PROCESS FOR CONTINUOUSLY SEPARATING IRRADIATION PRODUCTS OF THORIUM

DOEpatents

Hatch, L.P.; Miles, F.T.; Sheehan, T.V.; Wiswall, R.H.; Heus, R.J.

1959-07-01

A method is presented for separating uranium-233 and protactinium from thorium-232 containing compositions which comprises irradiating finely divided particles of said thorium with a neutron flux to form uranium-233 and protactinium, heating the neutron-irradiated composition in a fluorine and hydrogen atmosphere to form volatile fluorides of uranium and protactinium and thereafter separating said volatile fluorides from the thorium.

Calcination process for radioactive wastes

DOEpatents

Kilian, Douglas C.

1976-05-04

The present invention provides a method for minimizing the volatilization of chlorides during solidification in a fluidized-bed calciner of liquids containing sodium, nitrate and chloride ions. Zirconium and fluoride are introduced into the liquid, and one-half mole of calcium nitrate is added per mole of fluoride present in the liquid mixture. The mixture is calcined in the fluidized-bed calciner at about 500.degree.C., producing a high bulk density calcine product containing the chloride, thus tying up the chloride in the solid product and minimizing chloride volatilization.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spencer, Barry B.; Bruffey, Stephanie H.; Jordan, Jacob A.

US regulations will require the removal of iodine and tritium, along with other volatile and semi-volatile radionuclides, from the off-gas streams of nuclear fuel reprocessing plants. Advanced tritium pretreatment (TPT) is an additional head-end operation that could be incorporated within nuclear fuel reprocessing plants. It utilizes nitrogen dioxide (NOR2R) as an oxidant to convert UOR2R to UR3ROR8R prior to traditional aqueous dissolution. Advanced TPT can result in the quantitative volatilization of both tritium and iodine. Up-front removal of iodine is of significant advantage because otherwise it distributes to several unit operations and the associated off-gas streams. The off-gas streams willmore » then require treatment to comply with US regulations. Advanced TPT is currently under development at Oak Ridge National Laboratory, and a kilogram-scale hot cell demonstration with used nuclear fuel (UNF) is planned for fiscal year (FY) 2018.« less

A Brief User's Guide to the Excel ® -Based DF Calculator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jubin, Robert T.

2016-06-01

To understand the importance of capturing penetrating forms of iodine as well as the other volatile radionuclides, a calculation tool was developed in the form of an Excel ® spreadsheet to estimate the overall plant decontamination factor (DF). The tool requires the user to estimate splits of the volatile radionuclides within the major portions of the reprocessing plant, speciation of iodine and individual DFs for each off-gas stream within the Used Nuclear Fuel reprocessing plant. The Impact to the overall plant DF for each volatile radionuclide is then calculated by the tool based on the specific user choices. The Excelmore » ® spreadsheet tracks both elemental and penetrating forms of iodine separately and allows changes in the speciation of iodine at each processing step. It also tracks 3H, 14C and 85Kr. This document provides a basic user's guide to the manipulation of this tool.« less

Study of fluoride corrosion of nickel alloys

NASA Technical Reports Server (NTRS)

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.

DRY FLUORINE SEPARATION METHOD

DOEpatents

Seaborg, G.T.; Gofman, J.W.; Stoughton, R.W.

1959-05-19

Preparation and separation of U/sup 233/ by irradiation of ThF/sub 4/ is described. During the neutron irradiation to produce Pa/sup 233/ a fluorinating agent such as HF, F/sub 2/, or HF + F/sub 2/ is passed through the ThF/sub 4/ powder to produce PaF/sub 5/. The PaF/sub 5/, being more volatile, is removed as a gas and allowed to decay radioactively to U/sup 233/ fluoride. A batch procedure in which ThO/sub 2/ or Th metal is irradiated and fluorinated is suggested. Some Pa and U fluoride volatilizes away. Then the remainder is fluorinated with F/sub 2/ to produce very volatile UF/sub 6/ which is recovered. (T.R.H.)

New insights into the mechanism of methoxyflurane nephrotoxicity and implications for anesthetic development (part 2): Identification of nephrotoxic metabolites.

PubMed

Kharasch, Evan D; Schroeder, Jesara L; Liggitt, H Denny; Ensign, Dustin; Whittington, Dale

2006-10-01

Methoxyflurane nephrotoxicity results from its metabolism, which occurs by both dechlorination (to methoxydifluoroacetic acid [MDFA]) and O-demethylation (to fluoride and dichloroacetic acid [DCAA]). Inorganic fluoride can be toxic, but it remains unknown why other anesthetics, commensurately increasing systemic fluoride concentrations, are not toxic. Fluoride is one of many methoxyflurane metabolites and may itself cause toxicity and/or reflect formation of other toxic metabolite(s). This investigation evaluated the disposition and renal effects of known methoxyflurane metabolites. Rats were given by intraperitoneal injection the methoxyflurane metabolites MDFA, DCAA, or sodium fluoride (0.22, 0.45, 0.9, or 1.8 mmol/kg followed by 0.11, 0.22, 0.45, or 0.9 mmol/kg on the next 3 days) at doses relevant to metabolite exposure after methoxyflurane anesthesia, or DCAA and fluoride in combination. Renal histology and function (blood urea nitrogen, urine volume, urine osmolality) and metabolite excretion in urine were assessed. Methoxyflurane metabolite excretion in urine after injection approximated that after methoxyflurane anesthesia, confirming the appropriateness of metabolite doses. Neither MDFA nor DCAA alone had any effects on renal function parameters or necrosis. Fluoride at low doses (0.22, then 0.11 mmol/kg) decreased osmolality, whereas higher doses (0.45, then 0.22 mmol/kg) also caused diuresis but not significant necrosis. Fluoride and DCAA together caused significantly greater tubular cell necrosis than fluoride alone. Methoxyflurane nephrotoxicity seems to result from O-demethylation, which forms both fluoride and DCAA. Because their co-formation is unique to methoxyflurane compared with other volatile anesthetics and they are more toxic than fluoride alone, this suggests a new hypothesis of methoxyflurane nephrotoxicity. This may explain why increased fluoride formation from methoxyflurane, but not other anesthetics, is associated with toxicity. These results may have implications for the interpretation of clinical anesthetic defluorination, use of volatile anesthetics, and the laboratory methods used to evaluate potential anesthetic toxicity.

METHOD OF PRODUCING PLUTONIUM TETRAFLUORIDE

DOEpatents

Tolley, W.B.; Smith, R.C.

1959-12-15

A process is presented for preparing plutonium tetrafluoride from plutonium(IV) oxalate. The oxalate is dried and decomposed at about 300 deg C to the dioxide, mixed with ammonium bifluoride, and the mixture is heated to between 50 and 150 deg C whereby ammonium plutonium fluoride is formed. The ammonium plutonium fluoride is then heated to about 300 deg C for volatilization of ammonium fluoride. Both heating steps are preferably carried out in an inert atmosphere.

Selective Fluorination and Separation of Metals with NF3 for Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, Richard A.; Barinaga, Charles J.; McNamara, Bruce K.

2016-03-01

We report recent progress on the development of a new methodology based on the generation of volatile metal fluorides through the use of nitrogen trifluoride (NF3), and the separation and measurement of these metal fluorides by electron ionization mass spectrometry. Though unreactive under ambient conditions, NF3 reacts selectively at specified temperatures with various metal-containing species to form volatile metal fluorides. Utilizing these species-dependent traits, elements of a sample may be sequentially produced and thus separated on-line. Metals were reacted inside a thermogravimetric analyzer, the gas outlet of which was directly coupled to a quadrupole mass spectrometer with an electron impactmore » ionization source via a molecular leak valve. We present results of this project including the electron ionization mass spectrum of gaseous tellurium hexafluoride.« less

Recovery of agricultural odors and odorous compounds from polyvinyl fluoride film bags

USDA-ARS?s Scientific Manuscript database

Accurate sampling methods are necessary when quantifying odor and volatile organic compound emissions at agricultural facilities. The commonly accepted methodology in the U.S. has been to collect odor samples in polyvinyl fluoride bags (PVF, brand name Tedlar®) and, subsequently, analyze with human ...

Novel Sorbent Development and Evaluation for the Capture of Krypton and Xenon from Nuclear Fuel Reprocessing Off-Gas Streams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Troy G. Garn; Mitchell R. Greenhalgh; Jack D. Law

2013-10-01

The release of volatile radionuclides generated during Used Nuclear Fuel reprocessing in the US will most certainly need to be controlled to meet US regulatory emission limits. A US DOE sponsored Off-Gas Sigma Team has been tasked with a multi-lab collaborative research and development effort to investigate and evaluate emissions and immobilization control technologies for the volatile radioactive species generated from commercial Used Nuclear Fuel (UNF) Reprocessing. Physical Adsorption technology is a simpler and potential economical alternative to cryogenic distillation processes that can be used for the capture of krypton and xenon and has resulted in a novel composite sorbentmore » development procedure using synthesized mordenite as the active material. Utilizing the sorbent development procedure, INL sigma team members have developed two composite sorbents that have been evaluated for krypton and xenon capacities at ambient and 191 K temperature using numerous test gas compositions. Adsorption isotherms have been generated to predict equilibration and maximum capacities enabling modeling to support process equipment scale-up.« less

Novel Sorbent Development and Evaluation for the Capture of Krypton and Xenon from Nuclear Fuel Reprocessing Off-Gas Streams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Troy G. Garn; Mitchell R. Greenhalgh; Jack D. Law

2013-09-01

The release of volatile radionuclides generated during Used Nuclear Fuel reprocessing in the US will most certainly need to be controlled to meet US regulatory emission limits. A US DOE sponsored Off-Gas Sigma Team has been tasked with a multi-lab collaborative research and development effort to investigate and evaluate emissions and immobilization control technologies for the volatile radioactive species generated from commercial Used Nuclear Fuel (UNF) Reprocessing. Physical Adsorption technology is a simpler and potential economical alternative to cryogenic distillation processes that can be used for the capture of krypton and xenon and has resulted in a novel composite sorbentmore » development procedure using synthesized mordenite as the active material. Utilizing the sorbent development procedure, INL sigma team members have developed two composite sorbents that have been evaluated for krypton and xenon capacities at ambient and 191 K temperature using numerous test gas compositions. Adsorption isotherms have been generated to predict equilibration and maximum capacities enabling modeling to support process equipment scale-up.« less

78 FR 37973 - Change of Address for Region 7; Technical Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-25

... recordkeeping requirements, Sulfur oxides, Volatile organic compounds. 40 CFR Part 59 Environmental protection... requirements, Volatile organic compounds. 40 CFR Part 60 Environmental protection, Administrative practice and..., Cement industry, Chemicals, Coal, Copper, Dry cleaners, Electric power plants, Fertilizers, Fluoride...

Effects of seasonal climatic variability on several toxic contaminants in urban lakes: Implications for the impacts of climate change.

PubMed

Wu, Qiong; Xia, Xinghui; Mou, Xinli; Zhu, Baotong; Zhao, Pujun; Dong, Haiyang

2014-12-01

Climate change is supposed to have influences on water quality and ecosystem. However, only few studies have assessed the effect of climate change on environmental toxic contaminants in urban lakes. In this research, response of several toxic contaminants in twelve urban lakes in Beijing, China, to the seasonal variations in climatic factors was studied. Fluorides, volatile phenols, arsenic, selenium, and other water quality parameters were analyzed monthly from 2009 to 2012. Multivariate statistical methods including principle component analysis, cluster analysis, and multiple regression analysis were performed to study the relationship between contaminants and climatic factors including temperature, precipitation, wind speed, and sunshine duration. Fluoride and arsenic concentrations in most urban lakes exhibited a significant positive correlation with temperature/precipitation, which is mainly caused by rainfall induced diffuse pollution. A negative correlation was observed between volatile phenols and temperature/precipitation, and this could be explained by their enhanced volatilization and biodegradation rates caused by higher temperature. Selenium did not show a significant response to climatic factor variations, which was attributed to low selenium contents in the lakes and soils. Moreover, the response degrees of contaminants to climatic variations differ among lakes with different contamination levels. On average, temperature/precipitation contributed to 8%, 15%, and 12% of the variations in volatile phenols, arsenic, and fluorides, respectively. Beijing is undergoing increased temperature and heavy rainfall frequency during the past five decades. This study suggests that water quality related to fluoride and arsenic concentrations of most urban lakes in Beijing is becoming worse under this climate change trend. Copyright © 2014. Published by Elsevier B.V.

URANIUM RECOVERY FROM COMPOSITE UF$sub 4$ REDUCTION BOMB WASTES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, E R; Doyle, R L; Coleman, J R

1954-01-28

A number of techniques have been investigated on a laboratory-scale for separating uranium from fluorides during the recovery of uranium from UF4 reduction bomb wastes (C-oxide) by an HCl leach - NH4OH precipitation process. Among these are included adsorption of fluorides from filtered leach liquors, fractional precipitation of fluorides and uranium, complexing of fluorides into forms soluble in slightly acid solutions, and fluoride volatilization from the uranium concentrate. Solubility studies of CaF2 and MgF2 in aqueous hydrochloric acid at various acidities and temperatures were also conducted. A description of the production-scale processing of C-oxide in the FMPC scrap plant hasmore » been included.« less

APPLICATION OF VACUUM SALT DISTILLATION TECHNOLOGY FOR THE REMOVAL OF FLUORIDE AND CHLORIDE FROM LEGACY FISSILE MATERIALS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, R.; Peters, T.

2011-11-01

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 (PuO{sub 2}). 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 (CaCl{sub 2}), calcium fluoride (CaF{sub 2}), and plutonium fluoride (PuF{sub 3}) were of particular concern. To enable the use of the same operating conditions for themore » 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 CaCl{sub 2}, CaF{sub 2} and PuF{sub 3} below 1000 C using VSD technology.« less

Molecular emission characteristics of various fluorides in a low-temperature-hydrogen diffusion flame.

PubMed

Dagnall, R M; Fleet, B; Risby, T H; Deans, D R

1971-02-01

A capillary burner supporting a nitrogen/hydrogen diffusion flame has been evaluated as a possible means of detection for several volatile fluorides after their gas-chromatographic separation. The fluorides of As, B, C, Ge, I, Mo, P, Re, S, Sb, Se, Si, Te and W were formed by the reaction of the element with chlorine trifluoride, and the intense molecular emission given by each was recorded. An attempt was made to identify the emitting species.

New insights into the mechanism of methoxyflurane nephrotoxicity and implications for anesthetic development (part 1): Identification of the nephrotoxic metabolic pathway.

PubMed

Kharasch, Evan D; Schroeder, Jesara L; Liggitt, H Denny; Park, Sang B; Whittington, Dale; Sheffels, Pamela

2006-10-01

Methoxyflurane nephrotoxicity results from biotransformation; inorganic fluoride is a toxic metabolite. Concern exists about potential renal toxicity from volatile anesthetic defluorination, but many anesthetics increase fluoride concentrations without consequence. Methoxyflurane is metabolized by both dechlorination to methoxydifluoroacetic acid (MDFA, which may degrade to fluoride) and O-demethylation to fluoride and dichloroacetatic acid. The metabolic pathway responsible for methoxyflurane nephrotoxicity has not, however, been identified, which was the aim of this investigation. Experiments evaluated methoxyflurane metabolite formation and effects of enzyme induction or inhibition on methoxyflurane metabolism and toxicity. Rats pretreated with phenobarbital, barium sulfate, or nothing were anesthetized with methoxyflurane, and renal function and urine methoxyflurane metabolite excretion were assessed. Phenobarbital effects on MDFA metabolism and toxicity in vivo were also assessed. Metabolism of methoxyflurane and MDFA in microsomes from livers of pretreated rats was determined in vitro. Phenobarbital pretreatment increased methoxyflurane nephrotoxicity in vivo (increased diuresis and blood urea nitrogen and decreased urine osmolality) and induced in vitro hepatic microsomal methoxyflurane metabolism to inorganic fluoride (2-fold), dichloroacetatic acid (1.5-fold), and MDFA (5-fold). In contrast, phenobarbital had no influence on MDFA renal effects in vivo or MDFA metabolism in vitro or in vivo. MDFA was neither metabolized to fluoride nor nephrotoxic. Barium sulfate diminished methoxyflurane metabolism and nephrotoxicity in vivo. Fluoride from methoxyflurane anesthesia derives from O-demethylation. Phenobarbital increases in methoxyflurane toxicity do not seem attributable to methoxyflurane dechlorination, MDFA toxicity, or MDFA metabolism to another toxic metabolite, suggesting that nephrotoxicity is attributable to methoxyflurane O-demethylation. Fluoride, one of many metabolites from O-demethylation, may be toxic and/or reflect formation of a different toxic metabolite. These results may have implications for interpreting anesthetic defluorination, volatile anesthetic use, and methods to evaluate anesthetic toxicity.

Comparison of storage stability of odorous VOCs in polyester aluminum and polyvinyl fluoride tedlar bags

USDA-ARS?s Scientific Manuscript database

Whole air sampling using containers such as flexible bags or rigid canisters is commonly used to collect samples of volatile organic compounds (VOC) in air. The objective of this study was to compare the stability of polyester aluminum (PEA) and polyvinyl fluoride (PVF, brand name Tedlar®) bags for ...

Effects of deuteration on the metabolism of halogenated anesthetics in the rat

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCarty, L.P.; Malek, R.S.; Larsen, E.R.

1979-08-01

The authors studied the effects of substituting deuterium for hydrogen in several volatile anesthetics on their metabolism in the Fischer rat. Substitution of deuterium in the ethyl portion of methoxyflurane increased the metabolic production of fluoride ion by 19 percent when administered at a concentration of 0.05%. Total replacement of hydrogen by deuterium resulted in a 29% decrease in the amount of fluoride produced, while deuteration of only the methoxyl group produced a 33% decrease in fluoride produced. Deuteration of halothane resulted in a 15 or 26% decrease in serum bromide at 0.75% or 1.0%, respectively. Deuteration in the ethylmore » portions of enflurane and two experimental agents, CF2HOCF2CFBrH and CF2HOCF2CCl2H resulted in 65, 76, and 29% decreases in urinary fluoride, respectively. Anesthesia with deuterated chloroform at a concentration of 0.36% produced a 35% decrease in serum glutamic pyruvic transaminase (SGPT). It is concluded that deuteration of volatile anesthetics changes their metabolism, in most cases producing decreases in metabolism. This effect may lessen the organ toxicity believed to occur with some of these anesthetics.« less

PILOT-SCALE REMOVAL OF FLUORIDE FROM LEGACY PLUTONIUM MATERIALS USING VACUUM SALT DISTILLATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, R. A.; Pak, D. J.

2012-09-11

Between September 2009 and January 2011, the Savannah River National Laboratory (SRNL) and HB-Line designed, developed, tested, and successfully deployed a system for the distillation of chloride salts. In 2011, SRNL adapted the technology for the removal of fluoride from fluoride-bearing salts. The method involved an in situ reaction between potassium hydroxide (KOH) and the fluoride salt to yield potassium fluoride (KF) and the corresponding oxide. The KF and excess KOH can be distilled below 1000{deg}C using vacuum salt distillation (VSD). The apparatus for vacuum distillation contains a zone heated by a furnace and a zone actively cooled using eithermore » recirculated water or compressed air. During a vacuum distillation operation, a sample boat containing the feed material is placed into the apparatus while it is cool, and the system is sealed. The system is evacuated using a vacuum pump. Once a sufficient vacuum is attaned, heating begins. Volatile salts distill from the heated zone to the cooled zone where they condense, leaving behind the non-volatile material in the feed boat. Studies discussed in this report were performed involving the use of non-radioactive simulants in small-scale and pilot-scale systems as well as radioactive testing of a small-scale system with plutonium-bearing materials. Aspects of interest include removable liner design considerations, boat materials, in-line moisture absorption, and salt deposition.« less

Evaluation of Ruthenium Capture Methods for Tritium Pretreatment Off-Gas Streams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spencer, Barry B.; Jubin, Robert Thomas; Bruffey, Stephanie H.

2017-07-01

In the reprocessing of used nuclear fuel, radioactive elements are released into various plant off-gas streams. While much research and development has focused on the abatement of the volatile nuclides 3H, 14C, 85Kr, and 129I, the potential release of semivolatile isotopes that could also report to the off-gas streams in a reprocessing facility has been examined. Ruthenium (as 106Ru) has been identified as one of the semivolatile nuclides requiring the greatest degree of abatement prior to discharging the plant off-gas to the environment.

APPLICATION OF VACUUM SALT DISTILLATION TECHNOLOGY FOR THE REMOVAL OF FLUORIDE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, R.; Pak, D.

2011-08-10

Vacuum distillation of chloride salts from plutonium oxide (PuO{sub 2}) and simulant PuO{sub 2} has been previously demonstrated at Department of Energy (DOE) sites using kilogram quantities of chloride salt. The apparatus for vacuum distillation contains a zone heated using a furnace and a zone actively cooled using either recirculated water or compressed air. During a vacuum distillation operation, a sample boat containing the feed material is placed into the apparatus while it is cool, and the system is sealed. The system is evacuated using a vacuum pump. Once a sufficient vacuum is attained, heating begins. Volatile salts distill frommore » the heated zone to the cooled zone where they condense, leaving behind the non-volatile materials in the feed boat. The application of vacuum salt distillation (VSD) is of interest to the HB-Line Facility and the MOX Fuel Fabrication Facility (MFFF) at the Savannah River Site (SRS). Both facilities are involved in efforts to disposition excess fissile materials. Many of these materials contain chloride and fluoride salt concentrations which make them unsuitable for dissolution without prior removal of the chloride and fluoride salts. Between September 2009 and January 2011, the Savannah River National Laboratory (SRNL) and HB-Line designed, developed, tested, and successfully deployed a system for the distillation of chloride salts. Subsequent efforts are attempting to adapt the technology for the removal of fluoride. Fluoride salts of interest are less-volatile than the corresponding chloride salts. Consequently, an alternate approach is required for the removal of fluoride without significantly increasing the operating temperature. HB-Line Engineering requested SRNL to evaluate and demonstrate the feasibility of an alternate approach using both non-radioactive simulants and plutonium-bearing materials. Whereas the earlier developments targeted the removal of sodium chloride (NaCl) and potassium chloride (KCl), the current activities are concerned with the removal of the halide ions associated with plutonium trifluoride (PuF{sub 3}), plutonium tetrafluoride (PuF{sub 4}), calcium fluoride (CaF{sub 2}), and calcium chloride (CaCl{sub 2}). 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.« less

Iodine Pathways and Off-Gas Stream Characteristics for Aqueous Reprocessing Plants – A Literature Survey and Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

R. T. Jubin; D. M. Strachan; N. R. Soelberg

2013-09-01

Used nuclear fuel is currently being reprocessed in only a few countries, notably France, England, Japan, and Russia. The need to control emissions of the gaseous radionuclides to the air during nuclear fuel reprocessing has already been reported for the entire plant. But since the gaseous radionuclides can partition to various different reprocessing off-gas streams, for example, from the head end, dissolver, vessel, cell, and melter, an understanding of each of these streams is critical. These off-gas streams have different flow rates and compositions and could have different gaseous radionuclide control requirements, depending on how the gaseous radionuclides partition. Thismore » report reviews the available literature to summarize specific engineering data on the flow rates, forms of the volatile radionuclides in off-gas streams, distributions of these radionuclides in these streams, and temperatures of these streams. This document contains an extensive bibliography of the information contained in the open literature.« less

Effect of a triclosan/PVM/MA copolymer/fluoride dentifrice on volatile sulfur compounds in vitro.

PubMed

Pilch, S; Williams, M I; Cummins, D

2005-01-01

The objective of the investigation was to document the in vitro efficacy of a triclosan/PVM/MA copolymer/fluoride (TCF) dentifrice against the formation of volatile sulfur compounds (VSC) as well as the growth of H2S-producing bacteria. Clinical studies using organoleptic judges, gas chromatography, or a portable sulfide monitor have generally been employed in the assessment of treatments for the control of oral malodor. However, these studies are not appropriate for screening purposes because of the expense and time required. An in vitro method was developed for the purpose of screening new compounds, agents or formulations for their ability to control VSC formation and for determining bio-equivalence of efficacy when implementing changes in existing formulations. The method combines basic microbiological methods, dynamic flow cell techniques and head space analysis. The in vitro VSC method was validated by comparing the efficacy of two dentifrices containing TCF with a control fluoride dentifrice as the TCF products have been clinically proven to control oral malodor. In the validation studies, the TCF-containing dentifrices were significantly better (P < 0.05) than the control dentifrice in inhibiting VSC formation and reducing H(2)S-producing bacteria. For example, when compared with baseline, the TCF dentifrices reduced VSC formation between 42 and 49% compared with the control dentifrice which reduced VSC formation 3%. There was no significant difference (P > 0.05) between the two TCF dentifrice formulations. Using an in vitro breath VSC model, it has been demonstrated that two variants of a dentifrice containing triclosan, PVM/MA copolymer and fluoride have efficacy that is significantly better than a control fluoridated dentifrice and that there is no significant difference between the triclosan/PVM/MA copolymer/fluoride dentifrice variants.

FLUORIDE VOLATILITY PROCESS FOR THE RECOVERY OF URANIUM

DOEpatents

Katz, J.J.; Hyman, H.H.; Sheft, I.

1958-04-15

The separation and recovery of uraniunn from contaminants introduced by neutron irradiation by a halogenation and volatilization method are described. The irradiated uranium is dissolved in bromine trifluoride in the liquid phase. The uranium is converted to the BrF/sub 3/ soluble urmium hexafluoride compound whereas the fluorides of certain contaminating elements are insoluble in liquid BrF/sub 3/, and the reaction rate of the BrF/sub 3/ with certain other solid uranium contamirnnts is sufficiently slower than the reaction rate with uranium that substantial portions of these contaminating elements will remain as solids. These solids are then separated from the solution by a distillation, filtration, or centrifugation step. The uranium hexafluoride is then separated from the balance of the impurities and solvent by one or more distillations.

Image Information Obtained Using a Charge-Coupled Device (CCD) Camera During an Immersion Liquid Evaporation Process for Measuring the Refractive Index of Solid Particles.

PubMed

Niskanen, Ilpo; Sutinen, Veijo; Thungström, Göran; Räty, Jukka

2018-06-01

The refractive index is a fundamental physical property of a medium, which can be used for the identification and purity issues of all media. Here we describe a refractive index measurement technique to determine simultaneously the refractive index of different solid particles by monitoring the transmittance of light from a suspension using a charge-coupled device (CCD) camera. An important feature of the measurement is the liquid evaporation process for the refractive index matching of the solid particle and the immersion liquid; this was realized by using a pair of volatile and non-volatile immersion liquids. In this study, refractive indices of calcium fluoride (CaF 2 ) and barium fluoride (BaF 2 ) were determined using the proposed method.

Method for reprocessing and separating spent nuclear fuels. [Patent application

DOEpatents

Krikorian, O.H.; Grens, J.Z.; Parrish, W.H. Sr.

1982-01-19

Spent nuclear fuels, including actinide fuels, volatile and nonvolatile fission products, are reprocessed and separated in a molten metal solvent housed in a separation vessel made of a carbon-containing material. A first catalyst, which promotes the solubility and permeability of carbon in the metal solvent, is included. By increasing the solubility and permeability of the carbon in the solvent, the rate at which actinide oxides are reduced (carbothermic reduction) is greatly increased. A second catalyst, included to increase the affinity for nitrogen in the metal solvent, is added to increase the rate at which actinide nitrides form after carbothermic reduction is complete.

Potential Signatures of Semi-volatile Compounds Associated With Nuclear Processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Probasco, Kathleen M.; Birnbaum, Jerome C.; Maughan, A. D.

2002-06-01

Semi-volatile chemicals associated with nuclear processes (e.g., the reprocessing of uranium to produce plutonium for nuclear weapons, or the separation of actinides from processing waste streams), can provide sticky residues or signatures that will attach to piping, ducting, soil, water, or other surface media. Volatile compounds, that are more suitable for electro-optical sensing, have been well studied. However, the semi-volatile compounds have not been well documented or studied. A majority of these semi-volatile chemicals are more robust than typical gaseous or liquid chemicals and can have lifetimes of several weeks, months, or years in the environment. However, large data gapsmore » exist concerning these potential signature compounds and more research is needed to fill these data gaps so that important signature information is not overlooked or discarded. This report investigates key semi-volatile compounds associated with nuclear separations, identifies available chemical and physical properties, and discusses the degradation products that would result from hydrolysis, radiolysis and oxidation reactions on these compounds.« less

Method for removing oxide contamination from silicon carbide powders

DOEpatents

Brynestad, J.; Bamberger, C.E.

1984-08-01

The described invention is directed to a method for removing oxide contamination in the form of oxygen-containing compounds such as SiO/sub 2/ and B/sub 2/O/sub 3/ from a charge of finely divided silicon carbide. The silicon carbide charge is contacted with a stream of hydrogen fluoride mixed with an inert gas carrier such as argon at a temperature in the range of about 200/sup 0/ to 650/sup 0/C. The oxides in the charge react with the heated hydrogen fluoride to form volatile gaseous fluorides such as SiF/sub 4/ and BF/sub 3/ which pass through the charge along with unreacted hydrogen fluoride and the carrier gas. Any residual gaseous reaction products and hydrogen fluoride remaining in the charge are removed by contacting the charge with the stream of inert gas which also cools the powder to room temperature. The removal of the oxygen contamination by practicing the present method provides silicon carbide powders with desirable pressing and sintering characteristics. 1 tab.

Separation of metallic residues from the dissolution of a high-burnup BWR fuel using nitrogen trifluoride

DOE Office of Scientific and Technical Information (OSTI.GOV)

McNamara, Bruce K.; Buck, Edgar C.; Soderquist, Chuck Z.

2014-03-23

Nitrogen trifluoride (NF 3) was used to fluorinate the metallic residue from the dissolution of a high burnup, boiling water reactor fuel (~70 MWd/kgU). The metallic residue included the noble metal phase (containing ruthenium, rhodium, palladium, technetium, and molybdenum), and smaller amounts of zirconium, selenium, tellurium, and silver. Exposing the noble metal phase to 10% NF 3 in argon between 400 and 550°C, removed molybdenum and technetium near 400°C as their volatile fluorides, and ruthenium near 500C as its volatile fluoride. The events were thermally and temporally distinct and the conditions specified are a recipe to separate these transition metalsmore » from each other and from the noble metal phase nonvolatile residue. Depletion of the volatile fluorides resulted in substantial exothermicity. Thermal excursion behavior was recorded under non-adiabatic, isothermal conditions that typically minimize heat release. Physical characterization of the metallic noble phase and its thermal behavior are consistent with high kinetic velocity reactions encouraged by the nanoparticulate phase or perhaps catalytic influences of the mixed platinum metals with nearly pure phase structure. Post-fluorination, only two phases were present in the residual nonvolatile fraction. These were identified as a nano-crystalline, metallic palladium cubic phase and a hexagonal rhodium trifluoride (RhF 3) phase. The two phases were distinct as the sub-µm crystallites of metallic palladium were in contrast to the RhF 3 phase, which grew from the parent nano-crystalline noble-metal phase during fluorination, to acicular crystals exceeding 20-µm in length.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bruffey, S. H.; Spencer, B. B.; Strachan, D. M.

