mediated activation of JNK and p53 in mESCs.

  9. Sodium fluoride induces apoptosis in mouse embryonic stem cells through ROS-dependent and caspase- and JNK-mediated pathways

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen Ngoc, Tam Dan [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Son, Young-Ok [Graduate Center for Toxicology, School of Medicine, University of Kentucky, Lexington, KY 40536-0305 (United States); Lim, Shin-Saeng [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Department of Bioactive Material Sciences and Research Center of Bioactive Materials, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Shi, Xianglin [Graduate Center for Toxicology, School of Medicine, University of Kentucky, Lexington, KY 40536-0305 (United States); Kim, Jong-Ghee [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Heo, Jung Sun [Department of Maxillofacial Biomedical Engineering and Institute of Oral Biology, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Choe, Youngji [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Jeon, Young-Mi, E-mail: young@jbnu.ac.kr [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Lee, Jeong-Chae, E-mail: leejc88@jbnu.ac.kr [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Graduate Center for Toxicology, School of Medicine, University of Kentucky, Lexington, KY 40536-0305 (United States); Department of Bioactive Material Sciences and Research Center of Bioactive Materials, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

    2012-03-15

    Sodium fluoride (NaF) is used as a source of fluoride ions in diverse applications. Fluoride salt is an effective prophylactic for dental caries and is an essential element required for bone health. However, fluoride is known to cause cytotoxicity in a concentration-dependent manner. Further, no information is available on the effects of NaF on mouse embryonic stem cells (mESCs). We investigated the mode of cell death induced by NaF and the mechanisms involved. NaF treatment greater than 1 mM reduced viability and DNA synthesis in mESCs and induced cell cycle arrest in the G{sub 2}/M phase. The addition of NaF induced cell death mainly by apoptosis rather than necrosis. Catalase (CAT) treatment significantly inhibited the NaF-mediated cell death and also suppressed the NaF-mediated increase in phospho-c-Jun N-terminal kinase (p-JNK) levels. Pre-treatment with SP600125 or z-VAD-fmk significantly attenuated the NaF-mediated reduction in cell viability. In contrast, intracellular free calcium chelator, but not of sodium or calcium ion channel blockers, facilitated NaF-induced toxicity in the cells. A JNK specific inhibitor (SP600125) prevented the NaF-induced increase in growth arrest and the DNA damage-inducible protein 45α. Further, NaF-mediated loss of mitochondrial membrane potential was apparently inhibited by pifithrin-α or CAT inhibitor. These findings suggest that NaF affects viability of mESCs in a concentration-dependent manner, where more than 1 mM NaF causes apoptosis through hydroxyl radical-dependent and caspase- and JNK-mediated pathways. -- Highlights: ► The mode of NaF-induced cell death and the mechanisms involved were examined. ► NaF induced mainly apoptotic death of mouse embryonic stem cells (mESCs). ► NaF induced mitochondrial-mediated and caspase-dependent apoptosis. ► JNK- and p53-mediated pathways are involved in NaF-mediated apoptosis in the cells. ► ROS are the up-stream effector in NaF-mediated activation of JNK and p53 in mESCs.

  10. Reverse calcium affinity purification of Fab with calcium derivatized hydroxyapatite

    OpenAIRE

    Gagnon, Pete; Cheung, Chia-wei; Yazaki, Paul J.

    2009-01-01

    This study introduces the application of calcium-derivatized hydroxyapatite for purification of Fab. Fab binds to native hydroxyapatite but fails to bind to the calcium derivatized form. IgG, Fc, and most other protein contaminants bind to the calcium form. This supports Fab purification by a simple flow-through method that achieves greater than 95% purity from papain digests and mammalian cell culture supernatants. Alternatively, Fab can be concentrated on native hydroxyapatite then eluted s...