Four radionuclides have been identified as being sufficiently volatile in the reprocessing of nuclear fuel that their gaseous release needs to be controlled to meet regulatory requirements (Jubin et al. 2011, 2012). These radionuclides are 3H, 14C, 85Kr, and 129I. Of these, 129I has the longest half-life and potentially high biological impact. Accordingly, control of the release of 129I is most critical with respect to the regulations for the release of radioactive material in stack emissions. It is estimated that current EPA regulations (EPA 2010) would require any reprocessing plant in the United States to limit 129I release to lessmore » than 0.05 Ci/MTIHM for a typical fuel burnup of 55 gigawatt days per metric tonne (GWd/t) (Jubin 2011). The study of inorganic iodide in off-gas systems has been almost exclusively limited to I2 and the focus of organic iodide studies has been CH3I. In this document, we provide the results of an examination of publically available literature that is relevant to the presence and sources of both inorganic and organic iodine-bearing species in reprocessing plants. We especially focus on those that have the potential to be poorly sequestered with traditional capture methodologies. Based on the results of the literature survey and some limited thermodynamic modeling, the inorganic iodine species hypoiodous acid (HOI) and iodine monochloride (ICl) were identified as potentially low-sorbing iodine species that could present in off-gas systems. Organic species of interest included both short chain alkyl iodides such as methyl iodide (CH3I) and longer alkyl iodides up to iodododecane (C10H21I). It was found that fuel dissolution may provide conditions conducive to HOI formation and has been shown to result in volatile long-chain alkyl iodides, though these may not volatilize until later in the reprocessing sequence. Solvent extraction processes were found to be significant sources of various organic iodine-bearing species; formation of these was facilitated by the presence of radiolytic decomposition products resulting from radiolysis of tri-n-butyl phosphate and dodecane. Primarily inorganic iodine compounds were expected from waste management processes, including chlorinated species such as ICl. Critical knowledge gaps that must still be addressed include confirmation of the existence and quantification of low-sorbing species in the off-gas of reprocessing facilities. The contributions from penetrating forms of iodine to the plant DF are largely unknown and highly dependent on the magnitude of their presence. These species are likely to be more difficult to remove and it is likely that their sequestration could be improved through the use of different sorbents, through design modifications of the off-gas capture system, or through chemical conversion prior to iodine abatement that would produce more easily captured forms.« less

76 FR 49669 - Change of Address for Region 1; Technical Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-11

... organic compounds. 40 CFR Part 59 Environmental protection, Air pollution control, Confidential business information, Labeling, Ozone, Reporting and recordkeeping requirements, Volatile organic compounds. 40 CFR..., Copper, Dry cleaners, Electric power plants, Fertilizers, Fluoride, Gasoline, Glass and glass products...

REGENERATION OF REACTOR FUEL ELEMENTS

DOEpatents

Lyon, W.L.

1960-04-01

A process is described for concentrating uranium and/or plutonium metal in aluminum alloys in which the actinide content was partially consumed by neutron bombardinent. Two embodiments are claimed: Either the alloy is heated, together with zinc chloride to at least 1000 deg C whereby some aluminum, in the form of aluminum chloride, and any zinc formed volatilize; or else aluminum fluoride is added and reacted at 800 to 1000 deg O and substmospheric pressure whereby pant of the aluminum volatilizes and aluminum subfluoride.

Synthesis and toxicity evaluation of hydrophobic ionic liquids for volatile organic compounds biodegradation in a two-phase partitioning bioreactor.

PubMed

Rodriguez Castillo, Alfredo Santiago; Guihéneuf, Solène; Le Guével, Rémy; Biard, Pierre-François; Paquin, Ludovic; Amrane, Abdeltif; Couvert, Annabelle

2016-04-15

Synthesis of several hydrophobic ionic liquids (ILs), which might be selected as good candidates for degradation of hydrophobic volatile organic compounds in a two-phase partitioning bioreactor (TPPB), were carried out. Several bioassays were also realized, such as toxicity evaluation on activated sludge and zebrafish, cytotoxicity, fluoride release in aqueous phase and biodegradability in order to verify their possible effects in case of discharge in the aquatic environment and/or human contact during industrial manipulation. The synthesized compounds consist of alkylimidazoliums, functionalized imidazoliums, isoqinoliniums, triazoliums, sulfoniums, pyrrolidiniums and morpholiniums and various counter-ions such as: PF6(-), NTf2(-) and NfO(-). Toxicity evaluation on activated sludge of each compound (5% v/v of IL) was assessed by using a glucose uptake inhibition test. Toxicity against zebrafish and cytotoxicity were evaluated by the ImPACCell platform of Rennes (France). Fluoride release in water was estimated by regular measurements using ion chromatography equipment. IL biodegradability was determined by measuring BOD28 of aqueous samples (compound concentration,1mM). All ILs tested were not biodegradable; while some of them were toxic toward activated sludge. Isoquinolinium ILs were toxic to human cancerous cell lines. Nevertheless no toxicity was found against zebrafish Danio rerio. Only one IL released fluoride after long-time agitation. Copyright © 2016 Elsevier B.V. All rights reserved.

CHEMICAL ENGINEERING DIVISION SUMMARY REPORT, OCTOBER, NOVEMBER, DECEMBER 1960

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1961-03-01

Chemical-metallurgical processing studies were made of pyrometallurgical development snd research, and fuel processing facilities for EBR-II. Fuel-cycle applications of fluidization and volatility techniques included laboratory investigations of fluoride volatility processes, engineeringscale development, and conversion of UF/sub 6/ to UO/sub 2/. Reactor safety studies consisted of metal oxidation and ignition kinetics, and metal-water reactions. Reactor chemistry investigations were conducted to determine nuclear constants and suitable reactor decontamination methods. Routine operations are summarized for the high-level gammairradiation facillty and waste processing. (B.O.G.)

REDUCTION OF FLUORIDE TO METAL

DOEpatents

Carlson, O.N.; Schmidt, F.A.; Spedding, F.H.

1960-08-30

A process is given for making yttrium metal by reducing yttrium fluoride with calcium plus magnesium. Calcium is added in an excess of from 10 to 20% and magnesium in a quantity to yield a magnesium--yttrium alloy containing from 12 to 25% magnesium when the reaction mass is heated in an inert atmosphere at from 900 to 1106 deg C, but preferably above the melting point of the alloy. Calcium chloride may be added so as to obtain a less viscous slag containing from 30 to 60% calcium chloride. After removal of the slag the alloy is vacuum-heated at about 1100 deg C for volatilization of the magnesium and calcium.

Waste Minimization Study on Pyrochemical Reprocessing Processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boussier, H.; Conocar, O.; Lacquement, J.

2006-07-01

Ideally a new pyro-process should not generate more waste, and should be at least as safe and cost effective as the hydrometallurgical processes currently implemented at industrial scale. This paper describes the thought process, the methodology and some results obtained by process integration studies to devise potential pyro-processes and to assess their capability of achieving this challenging objective. As example the assessment of a process based on salt/metal reductive extraction, designed for the reprocessing of Generation IV carbide spent fuels, is developed. Salt/metal reductive extraction uses the capability of some metals, aluminum in this case, to selectively reduce actinide fluoridesmore » previously dissolved in a fluoride salt bath. The reduced actinides enter the metal phase from which they are subsequently recovered; the fission products remain in the salt phase. In fact, the process is not so simple, as it requires upstream and downstream subsidiary steps. All these process steps generate secondary waste flows representing sources of actinide leakage and/or FP discharge. In aqueous processes the main solvent (nitric acid solution) has a low boiling point and evaporate easily or can be removed by distillation, thereby leaving limited flow containing the dissolved substance behind to be incorporated in a confinement matrix. From the point of view of waste generation, one main handicap of molten salt processes, is that the saline phase (fluoride in our case) used as solvent is of same nature than the solutes (radionuclides fluorides) and has a quite high boiling point. So it is not so easy, than it is with aqueous solutions, to separate solvent and solutes in order to confine only radioactive material and limit the final waste flows. Starting from the initial block diagram devised two years ago, the paper shows how process integration studies were able to propose process fittings which lead to a reduction of the waste variety and flows leading at an 'ideal' new block diagram allowing internal solvent recycling, and self eliminating reactants. This new flowsheet minimizes the quantity of inactive inlet flows that would have inevitably to be incorporated in a final waste form. The study identifies all knowledge gaps to be filled and suggest some possible R and D issues to confirm or infirm the feasibility of the proposed process fittings. (authors)« less

Dependence of microsomal methoxyflurane O-demethylation on cytochrome P-450 reductase and the stoichiometry of fluoride ion and formaldehyde release.

PubMed

Waskell, L; Gonzales, J

1982-07-01

In order to characterize further the in vitro liver microsomal O-demethylation and defluorination of the volatile anesthetic methoxyflurane, and obtain additional information regarding the participation of cytochrome P-450 in the oxidation, the stoichiometry of the reaction was determined and the effect of antibody to cytochrome P-450 reductase on this unique biotransformation was examined. Liver microsomes were isolated from rabbits and rats in which enzyme induction had previously been produced by phenobarbital. The O-demethylation of methoxyflurane by phenobarbital-induced microsomes results in the production of 1 mol of formaldehyde for every 2 mol of fluoride ion produced. Dichloroacetic acid is also a product of methoxyflurane O-demethylation. Antibody to cytochrome P-450 reductase inhibits by 85% the amount of fluoride ion produced by the microsomal metabolism of methoxyflurane. Thus critical indirect supportive data are contributed to the hypothesis that at least one, but perhaps more, cytochrome P-450 is indeed responsible for methoxyflurane O-demethylation and defluorination.

Benefits of a silica-based fluoride toothpaste containing o-cymen-5-ol, zinc chloride and sodium fluoride.

PubMed

Newby, Craig S; Rowland, Joanna L; Lynch, Richard J M; Bradshaw, David J; Whitworth, Darren; Bosma, Mary Lynn

2011-08-01

Fluoride toothpastes in conjunction with tooth brushing are used to clean teeth, control plaque build-up and for anti-caries benefits. Toothpastes are designed with attractive flavours and appearances to encourage regular prolonged use to maximise these benefits. The incorporation of additional ingredients into toothpaste is a convenient way to provide supplementary protection that fits into people's everyday oral care routine. Such ingredients should not compromise the primary health benefits of toothpaste nor discourage its use. o-Cymen-5-ol and zinc chloride have been incorporated into a sodium fluoride (NaF)/silica toothpaste at 0.1%w/w and 0.6%w/w respectively to provide additional benefits. These include improved gingival health maintenance, in terms of the reduction of plaque, gingival index and bleeding, and an immediate and long lasting reduction in volatile sulfur compounds (VSCs) measured on breath. These benefits can be attributed to the antimicrobial and neutralisation actions of the toothpaste. The use of established fluoride models demonstrated no compromise in NaF bioavailability. The toothpaste was formulated without compromising product aesthetics. The combination of o-cymen-5-ol and zinc chloride in toothpaste gave superior maintenance of gingival health and reduction in malodour related VSCs without compromising the primary health benefits of the toothpaste or diminishing attributes preferred for the product's use. © 2011 FDI World Dental Federation.

Facile fabrication of highly ordered poly(vinylidene fluoride-trifluoroethylene) nanodot arrays for organic ferroelectric memory

NASA Astrophysics Data System (ADS)

Fang, Huajing; Yan, Qingfeng; Geng, Chong; Chan, Ngai Yui; Au, Kit; Yao, Jianjun; Ng, Sheung Mei; Leung, Chi Wah; Li, Qiang; Guo, Dong; Wa Chan, Helen Lai; Dai, Jiyan

2016-01-01

Nano-patterned ferroelectric materials have attracted significant attention as the presence of two or more thermodynamically equivalent switchable polarization states can be employed in many applications such as non-volatile memory. In this work, a simple and effective approach for fabrication of highly ordered poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) nanodot arrays is demonstrated. By using a soft polydimethylsiloxane mold, we successfully transferred the 2D array pattern from the initial monolayer of colloidal polystyrene nanospheres to the imprinted P(VDF-TrFE) films via nanoimprinting. The existence of a preferred orientation of the copolymer chain after nanoimprinting was confirmed by Fourier transform infrared spectra. Local polarization switching behavior was measured by piezoresponse force microscopy, and each nanodot showed well-formed hysteresis curve and butterfly loop with a coercive field of ˜62.5 MV/m. To illustrate the potential application of these ordered P(VDF-TrFE) nanodot arrays, the writing and reading process as non-volatile memory was demonstrated at a relatively low voltage. As such, our results offer a facile and promising route to produce arrays of ferroelectric polymer nanodots with improved piezoelectric functionality.

Fluorination process using catalyst

DOEpatents

Hochel, Robert C.; Saturday, Kathy A.

1985-01-01

A process for converting an actinide compound selected from the group consisting of uranium oxides, plutonium oxides, uranium tetrafluorides, plutonium tetrafluorides and mixtures of said oxides and tetrafluorides, to the corresponding volatile actinide hexafluoride by fluorination with a stoichiometric excess of fluorine gas. The improvement involves conducting the fluorination of the plutonium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3, AgF.sub.2 and NiF.sub.2, whereby the fluorination is significantly enhanced. The improvement also involves conducting the fluorination of one of the uranium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3 and AgF.sub.2, whereby the fluorination is significantly enhanced.

Fluorination process using catalysts

DOEpatents

Hochel, R.C.; Saturday, K.A.

1983-08-25

A process is given for converting an actinide compound selected from the group consisting of uranium oxides, plutonium oxides, uranium tetrafluorides, plutonium tetrafluorides and mixtures of said oxides and tetrafluorides, to the corresponding volatile actinide hexafluoride by fluorination with a stoichiometric excess of fluorine gas. The improvement involves conducting the fluorination of the plutonium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF/sub 3/, AgF/sub 2/ and NiF/sub 2/, whereby the fluorination is significantly enhanced. The improvement also involves conducting the fluorination of one of the uranium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF/sub 3/ and AgF/sub 2/, whereby the fluorination is significantly enhanced.

Thermal reactions of uranium metal, UO 2, U 3O 8, UF 4, and UO 2F 2 with NF 3 to produce UF 6

NASA Astrophysics Data System (ADS)

McNamara, Bruce; Scheele, Randall; Kozelisky, Anne; Edwards, Matthew

2009-11-01

This paper demonstrates that NF 3 fluorinates uranium metal, UO 2, UF 4, UO 3, U 3O 8, and UO 2F 2·2H 2O to produce the volatile UF 6 at temperatures between 100 and 550 °C. Thermogravimetric and differential thermal analysis reaction profiles are described that reflect changes in the uranium fluorination/oxidation state, physiochemical effects, and instances of discrete chemical speciation. Large differences in the onset temperatures for each system investigated implicate changes in mode of the NF 3 gas-solid surface interaction. These studies also demonstrate that NF 3 is a potential replacement fluorinating agent in the existing nuclear fuel cycle and in actinide volatility reprocessing.

Metal–organic framework with optimally selective xenon adsorption and separation

DOE PAGES

Banerjee, Debasis; Simon, Cory M.; Plonka, Anna M.; ...

2016-06-13

Nuclear energy is considered among the most viable alternatives to our current fossil fuel based energy economy.1 The mass-deployment of nuclear energy as an emissions-free source requires the reprocessing of used nuclear fuel to mitigate the waste.2 One of the major concerns with reprocessing used nuclear fuel is the release of volatile radionuclides such as Xe and Kr. The most mature process for removing these radionuclides is energy- and capital-intensive cryogenic distillation. Alternatively, porous materials such as metal-organic frameworks (MOFs) have demonstrated the ability to selectively adsorb Xe and Kr at ambient conditions.3-8 High-throughput computational screening of large databases ofmore » porous materials has identified a calcium-based nanoporous MOF, SBMOF-1, as the most selective for Xe over Kr.9,10 Here, we affirm this prediction and report that SBMOF-1 exhibits by far the highest Xe adsorption capacity and a remarkable Xe/Kr selectivity under relevant nuclear reprocessing conditions. The exceptional selectivity of SBMOF-1 is attributed to its pore size tailored to Xe and its dense wall of atoms that constructs a binding site with a high affinity for Xe, as evident by single crystal X-ray diffraction and molecular simulation.« less

Rare earth elements in apatite: Uptake from H{sub 2}O-bearing phosphate-fluoride melts and the role of volatile components

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleet, M.E.; Pan, Yuanming

The partitioning of rare earth elements (REEs) between fluorapatite (FAp) and H{sub 2}O- bearing phosphate-fluoride melts has been studied at about 700 and 800{degrees}C and 0.10-0.15 GPa. REE uptake patterns, i.e., plots of D(REE:FAp/melt), are convex upwards and peak near Nd for single-REE substituted FAp at minor (0.03-0.25 wt% REE{sub 2}O{sub 3}) abundances, and binary (LREE + HREE)-substituted FAp, and hexa-REE-substituted FAp at minor to major (0.25-7.8 wt% REE{sub 2}O{sub 3}) abundances. Partition coefficients for minor abundances of REE and depolymerized phosphate melts are about 5, 8, and 1 for La, Nd, and Lu, respectively and broadly comparable to thosemore » for early fluorapatite in the fractionation of melts of basaltic composition. The Ca2 site exerts marked control on the selectivity of apatite for REE because it preferentially incorporates LREE and its effective size varies with substitution of the A-site volatile anion component (F, Cl, OH). Using simple crystal-chemical arguments, melt(or fluid)-normalized REE patterns are predicted to peak near Nd for fluorapatite and be more LREE-enriched for chlorapatite. These predictions are consistent with data from natural rocks and laboratory experiments. The wide variation in D(REE:apatite/melt) in nature (from <1 for whitlockite-bearing lunar rocks to about 100 for evolved alkalic rocks) is attributed largely to the influence of the volatile components. 49 refs., 8 figs., 3 tabs.« less

Iodine Adsorption in Metal Organic Frameworks in the Presence of Humidity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Banerjee, Debasis; Chen, Xianyin; Lobanov, Sergey S.

Used nuclear fuel (UNF) reprocessing represents a unique challenge when dealing with radionuclides such as isotopes of 85Kr and 129I 2, due to their volatility and long half-life. However, efficient capture of 129I 2 (t 1/2 = 15.7 x 10 6 years) from the nuclear waste stream can help to reduce the risk of releasing I 2 radionuclide into the environment and mitigate concerns about human health problems. Metal organic frameworks (MOFs) have been reported to be potential I 2 adsorbents: but the effect of water vapor, generally present in the reprocessing off-gas stream is rarely taken into account. Moisturemore » stable porous MOFs, which can selectively adsorb I 2 in presence of water vapor is thus of great interest. Herein, the I 2 adsorption performance of two microporous MOFs is reported in presence of different humidity. I…π phenyl ring interactions are mainly responsible for the adsorption as revealed by single crystal XRD« less

FY90 R&D Project Descriptions ESL (Engineering & Services Laboratory) Environics Division

DTIC Science & Technology

1989-07-01

and Development Support for Subsurface Monitoring Technology 15 19007048 Pumping and Purging Contaminants 16 19007049 Methods for Selecting In Situ...Decontamination 40 3788VW17 Treatment of Chlorinated Organics with Aboveground Bioreactors 41 3788VW18 Improved Methods for Monitoring Fuel Biodegradation 42 2...Fluoride (HF) Dispersion Model 63 21036093 Solvent Capacity Field Test Method 64 21037097 Volatile Organic Compound (VOC) Control Technology 65 21037102

Metabolite Identification of Halon Replacement Compounds.

DTIC Science & Technology

1992-06-01

inhalation to a 1 % atmosphere for 2 h. Tlissues were analyzed for volatile metabolites, and urine was analyzed for fluoride and carboxylic acid metabolites...M*vass Spectrometry, lialocarbons, 35 lialon 1211, IICFC- 123, IICIFC 124, IICFC 142b, llvdro~chlorofluoro-tcarbIonis ( 1 ICFCs), Inhalation Exposure...trifluoroethane HCFC- 142b 1 -Chloro-1,1 - difluoroethane HCI Hydrochloric acid kg Kilogram L Liter m Meter M Moles/liter mg Milligram MHz Megahertz min Minute

Technetium-99 and strontium-90: Abundance determination at ultratrace sensitivity by AMS as signatures of undeclared nuclear reprocessing activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

McAninch, J.E.; Proctor, I.D.

1995-03-01

The purpose of this White Paper is to examine the use of the ultratrace technique Accelerator Mass Spectrometry (AMS) to lower detection limits for {sup 99}Tc and {sup 90}Sr, and to examine the utility of these isotopes as signatures of a convert reprocessing facility. The International Atomic Energy Agency (IAEA) has committed to improving the effectiveness of the IAEA Safeguards System. This is in some degree a result of the discovery in 1991 of an undeclared Iraqi EMIS program. Recommendations from the March 1993 Consultants Group Meeting have resulted in several studies and follow on field trials to identify environmentalmore » signatures from covert nuclear fuel reprocessing activity. In particular, the April, 1993 reports of the Standing Advisory Group on Safeguards Implementation (SAGSI) identified the long-lived radioisotopes Technetium-99 and strontium-90 as two reliable signatures of fuel reprocessing activity. This report also suggested pathways in the chemical processing of irradiated fuel where these elements would be volatilized and potentially released in amounts detectable with ultratrace sensitivity techniques. Based on measured {sup 99}Tc background levels compiled from a variety of sources, it is estimated that AMS can provide 10% measurements of environmental levels of {sup 99}Tc in a few minutes using modestly sized samples: a few grams for soils, plants, or animal tissues; one to several liters for rain or seawater samples; and tens to hundreds of cubic meters for air sampling. Small sample sizes and high sample throughput result in significant increases in feasibility, cost effectiveness, and quality of data for a regional monitoring program. Similar results are expected for {sup 90}Sr.« less

Solution of rocks and refractory minerals by acids at high temperatures and pressures. Determination of silica after decomposition with hydrofluoric acid

USGS Publications Warehouse

May, I.; Rowe, J.J.

1965-01-01

A modified Morey bomb was designed which contains a removable nichromecased 3.5-ml platinium crucible. This bomb is particularly useful for decompositions of refractory samples for micro- and semimicro-analysis. Temperatures of 400-450?? and pressures estimated as great as 6000 p.s.i. were maintained in the bomb for periods as long as 24 h. Complete decompositions of rocks, garnet, beryl, chrysoberyl, phenacite, sapphirine, and kyanite were obtained with hydrofluoric acid or a mixture of hydrofluoric and sulfuric acids; the decomposition of chrome refractory was made with hydrochloric acid. Aluminum-rich samples formed difficultly soluble aluminum fluoride precipitates. Because no volatilization losses occur, silica can be determined on sample solutions by a molybdenum-blue procedure using aluminum(III) to complex interfering fluoride. ?? 1965.

Aerodynamic Levitation Reactor Studies of Fluorine Reactions with Refractory Ceramics

DTIC Science & Technology

1981-05-01

Melting Points of Rare-Earth Metals and Rare-Earth Trifluorides . 14 3. Aerodynamic Lavitation Flow Reactor. 15 4 Lanthanutm-Boron-Carbon Ternary Phase...the least volatile fluorides (CaF , SrT and rare-earth trifluorides ) would yield a 10% increase in w* (initially O.O cam) in about 1 hour at 1300K...measurement, and are, therefore, somewhat uncertain. The melting points of the rare-earth metals and their trifluorides are illustrated in Fig. 2. The melting

Volatiles on the surface of Apollo 15 green glass and trace-element distributions among Apollo 15 soils

NASA Technical Reports Server (NTRS)

Chou, C.-L.; Boynton, W. V.; Sundberg, L. L.; Wasson, J. T.

1975-01-01

Zn, Ge, Cd, In, and Au have been detected in surficial deposits on Apollo 15 green-glass spherules, and it is suggested that these deposits are condensates from the magmatic gas phase which was responsible for the pneumatic expulsion of the green glass from the lunar interior. Thermodynamic data indicate that chlorides and fluorides were the dominant forms of the volatile metals. The Ar-40x content of a nongreen-glass soil fraction is greater than that found in green-glass. Mare and low-K Fra Mauro basalts seem to be the most prominent components of Apollo 15 soil. The correlation of Zn with Ar-40x and with Pb-204 is studied, and the distribution of quartz-normative and olivine-normative basalts is considered.

Lunar mining of oxygen using fluorine

NASA Technical Reports Server (NTRS)

Burt, Donald M.

1992-01-01

An important aspect of lunar mining will be the extraction of volatiles, particularly oxygen, from lunar rocks. Thermodynamic data show that oxygen could readily be recovered by fluorination of abundant lunar anorthite, CaAl2Si2O8. Fluorine is the most reactive element, and the only reagent able to extract 100 percent of the oxygen from any mineral, yet it can safely be stored or reacted in nickel or iron containers. The general fluorination reaction, mineral + 2F2 = mixed fluorides = O2, has been used for more than 30 years at a laboratory scale by stable-isotope geochemists. For anorthite, metallic Al and Si may be recovered from the mixed fluorides by Na-reduction, and CaO via exchange with Na2O; the resulting NaF may be recycled into F2 and Na by electrolysis, using lanthanide-doped CaF2 as the inert anode.

Assessment of relative flammability and thermochemical properties of some thermoplastic materials

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Parker, J. A.

1978-01-01

The thermochemical and flammability characteristics of some typical thermoplastic materials currently in use and others being considered for use in aircraft interiors are described. The properties studied included (1) thermal mechanical properties such as glass transition and melt temperature, (2) changes in polymer enthalpy by differential scanning calorimetry, (3) thermogravimetric analysis in an anaerobic and oxidative environment, (4) oxygen index, (5) smoke evolution, (6) relative toxicity of the volatile products of pyrolysis, and (7) selected physical properties. The generic polymers which were evaluated included: acrylonitrile-butadiene-styrene, bisphenol A polycarbonate, bisphenol fluorenone carbonatedimethylsiloxane block polymer, phenolphthalein-bisphenol A polycarbonate, phenolphthalein polycarbonate, polyether sulfone, polyphenylene oxide, polyphenylene sulfide, polyaryl sulfone, chlorinated polyvinyl chloride homopolymer, polyvinyl fluoride, and polyvinylidene fluoride. Processing parameters including molding characteristics of some of the advanced polymers are described. Test results and relative rankings of some of the flammability, smoke and toxicity properties are presented.

Thermoplastic polymers for improved fire safety

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Parker, J. A.; Hilado, C. J.

1976-01-01

The thermochemical and flammability characteristics of some typical thermoplastic materials currently in use and others being considered for use in aircraft interiors are described. The properties studied included (1) thermomechanical properties such as glass transition and melt temperature, (2) changes in polymer enthalpy by differential scanning calorimetry, (3) thermogravimetric analysis in anaerobic and oxidative environments, (4) oxygen index, (5) smoke evolution, (6) relative toxicity of the volatile products of pyrolysis, and (7) selected physical properties. The generic polymers that were evaluated included: acrylonitrile butadiene styrene, bisphenol A polycarbonate, 9,9 bis (4-hydroxyphenyl) fluorene polycarbonatepoly (dimethyl siloxane) block polymer, phenolphthalein bisphenol A polycarbonate, phenolphthalein polycarbonate, polyether sulfone, polyphenylene oxide, polyphenylene sulfide, polyaryl sulfone, chlorinated polyvinyl chloride homopolymer, polyvinyl fluoride, and polyvinylidene fluoride. Processing parameters, including molding characteristics of some of the advanced polymers, are described. Test results and relative ranking of some of the flammability, smoke, and toxicity properties are presented.

Massachusetts Institute of Technology Lincoln Laboratory Facilities Replacement on Hanscom Air Force Base Phase 1 Final Environmental Assessment

DTIC Science & Technology

2014-07-24

Service UST Underground Storage Tank VC Vitrified Clay VOCs Volatile Organic Compounds W Watts 1 1.0 PURPOSE AND NEED FOR ACTION 1.1 INTRODUCTION The...discharged to sanitary drain and the solids slurry is hauled off site for disposal Fluoride drain: welded stainless steel drain piping from wet...diameter vitrified clay (VC) gravity sewer collection pipe, flowing north/northeast to the upper pumping station at Building 1306, is located within the

FUEL ELEMENT CONSTRUCTION

DOEpatents

Zumwalt, L.R.

1961-08-01

Fuel elements having a solid core of fissionable material encased in a cladding material are described. A conversion material is provided within the cladding to react with the fission products to form stable, relatively non- volatile compounds thereby minimizing the migration of the fission products into the coolant. The conversion material is preferably a metallic fluoride, such as lead difluoride, and may be in the form of a coating on the fuel core or interior of the cladding, or dispersed within the fuel core. (AEC)

PLATINUM HEXAFLUORIDE AND METHOD OF FLUORINATING PLUTONIUM CONTAINING MIXTURES THERE-WITH

DOEpatents

Malm, J.G.; Weinstock, B.; Claassen, H.H.

1959-07-01

The preparation of platinum hexafluoride and its use as a fluorinating agent in a process for separating plutonium from fission products is presented. According to the invention, platinum is reacted with fluorine gas at from 900 to 1100 deg C to form platinum hexafluoride. The platinum hexafluoride is then contacted with the plutonium containing mixture at room temperature to form plutonium hexafluoride which is more volatile than the fission products fluorides and therefore can be isolated by distillation.

Potential of metal-organic frameworks for separation of xenon and krypton.

PubMed

Banerjee, Debasis; Cairns, Amy J; Liu, Jian; Motkuri, Radha K; Nune, Satish K; Fernandez, Carlos A; Krishna, Rajamani; Strachan, Denis M; Thallapally, Praveen K

2015-02-17

CONSPECTUS: The total world energy demand is predicted to rise significantly over the next few decades, primarily driven by the continuous growth of the developing world. With rapid depletion of nonrenewable traditional fossil fuels, which currently account for almost 86% of the worldwide energy output, the search for viable alternative energy resources is becoming more important from a national security and economic development standpoint. Nuclear energy, an emission-free, high-energy-density source produced by means of controlled nuclear fission, is often considered as a clean, affordable alternative to fossil fuel. However, the successful installation of an efficient and economically viable industrial-scale process to properly sequester and mitigate the nuclear-fission-related, highly radioactive waste (e.g., used nuclear fuel (UNF)) is a prerequisite for any further development of nuclear energy in the near future. Reprocessing of UNF is often considered to be a logical way to minimize the volume of high-level radioactive waste, though the generation of volatile radionuclides during reprocessing raises a significant engineering challenge for its successful implementation. The volatile radionuclides include but are not limited to noble gases (predominately isotopes of Xe and Kr) and must be captured during the process to avoid being released into the environment. Currently, energy-intensive cryogenic distillation is the primary means to capture and separate radioactive noble gas isotopes during UNF reprocessing. A similar cryogenic process is implemented during commercial production of noble gases though removal from air. In light of their high commercial values, particularly in lighting and medical industries, and associated high production costs, alternate approaches for Xe/Kr capture and storage are of contemporary research interest. The proposed pathways for Xe/Kr removal and capture can essentially be divided in two categories: selective absorption by dissolution in solvents and physisorption on porous materials. Physisorption-based separation and adsorption on highly functional porous materials are promising alternatives to the energy-intensive cryogenic distillation process, where the adsorbents are characterized by high surface areas and thus high removal capacities and often can be chemically fine-tuned to enhance the adsorbate-adsorbent interactions for optimum selectivity. Several traditional porous adsorbents such as zeolites and activated carbon have been tested for noble gas capture but have shown low capacity, selectivity, and lack of modularity. Metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) are an emerging class of solid-state adsorbents that can be tailor-made for applications ranging from gas adsorption and separation to catalysis and sensing. Herein we give a concise summary of the background and development of Xe/Kr separation technologies with a focus on UNF reprocessing and the prospects of MOF-based adsorbents for that particular application.