  11. Remineralizing efficacy of silver diamine fluoride and glass ionomer type VII for their proposed use as indirect pulp capping materials - Part II (A clinical study

    Directory of Open Access Journals (Sweden)

    N Sinha

    2011-01-01

    Full Text Available Aim: To evaluate in vivo the remineralizing efficacy of silver diamine fluoride (SDF, glass ionomer Type VII (GC VII and calcium hydroxide (Dycal. Materials and Methods: 60 subjects in the age group of 18-35 years, matching the inclusion criteria and having deep carious lesions in the permanent first and second molars were selected. The teeth were aseptically opened under rubber dam and after gross caries removal, approximately 0.4mg of soft discolored dentin was removed with a sharp spoon excavator from the mesial or distal aspect of the cavity. The test material was randomly selected and applied in a thickness of 1.5-2mm and the cavity sealed with cavit. The patients were followed up at regular intervals with radiographic evaluation at 12 weeks. At 3 months the temporary restoration was removed and dentin samples were collected from the other half of the cavity which was left in the first appointment. Atomic absorption spectrophotometry, Colorimetric test using UV-vis spectrometer and potentiometric titration were used for determining calcium, phosphorous and fluoride respectively. Results: Almost equivalent rise in the percentage of calcium level was seen in GC VII and Ca(OH 2 groups, followed by SDF group. Highest percentage rise in phosphate ions was seen in GC VII group followed by SDF group and Ca(OH 2 group. Highest percentage of fluoride rise was seen in GC VII group followed by SDF group and Ca(OH 2 group. Conclusions: The results indicated that both GC VII and SDF can be potential indirect pulp capping materials.

  12. Water Fluoridation: A Critical Review of the Physiological Effects of Ingested Fluoride as a Public Health Intervention

    OpenAIRE

    Stephen Peckham; Niyi Awofeso

    2014-01-01

    Fluorine is the world's 13th most abundant element and constitutes 0.08% of the Earth crust. It has the highest electronegativity of all elements. Fluoride is widely distributed in the environment, occurring in the air, soils, rocks, and water. Although fluoride is used industrially in a fluorine compound, the manufacture of ceramics, pesticides, aerosol propellants, refrigerants, glassware, and Teflon cookware, it is a generally unwanted byproduct of aluminium, fertilizer, and iron ore manuf...

  13. Using High Fluoride Concentration Products in Public Policy – A Rapid Review of Current Guidelines for High Fluoride Concentration products

    OpenAIRE

    Douglas, GVA; Ramsdale, M; Vinall, K.; Csikar, J

    2016-01-01

    Despite improvements in caries levels since widespread introduction of fluoride toothpastes it remains a priority in many countries around the world. Higher caries risk individuals can be targeted with products with a high fluoride concentration to help reduce the amount and severity of disease. This paper compares guidance from around the world on the use of such products and gives examples of how guidance has been translated into activity in primary care dental practice. A rapid review of e...

  14. High Temperature Fluoride Salt Test Loop

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, Adam M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cunningham, Richard Burns [Univ. of Tennessee, Knoxville, TN (United States); Fugate, David L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holcomb, David Eugene [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kisner, Roger A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Peretz, Fred J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Robb, Kevin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wilson, Dane F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yoder, Jr, Graydon L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    Effective high-temperature thermal energy exchange and delivery at temperatures over 600°C has the potential of significant impact by reducing both the capital and operating cost of energy conversion and transport systems. It is one of the key technologies necessary for efficient hydrogen production and could potentially enhance efficiencies of high-temperature solar systems. Today, there are no standard commercially available high-performance heat transfer fluids above 600°C. High pressures associated with water and gaseous coolants (such as helium) at elevated temperatures impose limiting design conditions for the materials in most energy systems. Liquid salts offer high-temperature capabilities at low vapor pressures, good heat transport properties, and reasonable costs and are therefore leading candidate fluids for next-generation energy production. Liquid-fluoride-salt-cooled, graphite-moderated reactors, referred to as Fluoride Salt Reactors (FHRs), are specifically designed to exploit the excellent heat transfer properties of liquid fluoride salts while maximizing their thermal efficiency and minimizing cost. The FHR s outstanding heat transfer properties, combined with its fully passive safety, make this reactor the most technologically desirable nuclear power reactor class for next-generation energy production. Multiple FHR designs are presently being considered. These range from the Pebble Bed Advanced High Temperature Reactor (PB-AHTR) [1] design originally developed by UC-Berkeley to the Small Advanced High-Temperature Reactor (SmAHTR) and the large scale FHR both being developed at ORNL [2]. The value of high-temperature, molten-salt-cooled reactors is also recognized internationally, and Czechoslovakia, France, India, and China all have salt-cooled reactor development under way. The liquid salt experiment presently being developed uses the PB-AHTR as its focus. One core design of the PB-AHTR features multiple 20 cm diameter, 3.2 m long fuel channels