Preparation of NO 2-Aged Silver-Functionalized Silica-Aerogel and Silver Mordenite Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jordan, Jacob A.; Bruffey, Stephanie H.

2016-10-01

Reprocessing used nuclear fuel can result in the volatilization of radioactive gaseous species, including 129I, into the various process off-gas streams. In order to comply with US regulatory requirements, plant off-gas streams must be treated to remove the iodine prior to discharging the off-gas into the environment. The performance of available gas removal methods depends not only on the concentration of the volatile radioisotope of interest, but also on other constituents that could be present in the reprocessing off-gas streams. Some of the constituents, such as NOx produced during fuel dissolution, are known to have deleterious effects on the capturemore » performance of silver-based sorbents used for iodine removal. Commercially available reduced silver mordenite (AgZ) has an iodine saturation concentration of 7.0-9.0 wt%, and its iodine sorption capacity is reduced by 20-50% as a result of NO2 aging. Silverfunctionalized silica aerogel (AgAerogel), an alternative for iodine capture, has an initial iodine saturation of 29.0 wt% and its iodine capacity is only reduced by 15% from NO2 aging. Understanding the differences in aging behavior between AgZ and AgAerogel is critical to determining the behavior of these sorbents under realistic off-gas conditions. To assist in future technical studies on this topic, samples of both AgZ and AgAerogel were aged with NO2. In the experiment, 10.2190 g of AgZ and 10.1771 g of AgAerogel were exposed to a static 0.75% NO 2/dry air blend for a period of 28 days. The samples were then removed and stored under argon until needed for future experiments.=« less

WO3 and W Thermal Atomic Layer Etching Using "Conversion-Fluorination" and "Oxidation-Conversion-Fluorination" Mechanisms.

PubMed

Johnson, Nicholas R; George, Steven M

2017-10-04

The thermal atomic layer etching (ALE) of WO 3 and W was demonstrated with new "conversion-fluorination" and "oxidation-conversion-fluorination" etching mechanisms. Both of these mechanisms are based on sequential, self-limiting reactions. WO 3 ALE was achieved by a "conversion-fluorination" mechanism using an AB exposure sequence with boron trichloride (BCl 3 ) and hydrogen fluoride (HF). BCl 3 converts the WO 3 surface to a B 2 O 3 layer while forming volatile WO x Cl y products. Subsequently, HF spontaneously etches the B 2 O 3 layer producing volatile BF 3 and H 2 O products. In situ spectroscopic ellipsometry (SE) studies determined that the BCl 3 and HF reactions were self-limiting versus exposure. The WO 3 ALE etch rates increased with temperature from 0.55 Å/cycle at 128 °C to 4.19 Å/cycle at 207 °C. W served as an etch stop because BCl 3 and HF could not etch the underlying W film. W ALE was performed using a three-step "oxidation-conversion-fluorination" mechanism. In this ABC exposure sequence, the W surface is first oxidized to a WO 3 layer using O 2 /O 3 . Subsequently, the WO 3 layer is etched with BCl 3 and HF. SE could simultaneously monitor the W and WO 3 thicknesses and conversion of W to WO 3 . SE measurements showed that the W film thickness decreased linearly with number of ABC reaction cycles. W ALE was shown to be self-limiting with respect to each reaction in the ABC process. The etch rate for W ALE was ∼2.5 Å/cycle at 207 °C. An oxide thickness of ∼20 Å remained after W ALE, but could be removed by sequential BCl 3 and HF exposures without affecting the W layer. These new etching mechanisms will enable the thermal ALE of a variety of additional metal materials including those that have volatile metal fluorides.

Genesis of kasolite associated with aplite-pegmatite at Jabal Sayid, Hijaz region, Kingdom of Saudi Arabia

NASA Astrophysics Data System (ADS)

Dawood, Yehia H.; Harbi, Hesham M.; Abd El-Naby, Hamdy H.

2010-01-01

In this study, we report kasolite Pb(UO 2)SiO 4·(H 2O) for the first time as a main uranyl mineral in the mineralized aplite-pegmatite of Jabal Sayid, Hijaz region. It commonly forms clusters of yellow acicular crystals in the voids and fractures. The mineral chemistry and mineralogical characteristics of kasolite were investigated using different techniques. Calcium, iron and phosphorus are detected in kasolite in addition to its major constituents; uranium, lead and silicon. Lead does not exist as a radiogenic product and not even as a substitute for uranium in the mineral structure. Alternatively, galena mineralization could be considered as a source for lead. The fluoride and carbonate complexes played a significant role in the formation of kasolite. High temperature hydrothermal solutions reacted with pre-existing uranium-bearing metamictized accessory minerals such as pyrochlore, U-rich thorite and zircon to form uranous fluoride complexes. These complexes are predominant in reducing environment and at pH 4. When the fluids approached the surface passing through fracture system, the oxygen fugacity ( fO 2) and the pH increased because of the loss of volatile components. At these conditions, uranous fluorides would convert to uranyl fluoride complexes UO 2F 3-. Further decrease in temperature was associated with the decay of the activity of fluorine ion by the dilution of hydrothermal solutions and precipitation of fluorite. At this condition, uranyl-carbonate complexes are favoured. These complexes were combined later with silica and lead to form kasolite.

Anomalous piezoelectric properties of poly(vinylidene fluoride-trifluoroethylene)/ionic liquid gels

NASA Astrophysics Data System (ADS)

Fukagawa, Miki; Koshiba, Yasuko; Fukushima, Tatsuya; Morimoto, Masahiro; Ishida, Kenji

2018-04-01

Piezoelectric gels were prepared from low-volatile ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][TFSI]) gels, and their structural, ferroelectric, and piezoelectric properties were investigated. Poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE)/IL gels were formed using thermally reversible physical gels. The structural characterization indicated that the P(VDF-TrFE) molecules in the gels predominantly formed a ferroelectric phase (Form I) of P(VDF-TrFE). Polarization switching peaks were clearly observed using a three-layer stacked device structure. The coercive field of the P(VDF-TrFE)/IL gels substantially decreased to 4-9 MV/m, and their remnant polarizations were maintained at 63-71 mC/m2, which is similar to that for typical solid-state P(VDF-TrFE). Finally, the P(VDF-TrFE)/IL gel films exhibited a piezoelectric response, and the highest piezoelectric coefficient was ˜300 pm/V at an applied voltage frequency of 4 kHz.

Thermochemical characterization of some thermoplastic materials. [flammability and toxicity properties for aircraft interiors

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Parker, J. A.; Hilado, C. J.

1977-01-01

The thermochemical and flammability characteristics of some typical thermoplastic materials currently in use or being considered for use in aircraft interiors are described. The properties studied included thermomechanical properties such as glass-transition and melt temperature, changes in polymer enthalpy, thermogravimetric analysis in anerobic and oxidative environments, oxygen index, smoke evolution, relative toxicity of the volatile products of pyrolysis, and selected physical properties. The generic polymers evaluated included acrylonitrile butadiene styrene, bisphenol A polycarbonate, 9,9 bis (4-hydroxyphenyl) fluorene polycarbonate-poly (dimethylsiloxane) block polymer, phenolphthalein-bisphenol A polycarbonate, phenolphthalein polycarbonate, polyether sulfone, polyphenylene oxide, polyphenylene sulfide, polyaryl sulfone, chlorinated polyvinyl chloride homopolymer, polyvinyl fluoride, and polyvinylidene fluoride. Processing parameters, including molding characteristics of some of the advanced polymers, are described. Test results and relative rankings of some of the flammability, smoke, and toxicity properties are presented. Under these test conditions, some of the advanced polymers evaluated were significantly less flammable and toxic than or equivalent to polymers in current use.

The effect of a mouthrinse containing chlorine dioxide in the clinical reduction of volatile sulfur compounds.

PubMed

Soares, Leo Guimaraes; Guaitolini, Roberto Luiz; Weyne, Sergio de Carvalho; Falabella, Marcio Eduardo Vieira; Tinoco, Eduardo Muniz Barretto; da Silva, Denise Gomes

2013-07-01

This study sought to evaluate the clinical effect of a mouthrinse containing 0.3% chlorine dioxide (ClO2) in reducing oral volatile sulfur compounds (VSC). Halitosis was induced by L-cysteine in 11 volunteers, and 4 solutions were compared: a test solution containing 0.3% ClO2, 0.07% cetylpyridinium chloride (CPC), and 0.05% sodium fluoride; a placebo; a solution containing 0.05% CPC; and a control solution of 0.2% chlorhexidine gluconate (CHX). VSC levels were assessed using a Halimeter, and 6 measurements were made from baseline to 3 hours postrinse. The VSC reduction rate of the test mouthrinse was superior to the placebo and the CPC solution. There was no difference between the test solution and the CHX solution in VSC reduction rates immediately postrinse, or at 2 and 3 hours postrinse; both solutions were statistically superior to the placebo and the CPC solution.

Effects of land use on water quality of the Fountain Creek alluvial aquifer, east-central Colorado

USGS Publications Warehouse

Chafin, Daniel T.

1996-01-01

Water-quality data were collected from the Fountain Creek alluvial aquifer in 1988 and 1989 as part of the Toxic-Waste Ground-Water Contamination Program. These data indicate that dissolved solids, most major ions, fluoride, ammonium, boron, lithium, selenium, and strontium were more concentrated in the agricultural land-use area than in the upgradient urban land-use area. Nitrate and phosphate had significantly larger concentrations, and volatile organic compounds had significantly greater detection frequencies in the urban land-use area.

The efficacy of two oral hygiene regimens in reducing oral malodour: a randomised clinical trial.

PubMed

Feres, Magda; Figueiredo, Luciene Cristina; Faveri, Marcelo; Guerra, Marcelo C; Mateo, Luis R; Stewart, Bernal; Williams, Malcolm; Panagakos, Foti

2015-12-01

This study compared the efficacy of two oral hygiene regimens in reducing oral malodour and the proportions of bacterial species involved in the production of volatile sulphur compounds. Seventy subjects who participated in a halitosis-induction phase and achieved an organoleptic score of ≥ 3.0 [time point 0 (T0)] randomised into two groups: brushing with regular fluoride toothpaste alone (control group) or brushing with regular fluoride toothpaste followed by rinsing with a 0.075% cetylpyridinium chloride (CPC) mouthwash (CPC group). Subjects followed their assigned oral hygiene regimen for 21 days. Then, they underwent an organoleptic examination and measurement of volatile sulphur compounds (VSCs) using a portable gas chromatograph, 12 hours after their last oral hygiene procedure (T1) and 4 hours after an on-site oral hygiene (T2). Microbiological samples (supragingival biofilm, tongue coating and saliva) were analysed using checkerboard DNA-DNA hybridisation. Both therapies statistically significantly improved the organoleptic scores (P < 0.05), but the VSC levels and/or concentrations were reduced only in the CPC group (P < 0.05). In subjects rinsing with CPC, oral malodour scores were reduced by 49% at the 4-hour assessment (T2) compared with those not rinsing (P < 0.05). Red-complex pathogens were reduced more effectively in the CPC group than in the control group. Brushing followed by rinsing with a 0.075% CPC mouthwash provided statistically significantly greater reductions in oral malodour, measured organoleptically and instrumentally, and in the proportions of red-complex species when compared with brushing alone. © 2015 FDI World Dental Federation.

Analgesic use of inhaled methoxyflurane: Evaluation of its potential nephrotoxicity.

PubMed

Dayan, A D

2016-01-01

Methoxyflurane is a volatile, halogenated analgesic, self-administered in a controlled low dose from the Penthrox(®) inhaler for short-term pain relief. It was formerly used in significantly higher doses to produce anaesthesia, when it caused a specific type of dose-related renal tubular damage. The pathogenesis of the renal damage and clinical use of methoxyflurane are discussed here with evidence that a low but effective analgesic dose is not associated with the risk of renal adverse effects. The maximum dose employed to produce analgesia is limited to methoxyflurane 6 mL/day and 15 mL/week, producing a minimum alveolar concentration (MAC) of 0.59 MAC-hours. Renal damage is due to the metabolism of methoxyflurane and release of fluoride ions. Exposure of humans to methoxyflurane ≤2.0 MAC-hours, resulting in serum fluoride ≤40 µmol/L, has not been associated with renal tubular toxicity. The safety margin of analgesic use of methoxyflurane in the Penthrox ((®)) inhaler is at least 2.7- to 8-fold, based on methoxyflurane MAC-hours or serum fluoride level, with clinical experience suggesting it is higher. It is concluded from clinical experience in emergency medicine, surgical procedures and various experimental and laboratory investigations that the analgesic use of methoxyflurane in subanaesthetic doses in the Penthrox inhaler does not carry a risk of nephrotoxicity. © The Author(s) 2015.

Surface chemistry associated with the cooling and subaerial weathering of recent basalt flows

USGS Publications Warehouse

White, A.F.; Hochella, M.F.

1992-01-01

The surface chemistry of fresh and weathered historical basalt flows was characterized using surface-sensitive X-ray photoelectron spectroscopy (XPS). Surfaces of unweathered 1987-1990 flows from the Kilauea Volcano, Hawaii, exhibited variable enrichment in Al, Mg, Ca, and F due to the formation of refractory fluoride compounds and pronounced depletion in Si and Fe from the volatilization of SiF4 and FeF3 during cooling. These reactions, as predicted from shifts in thermodynamic equilibrium with temperature, are induced by diffusion of HF from the flow interiors to the cooling surface. The lack of Si loss and solid fluoride formation for recent basalts from the Krafla Volcano, Iceland, suggest HF degassing at higher temperatures. Subsequent short-term subaerial weathering reactions are strongly influenced by the initial surface composition of the flow and therefore its cooling history. Successive samples collected from the 1987 Kilauea flow demonstrated that the fluoridated flow surfaces leached to a predominantly SiO2 composition by natural weathering within one year. These chemically depleted surfaces were also observed on Hawaiian basalt flows dating back to 1801 AD. Solubility and kinetic models, based on thermodynamic and kinetic data for crystalline AlF3, MgF2, and CaF2, support observed elemental depletion rates due to chemical weathering. Additional loss of alkalis from the Hawaiian basalt occurs from incongruent dissolution of the basalt glass substrate during weathering. ?? 1992.

Comets and the origin of the solar system - Reading the Rosetta Stone

NASA Technical Reports Server (NTRS)

Mumma, Michael J.; Weissman, Paul R.; Stern, S. A.

1993-01-01

It is argued that, from the measured volatile abundances, comets formed at temperatures near or below about 60 K and possibly as low as about 25 K. Grains in Comet Halley were found to be of two types: silicates and organics. Isotopic evidence shows that Comet Halley formed from material with the same compositional mix as the rest of the solar system, and is consistent with comets having been a major contributor to the volatile reservoirs on the terrestrial planets. A variety of processes have been shown to modify and reprocess the outer layers of comets both during their long residence time in the Oort cloud and following their entry back into the planetary system. The most likely formation site for comets is in the Uranus-Neptune zone or just beyond, with dynamical ejection by the growing protoplanets to distant orbits to form the Oort cloud. A substantial flux of interstellar comets was likely created by the same process, and may be detectable if cometary formation is common in planetary systems around other stars.

QUANTITATIVE RADIO-CHEMICAL ANALYSIS-SOLVENT EXTRACTION OF MOLYBDENUM-99

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wish, L.

1961-09-12

A method was developed for the rapid quantitative separation of Mo/sup 99/ from fission product mixtures. It is based on the extraction of Mo into a solution of alpha -benzoin oxime in chloroform. The main contaminants are Zr, Nb, and 1. The first two are eliminated by couple with fluoride and the third by volatilization or solvent extraction. About 5% of the Te/sup 99/ daughter is extracted with its parent, and it is necessary to wait 48 hrs for equilibrium of fission product mixtures by this method and a standard radiochemical gravimetric procedure showed agreement within 1 to 2%. (auth)

Cross-Linked Poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-co-HFP) Gel Polymer Electrolyte for Flexible Li-Ion Battery Integrated with Organic Light Emitting Diode (OLED)

PubMed Central

Kim, Ilhwan; Kim, Bong Sung; Nam, Seunghoon; Lee, Hoo-Jeong; Chung, Ho Kyoon; Cho, Sung Min; Luu, Thi Hoai Thuong; Hyun, Seungmin; Kang, Chiwon

2018-01-01

Here, we fabricate poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-co-HFP) by electrospinning for a gel polymer electrolyte (GPE) for use in flexible Li-ion batteries (LIBs). As a solvent, we use N-methyl-2-pyrrolidone (NMP), which helps produce the cross-linked morphology of PVDF-co-HFP separator, owing to its low volatility. The cross-linked PVDF-co-HFP separator shows an uptake rate higher than that of a commercialized polypropylene (PP) separator. Moreover, the PVDF-co-HFP separator shows an ionic conductivity of 2.3 × 10−3 S/cm at room temperature, comparable with previously reported values. An LIB full-cell assembled with the PVDF-co-HFP-based GPE shows capacities higher than its counterpart with the commercialized PP separator, confirming that the cross-linked PVDF-co-HFP separator provides highly efficient ionic conducting pathways. In addition, we integrate a flexible LIB cell using the PVDF-co-HFP GPE with a flexible organic light emitting diode (OLED), demonstrating a fully flexible unit of LIB and OLED. PMID:29614800

Cross-Linked Poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-co-HFP) Gel Polymer Electrolyte for Flexible Li-Ion Battery Integrated with Organic Light Emitting Diode (OLED).

PubMed

Kim, Ilhwan; Kim, Bong Sung; Nam, Seunghoon; Lee, Hoo-Jeong; Chung, Ho Kyoon; Cho, Sung Min; Luu, Thi Hoai Thuong; Hyun, Seungmin; Kang, Chiwon

2018-04-02

Here, we fabricate poly(vinylidene fluoride- co -hexafluoropropene) (PVDF- co -HFP) by electrospinning for a gel polymer electrolyte (GPE) for use in flexible Li-ion batteries (LIBs). As a solvent, we use N -methyl-2-pyrrolidone (NMP), which helps produce the cross-linked morphology of PVDF- co -HFP separator, owing to its low volatility. The cross-linked PVDF- co -HFP separator shows an uptake rate higher than that of a commercialized polypropylene (PP) separator. Moreover, the PVDF- co -HFP separator shows an ionic conductivity of 2.3 × 10 -3 S/cm at room temperature, comparable with previously reported values. An LIB full-cell assembled with the PVDF- co -HFP-based GPE shows capacities higher than its counterpart with the commercialized PP separator, confirming that the cross-linked PVDF- co -HFP separator provides highly efficient ionic conducting pathways. In addition, we integrate a flexible LIB cell using the PVDF- co -HFP GPE with a flexible organic light emitting diode (OLED), demonstrating a fully flexible unit of LIB and OLED.

Recovery of Agricultural Odors and Odorous Compounds from Polyvinyl Fluoride Film Bags

PubMed Central

Parker, David B.; Perschbacher-Buser, Zena L.; Cole, N. Andy; Koziel, Jacek A.

2010-01-01

Accurate sampling methods are necessary when quantifying odor and volatile organic compound emissions at agricultural facilities. The commonly accepted methodology in the U.S. has been to collect odor samples in polyvinyl fluoride bags (PVF, brand name Tedlar®) and, subsequently, analyze with human panelists using dynamic triangular forced-choice olfactometry. The purpose of this research was to simultaneously quantify and compare recoveries of odor and odorous compounds from both commercial and homemade PVF sampling bags. A standard gas mixture consisting of p-cresol (40 μg m−3) and seven volatile fatty acids: acetic (2,311 μg m−3), propionic (15,800 μg m−3), isobutyric (1,686 μg m−3), butyric (1,049 μg m−3), isovaleric (1,236 μg m−3), valeric (643 μg m−3), and hexanoic (2,158 μg m−3) was placed in the PVF bags at times of 1 h, 1 d, 2 d, 3 d, and 7 d prior to compound and odor concentration analyses. Compound concentrations were quantified using sorbent tubes and gas chromatography/mass spectrometry. Odor concentration, intensity, and hedonic tone were measured using a panel of trained human subjects. Compound recoveries ranged from 2 to 40% after 1 h and 0 to 14% after 7 d. Between 1 h and 7 d, odor concentrations increased by 45% in commercial bags, and decreased by 39% in homemade bags. Minimal changes were observed in intensity and hedonic tone over the same time period. These results suggest that PVF bags can bias individual compound concentrations and odor as measured by dynamic triangular forced-choice olfactometry. PMID:22163671

Production of Bulk and Fiber Glass in Space

NASA Technical Reports Server (NTRS)

Tucker, Dennis S.; Whitaker, Ann F. (Technical Monitor)

2001-01-01

The production of bulk glass and fiber glass in space and on the moon and Mars should lead to superior products. Specifically glass plates for windows and optical elements could be produced with theoretical strengths by production in vacuum. Water vapor is known to decrease glass strength by up to two orders of magnitude from theoretical. A low gravity glass plate apparatus prototype has been designed and built which uses centrifugal force to shape the glass and solar energy to melt the glass. Glass fiber could be produced on the moon or Mars from in-situ materials using standard technologies. This material could then be used as reinforcement in composite materials in construction of bases. Also, it has been shown that processing in reduced gravity suppresses crystallization in certain heavy metal fluoride glasses. It is proposed to reprocess optical fiber preforms on the space station and then pull these into optical fiber. It is estimated that the attenuation coefficient should be reduced by two orders of magnitude.

Molten salts and nuclear energy production

NASA Astrophysics Data System (ADS)

Le Brun, Christian

2007-01-01

Molten salts (fluorides or chlorides) were considered near the beginning of research into nuclear energy production. This was initially due to their advantageous physical and chemical properties: good heat transfer capacity, radiation insensitivity, high boiling point, wide range solubility for actinides. In addition it was realised that molten salts could be used in numerous situations: high temperature heat transfer, core coolants with solid fuels, liquid fuel in a molten salt reactor, solvents for spent nuclear solid fuel in the case of pyro-reprocessing and coolant and tritium production in the case of fusion. Molten salt reactors, one of the six innovative concepts chosen by the Generation IV international forum, are particularly interesting for use as either waste incinerators or thorium cycle systems. As the neutron balance in the thorium cycle is very tight, the possibility to perform online extraction of some fission product poisons from the salt is very attractive. In this article the most important questions that must be addressed to demonstrate the feasibility of molten salt reactor will be reviewed.

Estimated probability of arsenic in groundwater from bedrock aquifers in New Hampshire, 2011

USGS Publications Warehouse

Ayotte, Joseph D.; Cahillane, Matthew; Hayes, Laura; Robinson, Keith W.

2012-01-01

The statewide maps generated by the probability models are not designed to predict arsenic concentration in any single well, but they are expected to provide useful information in areas of the State that currently contain little to no data on arsenic concentration. They also may aid in resource decision making, in determining potential risk for private wells, and in ecological-level analysis of disease outcomes. The approach for modeling arsenic in groundwater could also be applied to other environmental contaminants that have potential implications for human health, such as uranium, radon, fluoride, manganese, volatile organic compounds, nitrate, and bacteria.

Fundamental Aspects of Zeolite Waste Form Production by Hot Isostatic Pressing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jubin, Robert Thomas; Bruffey, Stephanie H.; Jordan, Jacob A.

The direct conversion of iodine-bearing sorbents into a stable waste form is a research topic of interest to the US Department of Energy. The removal of volatile radioactive 129I from the off-gas of a nuclear fuel reprocessing facility will be necessary in order to comply with the regulatory requirements that apply to facilities sited within the United States (Jubin et al., 2012a), and any iodine-containing media or solid sorbents generated by this process would contain 129I and would be destined for eventual geological disposal. While recovery of iodine from some sorbents is possible, a method to directly convert iodineloaded sorbentsmore » to a durable waste form with little or no additional waste materials being formed and a potentially reduced volume would be beneficial. To this end, recent studies have investigated the conversion of iodine-loaded silver mordenite (I-AgZ) directly to a waste form by hot isostatic pressing (HIPing) (Bruffey and Jubin, 2015). Silver mordenite (AgZ), of the zeolite class of minerals, is under consideration for use in adsorbing iodine from nuclear reprocessing off-gas streams. Direct conversion of I-AgZ by HIPing may provide the following benefits: (1) a waste form of high density that is tolerant to high temperatures, (2) a waste form that is not significantly chemically hazardous, and (3) a robust conversion process that requires no pretreatment.« less

Ethical and hygiene aspects of the reprocessing of medical devices in Germany

PubMed Central

Kramer, Axel; Assadian, Ojan

2008-01-01

Based on safety and quality principles, for each medical device (MD), regardless of its declared status as single- or multi-use device, careful considerations must be made. This includes assessment whether reprocessing is economical and ecological meaningful, and technical feasible. So far, however, in Germany reprocessing of declared single use MD is legally allowed, provided that the above aspects are well covered. The purpose of this paper is to elucidate, when circumstances allow reprocessing of declared single-use MD. For reprocessing of single use MD the following preconditions must be fulfilled: The security level of the reprocessed MD must be equivalent to the status of the newly delivered item; this means that a patient is not exposed to a higher risk through a reprocessed disposable MD than through the new, i.e. un-processed product. The reprocessing must be based on a detailed risk assessment and risk analysis, and must be described in detail regarding selection of the reprocessing method. Additionally, all necessary safety- and quality assurance measures must be stated. The reprocessing measure needs to be accompanied with a quality management system which determines and documents the responsibility of all stages of reprocessing; where the corresponding reprocessing procedures are well defined; and the efficacy of the procedure is proven by product-specific or product-group-specific tests and reports. The process must be validated according to recognised methods of science and technology, taking into account potential negative influences of the reprocessing on the properties of the material and the technical and functional safety. For reprocessing of MDs of the category Critical C the quality assurance must be certified by an accredited certifying body. PMID:20204097

Dry halide method for separating the components of spent nuclear fuels

DOEpatents

Christian, Jerry Dale; Thomas, Thomas Russell; Kessinger, Glen F.

1998-01-01

The invention is a nonaqueous, single method for processing multiple spent nuclear fuel types by separating the fission- and transuranic products from the nonradioactive and fissile uranium product. The invention has four major operations: exposing the spent fuels to chlorine gas at temperatures preferably greater than 1200.degree. C. to form volatile metal chlorides; removal of the fission product chlorides, transuranic product chlorides, and any nickel chloride and chromium chloride in a molten salt scrubber at approximately 400.degree. C.; fractional condensation of the remaining volatile chlorides at temperatures ranging from 164.degree. C. to 2.degree. C.; and regeneration and recovery of the transferred spent molten salt by vacuum distillation. The residual fission products, transuranic products, and nickel- and chromium chlorides are converted to fluorides or oxides for vitrification. The method offers the significant advantages of a single, compact process that is applicable to most of the diverse nuclear fuels, minimizes secondary wastes, segregates fissile uranium from the high level wastes to resolve potential criticality concerns, segregates nonradioactive wastes from the high level wastes for volume reduction, and produces a common waste form glass or glass-ceramic.

Dry halide method for separating the components of spent nuclear fuels

DOEpatents

Christian, J.D.; Thomas, T.R.; Kessinger, G.F.

1998-06-30

The invention is a nonaqueous, single method for processing multiple spent nuclear fuel types by separating the fission and transuranic products from the nonradioactive and fissile uranium product. The invention has four major operations: exposing the spent fuels to chlorine gas at temperatures preferably greater than 1200 C to form volatile metal chlorides; removal of the fission product chlorides, transuranic product chlorides, and any nickel chloride and chromium chloride in a molten salt scrubber at approximately 400 C; fractional condensation of the remaining volatile chlorides at temperatures ranging from 164 to 2 C; and regeneration and recovery of the transferred spent molten salt by vacuum distillation. The residual fission products, transuranic products, and nickel- and chromium chlorides are converted to fluorides or oxides for vitrification. The method offers the significant advantages of a single, compact process that is applicable to most of the diverse nuclear fuels, minimizes secondary wastes, segregates fissile uranium from the high level wastes to resolve potential criticality concerns, segregates nonradioactive wastes from the high level wastes for volume reduction, and produces a common waste form glass or glass-ceramic. 3 figs.

MRI brain in monohalomethane toxic encephalopathy: A case report.

PubMed

Deshmukh, Yogeshwari S; Atre, Ashish; Shah, Darshan; Kothari, Sudhir

2013-07-01

Monohalomethanes are alkylating agents that have been used as methylating agents, laboratory reagents, refrigerants, aerosol propellants, pesticides, fumigants, fire-extinguishing agents, anesthetics, degreasers, blowing agents for plastic foams, and chemical intermediates. Compounds in this group are methyl chloride, methyl bromide, methyl iodide (MI), and methyl fluoride. MI is a colorless volatile liquid used as a methylating agent to manufacture a few pharmaceuticals and is also used as a fumigative insecticide. It is a rare intoxicant. Neurotoxicity is known with both acute and chronic exposure to MI. We present the characteristic magnetic resonance imaging (MRI) brain findings in a patient who developed neuropsychiatric symptoms weeks after occupational exposure to excessive doses of MI.

An update of the federal drinking water regs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pontius, F.W.

1995-02-01

Previous reviews have summarized the regulations promulgated for volatile organic chemicals (VOCs), fluoride, surface water treatment, total coliform bacteria, lead and copper, and Phase 2 and Phase 5 synthetic organic contaminants (SOCs) and inorganic contaminants (IOCs). Current developments related to these rules and anticipated new rules are reviewed in this article. Current numerical drinking water standards and best available technology (BAT) are summarized. The status of all current, proposed, and anticipated regulations is also summarized. Dates for anticipated agency actions are based on the US Environmental Protection Agency's (USEPA's) published regulatory agenda and on information released by the agency throughmore » December 1994; these dates can change as the agency reconsiders its regulatory policies.« less

Quantitative analysis of residual protein contamination of podiatry instruments reprocessed through local and central decontamination units

PubMed Central

2011-01-01

Background The cleaning stage of the instrument decontamination process has come under increased scrutiny due to the increasing complexity of surgical instruments and the adverse affects of residual protein contamination on surgical instruments. Instruments used in the podiatry field have a complex surface topography and are exposed to a wide range of biological contamination. Currently, podiatry instruments are reprocessed locally within surgeries while national strategies are favouring a move toward reprocessing in central facilities. The aim of this study was to determine the efficacy of local and central reprocessing on podiatry instruments by measuring residual protein contamination of instruments reprocessed by both methods. Methods The residual protein of 189 instruments reprocessed centrally and 189 instruments reprocessed locally was determined using a fluorescent assay based on the reaction of proteins with o-phthaldialdehyde/sodium 2-mercaptoethanesulfonate. Results Residual protein was detected on 72% (n = 136) of instruments reprocessed centrally and 90% (n = 170) of instruments reprocessed locally. Significantly less protein (p < 0.001) was recovered from instruments reprocessed centrally (median 20.62 μg, range 0 - 5705 μg) than local reprocessing (median 111.9 μg, range 0 - 6344 μg). Conclusions Overall, the results show the superiority of central reprocessing for complex podiatry instruments when protein contamination is considered, though no significant difference was found in residual protein between local decontamination unit and central decontamination unit processes for Blacks files. Further research is needed to undertake qualitative identification of protein contamination to identify any cross contamination risks and a standard for acceptable residual protein contamination applicable to different instruments and specialities should be considered as a matter of urgency. PMID:21219613

Quantitative analysis of residual protein contamination of podiatry instruments reprocessed through local and central decontamination units.