  15. Phytotoxicity of sodium fluoride and uptake of fluoride in willow trees.

    Science.gov (United States)

    Clausen, Lauge Peter Westergaard; Karlson, Ulrich Gosewinkel; Trapp, Stefan

    2015-01-01

    The willow tree (Salix viminalis) toxicity test and a cress seed germination test (Lepidium sativum) were used to determine uptake of F and phytotoxicity of NaF. Concentrations in hydroponic solutions were 0-1000 mg F/L and 0-400 mg F/L in the preliminary and definitive test. A third test was done with soils collected from a fluoride-contaminated site at Fredericia, Denmark. The EC10, EC20 and EC50-values for inhibition of transpiration were determined to 38.0, 59.6 and 128.7 mg F/L, respectively. The toxicity test with soil showed strong inhibition for the sample with the highest fluoride concentration (405 mg free F per kg soil, 75 mg F per L soil solution). The seed germination and root elongation test with cress gave EC10, EC20 and EC50-values of 61.4, 105.0 and 262.8 mg F/L, respectively. At low external concentrations, fluoride was taken up more slowly than water and at high external concentrations at the same velocity. This indicates that an efflux pump becomes overloaded at concentrations above 210 mg F/L. Uptake kinetics were simulated with a non-linear mathematical model, and the Michaelis-Menten parameters were determined to half-saturation constant KM near 2 g F/L and maximum enzymatic removal rate vmax at 9 g/(kg d). PMID:25409250

  16. Glycochenodeoxycholic acid inhibits calcium phosphate precipitation in vitro by preventing the transformation of amorphous calcium phosphate to calcium hydroxyapatite.

    OpenAIRE

    Qiu, S M; Wen, G.; Hirakawa, N; Soloway, R D; Hong, N K; Crowther, R S

    1991-01-01

    Calcium hydroxyapatite can be a significant component of black pigment gallstones. Diverse molecules that bind calcium phosphate inhibit hydroxyapatite precipitation. Because glycine-conjugated bile acids, but not their taurine counterparts, bind calcium phosphate, we studied whether glycochenodeoxycholic acid inhibits calcium hydroxyapatite formation. Glycochenodeoxycholic acid (2 mM) totally inhibited transformation of amorphous calcium phosphate microprecipitates to macroscopic crystalline...

  17. Chemico-therapeutic approach to prevention of dental caries. [using stannous fluoride gel

    Science.gov (United States)

    Shannon, I. L.

    1975-01-01

    The program of chemical preventive dentistry is based primarily upon the development of a procedure for stabilizing stannous fluoride in solution by forcing it into glycerin. New topical fluoride treatment concentrates, fluoride containing gels and prophylaxis pastes, as well as a completely stable stannous fluoride dentifrice are made possible by the development of a rather complicated heat application method to force stannous fluoride into solution in glycerin. That the stannous fluoride is clinically effective in such a preparation is demonstrated briefly on orthodontic patients.

  18. The effect of different fluoride application methods on the remineralization of initial carious lesions

    OpenAIRE

    Byeon, Seon Mi; Lee, Min Ho; Bae, Tae Sung

    2016-01-01

    Objectives The purpose of this study was to assess the effect of single and combined applications of fluoride on the amount of fluoride release, and the remineralization and physical properties of enamel. Materials and Methods Each of four fluoride varnish and gel products (Fluor Protector, FP, Ivoclar Vivadent; Tooth Mousse Plus, TM, GC; 60 Second Gel, A, Germiphene; CavityShield, CS, 3M ESPE) and two fluoride solutions (2% sodium fluoride, N; 8% tin(ii) fluoride, S) were applied on bovine t...

  19. Calcium – how and why?

    Indian Academy of Sciences (India)

    J K Jaiswal

    2001-09-01

    Calcium is among the most commonly used ions, in a multitude of biological functions, so much so that it is impossible to imagine life without calcium. In this article I have attempted to address the question as to how calcium has achieved this status with a brief mention of the history of calcium research in biology. It appears that during the origin and early evolution of life the Ca2+ ion was given a unique opportunity to be used in several biological processes because of its unusual physical and chemical properties.

  20. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

    Risnes, H.; Fjellerup, Jan Søren; Henriksen, Ulrik Birk; Moilanen, A.; Norby, P.; Papadakis, K.; Posselt, D.; Sørensen, L. H.

    2003-01-01

    The present work focuses on the influence of calcium addition in gasification. The inorganic¿organic element interaction as well as the detailed inorganic¿inorganic elements interaction has been studied. The effect of calcium addition as calcium sugar/molasses solutions to straw significantly...... affected the ash chemistry and the ash sintering tendency but much less the char reactivity. Thermo balance test are made and high-temperature X-ray diffraction measurements are performed, the experimental results indicate that with calcium addition major inorganic¿inorganic reactions take place very late...

  1. Calcium Phosphate Biomaterials: An Update

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Current calcium phosphate (CaP) biomaterials for bone repair, substitution, augmentation and regeneration include hydroxyapatite ( HA ) from synthetic or biologic origin, beta-tricalcium phosphate ( β-TCP ) , biphasic calcium phosphate (BCP), and are available as granules, porous blocks, components of composites (CaP/polymer) cements, and as coatings on orthopedic and dental implants. Experimental calcium phosphate biomaterials include CO3- and F-substituted apatites, Mg-and Zn-substituted β-TCP, calcium phosphate glasses. This paper is a brief review of the different types of CaP biomaterials and their properties such as bioactivity, osteoconductivity, osteoinductivity.

  2. Characterization of cerium fluoride nanocomposite scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Stange, Sy [Los Alamos National Laboratory; Esch, Ernst I [Los Alamos National Laboratory; Brown, Leif O [Los Alamos National Laboratory; Couture, Aaron J [Los Alamos National Laboratory; Mckigney, Edward A [Los Alamos National Laboratory; Muenchausen, Ross E [Los Alamos National Laboratory; Del Sesto, Rico E [Los Alamos National Laboratory; Gilbertson, Robert D [Los Alamos National Laboratory; Mccleskey, T Mark [Los Alamos National Laboratory; Reifarth, Rene [Los Alamos National Laboratory

    2009-01-01

    Measurement of the neutron capture cross-sections of a number of short-lived isotopes would advance both pure and applied scientific research. These cross-sections are needed for calculation of criticality and waste production estimates for the Advanced Fuel Cycle Initiative, for analysis of data from nuclear weapons tests, and to improve understanding of nucleosynthesis. However, measurement of these cross-sections would require a detector with a faster signal decay time than those used in existing neutron capture experiments. Crystals of faster detector materials are not available in sufficient sizes and quantities to supply these large-scale experiments. Instead, we propose to use nanocomposite detectors, consisting of nanoscale particles of a scintillating material dispersed in a matrix material. We have successfully fabricated cerium fluoride (CeF{sub 3}) nanoparticles and dispersed them in a liquid matrix. We have characterized this scintillator and have measured its response to neutron capture. Results of the optical, structural, and radiation characterization will be presented.

  3. Magnetic separation of uranium from magnesium fluoride

    International Nuclear Information System (INIS)

    The attraction or repulsion of particles by a magnetic gradient, based on the respective susceptibilities, provides the basis for physical separation of particles that are comprised predominantly of uranium from those that are predominantly magnesium fluoride (MgF2). To determine the effectiveness of this approach, a bench-scale magnetic separator from the S.G. Frantz Co., Inc. was used. In the Frantz Model L-1, particles are fed through a funnel onto a vibration tray and through a magnetic field. The specific design of the Frantz magnet causes the magnetic field strength to vary along the width of the magnet, setting up a gradient. The tray in the magnetic field is split at a point about half way down its length so that the separated material does not recombine. A schematic is presented of Frantz Model L-1 CN - the same magnet configured for high gradient magnetic separation of liquid-suspended particles. Here different pole pieces create a uniform magnetic field, and stainless steel wood in the canister between the pole pieces creates the high gradient. 1 ref., 6 figs., 2 tabs