PubMed

Smith, Gordon Wg; Goldie, Frank; Long, Steven; Lappin, David F; Ramage, Gordon; Smith, Andrew J

2011-01-10

The cleaning stage of the instrument decontamination process has come under increased scrutiny due to the increasing complexity of surgical instruments and the adverse affects of residual protein contamination on surgical instruments. Instruments used in the podiatry field have a complex surface topography and are exposed to a wide range of biological contamination. Currently, podiatry instruments are reprocessed locally within surgeries while national strategies are favouring a move toward reprocessing in central facilities. The aim of this study was to determine the efficacy of local and central reprocessing on podiatry instruments by measuring residual protein contamination of instruments reprocessed by both methods. The residual protein of 189 instruments reprocessed centrally and 189 instruments reprocessed locally was determined using a fluorescent assay based on the reaction of proteins with o-phthaldialdehyde/sodium 2-mercaptoethanesulfonate. Residual protein was detected on 72% (n = 136) of instruments reprocessed centrally and 90% (n = 170) of instruments reprocessed locally. Significantly less protein (p < 0.001) was recovered from instruments reprocessed centrally (median 20.62 μg, range 0 - 5705 μg) than local reprocessing (median 111.9 μg, range 0 - 6344 μg). Overall, the results show the superiority of central reprocessing for complex podiatry instruments when protein contamination is considered, though no significant difference was found in residual protein between local decontamination unit and central decontamination unit processes for Blacks files. Further research is needed to undertake qualitative identification of protein contamination to identify any cross contamination risks and a standard for acceptable residual protein contamination applicable to different instruments and specialities should be considered as a matter of urgency.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonamici, Chloë E.; Kinman, William S.; Fournelle, John H.

Reprocessed earth material is a glassy nuclear fallout debris from near-surface nuclear tests. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. Our study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclearmore » test (“trinitite”) and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. Furthermore, the volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionally with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.« less

Design and Test Plan for an Integrated Iodine Scrubber and Polishing Bed System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jubin, Robert Thomas

The capture and subsequent immobilization of four regulated volatile radionuclides ( 3H, 14C, 85Kr, and 129I) and relevant semivolatile species from the off-gas streams of a used nuclear fuel (UNF) reprocessing facility has been a topic of significant research interest on the part of the US Department of Energy and other international organizations. Significant research and development has been conducted over the past decade. In 2016 an initial engineering evaluation and design of the off-gas abatement systems required for a hypothetical 1000 t/yr UNF reprocessing facility treating 5 yr–cooled, 60 GWd/tIHM UNF was completed. One of the key findings ofmore » that report was that the consumption rate of silver-based iodine sorbents in the dissolver off-gas primary iodine capture bed is very high and may warrant the evaluation of alternative methods to capture the bulk of the iodine that could significantly reduce the associated frequent remote handing of the iodine filter beds. This report is intended to describe the design of an experimental system that can be used to examine the use of aqueous scrubbing to remove the bulk of the iodine from the dissolver off-gas stream prior to a silver-based solid sorbent that would be used to provide the final iodine capture or polishing step. This report also provides a description of the initial series of tests that are proposed for this system.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Venkataraman, M.; Natarajan, R.; Raj, Baldev

The reprocessing of spent fuel from Fast Breeder Test Reactor (FBTR) has been successfully demonstrated in the pilot plant, CORAL (COmpact Reprocessing facility for Advanced fuels in Lead shielded cell). Since commissioning in 2003, spent mixed carbide fuel from FBTR of different burnups and varying cooling period, have been reprocessed in this facility. Reprocessing of the spent fuel with a maximum burnup of 100 GWd/t has been successfully carried out so far. The feed backs from these campaigns with progressively increasing specific activities, have been useful in establishing a viable process flowsheet for reprocessing the Prototype Fast Breeder Reactor (PFBR)more » spent fuel. Also, the design of various equipments and processes for the future plants, which are either under design for construction, namely, the Demonstration Fast Reactor Fuel Reprocessing Plant (DFRP) and the Fast reactor fuel Reprocessing Plant (FRP) could be finalized. (authors)« less

Reprocessing Multiyear GPS Data from Continuously Operating Reference Stations on Cloud Computing Platform

NASA Astrophysics Data System (ADS)

Yoon, S.

2016-12-01

To define geodetic reference frame using GPS data collected by Continuously Operating Reference Stations (CORS) network, historical GPS data needs to be reprocessed regularly. Reprocessing GPS data collected by upto 2000 CORS sites for the last two decades requires a lot of computational resource. At National Geodetic Survey (NGS), there has been one completed reprocessing in 2011, and currently, the second reprocessing is undergoing. For the first reprocessing effort, in-house computing resource was utilized. In the current second reprocessing effort, outsourced cloud computing platform is being utilized. In this presentation, the outline of data processing strategy at NGS is described as well as the effort to parallelize the data processing procedure in order to maximize the benefit of the cloud computing. The time and cost savings realized by utilizing cloud computing approach will also be discussed.

Improving the Estimates of Waste from the Recycling of Used Nuclear Fuel - 13410

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, Chris; Willis, William; Carter, Robert

2013-07-01

Estimates are presented of wastes arising from the reprocessing of 50 GWD/tonne, 5 year and 50 year cooled used nuclear fuel (UNF) from Light Water Reactors (LWRs), using the 'NUEX' solvent extraction process. NUEX is a fourth generation aqueous based reprocessing system, comprising shearing and dissolution in nitric acid of the UNF, separation of uranium and mixed uranium-plutonium using solvent extraction in a development of the PUREX process using tri-n-butyl phosphate in a kerosene diluent, purification of the plutonium and uranium-plutonium products, and conversion of them to uranium trioxide and mixed uranium-plutonium dioxides respectively. These products are suitable for usemore » as new LWR uranium oxide and mixed oxide fuel, respectively. Each unit process is described and the wastes that it produces are identified and quantified. Quantification of the process wastes was achieved by use of a detailed process model developed using the Aspen Custom Modeler suite of software and based on both first principles equilibrium and rate data, plus practical experience and data from the industrial scale Thermal Oxide Reprocessing Plant (THORP) at the Sellafield nuclear site in the United Kingdom. By feeding this model with the known concentrations of all species in the incoming UNF, the species and their concentrations in all product and waste streams were produced as the output. By using these data, along with a defined set of assumptions, including regulatory requirements, it was possible to calculate the waste forms, their radioactivities, volumes and quantities. Quantification of secondary wastes, such as plant maintenance, housekeeping and clean-up wastes, was achieved by reviewing actual operating experience from THORP during its hot operation from 1994 to the present time. This work was carried out under a contract from the United States Department of Energy (DOE) and, so as to enable DOE to make valid comparisons with other similar work, a number of assumptions were agreed. These include an assumed reprocessing capacity of 800 tonnes per year, the requirement to remove as waste forms the volatile fission products carbon-14, iodine-129, krypton-85, tritium and ruthenium-106, the restriction of discharge of any water from the facility unless it meets US Environmental Protection Agency drinking water standards, no intentional blending of wastes to lower their classification, and the requirement for the recovered uranium to be sufficiently free from fission products and neutron-absorbing species to allow it to be re-enriched and recycled as nuclear fuel. The results from this work showed that over 99.9% of the radioactivity in the UNF can be concentrated via reprocessing into a fission-product-containing vitrified product, bottles of compressed krypton storage and a cement grout containing the tritium, that together have a volume of only about one eighth the volume of the original UNF. The other waste forms have larger volumes than the original UNF but contain only the remaining 0.1% of the radioactivity. (authors)« less

Thermodynamic Model of the Na-Al-Si-O-F Melts

NASA Astrophysics Data System (ADS)

Dolejs, D.; Baker, D. R.

2004-05-01

Fluorine is a common volatile element in magmatic-hydrothermal systems, but its solution mechanisms in highly polymerized silicate melts are poorly known. We have developed a thermodynamic model for fluorosilicate liquids which links experimentally determined phase equilibria and spectroscopic information on melt structure. The model is applicable to crystallization of fluoride minerals or fluoride-silicate immiscibility in natural felsic melts. Configurational properties of the liquid are defined by mixing of alkali fluoride, polyhedral aluminofluoride and silicofluoride species and non-bridging terminations of the silicate network. Abundances of individual structural species are described by a homogeneous equilibrium, representing melt depolymerization: F- (free) + O0 (bridging) = F0 (terminal) + O- (non-bridging), which is a replacement of one oxygen bridge, Si-O-Si, by two terminations, Si-F | Na-O-Si. In cryolite-bearing systems, the self-dissociation of octahedral aluminofluoride complexes: Na3[AlF6] = Na[AlF4] + 2 NaF, and the short-range order between (O,F)-corners and (Si,NaAl)-centers of tetrahedra: Si-O-Si + 2 [NaAl]-F = [NaAl]-O-[NaAl] + 2 Si-F, represent two additional interaction mechanisms. Portrayal of these equilibria in ternary Thompson reaction space allows to decrease the number of interaction mechanisms by linearly combining melt depolymerization with tetrahedral short-range order. In this formulation, the interaction parameters are incorporated directly in configurational properties, thus the complete melt speciation can be calculated, and the activities of any macroscopic species are readily derived. The model has been applied to subsystems of the Na2O-NaAlO2-SiO2-F2O-1 compositional space. Activity-composition relationships in the villiaumite-sodium silicate binaries require clustering of silicate tetrahedra in fluoride solvent. Phase-equilibria in cryolite-nepheline and cryolite-albite systems illustrate an overall increase of Na3AlF6 self-association in both joins. On the other hand, melt depolymerization by fluorine controls depression of silicate liquidi. The present model is useful for modeling the differentiation of peralkaline fluorine-bearing magmas and provides a starting point for predicting halide, carbonate, sulfide or sulfate saturation in natural melts.

Chemical hazards from acid crater lakes

NASA Astrophysics Data System (ADS)

van Bergen, M. J.; Sumarti, S.; Heikens, A.; Bogaard, T. A.; Hartiyatun, S.

2003-04-01

Acid crater lakes, which are hosted by a considerable number of active volcanoes, form a potential threat for local ecosystems and human health, as they commonly contain large amounts of dissolved chemicals. Subsurface seepage or overflow can lead to severe deterioration of the water quality of rivers and wells, as observations around several of these volcanoes have shown. The Ijen crater lake in East Java (Indonesia) is a striking example, as this reservoir of hyperacid (pH<0.5) sulphate, chloride and fluoride-rich water is the source of a ca. 50 km long acid river that transports substantial quantities of potentially toxic elements. A downstream trend of increasing pH from <1 to 2.5-4 is largely due to dilution with moderately acid springs (pH= ca. 4) and neutral tributaries (pH= ca. 7) inside the Ijen caldera. Geochemical controls that regulate element transport are subject to seasonal fluctuations in rainfall. Long-term monitoring has shown that fluoride levels pose some of the most severe environmental threats. Its concentration decreases from ca. 1300 mg/kg in the lake to ca. 10 mg/kg in a coastal area downstream, where virtually all of the river water is used for irrigating rice fields and other cropland. Apart from serious problems for agriculture, our survey of 55 drinking water wells in the irrigation area shows that 50% contain fluoride above the 1.5 ppm WHO limit, in line with the observation that dental fluorosis is widespread among the ca. 100,000 residents of the area. A conspicuous spatial correlation between fluoride concentrations and the irrigation system suggest that long-term (century) infiltration of irrigation water may have affected the quality of groundwater. Fluorosis is also a problem in some villages within the caldera, where well water sources may have a more direct subsurface connection with the lake system. From our observations we conclude that water-quality monitoring is especially needed for health reasons in volcanic areas where volatile elements, derived from passively degassing magma, are intercepted by (sub) surface water bodies.

Defining the Costs of Reusable Flexible Ureteroscope Reprocessing Using Time-Driven Activity-Based Costing.

PubMed

Isaacson, Dylan; Ahmad, Tessnim; Metzler, Ian; Tzou, David T; Taguchi, Kazumi; Usawachintachit, Manint; Zetumer, Samuel; Sherer, Benjamin; Stoller, Marshall; Chi, Thomas

2017-10-01

Careful decontamination and sterilization of reusable flexible ureteroscopes used in ureterorenoscopy cases prevent the spread of infectious pathogens to patients and technicians. However, inefficient reprocessing and unavailability of ureteroscopes sent out for repair can contribute to expensive operating room (OR) delays. Time-driven activity-based costing (TDABC) was applied to describe the time and costs involved in reprocessing. Direct observation and timing were performed for all steps in reprocessing of reusable flexible ureteroscopes following operative procedures. Estimated times needed for each step by which damaged ureteroscopes identified during reprocessing are sent for repair were characterized through interviews with purchasing analyst staff. Process maps were created for reprocessing and repair detailing individual step times and their variances. Cost data for labor and disposables used were applied to calculate per minute and average step costs. Ten ureteroscopes were followed through reprocessing. Process mapping for ureteroscope reprocessing averaged 229.0 ± 74.4 minutes, whereas sending a ureteroscope for repair required an estimated 143 minutes per repair. Most steps demonstrated low variance between timed observations. Ureteroscope drying was the longest and highest variance step at 126.5 ± 55.7 minutes and was highly dependent on manual air flushing through the ureteroscope working channel and ureteroscope positioning in the drying cabinet. Total costs for reprocessing totaled $96.13 per episode, including the cost of labor and disposable items. Utilizing TDABC delineates the full spectrum of costs associated with ureteroscope reprocessing and identifies areas for process improvement to drive value-based care. At our institution, ureteroscope drying was one clearly identified target area. Implementing training in ureteroscope drying technique could save up to 2 hours per reprocessing event, potentially preventing expensive OR delays.

Visual and infrared observations of the distant Comets P/Stephan-Oterma /1980g/, Panther /1980u/, and Bowell /1980b/

NASA Technical Reports Server (NTRS)

Jewitt, D. C.; Soifer, B. T.; Neugebauer, G.; Matthews, K.; Danielson, G. E.

1982-01-01

The paper reports combined visual imagery and spectroscopy, near-infrared spectroscopy, and broadband infrared photometry of comets P/Stephan-Oterma (1980g), Bowell (1980b), and Panther (1980u) at intermediate heliocentric distances. The visual data indicate the existence of solid grains in extended halos around the nuclei of the three comets. Broadband near-infrared and thermal infrared measurements of Comet Panther suggest the presence of 2-4-micron-radius particles in the coma which most likely contain molecules incorporating the N-H bond, but which are more complex and less volatile than NH3. Such molecules can be produced in the grains by cosmic-ray reprocessing. Near infrared spectral features identical to those seen in comet Panther similary suggest the presence of a molecule incorporating the N-H bond in comet Bowell.

Visual and infrared observations of the distant Comets P/Stephan-Oterma /1980g/, Panther /1980u/, and Bowell /1980b/

NASA Astrophysics Data System (ADS)

Jewitt, D. C.; Soifer, B. T.; Neugebauer, G.; Matthews, K.; Danielson, G. E.

1982-12-01

The paper reports combined visual imagery and spectroscopy, near-infrared spectroscopy, and broadband infrared photometry of comets P/Stephan-Oterma (1980g), Bowell (1980b), and Panther (1980u) at intermediate heliocentric distances. The visual data indicate the existence of solid grains in extended halos around the nuclei of the three comets. Broadband near-infrared and thermal infrared measurements of Comet Panther suggest the presence of 2-4-micron-radius particles in the coma which most likely contain molecules incorporating the N-H bond, but which are more complex and less volatile than NH3. Such molecules can be produced in the grains by cosmic-ray reprocessing. Near infrared spectral features identical to those seen in comet Panther similary suggest the presence of a molecule incorporating the N-H bond in comet Bowell.

Surface evaluation of cardiac angiographic catheters after simulated use and reprocessing

NASA Astrophysics Data System (ADS)

Lucas, Thabata Coaglio; Oréfice, Rodrigo Lambert; Pinotti, Marcos; Huebner, Rudolf

2009-12-01

Reprocessing of single-use intravascular catheters is a common practice in public health services and hospitals. The determination of safe number of reprocessing cycles before the catheter integrity becomes compromised has been a priority issue. The present paper addresses the evaluating molecular and micro-structural integrity of reprocessed cardiac angiographic catheters. The Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy were carried out to elucidate morphological changes. The tensile test was performed on catheters to examine changes in bulk characteristics. In this work, samples of catheters were reprocessed until nine times and sterilized by hydrogen peroxide plasma. It was observed that the number of hydrogen-bonded carbonyls groups increased in 0.05 u.a. ( p < 0.001) after each reprocessing cycle. The spectra indicated degradation products included acids, esters, alcohols, and small amounts of other products containing a carbonyl functional group. The micrographs revealed that only after the fourth reprocessing cycle the effect increased in the surface roughness was more pronounced. On the other hand, after each reprocessing cycle and as consequence of extensive aging of polyamide/polyurethane blends of the catheters surface, it was observed that the micro-fissures, micro-scratches and micro-pores increased in quantity and length. The mechanical test proved that the Young modulus increased in average 3.26 MPa ( p = 0.0003) at increasing number of reprocessing cycles, also suggestive of crosslinking in this material.

Flory-Stockmayer analysis on reprocessable polymer networks

NASA Astrophysics Data System (ADS)

Li, Lingqiao; Chen, Xi; Jin, Kailong; Torkelson, John

Reprocessable polymer networks can undergo structure rearrangement through dynamic chemistries under proper conditions, making them a promising candidate for recyclable crosslinked materials, e.g. tires. This research field has been focusing on various chemistries. However, there has been lacking of an essential physical theory explaining the relationship between abundancy of dynamic linkages and reprocessability. Based on the classical Flory-Stockmayer analysis on network gelation, we developed a similar analysis on reprocessable polymer networks to quantitatively predict the critical condition for reprocessability. Our theory indicates that it is unnecessary for all bonds to be dynamic to make the resulting network reprocessable. As long as there is no percolated permanent network in the system, the material can fully rearrange. To experimentally validate our theory, we used a thiol-epoxy network model system with various dynamic linkage compositions. The stress relaxation behavior of resulting materials supports our theoretical prediction: only 50 % of linkages between crosslinks need to be dynamic for a tri-arm network to be reprocessable. Therefore, this analysis provides the first fundamental theoretical platform for designing and evaluating reprocessable polymer networks. We thank McCormick Research Catalyst Award Fund and ISEN cluster fellowship (L. L.) for funding support.

Characteristics of potential repository wastes. Volume 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1992-07-01

The LWR spent fuels discussed in Volume 1 of this report comprise about 99% of all domestic non-reprocessed spent fuel. In this report we discuss other types of spent fuels which, although small in relative quantity, consist of a number of diverse types, sizes, and compositions. Many of these fuels are candidates for repository disposal. Some non-LWR spent fuels are currently reprocessed or are scheduled for reprocessing in DOE facilities at the Savannah River Site, Hanford Site, and the Idaho National Engineering Laboratory. It appears likely that the reprocessing of fuels that have been reprocessed in the past will continuemore » and that the resulting high-level wastes will become part of defense HLW. However, it is not entirely clear in some cases whether a given fuel will be reprocessed, especially in cases where pretreatment may be needed before reprocessing, or where the enrichment is not high enough to make reprocessing attractive. Some fuels may be canistered, while others may require special means of disposal. The major categories covered in this chapter include HTGR spent fuel from the Fort St. Vrain and Peach Bottom-1 reactors, research and test reactor fuels, and miscellaneous fuels, and wastes generated from the decommissioning of facilities.« less

Endoscope reprocessing methods: a prospective study on the impact of human factors and automation.

PubMed

Ofstead, Cori L; Wetzler, Harry P; Snyder, Alycea K; Horton, Rebecca A

2010-01-01

The main cause of endoscopy-associated infections is failure to adhere to reprocessing guidelines. More information about factors impacting compliance is needed to support the development of effective interventions. The purpose of this multisite, observational study was to evaluate reprocessing practices, employee perceptions, and occupational health issues. Data were collected utilizing interviews, surveys, and direct observation. Written reprocessing policies and procedures were in place at all five sites, and employees affirmed the importance of most recommended steps. Nevertheless, observers documented guideline adherence, with only 1.4% of endoscopes reprocessed using manual cleaning methods with automated high-level disinfection versus 75.4% of those reprocessed using an automated endoscope cleaner and reprocessor. The majority reported health problems (i.e., pain, decreased flexibility, numbness, or tingling). Physical discomfort was associated with time spent reprocessing (p = .041). Discomfort diminished after installation of automated endoscope cleaners and reprocessors (p = .001). Enhanced training and accountability, combined with increased automation, may ensure guideline adherence and patient safety while improving employee satisfaction and health.

Reprocessing anesthesia instruments and devices.

PubMed

Ball, K

2000-02-01

Reprocessing anesthesia instruments and devices can often present a challenge for anesthesia providers because anesthesia devices have become more complex, cross-contamination with disease-forming pathogens can occur, and the importance of appropriate reprocessing may not be fully understood. Based on accepted practice recommendations, regulations, and research, reprocessing must be performed by skilled individuals who understand asepsis, cleaning, disinfection, and sterilization principles. This article describes the art of reprocessing and includes highlighted information on recommended practices, Spaulding's classifications, personal protective attire, precleaning, leak testing of flexible endoscopes, device disassembly, cleaning supplies and solutions, cleaning methods, rinsing, reassembly of the device, inspection, disinfection, and sterilization.

A randomised clinical evaluation of a fluoride mouthrinse and dentifrice in an in situ caries model.

PubMed

Parkinson, Charles R; Hara, Anderson T; Nehme, Marc; Lippert, Frank; Zero, Domenick T

2018-03-01

Fluoride mouthrinses provide advantages for fluoride delivery by maintaining elevated intra-oral fluoride concentrations following fluoride dentifrice use. This in situ caries study investigated potential anti-caries efficacy of a 220 ppm fluoride mouthrinse. This was an analyst-blinded, four-treatment, randomised, crossover study using partially demineralised, gauze-wrapped, human enamel samples mounted in a mandibular partial denture. Participants brushed twice daily for 14 days with either a 1150 ppm fluoride or a fluoride-free placebo dentifrice and either rinsed once daily with the 220 ppm fluoride mouthrinse or not. Following each treatment period, percent surface microhardness recovery (%SMHR) and enamel fluoride uptake (EFU) were assessed. Fifty three participants completed the study. Compared with the placebo dentifrice/no rinse treatment, the fluoride-containing regimens demonstrated greater enamel remineralisation (%SMHR) and fluoridation (EFU): fluoride dentifrice/fluoride rinse (%SMHR difference: 21.55 [95% CI: 15.78,27.32]; EFU difference 8.35 [7.21,9.29]); fluoride dentifrice/no rinse: 19.48 [13.81,25.15]; 6.47 [5.35,7.60]; placebo dentifrice/fluoride rinse: 16.76 [11.06,22.45]; 5.87 [4.72,7.00] (all P < .0001). There were no significant differences in%SMHR between fluoride regimens. The fluoride dentifrice/fluoride rinse regimen was associated with higher EFU than the fluoride dentifrice/no rinse (1.88 [0.75,3.01], P = .0013) and placebo dentifrice/fluoride rinse regimens (2.48 [1.34,3.62], P < .0001). Treatments were generally well-tolerated. The in situ caries model demonstrated that the fluoride mouthrinse is effective in promoting enamel caries lesion remineralisation and fluoridation whether used following a fluoride or non-fluoride dentifrice. Additive (potential) anti-caries benefits of a fluoride rinse after a fluoride dentifrice were confined to enhancements in lesion fluoridation (EFU). In conjunction with a fluoride dentifrice, fluoride mouthrinses enhance enamel fluoridation, which may be useful in caries prevention. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Contemporary biological markers of exposure to fluoride.

PubMed

Rugg-Gunn, Andrew John; Villa, Alberto Enrique; Buzalaf, Marília Rabelo Afonso

2011-01-01

Contemporary biological markers assess present, or very recent, exposure to fluoride: fluoride concentrations in blood, bone surface, saliva, milk, sweat and urine have been considered. A number of studies relating fluoride concentration in plasma to fluoride dose have been published, but at present there are insufficient data on plasma fluoride concentrations across various age groups to determine the 'usual' concentrations. Although bone contains 99% of the body burden of fluoride, attention has focused on the bone surface as a potential marker of contemporary fluoride exposure. From rather limited data, the ratio surface-to-interior concentration of fluoride may be preferred to whole bone fluoride concentration. Fluoride concentrations in the parotid and submandibular/sublingual ductal saliva follow the plasma fluoride concentration, although at a lower concentration. At present, there are insufficient data to establish a normal range of fluoride concentrations in ductal saliva as a basis for recommending saliva as a marker of fluoride exposure. Sweat and human milk are unsuitable as markers of fluoride exposure. A proportion of ingested fluoride is excreted in urine. Plots of daily urinary fluoride excretion against total daily fluoride intake suggest that daily urinary fluoride excretion is suitable for predicting fluoride intake for groups of people, but not for individuals. While fluoride concentrations in plasma, saliva and urine have some ability to predict fluoride exposure, present data are insufficient to recommend utilizing fluoride concentrations in these body fluids as biomarkers of contemporary fluoride exposure for individuals. Daily fluoride excretion in urine can be considered a useful biomarker of contemporary fluoride exposure for groups of people, and normal values have been published. Copyright © 2011 S. Karger AG, Basel.

Commercial Nuclear Reprocessing in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sherrill, Charles Leland; Balatsky, Galya Ivanovna

2015-09-09

The short presentation outline: Reprocessing Overview; Events leading up to Carter’s Policy; Results of the decision; Policy since Nuclear Nonproliferation Act. Conclusions reached: Reprocessing ban has become an easy and visible fix to the public concern about proliferation, but has not completely stopped proliferation; and, Reprocessing needs to become detached from political considerations, so technical research can continue, regardless of the policy decisions we decide to take.

Reprocessing of research reactor fuel the Dounreay option

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cartwright, P.

1997-08-01

Reprocessing is a proven process for the treatment of spent U/Al Research Reactor fuel. At Dounreay 12679 elements have been reprocessed during the past 30 years. For reactors converting to LEU fuel the uranium recovered in reprocessing can be blended down to less than 20% U{sub 235}, enrichment and be fabricated into new elements. For reactors already converted to LEU it is technically possible to reprocess spent silicide fuel to reduce the U{sub 235} burden and present to a repository only stable conditioned waste. The main waste stream from reprocessing which contains the Fission products is collected in underground storagemore » tanks where it is kept for a period of at least five years before being converted to a stable solid form for return to the country of origin for subsequent storage/disposal. Discharges to the environment from reprocessing are low and are limited to the radioactive gases contained in the spent fuel and a low level liquid waste steam. Both of these discharges are independently monitored, and controlled within strict discharge limits set by the UK Government`s Scottish Office. Transportation of spent fuel to Dounreay has been undertaken using many routes from mainland Europe and has utilised over the past few years both chartered and scheduled vessel services. Several different transport containers have been handled and are currently licensed in the UK. This paper provides a short history of MTR reprocessing at Dounreay, and provides information to show reprocessing can satisfy the needs of MTR operators, showing that reprocessing is a valuable asset in non-proliferation terms, offers a complete solution and is environmentally acceptable.« less

Effectiveness of reprocessing for flexible bronchoscopes and endobronchial ultrasound bronchoscopes.

PubMed

Ofstead, Cori L; Quick, Mariah R; Wetzler, Harry P; Eiland, John E; Heymann, Otis L; Sonetti, David A; Ferguson, J Scott

2018-05-30

Infections have been linked to inadequately-reprocessed flexible bronchoscopes, and recent investigations determined that pathogen transmission occurred even when bronchoscope cleaning and disinfection practices aligned with current guidelines. This multisite, prospective study evaluated the effectiveness of real-world bronchoscope reprocessing methods using a systematic approach. This study involved direct observation of reprocessing methods for flexible bronchoscopes, multifaceted evaluations performed after manual cleaning and after high-level disinfection, and assessments of storage conditions. Visual inspections of ports and channels were performed using lighted magnification and borescopes. Contamination was detected using microbial cultures and tests for protein, hemoglobin, and adenosine triphosphate. Researchers assessed reprocessing practices, and storage cabinet cleanliness was evaluated by visual inspection and adenosine triphosphate tests. Researchers examined 24 clinically used bronchoscopes. After manual cleaning, 100% of bronchoscopes had residual contamination. Microbial growth was found in 14 (58%) fully-reprocessed bronchoscopes, including mold, Stenotrophomonas maltophilia, and Escherichia coli/Shigella spp. Visible irregularities were observed in 100% of bronchoscopes, including retained fluid; brown, red, or oily residue; scratches; damaged insertion tubes and distal ends; and filamentous debris in channels. Reprocessing practices were substandard at two of three sites. Damaged and contaminated bronchoscopes were in use at all sites. Inadequate reprocessing practices may have contributed to bioburden found on bronchoscopes. However, even when guidelines were followed, high-level disinfection was not effective. A shift toward the use of sterilized bronchoscopes is recommended. In the meantime, quality management programs and updated reprocessing guidelines are needed. Copyright © 2018. Published by Elsevier Inc.

Fluoride mechanisms.

PubMed

ten Cate, J M; van Loveren, C

1999-10-01

This article discusses fluoride mechanisms in relation to dental caries. The authors specifically address firmly bound versus loosely bound fluoride; different fluoride active ingredients; fluoride and demineralization and remineralization; fluoride slow-release devices and F-releasing dental materials; antimicrobial effects of fluoride; the uptake of fluoride by oral bacteria; inhibition of enolase, protein-intruding ATPase and sugar transport; the various aspects of plaque as it relates to fluoride; and the rational use of fluoride.

Gloves Reprocessing: Does It Really Save Money?

PubMed

Arora, Pankaj; Kumari, Santosh; Sodhi, Jitender; Talati, Shweta; Gupta, Anil Kumar

2015-12-01

Gloves are reprocessed and reused in health-care facilities in resource-limited settings to reduce the cost of availability of gloves. The study was done with the aim to compute the cost of reprocessing of gloves so that an economically rationale decision can be taken. A retrospective record-based cross-sectional study was undertaken in a central sterile supply department where different steps during reprocessing of gloves were identified and the cost involved in reprocessing per pair of gloves was calculated. The cost of material and manpower was calculated to arrive at the cost of reprocessing per pair of gloves. The cost of a reprocessed pair of surgical gloves was calculated to be Indian Rupee (INR) 14.33 which was greater than the cost of a new pair of disposable surgical gloves (INR 9.90) as the cost of sterilization of one pair of gloves itself came out to  be INR 10.97. The current study showed that the purchase of sterile disposable single-use gloves is cheaper than the process of recycling. Reprocessing of gloves is not economical on tangible terms even in resource-limited settings, and from the perspective of better infection control as well as health-care worker safety, it further justifies the use of disposable gloves.

A geochemical approach to constraining the formation of glassy fallout debris from nuclear tests

DOE PAGES

Bonamici, Chloë E.; Kinman, William S.; Fournelle, John H.; ...

2016-12-15

Reprocessed earth material is a glassy nuclear fallout debris from near-surface nuclear tests. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. Our study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclearmore » test (“trinitite”) and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. Furthermore, the volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionally with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.« less

A geochemical approach to constraining the formation of glassy fallout debris from nuclear tests

NASA Astrophysics Data System (ADS)

Bonamici, Chloë E.; Kinman, William S.; Fournelle, John H.; Zimmer, Mindy M.; Pollington, Anthony D.; Rector, Kirk D.

2017-01-01

Glassy nuclear fallout debris from near-surface nuclear tests is fundamentally reprocessed earth material. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. This study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclear test ("trinitite") and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. The volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionally with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.