  4. Characterization of cerium fluoride nanocomposite scintillators

    International Nuclear Information System (INIS)

    Measurement of the neutron capture cross-sections of a number of short-lived isotopes would advance both pure and applied scientific research. These cross-sections are needed for calculation of criticality and waste production estimates for the Advanced Fuel Cycle Initiative, for analysis of data from nuclear weapons tests, and to improve understanding of nucleosynthesis. However, measurement of these cross-sections would require a detector with a faster signal decay time than those used in existing neutron capture experiments. Crystals of faster detector materials are not available in sufficient sizes and quantities to supply these large-scale experiments. Instead, we propose to use nanocomposite detectors, consisting of nanoscale particles of a scintillating material dispersed in a matrix material. We have successfully fabricated cerium fluoride (CeF3) nanoparticles and dispersed them in a liquid matrix. We have characterized this scintillator and have measured its response to neutron capture. Results of the optical, structural, and radiation characterization will be presented.

  5. Thermodynamic data for treatment of fluoride

    International Nuclear Information System (INIS)

    To obtain uranium from Al2O3 with uranium by the electrolytic deduction method, the equilibrium potential of Ni(0)/Ni(2) in NaF-AlF3-Al2O3-NiF2 and its dependence on the concentration of Al2O3 were determined. On the coexistence system of Al2O3 and NiF2 in the molten salt, NiF2 was oxidized to NiO by the oxygen ion from Al2O3. Dependence of the equilibrium potential of Ni(0)/Ni(2) in NaF-AlF3-NiF2 on temperature was measured and the potential data were consistent with the Nernst equation, which showed the large effect of Al2O3 on oxidation of metallic fluoride in molten salt. These results proved that the stripping treatment of uranium in the coexistence system of Al2O3 by the electrolytic deduction method was difficult, because the effect of oxygen ion of Al2O3 was larger than the level of oxidation- reduction potential. (S.Y.)

  6. Magnetic separation of uranium from magnesium fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Hoegler, J.M.

    1987-01-01

    The attraction or repulsion of particles by a magnetic gradient, based on the respective susceptibilities, provides the basis for physical separation of particles that are comprised predominantly of uranium from those that are predominantly magnesium fluoride (MgF/sub 2/). To determine the effectiveness of this approach, a bench-scale magnetic separator from the S.G. Frantz Co., Inc. was used. In the Frantz Model L-1, particles are fed through a funnel onto a vibration tray and through a magnetic field. The specific design of the Frantz magnet causes the magnetic field strength to vary along the width of the magnet, setting up a gradient. The tray in the magnetic field is split at a point about half way down its length so that the separated material does not recombine. A schematic is presented of Frantz Model L-1 CN - the same magnet configured for high gradient magnetic separation of liquid-suspended particles. Here different pole pieces create a uniform magnetic field, and stainless steel wood in the canister between the pole pieces creates the high gradient. 1 ref., 6 figs., 2 tabs.

  7. Investigation of solubility of cesium, strontium, barium, rare-earth, uranium and americium fluorides in acid nitrosyl fluoride (NOFx3HF)

    International Nuclear Information System (INIS)

    Solubility of Am and other elements, which are fission products, in acid nitrosylfluoride has been studied. Cesium fluoride has maximum solubility; uranium tetrafluoride is also noticeably soluble; americium trifluoride is practically insoluble; fluorides of rare earth elements are slightly soluble in NOFx3HF. Analysis of the solid phase obtained after treating the mixture of the above fluorides with acid nitrosylfluoride has shown that cesium fluoride reacts with NOFx3HF with the formation of an acid salt (CsFxHF), whereas fluorides of alkaline and rare earth elements remain unchanged. The behaviour of a mixture of cesium, barium, and lanthanum fluorides in the process of three-multiple treating with acid nitrosylfluoride has been studied. It is shown that more than 98% of cesium fluoride and 5% of barium fluoride pass into the mother liquor while lanthanum fluoride remains completely in the solid phase. The data on americium fluoride solubility in acid nitrosylfluoride have indicated that it behaves in the same way as fluorides of rare earth elements; it is practically insoluble in HOFx3HF

  8. 21 CFR 573.240 - Calcium periodate.