Superconducting RF Linacs Driving Subcritical Reactors for Profitable Disposition of Surplus Weapons-grade Plutonium

NASA Astrophysics Data System (ADS)

Cummings, Mary Anne; Johnson, Rolland

Acceptable capital and operating costs of high-power proton accelerators suitable for profitable commercial electric-power and process-heat applications have been demonstrated. However, studies have pointed out that even a few hundred trips of an accelerator lasting a few seconds would lead to unacceptable thermal stresses as each trip causes fission to be turned off in solid fuel structures found in conventional reactors. The newest designs based on the GEM*STAR concept take such trips in stride by using molten-salt fuel, where fuel pin fatigue is not an issue. Other aspects of the GEM*STAR concept which address all historical reactor failures include an internal spallation neutron target and high temperature molten salt fuel with continuous purging of volatile radioactive fission products such that the reactor contains less than a critical mass and almost a million times fewer volatile radioactive fission products than conventional reactors. GEM*STAR is a reactor that without redesign will burn spent nuclear fuel, natural uranium, thorium, or surplus weapons material. It will operate without the need for a critical core, fuel enrichment, or reprocessing making it an excellent candidate for export. As a first application, the design for a pilot plant is described for the profitable disposition of surplus weapons-grade plutonium by using process heat to produce green diesel fuel for the Department of Defense (DOD) from natural gas and renewable carbon.

The in-plant evaluation of a uranium NDA system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sprinkle, J.K. Jr.; Baxman, H.R.; Langner, D.G.

1979-12-31

The Los Alamos Scientific Laboratory has an unirradiated enriched uranium reprocessing facility. Various types of solutions are generated in this facility, including distillates and raffinates containing ppm of uranium and concentrated solutions with up to 400 grams U/t. In addition to uranyl nitrate and HNO{sub 3}, the solutions may also contain zirconium, niobium, fluoride, and small amounts of many metals. A uranium solution assay system (USAS) has been installed to allow accurate and more timely process control, accountability, and criticality data to be obtained. The USAS assays are made by a variety of techniques that depend upon state-of-the-art high-resolution Ge(Li)more » gamma-ray spectroscopy integrated with an interactive, user-oriented computer software package. Tight control of the system`s performance is maintained by constantly monitoring the USAS status. Daily measurement control sequences are required, and the user is forced by the software to perform these sequences. Routine assays require 400 or 1000 seconds for a precision of 0.5% over the concentration range of 5--400 g/t. A comparison of the USAS precision and accuracy with that obtained by traditional destructive analytical chemistry techniques (colorimetric and volumetric) is presented.« less

The in-plant evaluation of a uranium NDA system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sprinkle, J.K. Jr.; Baxman, H.R.; Langner, D.G.

1979-01-01

The Los Alamos Scientific Laboratory has an unirradiated enriched uranium reprocessing facility. Various types of solutions are generated in this facility, including distillates and raffinates containing ppm of uranium and concentrated solutions with up to 400 grams U/t. In addition to uranyl nitrate and HNO{sub 3}, the solutions may also contain zirconium, niobium, fluoride, and small amounts of many metals. A uranium solution assay system (USAS) has been installed to allow accurate and more timely process control, accountability, and criticality data to be obtained. The USAS assays are made by a variety of techniques that depend upon state-of-the-art high-resolution Ge(Li)more » gamma-ray spectroscopy integrated with an interactive, user-oriented computer software package. Tight control of the system's performance is maintained by constantly monitoring the USAS status. Daily measurement control sequences are required, and the user is forced by the software to perform these sequences. Routine assays require 400 or 1000 seconds for a precision of 0.5% over the concentration range of 5--400 g/t. A comparison of the USAS precision and accuracy with that obtained by traditional destructive analytical chemistry techniques (colorimetric and volumetric) is presented.« less

Divalent fluoride doped cerium fluoride scintillator

DOEpatents

Anderson, David F.; Sparrow, Robert W.

1991-01-01

The use of divalent fluoride dopants in scintillator materials comprising cerium fluoride is disclosed. The preferred divalent fluoride dopants are calcium fluoride, strontium fluoride, and barium fluoride. The preferred amount of divalent fluoride dopant is less than about two percent by weight of the total scintillator. Cerium fluoride scintillator crystals grown with the addition of a divalent fluoride have exhibited better transmissions and higher light outputs than crystals grown without the addition of such dopants. These scintillators are useful in radiation detection and monitoring applications, and are particularly well suited for high-rate applications such as positron emission tomography (PET).

Fluoride intake of infants living in non-fluoridated and fluoridated areas.

PubMed

Zohoori, F V; Whaley, G; Moynihan, P J; Maguire, A

2014-01-01

Data on fluoride exposure of infants are sparse. This study aimed to estimate total daily fluoride intake (TDFI) of infants aged 1-12 months, living in non-fluoridated and fluoridated areas in north-east England. Daily dietary fluoride intake was assessed using a three-day food diary coupled with analysis of fluoride content of food/drink consumed, using a F-ISE and diffusion method. A questionnaire with an interview was used to collect information on toothbrushing habits. TDFI was estimated from diet, plus fluoride supplements and dentifrice ingestion where used. Thirty-eight infants completed the study; 19 receiving fluoridated water (mean 0.97 mgF/l) and 19 receiving non-fluoridated water (mean 0.19 mgF/l). Mean (SD) TDFI for the infants living in fluoridated and non-fluoridated areas was 0.107 (0.054) and 0.024 (0.015) mg/kg body weight per day, respectively. Diet was the only fluoride source for 87% of infants and none used fluoride supplements. For infants for whom mouth/teeth cleaning was undertaken, dentifrice contribution to TDFI ranged from 24 to 78%. Infants living in fluoridated areas, in general, may receive a fluoride intake, from diet only, of more than the suggested optimal range for TDFI. This emphasises the importance of estimating TDFI at an individual level when recommendations for fluoride use are being considered.

Estimated dietary fluoride intake for New Zealanders.

PubMed

Cressey, Peter; Gaw, Sally; Love, John

2010-01-01

Existing fluoride concentration and consumption data were used to estimate fluoride intakes from the diet and toothpaste use, for New Zealand subpopulations, to identify any population groups at risk of high-fluoride intake. For each sub-population, two separate dietary intake estimates were made--one based on a non-fluoridated water supply (fluoride concentration of 0.1 mg/L), and the other based on a water supply fluoridated to a concentration of 1.0 mg/L. Fluoride concentration data were taken from historical surveys, while food consumption data were taken from national 24-hour dietary recall surveys or from simulated diets. Mean and 95th percentile estimations of dietary fluoride intake were well below the upper level of intake (UL), whether intakes were calculated on the basis of a non-fluoridated or fluoridated water supply. The use of fluoride-containing toothpastes provides additional fluoride intake. For many of the population groups considered, mean fluoride intakes were below the adequate intake (AI) level for caries protection, even after inclusion of the fluoride contribution from toothpaste. Intake of fluoride was driven by consumption of dietary staples (bread, potatoes),beverages (particularly tea, soft drinks, and beer), and the fluoride status of drinking water. Estimates of fluoride intake from the diet and toothpaste did not identify any groups at risk of exceeding the UL, with the exception of infants (6-12 months) living in areas with fluoridated water supplies and using high-fluoride toothpaste. In contrast, much of the adult population may be receiving insufficient fluoride for optimum caries protection from these sources, as represented by the AI.

Metabolism of 2-chloro-1,1-difluoroethene to glyoxylic and glycolic acid in rat hepatic microsomes.

PubMed

Baker, M T; Vasquez, M T; Bates, J N; Chiang, C K

1990-01-01

The complete metabolic fate of the volatile anesthetic halothane is unclear since 2-chloro-1,1-diflurorethene (CDE), a reductive halothane metabolite, is known to readily release inorganic fluoride upon oxidation by cytochrome P-450. This study sought to clarify the metabolism of CDE by determining its metabolites and the roles of induce cytochrome P-450 forms in its metabolism. Upon incubation of [14C]CDE with rat hepatic microsomes, two major radioactive products were found which accounted for greater than 94% of the total metabolites. These compounds were determined to be the nonhalogenated compounds, glyoxylic and glycolic acids, which were formed in a ratio of approximately 1 to 2 of glyoxylic to glycolic acid. No other radioactive metabolites could be detected. Following incubation of CDE with hepatic microsomes isolated from rats treated with cytochrome P-450 inducers, measurement of fluoride release showed that phenobarbital induced CDE metabolism to the greatest degree at high CDE levels, isoniazid was the most effective inducer at low CDE concentrations, and beta-naphthoflavone was ineffective as an inducer. These results suggest that CDE biotransformation primarily involves the generation of an epoxide intermediate, which undergoes mechanisms of decay leading to total dehalogenation of the molecule, and that this metabolism is preferentially carried out by the phenobarbital- and ethanol-inducible forms of cytochrome P-450.

Using eye movement desensitization and reprocessing to enhance treatment of couples.

PubMed

Protinsky, H; Sparks, J; Flemke, K

2001-04-01

Eye Movement Desensitization and Reprocessing (EMDR) as a clinical technique may enhance treatment effectiveness when applied within a couple therapy approach that is emotionally and experientially oriented. Clinical experience indicates that EMDR-based interventions are useful for accessing, activating, tolerating, and reprocessing the intense emotions that often fuel dysfunctional couple interactions. Using EMDR within conjoint sessions to reprocess negative emotions can amplify intimacy, increase connection, and subsequently lead to a change in problematic relationship patterns.

Case outsourcing medical device reprocessing.

PubMed

Haley, Deborah

2004-04-01

IN THE INTEREST OF SAVING MONEY, many hospitals are considering extending the life of some single-use medical devices by using medical device reprocessing programs. FACILITIES OFTEN LACK the resources required to meet the US Food and Drug Administration's tough quality assurance standards. BY OUTSOURCING, hospitals can reap the benefits of medical device reprocessing without assuming additional staffing and compliance burdens. OUTSOURCING enables hospitals to implement a medical device reprocessing program quickly, with no capital investment and minimal effort.

Investigating the effect of Eye Movement Desensitization and Reprocessing (EMDR) on postoperative pain intensity in adolescents undergoing surgery: a randomized controlled trial.

PubMed

Maroufi, Mohsen; Zamani, Shahla; Izadikhah, Zahra; Marofi, Maryam; O'Connor, Peter

2016-09-01

To investigate the efficacy of Eye Movement Desensitization and Reprocessing for postoperative pain management in adolescents. Eye Movement Desensitization and Reprocessing is an inexpensive, non-pharmacological intervention that has successfully been used to treat chronic pain. It holds promise in the treatment of acute, postsurgical pain based on its purported effects on the brain and nervous system. A randomized controlled trial was used. Fifty-six adolescent surgical patients aged between 12-18 years were allocated to gender-balanced Eye Movement Desensitization and Reprocessing (treatment) or non-Eye Movement Desensitization and Reprocessing (control) groups. Pain was measured using the Wong-Baker FACES(®) Pain Rating Scale (WBFS) before and after the intervention (or non-intervention for the control group). A Wilcoxon signed-rank test demonstrated that the Eye Movement Desensitization and Reprocessing group experienced a significant reduction in pain intensity after treatment intervention, whereas the control group did not. Additionally, a Mann-Whitney U-test showed that, while there was no significant difference between the two groups at time 1, there was a significant difference in pain intensity between the two groups at time 2, with the Eye Movement Desensitization and Reprocessing group experiencing lower levels of pain. These results suggest that Eye Movement Desensitization and Reprocessing may be an effective treatment modality for postoperative pain. © 2016 John Wiley & Sons Ltd.

Fluoride toothpastes and fluoride mouthrinses for home use.

PubMed

Rugg-Gunn, Andrew; Bánóczy, Jolán

2013-11-01

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 fluoridecontaining 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. Fluoride toothpastes and mouthrinses have been developed and extensive testing has demonstrated that they are effective and their use should be encouraged. Copyright © 2013 by Academy of Sciences and Arts of Bosnia and Herzegovina.

Oral fluoride retention after use of fluoride dentifrices.

PubMed

Duckworth, R M; Morgan, S N

1991-01-01

Fluoride is the only extensively clinically proven means of reducing dental caries. Despite a large body of epidemiological data on the effectiveness of fluoride, delivered in the form of dentifrices, mouthrinses, drinking water, etc., the precise mode of action of fluoride is not completely understood. The purpose of this paper is to report an investigation of the link between oral fluoride levels and applied fluoride dose from dentifrices. Human salivary fluoride clearance studies and equilibrium baseline studies of fluoride in saliva and plaque have been carried out with dentifrices which contained 1,000, 1,500 and 2,500 micrograms fluoride per gram as sodium monofluorophosphate. After a single brushing with a fluoride dentifrice, salivary fluoride decreased in two distinct phases: an initial rapid phase which lasted for 40-80 min, depending on the individual, and a second slow phase lasting for several hours. The latter phase is believed to be due to fluoride released from an oral fluoride reservoir. During regular repeated use of the test dentifrices, the equilibrium baseline fluoride concentration, attained in both saliva and plaque between one application and the next, increased significantly compared with placebo values. Such elevated baseline fluoride concentrations also increased with increasing Na2FPO3 content of the dentifrices. The present work supports the concept that labile fluoride, stored in an oral fluoride reservoir at the time of treatment application, may maintain a prolonged protective effect against dental caries.

Calibration of equipment for analysis of drinking water fluoride: a comparison study.

PubMed

Quock, Ryan L; Chan, Jarvis T

2012-03-01

Current American Dental Association evidence-based recommendations for prescription of dietary fluoride supplements are based in part on the fluoride concentration of a pediatric patient's drinking water. With these recommendations in mind, this study compared the relative accuracy of fluoride concentration analysis when a common apparatus is calibrated with different combinations of standard values. Fluoride solutions in increments of 0.1 ppm, from a range of 0.1 to 1.0 ppm fluoride, as well as 2.0 and 4.0 ppm, were gravimetrically prepared and fluoride concentration measured in pentad, using a fluoride ion-specific electrode and millivolt meter. Fluoride concentrations of these solutions were recorded after calibration with the following 3 different combinations of standard fluoride solutions: 0.1 ppm and 0.5 ppm, 0.1 ppm and 1.0 ppm, 0.5 ppm and 1.0 ppm. Statistical analysis showed significant differences in the fluoride content of water samples obtained with different two-standard fluoride solutions. Among the two-standard fluoride solutions tested, using 0.5 ppm and 1.0 ppm as two-standard fluoride solutions provided the most accurate fluoride measurement of water samples containing fluoride in the range of 0.1 ppm to 4.0 ppm. This information should be valuable to dental clinics or laboratories in fluoride analysis of drinking water samples.

Effects of heat/citric acid reprocessing on high-flux polysulfone dialyzers.

PubMed

Cornelius, Rena M; McClung, W Glenn; Richardson, Robert M A; Estridge, Charles; Plaskos, Nicholas; Yip, Christopher M; Brash, John L

2002-01-01

The surface features, morphology, and tensile properties of fibers obtained from pristine, reprocessed, and reused Fresenius Polysulfone High-Flux (Hemoflow F80A) hemodialyzers have been studied. Scanning electron microscopy of the dialyzer fibers revealed a dense skin layer on the inner surface of the membrane and a relatively thick porous layer on the outer surface. Transmission electron microscopy and atomic force microscopy showed an alteration in membrane morphology due to reprocessing and reuse, or to a deposition of blood-borne material on the membrane that is not removed with reprocessing. Fluorescent microscopy images also showed that a fluorescent material not removed by heat/citric acid reprocessing builds up with continued use of the dialyzers. The tensile properties of the dialyzer fibers were not affected by the heat/citric acid reprocessing procedure. The protein layers formed on pristine and reused hemodialyzer membranes during clinical use were also studied using sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting. A considerable amount of protein was found on the blood side of single and multiple use dialyzers. Proteins adsorbed on the dialysate side of the membrane were predominantly in the molecular weight region below 30 kDa. Little protein was detected on the membranes of reprocessed hemodialyzers.

76 FR 45268 - Reprocessing of Reusable Medical Devices

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-28

... personal information provided. For additional information on submitting comments, see the ``Comments... problems in all steps of medical device reprocessing,\\1\\ including cleaning, disinfecting, and sterilizing... following issues: 1. What are the nature, scope, and impact of reusable medical device reprocessing problems...

Urinary fluoride excretion in preschool children after intake of fluoridated milk and use of fluoride-containing toothpaste.

PubMed

Norman, M; Twetman, S; Hultgren Talvilahti, A; Granström, E; Stecksén-Blicks, C

2017-03-01

To assess the urinary fluoride excretion in preschool children after drinking fluoridated milk with 0.185 mg F and 0.375 mg F and to study the impact of use of fluoride toothpaste. Double-blind cross-over study. Nine healthy children, 2.5-4.5 years of age. In a randomized order, participants drank 1.5 dl milk once daily for 7 days with no fluoride added (control), 0.185 mg fluoride added and 0.375 mg fluoride added. The experiment was performed twice with (Part I) and without (Part II) parental tooth brushing with 1,000 ppm fluoride toothpaste. The fluoride content in the piped drinking water was 0.5 mg F/L. Urinary fluoride excretion. The 24-hour urinary fl uoride excretion/kg body weight varied from 0.014 mg F for the placebo intervention and non-fluoride toothpaste to 0.027 mg F for the 0.375 mg intervention with use of 1,000 ppm fluoride toothpaste. The difference compared with the placebo intervention was not statistically significant for any of the interventions when fluoride toothpaste was used (p⟩0.05) while it was statistically significantly different when non-fluoride toothpaste was used (p⟨0.05). All sources of fluoride must be considered when designing community programs. With 0.5 mg F/L in the drinking water and daily use of fluoride toothpaste, most children had a fluoride intake optimal for dental health. In this setting, additional intake of fluoride milk was within safe limits up to 0.185 mg/day while conclusions about the safety of 0.375 mg/day were uncertain. Copyright© 2017 Dennis Barber Ltd

Determining the optimal fluoride concentration in drinking water for fluoride endemic regions in South India.

PubMed

Viswanathan, Gopalan; Jaswanth, A; Gopalakrishnan, S; Siva Ilango, S; Aditya, G

2009-10-01

Fluoride ion in drinking water is known for both beneficial and detrimental effects on health. The prevalence of fluorosis is mainly due to the intake of large quantities of fluoride through drinking water owing to more than 90% bioavailability. The objective of this study is to predict optimal fluoride level in drinking water for fluoride endemic regions by comprising the levels of fluoride and other water quality parameters in drinking water, prevalence of fluorosis, fluoride intake through water, food and beverages such as tea and coffee and also considering the progressive accumulation of fluoride in animal bones, by comparing with non fluoride endemic areas comprise of the same geological features with the aid of regression analysis. Result of this study shows that increase of fluoride level above 1.33 mg/l in drinking water increases the community fluorosis index (CFI) value more than 0.6, an optimum index value above which fluorosis is considered to be a public health problem. Regression plot between water fluoride and bone fluoride levels indicates that, every increase of 0.5mg/l unit of water fluoride level increases the bone fluoride level of 52 mg/kg unit within 2 to 3 years. Furthermore, the consumption of drinking water containing more than 0.65 mg/l of fluoride can raise the total fluoride intake per day more than 4 mg, which is the optimum fluoride dose level recommended for adults by the Agency for Toxic Substances and Disease Registry. From the result, the people in fluoride endemic areas in South India are advised to consume drinking water with fluoride level within the limit of 0.5 to 0.65 mg/l to avoid further fluorosis risk.

Effect of reprocessing cycles on the degradation of polypropylene copolymer filled with talc or montmorillonite during injection molding process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demori, R.; Mauler, R. S., E-mail: raquel.mauler@ufrgs.br; Ashton, E.

Mechanical recycling of polymeric materials is a favorable technique resulting in economic and environmental benefits, especially in the case of polymers with a high production volume as the polypropylene copolymer (PP). However, recycling by reprocessing techniques can lead to thermal, mechanical or thermo-oxidative degradation that can affect the structure of the polymer and subsequently the material properties. PP filled with montmorillonite (MMT) or talc are widely produced and studied, however, its degradation reactions by reprocessing cycles are poorly studied so far. In this study, the effects of reprocessing cycles in the structure and in the properties of the PP/MMT andmore » PP/Talc were evaluated. The samples were mixed with 5% talc or MMT Cloisite C15A in a twin-screw extrusion. After extrusion, this filled material was submitted to five reprocessing cycles through an injection molding process. In order to evaluate the changes induced by reprocessing techniques, the samples were characterized by DSC, FT-IR, Izod impact and tensile strength tests. The study showed that Young modulus, elongation at brake and Izod impact were not affected by reprocessing cycles, except when using talc. In this case, the elongation at brake reduced until the fourth cycle, showing rigidity increase. The DSC results showed that melting and crystallization temperature were not affected. A comparison of FT-IR spectra of the reprocessed indicated that in both samples, between the first and the fifth cycle, no noticeable change has occurred. Thus, there is no evidence of thermo oxidative degradation. In general, these results suggest that PP reprocessing cycles using MMT or talc does not change the material properties until the fifth cycle.« less

Reprocessing and reuse of urological armamentarium: How correct are we!

PubMed Central

Raval, Krutik Vipulbhai; Chaudhari, Rajeev; Khant, Shahil Rameshbhai; Joglekar, Omkar; Patel, Dipen

2017-01-01

Healthcare is expensive for a large proportion of the population in spite of high per capita income and good health insurance penetration. In an effort to reduce cost of the procedure, reprocessing of devices was started in the late 1970s. Reprocessing practice includes various measures such as proper cleaning, disinfection, and sterilization procedures. As reprocessing is aimed at reducing cost, there is a potential risk of compromising patient safety due to cross contamination after inadequate sterilization. There is also risk of performance alteration of urological reprocessed devices during sterilization/disinfection processing. Therefore, there is a need for formulating proper guidelines to decide methods of reprocessing for various urological equipment. There is also need to discuss the problematic areas that urologists face and to find their solutions. A PubMed search was made in September 2016, using key words “reprocessing of medical devices,” “Single Use Devices,” “methods of reprocessing of devices in clinical practice,” “use of formalin chamber,” “urological disposable sterilization,” etc., After excluding duplicates, all English articles were reviewed by title and abstract. Full texts of selected articles were obtained, and these articles were cross-referenced to find any other related articles. All the articles were reviewed. A product can be reused if it can be economically reprocessed with validated protocols with preservation of its function. There is no reason to discard it after one use. This practice is useful for controlling economics of a urological case and to reduce the financial burden. Current Food and Drug Administration guidelines are stringent. The contamination described to test the sterilization process in the suggested guidelines actually does never exist in clinical practice. Therefore, new guidelines considering the clinical practice scenario are desirable. PMID:28479760

[The dose-effect relationship of water fluoride levels and renal damage in children].

PubMed

Liu, Jun-Ling; Xia, Tao; Yu, Yao-Yong; Sun, Xian-Zhong; Zhu, Qilong; He, Weihong; Zhang, Ming; Wang, Aiguo

2005-05-01

To explore the dose-effect relationship of water fluoride levels and renal damage in children and observe the difference of renal function between high-loaded fluoride people and dental fluorosis people in the same water fluoride level region. 210 children were divided into seven groups in term of drinking water fluoride levels and whether they suffered from dental fluorosis. Fluoride concentrations in urine and serum and activities of urine NAG and gamma-GT were determined. The urine and serum fluoride of high-loaded fluoride people and dental fluorosis people increased compared with control, moreover fluoride contents in urine and serum increased gradually with the increase of fluoride level in drinking water. Urine NAG and gamma-GT activities significantly increased in dental fluorosis people from area of 2.58 mg/L fluoride in drinking water and in those two groups from area of 4.51 mg/L fluoride in drinking water. Moreover, there existed an obvious dose-effect relationship between the drinking water fluoride concentration and NAG and gamma-GT activity. Over 2.0 mg/L fluoride in drinking water can cause renal damage in children, and the damage degree increases with the drinking water fluoride content. Renal damage degree is not related to whether the children suffered from dental fluorosis and mainly due to water fluoride concentration.

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

ERIC Educational Resources Information Center

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…

Fluoride content of tank water in Australia.

PubMed

Cochrane, N J; Hopcraft, M S; Tong, A C; Thean, H l; Thum, Y S; Tong, D E; Wen, J; Zhao, S C; Stanton, D P; Yuan, Y; Shen, P; Reynolds, E C

2014-06-01

The aims of this study were to: (1) analyse the fluoride content of tank water; (2) determine whether the method of water collection or storage influenced fluoride content; and (3) survey participant attitudes towards water fluoridation. Plastic tubes and a questionnaire were distributed through dentists to households with water tanks in Victoria. A midstream tank water sample was collected and fluoride analysed in triplicate using ion chromatography All samples (n = 123) contained negligible amounts of fluoride, with a mean fluoride concentration of <0.01 ppm (range: <0.01-0.18 ppm). No statistically significant association was found between fluoride content and variables investigated such as tank material, tank age, roof material and gutter material. Most people did not know whether their tank water contained fluoride and 40.8% preferred to have access to fluoridated water. The majority thought fluoride was safe and more than half of the respondents supported fluoridation. Fluoride content of tank water was well below the optimal levels for caries prevention. People who rely solely on tank water for drinking may require additional exposure to fluoride for optimal caries prevention. © 2014 Australian Dental Association.

Kinetics of fluoride bioavailability in supernatant saliva and salivary sediment.

PubMed

Naumova, E A; Sandulescu, T; Bochnig, C; Gaengler, P; Zimmer, S; Arnold, W H

2012-07-01

The assessment of the fluoride kinetics in whole saliva as well as in the different salivary phases (supernatant saliva and sediment) is essential for the understanding of fluoride bioavailability. To assess the fluoride content, provided by sodium fluoride and amine fluoride, in the supernatant saliva and in salivary sediment. Seven trained volunteers were randomly attributed to 2 groups in a cross-over design and brushed their teeth in the morning for 3 min with a product containing either sodium fluoride or amine fluoride. Saliva was collected before, immediately after tooth brushing and 30, 120, and 360 min later and measured. The samples were centrifuged 10 min at 3024 × g. Fluoride content of the supernatant saliva and of the sediment was analysed using a fluoride sensitive electrode. All subjects repeated the study cycles 2 times, and statistical analyses were made using the nonparametric sign test for related samples, the Wilcoxon-Mann-Whitney-test for independent samples. There was a significant increase in fluoride immediately after tooth brushing in both groups in saliva and sediment. The distribution of fluoride between salivary sediment and supernatant saliva (ratio) varied considerably at the different collection times: decreased from 17.87 in baseline samples of saliva to 0.07 immediately and to 0.86 half an hour after tooth brushing in the sodium fluoride group and from 14.33 to 2.85 and to 3.09 in the amine fluoride group. Furthermore after 120 min and after 360 min after tooth brushing the ratio increased from 17.6 to 31.6 in the sodium fluoride group and from 20.5 to 25.76 in the amine fluoride group. No difference was found in the sediment-supernatant saliva ratio between the sodium fluoride and the amine fluoride groups 360 min after tooth brushing. For the assessment of fluoride kinetics in whole saliva it is necessary to pay attention to at least four factors: fluoride formulation, time after fluoride application, fluoride concentration in supernatant saliva and fluoride concentration in salivary sediment. This study was approved by the Ethical Committee of the University of Witten/Herdecke permission 21/2008. Copyright © 2012 Elsevier Ltd. All rights reserved.

On the influence of the americium isotopic vector on the cooling time of minor actinides bearing blankets in fast reactors

NASA Astrophysics Data System (ADS)

Kooyman, Timothée; Buiron, Laurent; Rimpault, Gerald

2018-05-01

In the heterogeneous minor actinides transmutation approach, the nuclei to be transmuted are loaded in dedicated targets often located at the core periphery, so that long-lived heavy nuclides are turned into shorter-lived fission products by fission. To compensate for low flux level at the core periphery, the minor actinides content in the targets is set relatively high (around 20 at.%), which has a negative impact on the reprocessing of the targets due to their important decay heat level. After a complete analysis of the main contributors to the heat load of the irradiated targets, it is shown here that the choice of the reprocessing order of the various feeds of americium from the fuel cycle depends on the actual limit for fuel reprocessing. If reprocessing of hot targets is possible, it is more interesting to reprocess first the americium feed with a high 243Am content in order to limit the total cooling time of the targets, while if reprocessing of targets is limited by their decay heat, it is more interesting to wait for an increase in the 241Am content before loading the americium in the core. An optimization of the reprocessing order appears to lead to a decrease of the total cooling time by 15 years compared to a situation where all the americium feeds are mixed together when two feeds from SFR are considered with a high reprocessing limit.

Focus on Fluorides: Update on the Use of Fluoride for the Prevention of Dental Caries

PubMed Central

Carey, Clifton M.

2014-01-01

Declarative Title: Improving the efficacy of fluoride therapies reduces dental caries and lowers fluoride exposure. Background Fluoride is delivered to the teeth systemically or topically to aid in the prevention of dental caries. Systemic fluoride from ingested sources is in blood serum and can be deposited only in teeth that are forming in children. Topical fluoride is from sources such as community water, processed foods, beverages, toothpastes, mouthrinses, gels, foams, and varnishes. The United States Centers for Disease Control and Prevention (CDC) and the American Dental Association (ADA) have proposed changes in their long standing recommendations for the amount of fluoride in community drinking water in response to concerns about an increasing incidence of dental fluorosis in children. Current research is focused on the development of strategies to improve fluoride efficacy. The purpose of this update is to inform the reader about new research and policies related to the use of fluoride for the prevention of dental caries. Methods Reviews of the current research and recent evidence based systematic reviews on the topics of fluoride are presented. Topics discussed include: updates on community water fluoridation research and policies; available fluoride in dentifrices; fluoride varnish compositions, use, and recommendations; and other fluoride containing dental products. This update provides insights into current research and discusses proposed policy changes for the use of fluoride for the prevention of dental caries. Conclusions The dental profession is adjusting their recommendations for fluoride use based on current observations of the halo effect and subsequent outcomes. The research community is focused on improving the efficacy of fluoride therapies thus reducing dental caries and lowering the amount of fluoride required for efficacy. PMID:24929594

Focus on fluorides: update on the use of fluoride for the prevention of dental caries.

PubMed

Carey, Clifton M

2014-06-01

Improving the efficacy of fluoride therapies reduces dental caries and lowers fluoride exposure. Fluoride is delivered to the teeth systemically or topically to aid in the prevention of dental caries. Systemic fluoride from ingested sources is in blood serum and can be deposited only in teeth that are forming in children. Topical fluoride is from sources such as community water, processed foods, beverages, toothpastes, mouthrinses, gels, foams, and varnishes. The United States Centers for Disease Control and Prevention (CDC) and the American Dental Association (ADA) have proposed changes in their long standing recommendations for the amount of fluoride in community drinking water in response to concerns about an increasing incidence of dental fluorosis in children. Current research is focused on the development of strategies to improve fluoride efficacy. The purpose of this update is to inform the reader about new research and policies related to the use of fluoride for the prevention of dental caries. Reviews of the current research and recent evidence based systematic reviews on the topics of fluoride are presented. Topics discussed include: updates on community water fluoridation research and policies; available fluoride in dentifrices; fluoride varnish compositions, use, and recommendations; and other fluoride containing dental products. This update provides insights into current research and discusses proposed policy changes for the use of fluoride for the prevention of dental caries. The dental profession is adjusting their recommendations for fluoride use based on current observations of the halo effect and subsequent outcomes. The research community is focused on improving the efficacy of fluoride therapies thus reducing dental caries and lowering the amount of fluoride required for efficacy. Copyright © 2014 Elsevier Inc. All rights reserved.

The cariostatic mechanisms of fluoride.

PubMed

Rošin-Grget, Kata; Peroš, Kristina; Sutej, Ivana; Bašić, Krešimir

2013-11-01

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 tissue. The source of this fluoride could either be fluorapatite (formed due to the incorporation of fluoride into enamel) or calcium fluoride (CaF2)-like precipitates, which are formed on the enamel and in the plaque after application of topical fluoride. Calcium fluoride deposits are protected from rapid dissolution by a phosphate -protein coating of salivary origin. At lower pH, the coating is lost and an increased dissolution rate of calcium fluoride occurs. The CaF2, therefore, act as an efficient source of free fluoride ions during the cariogenic challenge. The current evidence indicates that fluoride has a direct and indirect effect on bacterial cells, although the in vivo implications of this are still not clear. A better understanding of the mechanisms of the action of fluoride is very important for caries prevention and control. The effectiveness of fluoride as a cariostatic agent depends on the availability of free fluoride in plaque during cariogenic challenge, i.e. during acid production. Thus, a constant supply of low levels of fluoride in biofilm/saliva/dental interference is considered the most beneficial in preventing dental caries. Copyright © 2013 by Academy of Sciences and Arts of Bosnia and Herzegovina.

Fluoride Supplementation Adherence and Barriers in a Community Without Water Fluoridation.

PubMed

Flood, Shannon; Asplund, Karin; Hoffman, Benjamin; Nye, Allison; Zuckerman, Katharine E

2017-04-01

To prevent early childhood caries, the American Dental Association recommends oral fluoride supplementation for children in communities lacking water fluoridation who are at high caries risk. However, patient adherence to oral fluoride supplementation has not been studied in this population. This study assessed adherence to oral fluoride and barriers to adherence in a community lacking water fluoridation. A self-administered survey was completed in a systematic sample of 209 parents of children aged 6 months to 4 years, during a primary care visit in an urban academic medical center. Participants reported frequency of administering oral fluoride to their children, as well as agreement or disagreement with proposed barriers to supplementation. Bivariate and multivariate analyses were used to assess adherence with oral supplementation and the association of barriers to supplementation and child receipt of fluoride on the day before. More than half of parents either had not or did not know if their child had received fluoride on the day before. Approximately 1 in 4 of parents had given fluoride in 0 of the previous 7 days. Difficulty remembering to give fluoride and agreeing that the child does not need extra fluoride were associated with not receiving fluoride on the day before. Adherence to oral fluoride supplementation in the primary care setting is low. Difficulty remembering to give fluoride daily is the greatest barrier to adherence. Further research on interventions to reduce common barriers is needed to increase fluoride administration and reduce early childhood caries in communities lacking water fluoridation. Copyright © 2016 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

Magmatic evolution and controls on rare metal-enrichment of the Strange Lake A-type peralkaline granitic pluton, Québec-Labrador

NASA Astrophysics Data System (ADS)

Siegel, Karin; Vasyukova, Olga V.; Williams-Jones, Anthony E.

2018-05-01

Although it is well known that A-type granites are enriched in the rare earth elements (REE) and other high field strength elements (HFSE), the magmatic processes that concentrate these elements are still poorly understood. The 1.24 Ga Strange Lake pluton in northern Québec-Labrador provides an extraordinary example of hyper-enrichment in the REE, Zr, and Nb in a peralkaline A-type granite. The pluton consists of two hypersolvus granite units (southern and northern) and a transsolvus granite, all of which contain perthitic alkali feldspar as the earliest major mineral; the transsolvus granite also contains separate albite and microcline crystals. Arfvedsonite, a sodic amphibole, occurs exclusively as phenocrysts in the transsolvus granite, whereas in the hypersolvus granite it is present as a late, interstitial phase. The primary HFSE minerals are zircon, monazite-(Ce), gagarinite-(Ce) and the pyrochlore group minerals. Magma evolution was monitored by the alumina content in the bulk rock, which decreases from the southern to the northern hypersolvus granite and is lowest in the transsolvus granite. Alkalinity indices and bulk Si, Fe, Rb, REE, Zr, Nb concentrations show the opposite trend. Alkali feldspar compositions mirror the trend shown by the bulk rock, i.e., decreasing Al contents are accompanied by increasing Si, Fe3+, REE, Zr and Nb contents. The major driving forces for the evolution of the hypersolvus magma prior to emplacement were the early separation of a fluoride melt from the silicate melt and the crystallization of alkali feldspar and HFSE-rich phases (zircon, monazite-(Ce), pyrochlore group). An alkali feldspar-rich crystal-mush containing LREE-fluoride melt droplets was emplaced as the least evolved southern hypersolvus granite. Massive fractionation of alkali feldspar led to a sharp increase in ƒH2O and F- activity in the magma chamber that triggered the crystallization of arfvedsonite and was followed by emplacement of the northern hypersolvus granite, which contained a higher proportion of LREE-fluoride melt droplets. Further evolution in the magma chamber led to a transition from a miaskitic to an agpaitic composition. The transsolvus granite was intruded in the form of a low viscosity crystal mush of alkali feldspar, quartz, arfvedsonite (after appreciable crystallization of arfvedsonite) and LREE-fluoride melt droplets. Upon emplacement, arfvedsonite (and gagarinite-(Ce)) crystals segregated as cumulates in response to a combination of flow differentiation and gravity settling. The immiscible fluoride melt accumulated in a volatile-rich residual silicate magma, which migrated to the top of the pluton where it formed the F-REE-rich cores of highly mineralized pegmatites.

Oral fluoride levels 1 h after use of a sodium fluoride rinse: effect of sodium lauryl sulfate.

PubMed

Vogel, Gerald L; Schumacher, Gary E; Chow, Laurence C; Tenuta, Livia M A

2015-01-01

Increasing the concentration of free fluoride in oral fluids is an important goal in the use of topical fluoride agents. Although sodium lauryl sulfate (SLS) is a common dentifrice ingredient, the influence of this ion on plaque fluid and salivary fluid fluoride has not been examined. The purpose of this study was to investigate the effect of SLS on these parameters and to examine the effect of this ion on total (or whole) plaque fluoride, an important source of plaque fluid fluoride after a sufficient interval following fluoride administration, and on total salivary fluoride, a parameter often used as a surrogate measure of salivary fluid fluoride. Ten subjects accumulated plaque for 48 h before rinsing with a 12 mmol/l NaF (228 µg/g F) rinse containing or not containing 0.5% (w/w) SLS. SLS had no statistically significant effect on total plaque and total saliva fluoride but significantly increased salivary fluid and plaque fluid fluoride (by 147 and 205%, respectively). These results suggest that the nonfluoride components of topical agents can be manipulated to improve the fluoride release characteristics from oral fluoride reservoirs and that statistically significant change may be observed in plaque fluid and salivary fluid fluoride concentrations that may not be observed in total plaque and total saliva fluoride concentrations.

The effect of fluoridation and its discontinuation on fluoride profiles in the alveolar bone of rat.

PubMed

Ohmi, Kyohei; Nakagaki, Haruo; Tsuboi, Shinji; Okumura, Akihiro; Sugiyama, Tomoko; Thuy, Tran Thu; Robinson, Colin

2005-10-01

We investigated the effect of fluoridation and its discontinuation on fluoride content in the alveolar portion of the mandible in rats. Drinking water with three different fluoride contents (0, 50, 100 ppmF) was given to rats for three different periods (4, 13 and 25 weeks). Fluoride concentrations were measured in the crest, the middle, and the apical parts of the alveolar bone and in the body of the mandible. Furthermore, after fluoridated drinking water was given to rats for 4 or 13 weeks, distilled water was given to them for 21 or 12 weeks respectively; and the effect of the discontinuation on fluoride profiles was investigated. Layer samples were analyzed by abrasive microsampling. Fluoride and phosphorus concentrations were determined by ion-specific electrode and colorimetric procedures, respectively. There was an increase in fluoride concentrations in the mandible in proportion to the fluoride content in the drinking water and the duration of fluoridation. After fluoridation was discontinued, fluoride concentrations in the surface layers of the mandible presented a decrease. Among the four different parts of the mandible, the upper part of the alveolar bone and the alveolar crest part presented the highest rates of reduction. The relative reduction rate of fluoride concentration was closely related to the duration of discontinuation. The alveolar crest was affected most by the discontinuation of fluoridation, presenting the greatest reduction.

Fluoride barriers in Nb/Pb Josephson junctions

NASA Astrophysics Data System (ADS)

Asano, H.; Tanabe, K.; Michikami, O.; Igarashi, M.; Beasley, M. R.

1985-03-01

Josephson tunnel junctions are fabricated using a new class of artificial barriers, metal fluorides (Al fluoride and Zr fluoride). These fluoride barriers are deposited on the surface of a Nb base electrode, which are previously cleaned using a CF4 cleaning process, and covered by a Pb counterelectrode. The junctions with both Al fluoride and Zr fluoride barriers exhibit good tunneling characteristics and have low specific capacitance. In the case of Zr fluoride, it is observed that reasonable resistances are obtained even at thickness greater than 100 A. This phenomenon might be explained by tunneling via localized states in Zr fluoride.

Eukaryotic resistance to fluoride toxicity mediated by a widespread family of fluoride export proteins.

PubMed

Li, Sanshu; Smith, Kathryn D; Davis, Jared H; Gordon, Patricia B; Breaker, Ronald R; Strobel, Scott A

2013-11-19

Fluorine is an abundant element and is toxic to organisms from bacteria to humans, but the mechanisms by which eukaryotes resist fluoride toxicity are unknown. The Escherichia coli gene crcB was recently shown to be regulated by a fluoride-responsive riboswitch, implicating it in fluoride response. There are >8,000 crcB homologs across all domains of life, indicating that it has an important role in biology. Here we demonstrate that eukaryotic homologs [renamed FEX (fluoride exporter)] function in fluoride export. FEX KOs in three eukaryotic model organisms, Neurospora crassa, Saccharomyces cerevisiae, and Candida albicans, are highly sensitized to fluoride (>200-fold) but not to other halides. Some of these KO strains are unable to grow in fluoride concentrations found in tap water. Using the radioactive isotope of fluoride, (18)F, we developed an assay to measure the intracellular fluoride concentration and show that the FEX deletion strains accumulate fluoride in excess of the external concentration, providing direct evidence of FEX function in fluoride efflux. In addition, they are more sensitive to lower pH in the presence of fluoride. These results demonstrate that eukaryotic FEX genes encode a previously unrecognized class of fluoride exporter necessary for survival in standard environmental conditions.

Eukaryotic resistance to fluoride toxicity mediated by a widespread family of fluoride export proteins

PubMed Central

Li, Sanshu; Smith, Kathryn D.; Davis, Jared H.; Gordon, Patricia B.; Breaker, Ronald R.; Strobel, Scott A.

2013-01-01

Fluorine is an abundant element and is toxic to organisms from bacteria to humans, but the mechanisms by which eukaryotes resist fluoride toxicity are unknown. The Escherichia coli gene crcB was recently shown to be regulated by a fluoride-responsive riboswitch, implicating it in fluoride response. There are >8,000 crcB homologs across all domains of life, indicating that it has an important role in biology. Here we demonstrate that eukaryotic homologs [renamed FEX (fluoride exporter)] function in fluoride export. FEX KOs in three eukaryotic model organisms, Neurospora crassa, Saccharomyces cerevisiae, and Candida albicans, are highly sensitized to fluoride (>200-fold) but not to other halides. Some of these KO strains are unable to grow in fluoride concentrations found in tap water. Using the radioactive isotope of fluoride, 18F, we developed an assay to measure the intracellular fluoride concentration and show that the FEX deletion strains accumulate fluoride in excess of the external concentration, providing direct evidence of FEX function in fluoride efflux. In addition, they are more sensitive to lower pH in the presence of fluoride. These results demonstrate that eukaryotic FEX genes encode a previously unrecognized class of fluoride exporter necessary for survival in standard environmental conditions. PMID:24173035

76 FR 24494 - Draft Guidance for Industry and FDA Staff: Processing/Reprocessing Medical Devices in Health Care...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-02

...] Draft Guidance for Industry and FDA Staff: Processing/ Reprocessing Medical Devices in Health Care... Devices in Health Care Settings: Validation Methods and Labeling.'' The recommendations in this guidance... Staff: Processing/Reprocessing Medical Devices in Health Care Settings: Validation Methods and Labeling...

Using Eye Movement Desensitization and Reprocessing To Enhance Treatment of Couples.

ERIC Educational Resources Information Center

Protinsky, Howard; Sparks, Jennifer; Flemke, Kimberly

2001-01-01

Eye Movement Desensitization and Reprocessing (EMDR) as a clinical technique may enhance treatment effectiveness when applied in couple therapy that is emotionally and experientially oriented. Clinical experience indicates EMDR-based interventions are useful for accessing and reprocessing intense emotions in couple interactions. EMDR can amplify…

Reprocessing system with nuclide separation based on chromatography in hydrochloric acid solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Tatsuya; Tachibana, Yu; Koyama, Shi-ichi

2013-07-01

We have proposed the reprocessing system with nuclide separation processes based on the chromatographic technique in the hydrochloric acid solution system. Our proposed system consists of the dissolution process, the reprocessing process, the minor actinide separation process, and nuclide separation processes. In the reprocessing and separation processes, the pyridine resin is used as a main separation media. It was confirmed that the dissolution in the hydrochloric acid solution is easily achieved by the plasma voloxidation and by the addition of oxygen peroxide into the hydrochloric acid solution.

Consolidated fuel reprocessing program

NASA Astrophysics Data System (ADS)

1985-02-01

Improved processes and components for the Breeder Reprocessing Engineering Test (BRET) were identified and developed as well as the design, procurement and development of prototypic equipment. The integrated testing of process equipment and flowsheets prototypical of a pilot scale full reprocessing plant, and also for testing prototypical remote features of specific complex components in the system are provided. Information to guide the long range activities of the Consolidated Fuel Reprocessing Program (CERP), a focal point for foreign exchange activities, and support in specialized technical areas are described. Research and development activities in HTGR fuel treatment technology are being conducted. Head-end process and laboratory scale development efforts, as well as studies specific to HTGR fuel, are reported. The development of off-gas treatment processes has generic application to fuel reprocessing, progress in this work is also reported.

Evaluation and quantification of reprocessing modification in single-use devices in interventional cardiology

NASA Astrophysics Data System (ADS)

Tessarolo, Francesco; Ferrari, Paolo; Silvia, Bortoluzzi; Motta, Antonella; Migliaresi, Claudio; Zennaro, Lucio; Rigo, Adelio; Guarrera, Giovanni Maria; Nollo, Giandomenico

2004-11-01

The increasing demand in interventional cardiology urges for reprocessing of single-use-labelled medical devices. To fulfil this aim, accurate and validated regeneration protocols are mandatory to guarantee sterility, functionality and safeness. The reprocessing protocol was realized by decontamination with chloro-donors, cleaning with enzymatic solutions and hydrogen peroxide gas plasma sterilization. Reprocessing effects on ablation and electrophysiology catheters were evaluated by assessing physical-chemical changes on surfaces and bulks, as a function of the reprocessing cycles number. Conventional optical microscopy and environmental scanning electron microscopy (ESEM) underlined the presence of micro-scratches on the polyurethane shaft surface. A clear correlation was found between surface damages and number of reprocessing cycles. Atomic force microscopy (AFM) confirmed the occurrence of physical-chemical etching of the polyurethane shaft caused by the hydrogen peroxide plasma sterilization, with increasing of nano-roughness at increasing number of the reprocessing cycles. UV-Vis spectra performed on the incubation solution of polymeric shaft sample, showed an absorbance increase at about 208 nm. This fact could be attributed to the water elution from the polymer of low molecular weight oligomers. The presence of hydrolysis products of the polymeric shaft after incubation demands both the characterization of the products released in the solution and the chemical characterization of the water exposed surface.

Fluoride metabolism when added to salt.

PubMed

Whitford, Gary M

2005-01-01

The purpose of this review is to present the general characteristics of the metabolism of fluoride particularly as it occurs when ingested with fluoridated salt. Following the absorption of salt-borne fluoride from the stomach and intestines, its metabolism is identical to that of water-borne fluoride or other vehicles containing ionized fluoride. Because fluoridated salt is almost always ingested with food, however, absorption from the gastrointestinal tract may be delayed or reduced. Reports dealing with this subject have shown that fluoride absorption is delayed and, therefore, peak plasma concentrations are lower than when fluoride is ingested with water. The amount of ingested fluoride that is finally absorbed, however, is not appreciably affected unless the meal is composed mainly of components with high calcium concentrations. In this case, the extent of absorption can be reduced by as much as 50%. Fluoridated salt is also ingested less frequently than fluoridated water. Data are presented to show that the dose size and frequency of ingestion have only minor effects on fluoride retention in the body and on the concentrations in plasma, bone and enamel. Finally, calculations are presented to show that the risk of acute toxicity from fluoridated salt is virtually non-existent.

Fluoride content of still bottled water in Australia.

PubMed

Cochrane, N J; Saranathan, S; Morgan, M V; Dashper, S G

2006-09-01

Recently there has been a considerable increase in the consumption of bottled water in Australia. Overseas studies have found the fluoride levels in many bottled waters are well below levels considered optimal for preventing dental caries. This raises the concern that if bottled water is regularly consumed an effective means of preventing dental caries is unavailable. The aim of this study was to determine the fluoride concentration in 10 popular brands of still bottled water currently sold in Australia. The fluoride content of water samples were determined using an ion analyser and compared to a fluoride standard. The fluoride concentration of all bottled waters was less than 0.08 ppm. Only three of the 10 brands indicated the fluoride content on their labels. Melbourne reticulated water was found to be fluoridated at 1.02 ppm. All bottled waters tested contained negligible fluoride which justifies the concern that regular consumption of bottled water may reduce the benefits gained from water fluoridation. It is recommended that all bottled water companies should consider stating their fluoride content on their labels. This will inform consumers and dental care providers of the levels of fluoride in bottled water and allow an informed decision regarding consumption of fluoridated versus non-fluoridated drinking water.

Health Effects Associated with Water Fluoridation.

ERIC Educational Resources Information Center

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)

Ionic liquids in tribology.

PubMed

Minami, Ichiro

2009-06-24

Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research on ionic liquids have been published through May 2009. A large majority of the cations examined in this area are derived from 1,3-dialkylimidazolium, with a higher alkyl group on the imidazolium cation being beneficial for good lubrication, while it reduces the thermo-oxidative stability. Hydrophobic anions provide both good lubricity and significant thermo-oxidative stability. The anions decompose through a tribochemical reaction to generate metal fluoride on the rubbed surface. Additive technology to improve lubricity is also explained. An introduction to tribology as an interdisciplinary field of lubrication is also provided.

Absorption, distribution and excretion of inhaled hydrogen fluoride in the rat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morris, J.B.

1979-01-01

Rats were subjected to whole body HF exposure for 6 hrs or to nose-only HF exposure for 1 hr. Total and/or ionic fluoride concentrations in selected tissues were determined at various times following exposure. In rats sacrificed 6 hrs after whole body exposure, dose-dependent increases in lung, plasma, and kidney total and ionic fluoride concentration occurred. Rats excreted more fluoride in the urine after whole body exposure than could be explained by the amount of HF inhaled. Considerable evidence suggests that airborne HF deposits on fur and is then ingested due to preening activity. Urinary fluoride excretion was increased bymore » nose-only exposure. The urinary fluoride excretion accounted for approximately twice the fluoride estimated to be inhaled during exposure. Tissue fluoride concentrations were elevated immediately after nose-only exposure. Fluoride concentrations in lung and kidney returned to control levels within 12 hrs. Plasma fluoride concentration was slightly elevated 24 hrs after the start of the 1 hr exposure but was at control levels at 96 hrs. Immediately following nose-only exposure, lung ionic fluoride concentrations were less than plasma ionic fluoride concentrations suggesting that the fluoride in the lung had reached that site via plasma transport rather than by inhalation. A dose-dependent increase in plasma ionic fluoride concentration occurred after upper respiratory tract HF exposure providing strong evidence that fluoride is absorbed systemically from that site. The plasma ionic fluoride concentration after upper respiratory tract exposure was of sufficient magnitude to account for the plasma fluoride concentrations observed in intact nose-only exposed rats. (ERB)« less

Exposure to water fluoridation and caries increment.

PubMed

Spencer, A J; Armfield, J M; Slade, G D

2008-03-01

The objective of this cohort study was to examine the association between exposure to water fluoridation and the increment of dental caries in two Australian states: Queensland (Qld)--5 per cent fluoridation coverage; and South Australia (SA)--70 per cent fluoridation coverage. Stratified random samples were drawn from fluoridated Adelaide and the largely non-fluoridated rest-of-state in SA, and fluoridated Townsville and non-fluoridated Brisbane in Qld. Children were enrolled between 1991 and 1992 (SA: 5-15 yrs old, n = 9,980; Qld: 5-12 yrs old, n = 10,695). Follow-up caries status data for 3 years (+/- 1/2 year) were available on 8,183 children in SA and 6,711 children in Qld. Baseline data on lifetime exposure to fluoridated water, use of other fluorides and socio-economic status (SES) were collected by questionnaire, and tooth surface caries status by dental examinations in school dental service clinics. Higher per cent lifetime exposure to fluoridated water (6 categories: 0;1-24; 25-49; 50-74; 75-99; 100 per cent) was a significant predictor (ANOVA, p < 0.01) of lower annualised Net Caries Increment (NCI) for the deciduous dentition in SA and Qld, but only for Qld in the permanent dentition. These associations persisted in multiple linear regression analyses controlling for age, gender, exposure to other fluorides and SES (p < 0.05). Water fluoridation was effective in reducing caries increment, even in the presence of a dilution effect from other fluorides. The effect of fluoridated water consumption was strongest in the deciduous dentition and where diffusion of food and beverages from fluoridated to non-fluoridated areas was less likely.

Identification of cytochrome P450 2E1 as the predominant enzyme catalyzing human liver microsomal defluorination of sevoflurane, isoflurane, and methoxyflurane.

PubMed

Kharasch, E D; Thummel, K E

1993-10-01

Renal and hepatic toxicity of the fluorinated ether volatile anesthetics is caused by biotransformation to toxic metabolites. Metabolism also contributes significantly to the elimination pharmacokinetics of some volatile agents. Although innumerable studies have explored anesthetic metabolism in animals, there is little information on human volatile anesthetic metabolism with respect to comparative rates or the identity of the enzymes responsible for defluorination. The first purpose of this investigation was to compare the metabolism of the fluorinated ether anesthetics by human liver microsomes. The second purpose was to test the hypothesis that cytochrome P450 2E1 is the specific P450 isoform responsible for volatile anesthetic defluorination in humans. Microsomes were prepared from human livers. Anesthetic metabolism in microsomal incubations was measured by fluoride production. The strategy for evaluating the role of P450 2E1 in anesthetic defluorination involved three approaches: for a series of 12 human livers, correlation of microsomal defluorination rate with microsomal P450 2E1 content (measured by Western blot analysis), correlation of defluorination rate with microsomal P450 2E1 catalytic activity using marker substrates (para-nitrophenol hydroxylation and chlorzoxazone 6-hydroxylation), and chemical inhibition by P450 isoform-selective inhibitors. The rank order of anesthetic metabolism, assessed by fluoride production at saturating substrate concentrations, was methoxyflurane > sevoflurane > enflurane > isoflurane > desflurane > 0. There was a significant linear correlation of sevoflurane and methoxyflurane defluorination with antigenic P450 2E1 content (r = 0.98 and r = 0.72, respectively), but not with either P450 1A2 or P450 3A3/4. Comparison of anesthetic defluorination with either para-nitrophenol or chlorzoxazone hydroxylation showed a significant correlation for sevoflurane (r = 0.93, r = 0.95) and methoxyflurane (r = 0.78, r = 0.66). Sevoflurane defluorination was also highly correlated with that of enflurane (r = 0.93), which is known to be metabolized by human P450 2E1. Diethyldithiocarbamate, a selective inhibitor of P450 2E1, produced a concentration-dependent inhibition of sevoflurane, methoxyflurane, and isoflurane defluorination. No other isoform-selective inhibitor diminished the defluorination of sevoflurane, whereas methoxyflurane defluorination was inhibited by the selective P450 inhibitors furafylline (P450 1A2), sulfaphenazole (P450 2C9/10), and quinidine (P450 2D6) but to a much lesser extent than by diethyldithiocarbamate. These results demonstrate that cytochrome P450 2E1 is the principal, if not sole human liver microsomal enzyme catalyzing the defluorination of sevoflurane. P450 2E1 is the principal, but not exclusive enzyme responsible for the metabolism of methoxyflurane, which also appears to be catalyzed by P450s 1A2, 2C9/10, and 2D6. The data also suggest that P450 2E1 is responsible for a significant fraction of isoflurane metabolism. Identification of P450 2E1 as the major anesthetic metabolizing enzyme in humans provides a mechanistic understanding of clinical fluorinated ether anesthetic metabolism and toxicity.

Physiologic Conditions Affect Toxicity of Ingested Industrial Fluoride

PubMed Central

Sauerheber, Richard

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 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. PMID:23840230

Physiologic conditions affect toxicity of ingested industrial fluoride.

PubMed

Sauerheber, Richard

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 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.

21 CFR 177.2510 - Polyvinylidene fluoride resins.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Polyvinylidene fluoride resins. 177.2510 Section... Repeated Use § 177.2510 Polyvinylidene fluoride resins. Polyvinylidene fluoride resins may be safely used... fluoride resins consist of basic resins produced by the polymerization of vinylidene fluoride. (b) The...

Comparison of in vitro fluoride uptake from whitening toothpastes and a conventional toothpaste in demineralised enamel.

PubMed

Altenburger, Markus J; Bernhart, Jasmin; Schicha, Thurid D; Wrbas, Karl-Thomas; Hellwig, Elmar

2010-01-01

Studies on the compatibility of abrasives and fluoride compounds deal exclusively with fluoride uptake and remineralization after storing the enamel specimens in a toothpaste-saliva mixture. The influence of brushing on the fluoride uptake when highly abrasive toothpastes are used has hardly been investigated so far. The aim of the present study was to investigate fluoride uptake in initially demineralised dental enamel after storage in, or brushing with, whitening toothpaste slurries, compared to a conventional toothpaste. For this purpose two widely available whitening toothpastes with ionically bound fluoride (sodium fluoride NaF), two with covalently-bound fluoride toothpastes (sodium monofluorophosphate, NaMFP) and a conventional amine fluoride toothpaste (AmF) were compared. The fluoride uptake after use of the AmF toothpaste was shown to be statistically significantly higher than that after application of the NaF toothpastes, which in turn was statistically significantly higher than the uptake resulting from NaMFP application. The fluoride uptake was slightly higher when the enamel samples were brushed with NaF toothpaste, rather than just stored in the respective toothpaste slurry. Brushing with highly abrasive toothpastes did not negatively influence fluoride uptake in demineralised dental enamel. The ionic form of the fluoride in toothpastes appears to be critical for increased fluoride uptake. The acidic components of the AmF toothpaste improved fluoride uptake compared to alkaline NaF toothpastes.

The effective use of fluorides in public health.

PubMed Central

Jones, Sheila; Burt, Brian A.; Petersen, Poul Erik; Lennon, Michael A.

2005-01-01

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, 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: recent water fluoridation schemes in California, USA; salt fluoridation in Jamaica; milk fluoridation in Chile; and the development of "affordable" fluoride toothpastes in Indonesia. Common themes are the concern to reduce demands for compliance with fluoride regimes that rely upon action by individuals and their families, and the issue of cost. We recommend that a community should use no more than one systemic fluoride (i.e. water or salt or milk fluoridation) combined with the use of fluoride toothpastes, and that the prevalence of dental fluorosis should be monitored in order to detect increases in or higher-than-acceptable levels. PMID:16211158

A review of plutonium oxalate decomposition reactions and effects of decomposition temperature on the surface area of the plutonium dioxide product

NASA Astrophysics Data System (ADS)

Orr, R. M.; Sims, H. E.; Taylor, R. J.

2015-10-01

Plutonium (IV) and (III) ions in nitric acid solution readily form insoluble precipitates with oxalic acid. The plutonium oxalates are then easily thermally decomposed to form plutonium dioxide powder. This simple process forms the basis of current industrial conversion or 'finishing' processes that are used in commercial scale reprocessing plants. It is also widely used in analytical or laboratory scale operations and for waste residues treatment. However, the mechanisms of the thermal decompositions in both air and inert atmospheres have been the subject of various studies over several decades. The nature of intermediate phases is of fundamental interest whilst understanding the evolution of gases at different temperatures is relevant to process control. The thermal decomposition is also used to control a number of powder properties of the PuO2 product that are important to either long term storage or mixed oxide fuel manufacturing. These properties are the surface area, residual carbon impurities and adsorbed volatile species whereas the morphology and particle size distribution are functions of the precipitation process. Available data and experience regarding the thermal and radiation-induced decompositions of plutonium oxalate to oxide are reviewed. The mechanisms of the thermal decompositions are considered with a particular focus on the likely redox chemistry involved. Also, whilst it is well known that the surface area is dependent on calcination temperature, there is a wide variation in the published data and so new correlations have been derived. Better understanding of plutonium (III) and (IV) oxalate decompositions will assist the development of more proliferation resistant actinide co-conversion processes that are needed for advanced reprocessing in future closed nuclear fuel cycles.

Hot Isostatic Pressing of Engineered Forms of I-AgZ

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jubin, Robert Thomas; Watkins, Thomas R.; Bruffey, Stephanie H.

Hot isostatic pressing (HIP) is being considered for direct conversion of 129I-bearing materials to a radiological waste form. The removal of volatile radioactive 129I from the off-gas of a nuclear fuel reprocessing facility will be necessary to comply with regulatory requirements regarding reprocessing facilities sited within the United States, and any iodine-containing media or solid sorbents generated by offgas abatement will require disposal. Zeolite minerals such as silver-exchanged mordenite (AgZ) have been studied as potential iodine sorbents and will contain 129I as chemisorbed AgI. Oak Ridge National Laboratory (ORNL) has conducted several recent studies on the HIP of both iodine-loadedmore » AgZ (I-AgZ) and other iodine-bearing zeolite minerals. The goal of these research efforts is to achieve a stable, highly leach resistant material that is reduced in volume as compared to bulk iodine-loaded I-AgZ. Through the use of HIP, it may be possible to achieve this with the addition of little or no additional materials (waste formers). Other goals for the process include that the waste form will be tolerant to high temperatures and pressures, not chemically hazardous, and that the process will result in minimal secondary waste generation. This document describes the preparation of 27 samples that are distinct from previous efforts in that they are prepared exclusively with an engineered form of AgZ that is manufactured using a binder. Iodine was incorporated solely by chemisorption. This base material is expected to be more representative of an operational system than were samples prepared previously with pure minerals.« less

Solid state electrochemical current source

DOEpatents

Potanin, Alexander Arkadyevich; Vedeneev, Nikolai Ivanovich

2002-04-30

A cathode and a solid state electrochemical cell comprising said cathode, a solid anode and solid fluoride ion conducting electrolyte. The cathode comprises a metal oxide and a compound fluoride containing at least two metals with different valences. Representative compound fluorides include solid solutions of bismuth fluoride and potassium fluoride; and lead fluoride and potassium fluoride. Representative metal oxides include copper oxide, lead oxide, manganese oxide, vanadium oxide and silver oxide.