    Science.gov (United States)

    2010-04-01

    ... with calcium hydroxide or calcium oxide to form a substance consisting of not less than 60 percent by... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium periodate. 573.240 Section 573.240 Food... Additive Listing § 573.240 Calcium periodate. The food additive calcium periodate may be safely used...

  9. 21 CFR 573.260 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium silicate. 573.260 Section 573.260 Food and... Listing § 573.260 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely used as an anticaking agent in animal feed, provided that the amount of calcium silicate does...

  10. Profile of Fluoride Release from a Nanohybrid Composite Resin

    Directory of Open Access Journals (Sweden)

    Raquel Assed Bezerra Silva

    2015-02-01

    Full Text Available The aim of this study was to evaluate in vitro the amount and profile of fluoride release from a fluoride-containing nanohybrid composite resin (Tetric® N-Ceram by direct potentiometry. Thirty specimens (5 mm diameter x 3 mm high; n=10/material were made of Tetric® N-Ceram, Vitremer® resin-modified glass ionomer cement (RMGIC (positive control or Filtek® Z350 nanofill composite resin (negative control. The specimens were stored individually in plastic tubes containing 1 mL of artificial saliva at 37°C, which was daily renewed during 15 days. At each renewal of saliva, the amount of fluoride ions released in the solution was measured using a fluoride ion-selective electrode with ion analyzer, and the values obtained in mV were converted to ppm (µg/mL. Data were analyzed statistically by ANOVA and Tukey’s post-hoc test at a significance level of 5%. The results showed that the resins Tetric® N-Ceram and Filtek® Z350 did not release significant amounts of fluoride during the whole period of evaluation (p>0.05. Only Vitremer® released significant amounts of fluoride ions during the 15 days of the experiment, with greater release in first 2 days (p0.05. In conclusion, the nanohybrid composite resin Tetric® N-Ceram did not present in vitro fluoride-releasing capacity throughout the 15 days of study.

  11. Calcium measurement methods

    Directory of Open Access Journals (Sweden)

    CarloAlberto Redi

    2010-09-01

    Full Text Available Rightly stressed by prof. Wolfgang Walz in the Preface to the series Neuromethods series, the “careful application of methods is probably the most important step in the process of scientific inquiry”. Thus, I strongly suggest to all those interested in calcium signaling and especially to the new-comers in the hot topic of neuroscience (which has so much space even in science-society debate for its implications in legal issues and in the judge-decision process to take profit from this so well edited book. I am saying this since prof. Verkhratsky and prof. Petersen......

  12. Extracellular calcium sensing and extracellular calcium signaling

    Science.gov (United States)

    Brown, E. M.; MacLeod, R. J.; O'Malley, B. W. (Principal Investigator)

    2001-01-01

    , localized changes in Ca(o)(2+) within the ECF can originate from several mechanisms, including fluxes of calcium ions into or out of cellular or extracellular stores or across epithelium that absorb or secrete Ca(2+). In any event, the CaR and other receptors/sensors for Ca(o)(2+) and probably for other extracellular ions represent versatile regulators of numerous cellular functions and may serve as important therapeutic targets.

  13. Stabilization of fluoroindate glasses by magnesium fluoride and other heavy metal fluorides

    Directory of Open Access Journals (Sweden)

    B. J. Costa

    1998-06-01

    Full Text Available Their extended transparency in the IR makes them attractive for use as optical fibers for CO laser power delivery and optical amplification. This paper firstly describes the spectacular stabilizing effect of MgF2 on the binary system InF3-BaF2. The investigation of the InF3-BaF2-MgF2 system led to samples up to 5mm in thickness. Further optimization of this system was achieved by incorporation of limited amounts of other fluorides and resulted in increased resistence to devitrification. The second approach of this work was concerned to the investigation of the pseudo-ternary system InF3-GdF3-GaF3 at constant concentrations of ZnF2-SrF2-BaF2-NaF. Several compositions were studied in this system. The samples presented a better thermal stability when compared to other families of fluoride glasses. Therefore, these glasses seem to be very promising for the fabrication of special optical fibers. Thermal data are reported.