76 FR 37129 - Determination That SODIUM FLUORIDE F 18 (Sodium Fluoride F-18) Injection, 10 to 200 Millicuries...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-24

...] Determination That SODIUM FLUORIDE F 18 (Sodium Fluoride F-18) Injection, 10 to 200 Millicuries per Milliliter... FLUORIDE F 18 (sodium fluoride F-18) injection, 10 to 200 millicuries per milliliter (mCi/mL), was not... abbreviated new drug applications (ANDAs) for SODIUM FLUORIDE F 18 injection, 10 to 200 mCi/mL, if all other...

Process for converting magnesium fluoride to calcium fluoride

DOEpatents

Kreuzmann, A.B.; Palmer, D.A.

1984-12-21

This invention is a process for the conversion of magnesium fluoride to calcium fluoride whereby magnesium fluoride is decomposed by heating in the presence of calcium carbonate, calcium oxide or calcium hydroxide. Magnesium fluoride is a by-product of the reduction of uranium tetrafluoride to form uranium metal and has no known commercial use, thus its production creates a significant storage problem. The advantage of this invention is that the quality of calcium fluoride produced is sufficient to be used in the industrial manufacture of anhydrous hydrogen fluoride, steel mill flux or ceramic applications.

Health effects of groundwater fluoride contamination.

PubMed

Nayak, Bishwajit; Roy, Madan Mohan; Das, Bhaskar; Pal, Arup; Sengupta, Mrinal Kumar; De, Shankar Prasad; Chakraborti, Dipankar

2009-04-01

The people in Berhait block, Sahibganj district, Jharkhand state, India, have been exposed chronically to fluoridecontaminated groundwater. Hereby, we report the clinical effects of chronic exposure to fluoride. The study population was a convenience sample of 342 adults and 258 children living in the affected area. All volunteers filled out questionnaires and were examined. Well water from the six affected villages and urine samples were analyzed for fluoride using an ion-sensitive electrode. Twenty nine percent of 89 well water samples had fluoride concentrations above the Indian permissible limit of fluoride in drinking water. Eighty-five children and 72 adults had clinical fluorosis. Urine fluoride concentrations in children were 0.758-2.88 mg/L whereas in adults they were 0.331-10.36 mg/L. Clinical effects of fluoride included abnormal tooth enamel in children; adults had joint pain and deformity of the limbs and spine, along with ligamentous calcifications and exostosis formations in seven patients. Elevated urine fluoride concentrations supported the clinical diagnosis of fluorosis. Owing to insufficient fluoride-safe wells and lack of awareness of the danger of fluoride toxicity, villagers often drink fluoride-contaminated water. Villagers of Berhait block, including children, are at risk from chronic fluoride toxicity. To combat the situation, villagers need fluoride-safe water, education, and awareness of the danger about fluoride toxicity.

77 FR 38789 - Notice of Availability of Draft Waste Incidental to Reprocessing Evaluation for the Concentrator...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-29

... DEPARTMENT OF ENERGY Notice of Availability of Draft Waste Incidental to Reprocessing Evaluation...: Notice of availability. SUMMARY: The Department of Energy (DOE) announces the availability of a draft... Center in West Valley, New York, are waste incidental to reprocessing and thus are not high-level...

Sterilization and reprocessing of materials and medical devices--reusability.

PubMed

Jayabalan, M

1995-07-01

Problems associated with reprocessing of disposable medical devices such as hemodialysers with resterilization for reuse and changes in material properties with resterilization of polymeric (PVC, polypropylene, polyester, polycarbonate) materials intended for development of disposable devices are reviewed. Reprocessing of hospital supplies, polystyrene microtiter plate and angiographic catheter for reuse is also discussed.

[Destruction of microsurgical devices by sterilisation].

PubMed

Berto, Raphaela; Strutz, Jürgen

2017-11-01

Hospital facilities issue numerous risk announcements on corrosion, deformation or premature wearout of medical devices every year. As there is yet little data on the impact of reprocessing on the quality and durability of microsurgical instruments, this paper aims at evaluating the effects of the reprocessing on microsurgical instruments. Material and Methods 22 brand new microsurgical instruments for stapes surgery were being reprocessed 30 times without being used for surgery or other purposes in the interim time. After each reprocessing the instruments were examined macroscopicly and microscopicly. The results were portrayed in a photo documentation and analysed on that basis. Results Almost all devices showed mechanical damage caused by the reprocessing procedure. The increasing deterioration was often associated with missing protective caps. Furthermore contaminations and stains were apparent in several cases. Conclusions The findings illustrate that careful handling of delicate surgical devices during reprocessing is vital. They also highlight problems of protective caps. As an alternative going forward it should be considered to store microsurgical instruments statically in special racks. Georg Thieme Verlag KG Stuttgart · New York.

Appropriate uses of fluorides for children: guidelines from the Canadian Workshop on the Evaluation of Current Recommendations Concerning Fluorides.

PubMed Central

Clark, D C

1993-01-01

OBJECTIVE: To prevent fluorosis caused by excessive fluoride ingestion by revising recommendations for fluoride intake by children. OPTIONS: Limiting fluoride ingestion from fluoridated water, fluoride supplements and fluoride dentifrices. OUTCOMES: Reduction in the prevalence of dental fluorosis and continued prevention of dental caries. EVIDENCE: Before the workshop, experts prepared comprehensive literature reviews of fluoride therapies, fluoride ingestion and the prevalence and causes of dental fluorosis. The papers, which were peer-reviewed, revised and circulated to the workshop participants, formed the basis of the workshop discussions. VALUES: Recommendations to limit fluoride intake were vigorously debated before being adopted as the consensus opinion of the workshop group. BENEFITS, HARMS AND COSTS: Decrease in the prevalence of dental fluorosis with continuing preventive effects of fluoride use. The only significant cost would be in preparing new, low-concentration fluoride products for distribution. RECOMMENDATIONS: Fluoride supplementation should be limited to children 3 years of age and older in areas where there is less than 0.3 ppm of fluoride in the water supply. Children in all areas should use only a "pea-sized" amount of fluoride dentifrice no more than twice daily under the supervision of an adult. VALIDATION: These recommendations are almost identical to changes to recommendations for the use of fluoride supplements recently proposed by a group of European countries. SPONSORS: The workshop was organized by Dr. D. Christopher Clark, of the University of British Columbia, and Drs. Hardy Limeback and Ralph C. Burgess, of the University of Toronto, and funded by Proctor and Gamble Inc., Toronto, the Medical Research Council of Canada and Health Canada (formerly the Department of National Health and Welfare). The recommendations were formally adopted by the Canadian Dental Association in April 1993. PMID:8261348

Review on fluoride-releasing restorative materials--fluoride release and uptake characteristics, antibacterial activity and influence on caries formation.

PubMed

Wiegand, Annette; Buchalla, Wolfgang; Attin, Thomas

2007-03-01

The purpose of this article was to review the fluoride release and recharge capabilities, and antibacterial properties, of fluoride-releasing dental restoratives, and discuss the current status concerning the prevention or inhibition of caries development and progression. Information from original scientific full papers or reviews listed in PubMed (search term: fluoride release AND (restorative OR glass-ionomer OR compomer OR polyacid-modified composite resin OR composite OR amalgam)), published from 1980 to 2004, was included in the review. Papers dealing with endodontic or orthodontic topics were not taken into consideration. Clinical studies concerning secondary caries development were only included when performed in split-mouth design with an observation period of at least three years. Fluoride-containing dental materials show clear differences in the fluoride release and uptake characteristics. Short- and long-term fluoride releases from restoratives are related to their matrices, setting mechanisms and fluoride content and depend on several environmental conditions. Fluoride-releasing materials may act as a fluoride reservoir and may increase the fluoride level in saliva, plaque and dental hard tissues. However, clinical studies exhibited conflicting data as to whether or not these materials significantly prevent or inhibit secondary caries and affect the growth of caries-associated bacteria compared to non-fluoridated restoratives. Fluoride release and uptake characteristics depend on the matrices, fillers and fluoride content as well as on the setting mechanisms and environmental conditions of the restoratives. Fluoride-releasing materials, predominantly glass-ionomers and compomers, did show cariostatic properties and may affect bacterial metabolism under simulated cariogenic conditions in vitro. However, it is not proven by prospective clinical studies whether the incidence of secondary caries can be significantly reduced by the fluoride release of restorative materials.

Streptozotocin Aggravated Osteopathology and Insulin Induced Osteogenesis Through Co-treatment with Fluoride.

PubMed

Yang, Chen; Zhang, Mengmeng; Li, Yagang; Wang, Yan; Mao, Weixian; Gao, Yuan; Xu, Hui

2015-12-01

The role of insulin in the mechanism underlying the excessive fluoride that causes skeletal lesion was studied. The in vitro bone marrow stem cells (BMSC) collected from Kunming mice were exposed to varying concentrations of fluoride with or without insulin. The cell viability and early differentiation of BMSC co-treated with fluoride and insulin were measured by using cell counting kit-8 and Gomori modified calcium-cobalt method, respectively. We further investigated the in vivo effects of varying dose of fluoride on rats co-treated with streptozotocin (STZ). Wistar rats were divided into six groups which included normal control, 10 mg fluoride/kg day group, 20 mg fluoride/kg day group, STZ control, STZ+10 mg fluoride/kg day group, and STZ+20 mg fluoride/kg day group. The rats were administered with sodium fluoride (NaF) by gavage with water at doses 10 and 20 mg fluoride/kg day for 2 months. In a period of one month, half of rats in every group were treated with streptozotocin (STZ) once through intraperitoneal injection at 52 mg/kg body weight. The serum glucose, HbA1c, and insulin were determined. Bone mineral content and insulin release were assessed. The results showed insulin combined with fluoride stimulated BMSC cell viability in vitro. The bone mineral content reduced in rats treated with higher dose of fluoride and decreased immensely in rat co-treated with fluoride and STZ. Similarly, a combination treatment of a high dose of fluoride and STZ decreased insulin sensitivity and activity. To sum up, these data indicated fluoride influenced insulin release, activity, and sensitivity. Furthermore, the insulin state in vivo interfered in the osteogenesis in turn and implied there was a close relation between insulin and bone pathogenesis in the mechanism of fluoride toxicity.

FLUORIDE: A REVIEW OF USE AND EFFECTS ON HEALTH.

PubMed

Kanduti, Domen; Sterbenk, Petra; Artnik, Barbara

2016-04-01

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. 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. Data we used in our review were systematically searched and collected from web pages and documents published from different international institutions. 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. 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 cariostatic effect.

FLUORIDE CONTENT OF COMMERCIALLY AVAILABLE BOTTLED DRINKING WATER IN BANGKOK, THAILAND.

PubMed

Rirattanapong, Praphasri; Rirattanapong, Opas

2016-09-01

The use of bottled drinking water may be a source of fluoride and could be a risk factor for fluorosis among infants and young children. The aim of this study was to evaluate the fluoride content of commercially available bottled drinking water in Bangkok, Thailand. Forty-five water samples (15 samples of plain water and 30 samples of mineral water) were purchased from several supermarkets in Bangkok, Thailand. Three bottles of each water sample were purchased, and the fluoride content of each sample was measured twice using a combination fluoride-ion selective electrode. The average reading for each sample was then calculated. Data were analyzed by descriptive statistics. Differences between mineral and plain water samples were determined by Student’s t-test. The mean (±SD) fluoride content for all the water samples was 0.17 (±0.17) mg F/l (range: 0.01-0.89 mg F/l). Six brands (13%) tested stated the fluoride content on the label. The actual fluoride content in each of their brands varied little from the label. Eight samples (18%) had a fluoride content >0.3 mg F/l and two samples (4%) had a fluoride content >0.6 mg F/l. The mean mineral water fluoride concentration was significantly higher than the mean fluoride concentration of plain water (p=0.001). We found commercially sold bottled drinking water in Bangkok, Thailand contained varying concentrations of fluoride; some with high concentrations of fluoride. Health professions need to be aware this varying fluoride content of bottled drinking water and educate the parents of infants and small children about this when prescribing fluoride supplements. Consideration should be made to have fluoride content put on the label of bottled water especially among brands with a content >0.3 mg F/l.

Evaluation of the direct and diffusion methods for the determination of fluoride content in table salt

PubMed Central

Martínez-Mier, E. Angeles; Soto-Rojas, Armando E.; Buckley, Christine M.; Margineda, Jorge; Zero, Domenick T.

2010-01-01

Objective The aim of this study was to assess methods currently used for analyzing fluoridated salt in order to identify the most useful method for this type of analysis. Basic research design Seventy-five fluoridated salt samples were obtained. Samples were analyzed for fluoride content, with and without pretreatment, using direct and diffusion methods. Element analysis was also conducted in selected samples. Fluoride was added to ultra pure NaCl and non-fluoridated commercial salt samples and Ca and Mg were added to fluoride samples in order to assess fluoride recoveries using modifications to the methods. Results Larger amounts of fluoride were found and recovered using diffusion than direct methods (96%–100% for diffusion vs. 67%–90% for direct). Statistically significant differences were obtained between direct and diffusion methods using different ion strength adjusters. Pretreatment methods reduced the amount of recovered fluoride. Determination of fluoride content was influenced both by the presence of NaCl and other ions in the salt. Conclusion Direct and diffusion techniques for analysis of fluoridated salt are suitable methods for fluoride analysis. The choice of method should depend on the purpose of the analysis. PMID:20088217

[Estimation of exposure to fluoride in "Los Altos de Jalisco", México].

PubMed

Hurtado-Jiménez, Roberto; Gardea-Torresdey, Jorge

2005-01-01

To estimate the level of fluoride exposure and human health risks in Los Altos de Jalisco (Jalisco State Heights) region. This study was conducted between May and July 2002. The fluoride concentrations of 105 water wells and six tap water samples were electrochemically measured. Exposure doses to fluoride and total intake of fluoride were estimated for babies (10 kg), children (20 kg), and adults (70 kg). The fluoride concentration of the water samples ranged from 0.1 to 17.7 mg/l. More than 45% of the water samples exceeded the national guideline value for fluoride of 1.5 mg/l. The estimated values of the exposure doses to fluoride and total intake of fluoride were in the range of 0.04-1.8 mg/kg/d and 0.5-18.4 mg/d, respectively. Dental fluorosis, skeletal fluorosis, and bone fractures are some of the potential health risks due to the intake of high doses of fluoride for the population of Los Altos de Jalisco. In order to reduce health risks, fluoridated salt,fluoridated toothpastes, and drinking water containing more than 0.7 mg/l of fluoride should be avoided.

Fluoride in the environment and its metabolism in humans.

PubMed

Jha, Sunil Kumar; Mishra, Vinay Kumar; Sharma, Dinesh Kumar; Damodaran, Thukkaram

2011-01-01

The presence of environmental fluoride and its impact on human health is well documented. When consumed in adequate quantity, fluoride prevents dental caries, assists in the formation of dental enamels, and prevents deficiencies in bone mineralization. At excessive exposure levels, ingestion of fluoride causes dental fluorosis skeletal fluorosis, and manifestations such as gastrointestinal, neurological, and urinary problems. The distribution of fluoride in the environment is uneven and largely is believed to derive from geogenic causes. The natural sources of fluoride are fluorite, fluorapatite, and cryolite, whereas anthropogenic sources include coal burning, oil refining, steel production, brick-making industries, and phosphatic fertilizer plants, among others. Among the various sources of fluoride in the environment, those of anthropogenic origin have occasionally been considered to be major ones. The gourndwater is more susceptible to fluoride accumulation and contamination than are other environmental media, primarily because of its contact with geological substrates underneath. The high fluoride concentration in water usually reflects the solubility of fluoride (CaF₂). High concentrations are also often associated with soft, alkaline, and calcium-deficient waters. The fluoride compounds that occur naturally in drinking water are almost totally bioavailable (90%) and are completely absorbed from the gastrointestinal tract. As a result, drinking water is considered to be the potential source of fluoride that causes fluorosis. Because the bioavailability of fluoride is generally reduced in humans when consumed with milk or a calcium-rich diet, it is highly recommended that the inhabitants of fluoride-contaminated areas should incorporate calcium-rich foods in their routine diet. Guidelines for limiting the fluoride intake from drinking water have been postulated by various authorities. Such limits are designed to protect public health and should reflect all fluoride intake sources, including dietary fluoride. The toxicological risks posed by fluoride could be better understood if epidemiological surveillance for dental and skeletal fluorosis would be systematically conducted in fluoride-affected areas. Such input would greatly improve understanding of the human dose-response relationship. Such surveillance of potentially high fluoride areas is also important because it would help to delineate, much earlier, the remedial measures that are appropriate for those areas.

Potential fluoride toxicity from oral medicaments: A review.

PubMed

Ullah, Rizwan; Zafar, Muhammad Sohail; Shahani, Nazish

2017-08-01

The beneficial effects of fluoride on human oral health are well studied. There are numerous studies demonstrating that a small amount of fluoride delivered to the oral cavity decreases the prevalence of dental decay and results in stronger teeth and bones. However, ingestion of fluoride more than the recommended limit leads to toxicity and adverse effects. In order to update our understanding of fluoride and its potential toxicity, we have described the mechanisms of fluoride metabolism, toxic effects, and management of fluoride toxicity. The main aim of this review is to highlight the potential adverse effects of fluoride overdose and poorly understood toxicity. In addition, the related clinical significance of fluoride overdose and toxicity has been discussed.

TIGA Tide Gauge Data Reprocessing at GFZ

NASA Astrophysics Data System (ADS)

Deng, Zhiguo; Schöne, Tilo; Gendt, Gerd

2014-05-01

To analyse the tide gauge measurements for the purpose of global long-term sea level change research a well-defined absolute reference frame is required by oceanographic community. To create such frame the data from a global GNSS network located at or near tide gauges are processed. For analyzing the GNSS data on a preferably continuous basis the International GNSS Service (IGS) Tide Gauge Benchmark Monitoring Working Group (TIGA-WG) is responsible. As one of the TIGA Analysis Centers the German Research Centre for Geosciences (GFZ) is contributing to the IGS TIGA Reprocessing Campaign. The solutions of the TIGA Reprocessing Campaign will also contribute to 2nd IGS Data Reprocessing Campaign with GFZ IGS reprocessing solution. After the first IGS reprocessing finished in 2010 some improvements were implemented into the latest GFZ software version EPOS.P8: reference frame IGb08 based on ITRF2008, antenna calibration igs08.atx, geopotential model (EGM2008), higher-order ionospheric effects, new a priori meteorological model (GPT2), VMF mapping function, and other minor improvements. GPS data of the globally distributed tracking network of 794 stations for the time span from 1994 until end of 2012 are used for the TIGA reprocessing. To handle such large network a new processing strategy is developed and described in detail. In the TIGA reprocessing the GPS@TIGA data are processed in precise point positioning (PPP) mode to clean data using the IGS reprocessing orbit and clock products. To validate the quality of the PPP coordinate results the rates of 80 GPS@TIGA station vertical movement are estimated from the PPP results using Maximum Likelihood Estimation (MLE) method. The rates are compared with the solution of University of LaRochelle Consortium (ULR) (named ULR5). 56 of the 80 stations have a difference of the vertical velocities below 1 mm/yr. The error bars of PPP rates are significant larger than those of ULR5, which indicates large time correlated noise in the PPP solutions.

Evaluation of Reprocessed Suomi NPP VIIRS Sensor Data Records based on Sensitivity of Environmental Data Records Trending to Changes in Sensor Data Records

NASA Astrophysics Data System (ADS)

Huang, J.; Weng, F.; Sun, N.

2017-12-01

As the inputs to satellite Environmental Data Records (EDR) that provide continuous monitoring of Earth System changes from space, Sensor Data Records (SDR) need to meet very high standards of accuracy. SDR reprocessing, aiming for accurately accounting sensor degradation and calibration issues, is therefore very important in satellite remote sensing. Previous studies on heritage Terra MODIS in NASA Earth Observation System (EOS) indicated that SDR degradation over time, if not correctly calibrated and reprocessed, can result in false trending in several key satellite EDR observations, such as aerosol optical depth (AOD) and vegetation index (VI). Yet the sensitivity of these EDRs to the changes in the reprocessed SDRs is still not comprehensively understood or quantified. As part of the Suomi NPP SDR long term monitoring efforts, the current ongoing SDR reprocessing at NOAA NESDIS STAR provides a unique test bed for quantifying the changes of EDRs to the reprocessed SDRs, and thus improves our understanding of the potential impacts of the SDR reprocessing on our capability of critical Earth observations. For the sensitivity investigation, we selected the VIIRS aerosol algorithm, which EDR algorithm uses most of the visible to near infrared (VIS-NIR) SDR bands. Several aerosol hotspot regions over the globe are selected for conducting AOD trending analysis under several prescribed SDR reprocessing scenarios, and the changes in the spatial and temporal characterizations of AOD are linked to the changes in SDR for exploration of any potential systematic relations. Preliminary results indicated that although changes varies by regions and seasons, some EDRs can be sensitive to even slight SDR changes in certain VIS-NIR bands. The study sheds important lights on how we can use the SDR-EDR relation as an additional approach to facilitate the SDR reprocessing evaluation. Details of the finding will be reported at the presentation.

SEPARATION OF METAL VALUES FROM NUCLEAR REACTOR

DOEpatents

Campbell, D.O.; Cathers, G.I.

1962-06-19

A method is given for separating beryllium fluoride and an alkali metal fluoride from a mixture containing same and rare earth fluorides. The method comprises contacting said mixture with a liquid hydrogen fluoride solvent containing no more than about 30 per cent water by weight and saturated with a fluoride salt characterized by its solubility in anhydrous hydrogen fluoride for a period of time sufficient to dissolve said beryllium fluoride in said solvent. (AEC)

Thirty years of fluoridation: a review.

PubMed

Richmond, V L

1985-01-01

Fluoride contributes to stability of both teeth and bones and to reduction of caries, especially if ingested before eruption of teeth. Reduction of caries continues at about 60% in persons drinking fluoridated water only as long as fluoride washes over teeth. One-half the population of the US does not have access to water with an optimal fluoride concentration of about 1 mg/L. Misinformation about fluoridation contributes to reluctance of communities to supplement the natural but inadequate fluoride of those water supplies. Fluoridation of water has no positive or negative effect on incidence or mortality rates due to cancer, heart disease, intracranial lesions, nephritis, cirrhosis, mongoloid births, or from all causes together. The collective decision to increase the natural fluoride content of water supplies is not an infringement of civil rights, nor does it establish a precedent in the binding sense of the law. Supplemental fluoride in water makes it available to all members of the community in a safe, practical, economical and reliable manner. Fluoridation saves money in dental costs and time lost from work. Fluoridation is an appropriate action of government in promoting the health and welfare of society.

Experimental study on thermal hazard of tributyl phosphate-nitric acid mixtures using micro calorimeter technique.

PubMed

Sun, Qi; Jiang, Lin; Gong, Liang; Sun, Jin-Hua

2016-08-15

During PUREX spent nuclear fuel reprocessing, mixture of tributyl phosphate (TBP) and hydrocarbon solvent are employed as organic solvent to extract uranium in consideration of radiation contaminated safety and resource recycling, meanwhile nitric acid is utilized to dissolve the spent fuel into small pieces. However, once TBP contacts with nitric acid or nitrates above 130°C, a heavy "red oil" layer would occur accompanied by thermal runaway reactions, even caused several nuclear safety accident. Considering nitric acid volatility and weak exothermic detection, C80micro calorimeter technique was used in this study to investigate thermal decomposition of TBP mixed with nitric acid. Results show that the concentration of nitric acid greatly influences thermal hazard of the system by direct reactions. Even with a low heating rate, if the concentration of nitric acid increases due to evaporation of water or improper operations, thermal runaway in the closed system could start at a low temperature. Copyright © 2016 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nan, Yue; Tavlarides, Lawrence L.; DePaoli, David W.

The adsorption process of iodine, a major volatile radionuclide in the off-gas streams of spent nuclear fuel reprocessing, on hydrogen-reduced silver-exchanged mordenite (Ag 0Z) was studied at the micro-scale. The gas-solid mass transfer and reaction involved in the adsorption process were investigated and evaluated with appropriate models. Optimal conditions for reducing the silver-exchanged mordenite (AgZ) in a hydrogen stream were determined. Kinetic and equilibrium data of iodine adsorption on Ag 0Z were obtained by performing single-layer adsorption experiments with experimental systems of high precision at 373–473 K over various iodine concentrations. Results indicate approximately 91% to 97% of the iodinemore » adsorption was through the silver-iodine reaction. The effect of temperature on the iodine loading capacity of Ag 0Z was discussed. In conclusion, the Shrinking Core model describes the data well, and the primary rate controlling mechanisms were macro-pore diffusion and silver-iodine reaction. © 2016 American Institute of Chemical Engineers AIChE J, 2016« less

Fluoride in groundwater: toxicological exposure and remedies.

PubMed

Jha, S K; Singh, R K; Damodaran, T; Mishra, V K; Sharma, D K; Rai, Deepak

2013-01-01

Fluoride is a chemical element that is found most frequently in groundwater and has become one of the most important toxicological environmental hazards globally. The occurrence of fluoride in groundwater is due to weathering and leaching of fluoride-bearing minerals from rocks and sediments. Fluoride when ingested in small quantities (<0.5 mg/L) is beneficial in promoting dental health by reducing dental caries, whereas higher concentrations (>1.5 mg/L) may cause fluorosis. It is estimated that about 200 million people, from among 25 nations the world over, may suffer from fluorosis and the causes have been ascribed to fluoride contamination in groundwater including India. High fluoride occurrence in groundwaters is expected from sodium bicarbonate-type water, which is calcium deficient. The alkalinity of water also helps in mobilizing fluoride from fluorite (CaF2). Fluoride exposure in humans is related to (1) fluoride concentration in drinking water, (2) duration of consumption, and (3) climate of the area. In hotter climates where water consumption is greater, exposure doses of fluoride need to be modified based on mean fluoride intake. Various cost-effective and simple procedures for water defluoridation techniques are already known, but the benefits of such techniques have not reached the rural affected population due to limitations. Therefore, there is a need to develop workable strategies to provide fluoride-safe drinking water to rural communities. The study investigated the geochemistry and occurrence of fluoride and its contamination in groundwater, human exposure, various adverse health effects, and possible remedial measures from fluoride toxicity effects.

Chronologic Trends in Studies on Fluoride Mechanisms of Action.

PubMed

Oh, H J; Oh, H W; Lee, D W; Kim, C H; Ahn, J Y; Kim, Y; Shin, H B; Kim, C Y; Park, S H; Jeon, J G

2017-11-01

Fluoride has been widely used for the prevention of dental caries since the mid-20th century. The aim of this study was to investigate the chronologic trends in studies on fluoride mechanisms of action against dental caries during the years 1950 to 2015. To this aim, queries such as "fluoride," "fluoride and demineralization," "fluoride and remineralization," "fluoride and (plaque or biofilms)," and "fluoride and (bacteria or microbials)" were submitted to PubMed to collect research article information, including titles, abstracts, publication dates, author affiliations, and publication journals. The article information that PubMed produced was then collected by an automatic web crawler and examined through informetrics and linguistic analyses. We found that the number of articles concerned with fluoride mechanisms of action against dental caries was 6,903 and gradually increased over time during the years 1950 to 2015. They were published by 1,136 journals-most notably, Caries Research and Journal of Dental Research. Of the articles published, those related to bacteria/microbials had a higher percentage (44%) than those dealing with plaque/biofilms, demineralization, and remineralization. With regard to the geographic distribution of authors, Europe and North America accounted for 65% of the articles during the years 1987 to 2015, although the number of authors in Asia sharply increased in recent years. Among the fluoride compounds, NaF was mentioned more frequently than SnF 2 , Na 2 PO 3 F, amine fluoride, and acidulated phosphate fluoride during the years 1986 to 2015. Water fluoridation received the most attention among the various fluoride application methods (toothpastes, mouthwashes, fluoride varnishes, and fluoride gels) during the same period. These results, obtained from employing informetrics and linguistic analyses, suggest that in studies on fluoride mechanisms of action, 1) the unbalanced geographic distribution of articles and 2) the heavy concentration of articles on particular fluoride compounds and application methods should be overcome in future research.

TRMM Data Improvement as Part of the GPM Data Processing

NASA Technical Reports Server (NTRS)

Stocker, Erich F.; Ji, Y.; Kwiatkowski, J.; Kelley, O.; Stout, J.; Woltz, L.

2016-01-01

NASA has a long standing commitment to the improvement of its mission datasets. Indeed, data reprocessing is always built into the plans, schedule and budget for the mission data processing system. However, in addition to these ongoing mission reprocessing, NASA also supports a final reprocessing of all the data for a mission upon its completion (known as Phase F). TRMM Phase F started with the end of the TRMM mission in June of 2015. This last reprocessing has two overall goals: improvement of the TRMM mission data products; incorporation of the 17+ years of TRMM data into the ongoing NASA/JAXA GPM data processing. The first goal guarantees that the latest algorithms used for precipitation retrievals will also be used in reprocessing the TRMM data. The second goal ensures that as GPM algorithms are improved, the entire TRMM data will always be reprocessed with each GPM reprocessing. In essence TRMM becomes another of the GPM constellation satellites. This paper will concentrate on presenting the improvements to TMI level 1 data including calibration, geolocation, and emissive antenna corrections. It will describe the format changes that will occur how the TMI level 1C product will be intercalibrated using GMI as the reference calibration. It will also provide an overview of changes in the precipitation radar products as well as the combined TMIPR product.

Fluoride content of infant formulas prepared with deionized, bottled mineral and fluoridated drinking water.

PubMed

Buzalaf, M A; Granjeiro, J M; Damante, C A; de Ornelas, F

2001-01-01

Usually infant milk formula is the major source of fluoride in infancy. Fluoride concentrations in ten samples of powdered milk formulas, prepared with deionized, bottled mineral, and fluoridated drinking water were determined after HMDS-facilitated diffusion, using a fluoride ion specific electrode(Orion 9609). Fluoride concentrations ranged from 0.01 to 0.75 ppm; from 0.02 to 1.37 ppm and from 0.91 to 1.65 ppm for formulas prepared with deionized, bottled mineral (0.02 to 0.69 ppm F) and fluorinated drinking water (0.9 ppm F), respectively. Possible fluoride ingestion per Kg body mass ws estimated. With deionized water, only the soy-based- formulas should provide a daily fluoride intake of above the suggested threshold for fluorosis. With water containing 0.9 ppm F, however, all of them would provide it. Hence, to limit fluoride intakes to amounts <0.1 mg/kg/day, it is necessary to avoid use fo fluoridated water (around 1 ppm) to dilute powdered infant formulas.

The fractional urinary fluoride excretion of adults consuming naturally and artificially fluoridated water and the influence of water hardness: a randomized trial.

PubMed

Villa, A; Cabezas, L; Anabalón, M; Rugg-Gunn, A

2009-09-01

To assess whether there was any significant difference in the average fractional urinary fluoride excretion (FUFE) values among adults consuming (NaF) fluoridated Ca-free water (reference water), naturally fluoridated hard water and an artificially (H2SiF6) fluoridated soft water. Sixty adult females (N=20 for each treatment) participated in this randomized, double-blind trial. The experimental design of this study provided an indirect estimation of the fluoride absorption in different types of water through the assessment of the fractional urinary fluoride excretion of volunteers. Average daily FUFE values (daily amount of fluoride excreted in urine/daily total fluoride intake) were not significantly different between the three treatments (Kruskal-Wallis; p = 0.62). The average 24-hour FUFE value (n=60) was 0.69; 95% C.I. 0.65-0.73. The results of this study suggest that the absorption of fluoride is not affected by water hardness.