  14. Electrochemical properties of uranium, cerium, and zirconium in the lithium fluoride - barium fluoride eutectic

    International Nuclear Information System (INIS)

    The aim of this work has been to determine the possibility of carrying out an electrochemical analysis of the ions U4+, Ce3+, Zr4+ in a fluoride melt, and to obtain some of the electrochemical properties of these ions. It was first of all necessary to develop a method for purifying the LiF-BaF2 eutectic so as to have melts of sufficient purity for carrying out an electrochemical study using linear chrono-amperometry and chrono-potentiometry. The polarization curves recorded in solutions for the ions U4+, Ce3+, Zr4+ show that the systems U4+/U3+, Ce3+/Ce4+ and Zr4+/Zr are rapid. After it had been checked that mass transport on the electrode is controlled by diffusion, the diffusion coefficients for the ions Ce3+, U4+ and Zr4+ were determined. The oxidizing nature of the ion Ce4+ makes it possible to dissolve ceric oxide in the molten fluoride. Furthermore the existence of two zirconium oxyfluorides has been demonstrated, they appear after dissolution of the zirconia in a solution of zirconium tetrafluoride. From a practical point of view these results are of interest for the preparation of metals by electrolytic reduction of their oxides. (author)

  15. In vivo and in vitro studies of a cetylamine fluoride mouthrinse: evaluation of a device used for in vitro experiments

    Directory of Open Access Journals (Sweden)

    CARVALHO Sílvia Magaly Sasso

    1999-01-01

    Full Text Available A mouthrinse containing cetylamine fluoride (230 ppm in fluoride was prepared for in vitro studies of fluoride clearance and adsorption by enamel and/or hydroxyapatite using a device that simulates the oral cavity. In vivo studies of fluoride clearance from this mouthrinse were conducted and compared with other fluoride sources. The amount of fluoride adsorbed to tooth blocks or powdered hydroxyapatite, both treated with this cetylamine fluoride mouthrinse once or twice a day, was determined. The results of these studies showed that it is possible to prepare a mouthrinse with cetylamine fluoride for alternative use by patients for the prevention and therapy of dental caries.

  16. Compartmentalization of the submembrane calcium activity during calcium influx and its significance in transmitter release.

    OpenAIRE

    Simon, S M; Llinás, R R

    1985-01-01

    Quantitative modeling indicates that, in presynaptic terminals, the intracellular calcium concentration profile during inward calcium current is characterized by discrete peaks of calcium immediately adjacent to the calcium channels. This restriction of intracellular calcium concentration suggests a remarkably well specified intracellular architecture such that calcium, as a second messenger, may regulate particular intracellular domains with a great degree of specificity.

  17. An Overview of Liquid Fluoride Salt Heat Transport Systems

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, David Eugene [ORNL; Cetiner, Sacit M [ORNL

    2010-09-01

    Heat transport is central to all thermal-based forms of electricity generation. The ever increasing demand for higher thermal efficiency necessitates power generation cycles transitioning to progressively higher temperatures. Similarly, the desire to provide direct thermal coupling between heat sources and higher temperature chemical processes provides the underlying incentive to move toward higher temperature heat transfer loops. As the system temperature rises, the available materials and technology choices become progressively more limited. Superficially, fluoride salts at {approx}700 C resemble water at room temperature being optically transparent and having similar heat capacity, roughly three times the viscosity, and about twice the density. Fluoride salts are a leading candidate heat-transport material at high temperatures. Fluoride salts have been extensively used in specialized industrial processes for decades, yet they have not entered widespread deployment for general heat transport purposes. This report does not provide an exhaustive screening of potential heat transfer media and other high temperature liquids such as alkali metal carbonate eutectics or chloride salts may have economic or technological advantages. A particular advantage of fluoride salts is that the technology for their use is relatively mature as they were extensively studied during the 1940s-1970s as part of the U.S. Atomic Energy Commission's program to develop molten salt reactors (MSRs). However, the instrumentation, components, and practices for use of fluoride salts are not yet developed sufficiently for commercial implementation. This report provides an overview of the current understanding of the technologies involved in liquid salt heat transport (LSHT) along with providing references to the more detailed primary information resources. Much of the information presented here derives from the earlier MSR program. However, technology has evolved over the intervening years

  18. Recommendations for fluoride limits in drinking water based on estimated daily fluoride intake in the Upper East Region, Ghana.

    Science.gov (United States)

    Craig, Laura; Lutz, Alexandra; Berry, Kate A; Yang, Wei

    2015-11-01

    Both dental and skeletal fluorosis caused by high fluoride intake are serious public health concerns around the world. Fluorosis is particularly pronounced in developing countries where elevated concentrations of naturally occurring fluoride are present in the drinking water, which is the primary route of exposure. The World Health Organization recommended limit of fluoride in drinking water is 1.5 mg F(-) L(-1), which is also the upper limit for fluoride in drinking water for several other countries such as Canada, China, India, Australia, and the European Union. In the United States the enforceable limit is much higher at 4 mg F(-) L(-1), which is intended to prevent severe skeletal fluorosis but does not protect against dental fluorosis. Many countries, including the United States, also have notably lower unenforced recommended limits to protect against dental fluorosis. One consideration in determining the optimum fluoride concentration in drinking water is daily water intake, which can be high in hot climates such as in northern Ghana. The results of this study show that average water intake is about two times higher in Ghana than in more temperate climates and, as a result, the fluoride intake is higher. The results also indicate that to protect the Ghanaian population against dental fluorosis, the maximum concentration of fluoride in drinking water for children under 6-8 years should be 0.6 mg F(-) L(-1) (and lower in the first two years of life), and the limit for older children and adults should be 1.0 mg F(-) L(-1). However, when considering that water treatment is not cost-free, the most widely recommended limit of 1.5 mg F(-) L(-1) - which is currently the limit in Ghana--may be appropriate for older children and adults since they are not vulnerable to dental fluorosis once the tooth enamel is formed. PMID:26058000

  19. Fluorides in groundwater and its impact on health.

    Science.gov (United States)

    Shailaja, K; Johnson, Mary Esther Cynthia

    2007-04-01

    Fluoride is a naturally occurring toxic mineral present in drinking water and causes yellowing of teeth, tooth problems etc. Fluorspar, Cryolite and Fluorapatite are the naturally occurring minerals, from which fluoride finds its path to groundwater through infiltration. In the present study two groundwater samples, Station I and Station II at Hyderabad megacity, the capital of Andhra Pradesh were investigated for one year from January 2001 to December 2001. The average fluoride values were 1.37 mg/l at Station I and 0.91 mg/l at Station II. The permissible limit given by BIS (1983) 0.6-1.2 mg/l and WHO (1984) 1.5 mg/l for fluoride in drinking water. The groundwaters at Station I exceeded the limit while at Station II it was within the limits. The study indicated that fluoride content of 0.5 mg/l is sufficient to cause yellowing of teeth and dental problems. PMID:17915775

  20. On the solubility of rare earth fluorides in mineral acids

    International Nuclear Information System (INIS)

    The results of the investigation of rare earth fluoride solubility in a wide range of nitric acid concentrations are presented. The fluoride solubility monotonously increases with the nitric acid concentration and upon attaining a certain maximum again decreases. The maximum solubility region for all fluorides studied is located in definite concentration limits of the acid. The YF3 these values correspond to 2.0 g/l, for NdF3-2.32, SmF3 -2.25, PrF3 - 0.72, EuF3 - 1.66 g/l within the limits of 3.1-6.0 mol/l of nitric acid. Such course of the solubility curve is bound up with the change of hydrogen ion concentration in the solution. Solubility product values have been obtained for rare earth fluorides in the HNO3 concentration range from 0.42 to 1.3 mol/l. It is shown that rare earth fluorides have low solubility product values in nitric acid and their solubility product values depend on hydrogen ion concentration