Does fluoride in the water close the dental caries gap between Indigenous and non-Indigenous children?

PubMed

Lalloo, R; Jamieson, L M; Ha, D; Ellershaw, A; Luzzi, L

2015-09-01

Indigenous children experience significantly more dental caries than non-Indigenous children. This study assessed if access to fluoride in the water closed the gap in dental caries between Indigenous and non-Indigenous children. Data from four states and two territories were sourced from the Child Dental Health Survey (CDHS) conducted in 2010. The outcomes were dental caries in the deciduous and permanent dentitions, and the explanatory variables were Indigenous status and access to fluoridated water (≥0.5 mg/L) prior to 2008. Dental caries prevalence and severity for Indigenous and non-Indigenous children, in both dentitions, was lower in fluoridated areas compared to non-fluoridated areas. Among non-Indigenous children, there was a 50.9% difference in mean dmft scores in fluoridated (1.70) compared to non-fluoridated (2.86) areas. The difference between Indigenous children in fluoridated (3.29) compared to non-fluoridated (4.16) areas was 23.4%. Among non-Indigenous children there was a 79.7% difference in the mean DMFT scores in fluoridated (0.68) compared to non-fluoridated (1.58) areas. The difference between Indigenous children in fluoridated (1.59) and non-fluoridated (2.23) areas was 33.5%. Water fluoridation is effective in reducing dental caries, but does not appear to close the gap between non-Indigenous children and Indigenous children. © 2015 Australian Dental Association.

Fluoride bioavailability in saliva and plaque

PubMed Central

2012-01-01

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 plaque was measured, and the fluoride content was analysed using a fluoride sensitive electrode. All subjects repeated all study cycles 5 times, and 3 cycles per subject underwent statistical analysis using the Wilcoxon-Mann-Whitney test. Results Immediately after brushing the fluoride concentration in saliva increased rapidly and dropped to the baseline level after 360 minutes. No difference was found between NaF and amine fluoride. All plaque fluoride levels were elevated after 30 minutes until 120 minutes after tooth brushing, and decreasing after 360 minutes to baseline. According to the highly individual profile of fluoride in saliva and plaque, both levels of bioavailability correlated for the first 30 minutes, and the fluoride content of saliva and plaque was back to baseline after 6 hours. Conclusions Fluoride levels in saliva and plaque are interindividually highly variable. However, no significant difference in bioavailability between NaF and amine fluoride, in saliva, or in plaque was found. PMID:22230722

Gramicidin D enhances the antibacterial activity of fluoride.

PubMed

Nelson, James W; Zhou, Zhiyuan; Breaker, Ronald R

2014-07-01

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 Bacillus subtilis and that the antibacterial activity of this compound is potentiated by fluoride. Polymyxin B, another membrane-targeting antibiotic with a different mechanism of action, shows no such improvement. These results, along with previous findings, indicate that certain compounds that destabilize bacterial cell envelopes can enhance the toxicity of fluoride. Copyright © 2014 Elsevier Ltd. All rights reserved.

The effect on human salivary fluoride concentration of consuming fluoridated salt-containing baked food items.

PubMed

Macpherson, L M; Stephen, K W

2001-10-01

Salt fluoridation is recognised world-wide as a proven and viable alternative means of consumer choice-related, community-based fluoridation where water fluoridation is either technically or politically impossible. However, as most salt consumed is contained within cooked food products, rather than sprinkled over prepared food at the table, the purpose of this study was to investigate the effects on salivary fluoride concentration of consuming baked food products prepared with 250 and 350 ppm fluoridated salt (as KF). Six food items were baked with (a) normal non-fluoridated salt, (b) 250 mg F/kg salt and (c) 350 mg F/kg salt. Eleven adult volunteers consumed these foodstuffs on separate occasions and salivary samples were collected for fluoride analyses before and at various time points (1-30 min) after eating. For most foodstuffs, small but significant increases in salivary fluoride concentration occurred for at least 5 min after ingestion of the fluoridated salt-containing items. Salivary fluoride concentrations peaked 1 or 2 min after eating, with highest values for the six test foods ranging from 0.16 to 0.25 ppm F, and from 0.18 to 0.44 ppm F for the 250 and 350 mg F/kg salt products, respectively. In all cases, salivary fluoride concentrations had returned to baseline by 20 min. The clinical significance of such small, short-term increases in salivary fluoride is uncertain, but the findings suggest that a more frequent intake of foods with fluoridated salt substituted for normal salt could help sustain slightly elevated salivary fluoride concentrations for more prolonged periods of the day, and might thus potentiate the cariostatic effects of saliva on tooth mineral.

Comparing activated alumina with indigenous laterite and bauxite as potential sorbents for removing fluoride from drinking water in Ghana

USGS Publications Warehouse

Craig, Laura; Stillings, Lisa; Decker, David L.; Thomas, James M.

2015-01-01

Fluoride is considered beneficial to teeth and bones when consumed in low concentrations, but at elevated concentrations it can cause dental and skeletal fluorosis. Most fluoride-related health problems occur in poor, rural communities of the developing world where groundwater fluoride concentrations are high and the primary sources of drinking water are from community hand-pump borehole drilled wells. One solution to drinking high fluoride water is to attach a simple de-fluoridation filter to the hand-pump; and indigenous materials have been recommended as low-cost sorbents for use in these filters. In an effort to develop an effective, inexpensive, and low-maintenance de-fluoridation filter for a high fluoride region in rural northern Ghana, this study conducted batch fluoride adsorption experiments and potentiometric titrations to investigate the effectiveness of indigenous laterite and bauxite as sorbents for fluoride removal. It also determined the physical and chemical properties of each sorbent. Their properties and the experimental results, including fluoride adsorption capacity, were then compared to those of activated alumina, which has been identified as a good sorbent for removing fluoride from drinking water. The results indicate that, of the three sorbents, bauxite has the highest fluoride adsorption capacity per unit area, but is limited by a low specific surface area. When considering fluoride adsorption per unit weight, activated alumina has the highest fluoride adsorption capacity because of its high specific surface area. Activated alumina also adsorbs fluoride well in a wider pH range than bauxite, and particularly laterite. The differences in adsorption capacity are largely due to surface area, pore size, and mineralogy of the sorbent.

Concentration of Fluoride in Cow's and Buffalo's Milk in Relation to Varying Levels of Fluoride Concentration in Drinking Water of Mathura City in India- A Pilot Study.

PubMed

Gupta, Prahlad; Gupta, Nidhi; Meena, Komal; Moon, Ninad Joshirao; Kumar, Puneet; Kaur, Ravneet

2015-05-01

To estimate fluoride concentration in drinking water, cow's milk and buffalo's milk and to correlate the concentration of fluoride in cow's milk and buffalo's milk with varying levels of fluoride concentration in drinking water. Ten households having both cows and buffalo's were selected by convenience in each of the 3 zones (below optimum fluoride <0.7 ppm (parts per million), optimum fluoride 0.7-1.2 ppm and above optimum fluoride areas > 1.2 ppm). From these selected households, 200 ml of fresh milk of both cows and buffaloes was collected along with 200 ml of drinking water for estimation of fluoride concentration by using a fluoride ion selective electrode method. The data was analysed using SPSS, version 11.5 for windows. The mean fluoride concentration of drinking water, cow's milk and buffalo's milk in three different fluoride zones was 0.89±0.39, 0.09±0.07, 0.09±0.08 respectively. Pearson's correlation found a statistically significant correlation between fluoride concentrations in cow's and buffalo's milk with varying levels of fluoride concentration in drinking water in zone B and zone C. However, this correlation was not statistically significant in zone A. With an increase in fluoride concentration in drinking water there was an increase in concentration of fluoride in cow's and buffalo's milk. We conclude that this association is seen in conjunction to not only a single factor but rather due to culmination of several other aspects. So, there is a need to elucidate the other factors that might be contributing to this increase and dental fluorosis.

Level of Fluoride in Soil, Grain and Water in Jalgaon District, Maharashtra, India.

PubMed

Naik, Rahul Gaybarao; Dodamani, Arun Suresh; Vishwakarma, Prashanth; Jadhav, Harish Chaitram; Khairnar, Mahesh Ravindra; Deshmukh, Manjiri Abhay; Wadgave, Umesh

2017-02-01

Fluoride has an influence on both oral as well as systemic health. The major source of fluoride to body is through drinking water as well as through diet. Staple diet mainly depends on local environmental factors, food grains grown locally, its availability etc. Determination of fluoride level in these food grains is important. So, estimation of the amount of fluoride in grains and its relation to the sources of fluoride used for their cultivation viz., soil and water is important. To estimate the relation of fluoride concentration in grains (Jowar) with respect to that of soil and water used for their cultivation. Fifteen samples each of soil, water and grains were collected using standardized method from the same farm fields of randomly selected villages of Jalgaon district. Fluoride ion concentration was determined in laboratory using SPADNS technique. Mean difference in fluoride levels in between the groups were analyzed using ANOVA and Post-Hoc Tukey test. Linear regression method was applied to analyse the association of the fluoride content of grain with water and soil. There was a significant difference in between mean fluoride levels of soil and water (p<0.001) and in between soil and grain (p<0.001); however, difference in between mean fluoride levels of water and grain was found to be non significant (p=0.591). Also fluoride levels in all the three groups showed significant association with each other. Fluoride level of soil, grains and water should be adjusted to an optimum level. Soil has positive correlation with respect to uptake of fluoride by Jowar grains. So, Jowar grains with optimum fluoride content should be made available in the commercial markets so that oral and general health can be benefitted.

Development of resistance of mutans streptococci and Porphyromonas gingivalis to chlorhexidine digluconate and amine fluoride/stannous fluoride-containing mouthrinses, in vitro.

PubMed

Kulik, Eva M; Waltimo, Tuomas; Weiger, Roland; Schweizer, Irene; Lenkeit, Krystyna; Filipuzzi-Jenny, Elisabeth; Walter, Clemens

2015-07-01

The aim if this study was to determine the minimal inhibitory concentrations of chlorhexidine digluconate and an amine fluoride/stannous fluoride-containing mouthrinse against Porphyromonas gingivalis and mutans streptococci during an experimental long-term subinhibitory exposition. Five P. gingivalis strains and four mutans streptococci were subcultivated for 20-30 passages in subinhibitory concentrations of chlorhexidine digluconate or an amine fluoride/stannous fluoride-containing mouthrinse. Pre-passaging minimal inhibitory concentrations for chlorhexidine ranged from 0.5 to 2 mg/l for mutans streptococci and from 2 to 4 mg/l for the P. gingivalis isolates. For the amine fluoride/stannous fluoride-containing mouthrinse minimal inhibitory values from 0.125 to 0.25% for the mutans streptococci and from 0.063 to 0.125% for the P. gingivalis isolates were determined. Two- to fourfold increased minimal inhibitory concentrations against chlorhexidine were detected for two of the five P. gingivalis isolates, whereas no increase in minimal inhibitory concentrations was found for the mutans streptococci after repeated passaging through subinhibitory concentrations. Repeated exposure to subinhibitory concentrations of the amine fluoride/stannous fluoride-containing mouthrinse did not alter the minimally inhibitory concentrations of the bacterial isolates tested. Chlorhexidine and the amine fluoride/stannous fluoride-containing mouthrinse are effective inhibitory agents against the oral bacterial isolates tested. No general development of resistance against chlorhexidine or the amine fluoride/stannous fluoride-containing mouthrinse was detected. However, some strains showed potential to develop resistance against chlorhexidine after prolonged exposure. The use of chlorhexidine should be limited to short periods of time. The amine fluoride/stannous fluoride-containing mouthrinse appears to have the potential to be used on a long-term basis.

An in situ caries study on the interplay between fluoride dose and concentration in milk.

PubMed

Lippert, F; Martinez-Mier, E A; Zero, D T

2014-07-01

This randomized, cross-over in situ study investigated the impact of sodium fluoride dose and concentration in milk on caries lesion rehardening, fluoridation and acid resistance. Twenty-eight subjects wore two gauze-covered enamel specimens with preformed lesions placed buccally on their mandibular partial dentures for three weeks. Participants used fluoride-free dentifrice throughout the study and consumed once daily one of the five study treatments: no fluoride in 200 ml milk (0F-200), 1.5 or 3 mg fluoride in either 100 (1.5F-100; 3F-100) or 200 ml milk (1.5F-200; 3F-200). After three weeks, specimens were retrieved. Knoop hardness was used to determine rehardening and resistance to a secondary acid challenge. Enamel fluoride uptake (EFU) was determined using a microbiopsy technique. A linear fluoride dose-response was observed for all study variables which exhibited similar overall patterns. All the treatments resulted in rehardening, with 0F-200 inducing the least and 3F-100 the most. Apart from 1.5F-200, all the treatments resulted in statistically significantly more rehardening compared to 0F-200. The fluoride doses delivered in 100 ml provided directionally although not statistically significantly more rehardening than those delivered in 200 ml milk. EFU data exhibited better differentiation between treatments: all fluoridated milk treatments delivered more fluoride to lesions than 0F-200; fluoride in 100 ml demonstrated statistically significantly higher EFU than fluoride in 200 ml milk. Findings for acid resistance were also more discerning than rehardening data. The present study has provided further evidence for the anti-caries benefits of fluoridated milk. Both fluoride dose and concentration appear to impact the cariostatic properties of fluoride in milk. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparison of short-term in vitro fluoride release and recharge from four different types of pit-and-fissure sealants.

PubMed

Koga, Hiroshi; Kameyama, Atsushi; Matsukubo, Takashi; Hirai, Yoshito; Takaesu, Yoshinori

2004-08-01

The purpose of this in vitro study was to assess the effects of four commercial fluoride-containing pit-and-fissure sealants on caries prevention. Four sealants containing fluoride, Fuji III, Fuji III LC (GC Co., Tokyo), Teethmate F-1 (Kuraray Medical Co., Osaka) and Helioseal F (Vivadent Co., Liechtenstein) were used to investigate fluoride release and recharge. Disk-shaped specimens prepared from each material were immersed in distilled water at a temperature of 37 degrees C. After seven days, acidulated phosphate fluoride solution (APF) was applied to each specimen, and it was then again immersed in distilled water for 14 days. We then determined how much fluoride had been released into the immersing water. Fuji III LC was used with APF solution to investigate the fluoride uptake. Fuji III had the highest fluoride release, and Fuji III LC had the highest fluoride recharge. Helioseal F and Teethmate F-1 had almost no fluoride recharge. Fuji III LC/APF had a higher fluoride uptake to enamel than Fuji III LC. These results suggest that GIC-sealants in the oral cavity can serve as a fluoride reservoir and contribute to retaining a low fluoride level in oral fluids, thereby preventing caries.

Low-levels of fluoride in plaque and saliva and their effects on the demineralisation and remineralisation of enamel; role of fluoride toothpastes.

PubMed

Lynch, R J M; Navada, R; Walia, R

2004-01-01

To summarise support for current consensus on the likely means by which fluoride toothpastes reduce caries and review some relevant studies of the effect of low levels of fluoride on the demineralisation and remineralisation of enamel. The major anti-caries effect of fluoride toothpastes is thought to result from small but protracted elevations in levels of fluoride in plaque and saliva. Fluoride incorporated into enamel systemically does not reduce enamel solubility sufficiently to exert an anti-caries effect. Fluoride has the potential to exert an anti-caries benefit largely through three mechanisms; inhibition of demineralisation, promotion of remineralisation and interference with bacterial growth and metabolism. However, the low levels of fluoride thought to influence caries are insufficient to have a significant effect via the latter mechanism. Thus reductions in caries resulting from the use of fluoride toothpastes can be linked to modification of the demineralisation/remineralisation balance by direct effects on dental mineral exerted topically by low levels of fluoride. Numerous in vitro studies have shown that low levels of fluoride, typical of those found after many hours in resting plaque and saliva, and resulting from the regular use of fluoride toothpastes, can have a profound effect on enamel demineralisation and remineralisation.

Groundwater fluoride contamination and its possible health implications in Indi taluk of Vijayapura District (Karnataka State), India.

PubMed

Ugran, Vidyavati; Desai, Naveen N; Chakraborti, Dipankar; Masali, Kallappa A; Mantur, Prakash; Kulkarni, Shreepad; Deshmukh, Niranjan; Chadchan, Kailash S; Das, Swastika N; Tanksali, Anuradha S; Arwikar, Asha S; Guggarigoudar, Suresh P; Vallabha, Tejaswini; Patil, Shailaja S; Das, Kusal K

2017-10-01

Groundwater fluoride concentration and fluoride-related health problems were studied in twenty-two villages of Indi taluk of Vijayapura district, Karnataka, India. Present study (2015) was also used to compare groundwater fluoride concentration in same 22 villages with previous government report (2000). Groundwater fluoride concentrations of 62 bore wells of 22 villages were analyzed by using an ion-sensitive electrode. A total of 660 adults and 600 children were screened for fluorosis symptoms and signs. Sixty clinically suspected fluorosis patients' urine samples were further analyzed for fluoride. The mean value (1.22 ± 0.75 mg/L) of fluoride concentration of 62 bore wells and 54.83 % bore wells with ≥1.0 mg/L of fluoride concentrations in Indi taluk indicates higher than the permissible limit of drinking water fluoride concentration recommended for India. Clinical symptoms like arthritis, joint pains, gastrointestinal discomfort and lower limb deformities with high urinary fluoride concentrations in some subjects suggest fluorosis. Results also showed an increase in groundwater fluoride concentration of the same 22 villages between previous and present study. Preliminary arthritis symptom of the villagers could be due to drinking fluoride-contaminated water. Increase in fluoride concentration with time to the bore wells definitely indicates future danger.

Black Tea Source, Production, and Consumption: Assessment of Health Risks of Fluoride Intake in New Zealand

PubMed Central

Godfrey, Michael; Limeback, Hardy

2017-01-01

In countries with fluoridation of public water, it is imperative to determine other dietary sources of fluoride intake to reduce the public health risk of chronic exposure. New Zealand has one of the highest per capita consumption rates of black tea internationally and is one of the few countries to artificially fluoridate public water; yet no information is available to consumers on the fluoride levels in tea products. In this study, we determined the contribution of black tea as a source of dietary fluoride intake by measuring the fluoride content in 18 brands of commercially available products in New Zealand. Fluoride concentrations were measured by potentiometric method with a fluoride ion-selective electrode and the contribution of black tea to Adequate Intake (AI) and Tolerable Upper Intake Level (UL) was calculated for a range of consumption scenarios. We examined factors that influence the fluoride content in manufactured tea and tea infusions, as well as temporal changes in fluoride exposure from black tea. We review the international evidence regarding chronic fluoride intake and its association with chronic pain, arthritic disease, and musculoskeletal disorders and provide insights into possible association between fluoride intake and the high prevalence of these disorders in New Zealand. PMID:28713433

Fluoride release from fluoride varnishes under acidic conditions.

PubMed

Lippert, F

2014-01-01

The aim was to investigate the in vitro fluoride release from fluoride varnishes under acidic conditions. Poly(methyl methacrylate) blocks (Perspex, n=3 per group) were painted with 80 ± 5 mg fluoride varnish (n=10) and placed into artificial saliva for 30 min. Then, blocks were placed into either 1% citric acid (pH 2.27) or 0.3% citric acid (pH 3.75) solutions (n=3 per solution and varnish) for 30 min with the solutions being replaced every 5 min. Saliva and acid solutions were analyzed for fluoride content. Data were analyzed using three-way ANOVA (varnish, solution, time). The three-way interaction was significant (p>0.0001). Fluoride release and release patterns varied considerably between varnishes. Fluoride release in saliva varied by a factor of more than 10 between varnishes. Some varnishes (CavityShield, Nupro, ProFluorid, Vanish) showed higher fluoride release in saliva than during the first 5 min of acid exposure, whereas other varnishes (Acclean, Enamel-Pro, MI Varnish, Vella) showed the opposite behavior. There was little difference between acidic solutions. Fluoride release from fluoride varnishes varies considerably and also depends on the dissolution medium. Bearing in mind the limitations of laboratory research, the consumption of acidic drinks after fluoride varnish application should be avoided to optimize the benefit/risk ratio.

Urinary fluoride as a monitoring tool for assessing successful intervention in the provision of safe drinking water supply in five fluoride-affected villages in Dhar district, Madhya Pradesh, India.

PubMed

Srikanth, R; Gautam, Anil; Jaiswal, Suresh Chandra; Singh, Pavitra

2013-03-01

Endemic fluorosis was detected in 31 villages in the Dhar district of Madhya Pradesh, Central India. Out of the 109 drinking water sources that were analyzed, about 67 % were found to contain high concentration of fluoride above the permissible level of 1.0 mg/l. Dental fluorosis among the primary school children in the age between 8 and 15 served as primary indicator for fluoride intoxication among the children. Urinary fluoride levels among the adults were found to be correlated with drinking water fluoride in 10 villages affected by fluoride. Intervention in the form of alternate safe water supply in five villages showed significant reduction in the urinary fluoride concentration when compared to the control village. Urinary fluoride serves as an excellent marker for assessing the effectiveness of intervention program in the fluoride-affected villages.

Isothermal vapor-liquid equilibria for the systems 1-chloro-1,1-difluoroethane + hydrogen fluoride, 1,1-dichloro-1-fluoroethane + hydrogen fluoride, and chlorodifluoromethane + hydrogen fluoride

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Y.W.; Lee, Y.Y.

1997-03-01

Isothermal vapor-liquid equilibria for the three binary systems (1-chloro-1,1-difluoroethane + hydrogen fluoride, 1,1-dichloro-1-fluoroethane + hydrogen fluoride, and chlorodifluoromethane + hydrogen fluoride) have been measured. The experimental data for the binary systems are correlated with the NRTL equation with the vapor-phase association model for the mixtures containing hydrogen fluoride, and the relevant parameters are presented. All of the systems form minimum boiling heterogeneous azeotropes.

Community effectiveness of public water fluoridation in reducing children's dental disease.

PubMed

Armfield, Jason Mathew

2010-01-01

Water fluoridation is one of the most effective public health programs of the past century. However, efforts to extend water fluoridation into currently non-fluoridated areas are often thwarted. Despite considerable evidence regarding the effectiveness of water fluoridation at an individual level, published national community-based studies are rare. This study compared children's decay experience and prevalence between areas with and without water fluoridation in Australia. Oral health data were obtained from clinical examinations of 128, 990 5- to 15-year-old children attending for a regular visit with their respective Australian state or territory School Dental Service in 2002. Water fluoridation status, residence remoteness, and socioeconomic status (SES) were obtained for each child's recorded residential postcode area. Children from every age group had greater caries prevalence and more caries experience in areas with negligible fluoride concentrations in the water (<0.3 parts per million [ppm]) than in optimally fluoridated areas (> or = 0.7 ppm). Controlling for child age, residential location, and SES, deciduous and permanent caries experience was 28.7% and 31.6% higher, respectively, in low-fluoride areas compared with optimally fluoridated areas. The odds ratios for higher caries prevalence in areas with negligible fluoride compared with optimal fluoride were 1.34 (95% confidence interval [CI] 1.29, 1.39) and 1.24 (95% CI 1.21, 1.28) in the deciduous and permanent dentitions, respectively. This study demonstrates the continued community effectiveness of water fluoridation and provides support for the extension of this important oral health intervention to populations currently without access to fluoridated water.

Fluoride-releasing restorative materials and secondary caries.

PubMed

Hicks, John; Garcia-Godoy, Franklin; Donly, Kevin; Flaitz, Catherine

2003-03-01

Secondary caries is responsible for 60 percent of all replacement restorations in the typical dental practice. Risk factors for secondary caries are similar to those for primary caries development. Unfortunately, it is not possible to accurately predict which patients are at risk for restoration failure. During the past several decades, fluoride-releasing dental materials have become a part of the dentist's armamentarium. Considerable fluoride is released during the setting reaction and for periods up to eight years following restoration placement. This released fluoride is readily taken up by the cavosurface tooth structure, as well as the enamel and root surfaces adjacent to the restoration. Resistance against caries along the cavosurface and the adjacent smooth surface has been shown in both in vitro and in vivo studies. Fluoride-releasing dental materials provide for improved resistance against primary and secondary caries in coronal and root surfaces. Plaque and salivary fluoride levels are elevated to a level that facilitates remineralization. In addition, the fluoride released to dental plaque adversely affects the growth of lactobacilli and mutans streptococci by interference with bacterial enzyme systems. Fluoride recharging of these dental materials is readily achieved with fluoridated toothpastes, fluoride mouthrinses, and other sources of topical fluoride. This allows fluoride-releasing dental materials to act as intraoral fluoride reservoirs. The improvement in the properties of dental materials with the ability to release fluoride has improved dramatically in the past decade, and it is anticipated that in the near future the vast majority of restorative procedures will employ fluoride-releasing dental materials as bonding agents, cavity liners, luting agents, adhesives for orthodontic brackets, and definitive restoratives.

Prevalence of fluorosis and identification of fluoride endemic areas in Manur block of Tirunelveli District, Tamil Nadu, South India

NASA Astrophysics Data System (ADS)

Gopalakrishnan, Subarayan Bothi; Viswanathan, Gopalan; Siva Ilango, S.

2012-12-01

Prevalence of fluorosis is mainly due to the consumption of more fluoride through drinking water. It is necessary to identify the fluoride endemic areas to adopt remedial measures for the people under the risk of fluorosis. The objectives of this study were to identify the exact location of fluoride endemic areas in Manur block of Tirunelveli District and to estimate fluoride exposure level through drinking water for different age groups. Identification of fluoride endemic areas was performed through Isopleth and Google earth mapping techniques. Fluoride level in drinking water samples was estimated by fluoride ion selective electrode method. A systematic clinical survey conducted in 19 villages of Manur block revealed the rate of prevalence of fluorosis. From this study, it has been found that Alavanthankulam, Melapilliyarkulam, Keezhapilliyarkulam, Nadupilliyarkulam, Keezhathenkalam and Papankulam are the fluoride endemic villages, where the fluoride level in drinking water is above 1 mg/l. Consumption of maximum fluoride exposure levels of 0.30 mg/kg/day for infants, 0.27 mg/kg/day for children and 0.15 mg/kg/day for adults were found among the respective age group people residing in high fluoride endemic area. As compared with adequate intake level of fluoride of 0.01 mg/kg/day for infants and 0.05 mg/kg/day for other age groups, the health risk due to excess fluoride intake to the people of Alavanthankulam and nearby areas has become evident. Hence the people of these areas are advised to consume drinking water with optimal fluoride to avoid further fluorosis risks.

In Vitro Inhibition of Enamel Demineralisation by Fluoride-releasing Restorative Materials and Dental Adhesives.

PubMed

Dionysopoulos, Dimitrios; Koliniotou-Koumpia, Eugenia; Helvatzoglou-Antoniades, Maria; Kotsanos, Nikolaos

2016-01-01

To determine the ability of 5 contemporary fluoride-releasing restoratives and 3 fluoride-releasing adhesives to inhibit enamel demineralisation surrounding restorations, and the associations between inhibition and the levels of fluoride released from these materials. Five fluoride-releasing restoratives (Fuji IX GP, Ketac N100, Dyract Extra, Beautifil II and Wave) and 3 fluoride-releasing adhesives (Stae, Prime & Bond NT and Fluoro Bond II) were investigated. Eight disks of each material were prepared. Fluoride release was measured daily using a fluoride-ion-selective electrode for 15 days. Twenty-four cavities for each group were restored with a restorative and an adhesive. Specimens were subjected to thermal stress and stored for 30 days in saline solution. After a 15-day pH-cycling regimen, two 150-μm-thick sections were derived from each specimen. Enamel lesion depth was measured at 0, 100, and 200 μm from each restoration's margin via polarised light microscopy. Of the restoratives investigated, Fuji IX GP released the most fluoride. The fluoride-releasing restoratives tested exhibited shallower enamel lesions than did the control group at all distances tested (p < 0.05). Fuji IX GP yielded significantly lower enamel lesion depth than did the other experimental materials. The depths of enamel lesions did not differ significantly when comparing restoratives applied with a fluoride-releasing adhesive with those applied with a non-fluoride-releasing adhesive. The fluoride-releasing materials tested reduced enamel demineralisation but to different extents, depending on their levels of fluoride release. Fluoride-releasing adhesives did not influence enamel lesion formation.

Alimentary fluoride intake in preschool children

PubMed Central

2011-01-01

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. These results showed that in preschool children, when trying to maximize the benefit of fluoride in caries prevention and to minimize its risk, caution should be exercised when giving advice on the fluoride containing components of child's diet or prescribing fluoride supplements. PMID:21974798

Effects of oral doses of fluoride on nestling European starlings

USGS Publications Warehouse

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.

PTH (1-34) affects bone turnover governed by osteocytes exposed to fluoride.

PubMed

Yu, Xiuhua; Yu, Haolan; Jiang, Ningning; Zhang, Xiuyun; Zhang, Mengmeng; Xu, Hui

2018-05-15

Exposure to fluoride from environmental sources remains an overlooked, but serious public health risk. In this study, we looked into the role osteocytes play on the mechanism underlying fluoride induced osteopathology. We analyzed bone formation and resorption related genes generated by osteocytes that were exposed to varied doses of fluoride with and without PTH in vitro. Correspondingly, osteogenesis and osteoclastogenesis related genes were also investigated in rats exposed to fluoride for 8 weeks, and the PTH(1-34)was applied at the last 3 weeks to observe its role in regulating bone turnover upon fluoride treatment. The data in vitro indicated that fluoride treatment inhibited Sost expression of mRNA and protein and stimulated RANKL mRNA protein expression as well as the RANKL/OPG ratio in the primary osteocytes. Single PTH treatment played the similar role on expression of these genes and proteins. The PTH combined administration enhanced the action of fluoride treatment on RNAKL/OPG and SOST/Sclerostin. The up-regulation of RANKL and decreasing of Sost induced by fluoride and/or PTH treatment was validated in vivo and suggests that osteocytes are a major source of RANKL and Sost, both of which play essential roles in fluoride affecting osteogenesis and osteoclastogenesis. Expression of Wnt/β-catenin was up-regulated in both in vitro osteocytes treated with high dose of fluoride and bone tissue of rats in the presence of fluoride and PTH. In vivo, fluoride and single PTH stimulated bone turnover respectively, furthermore, PTH combined with low dose of fluoride treatment reinforced the osteogenesis and osteoclastogenesis genes expression, however, co-treatment of PTH reversed the effect of high dose of fluoride on osteogenesis and osteoclastogenensis related factors. In conclusion, this study demonstrated that osteocytes play a key role in fluoride activated bone turnover, and PTH participates in the process of fluoride modulating SOST/Sclerostin and RANKL expression. Copyright © 2018 Elsevier B.V. All rights reserved.

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

PubMed

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

2015-11-19

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 taking a 1-mg Fluoride tablet. After no, light, moderate and vigorous exercise, respectively, the mean (SD) baseline-adjusted i) plasma fluoride concentration was 9.6(6.3), 11.4(6.3), 15.6(7.7) and 14.9(10.0) ng/ml; ii) rate of urinary fluoride excretion over 0-8 h was 46(15), 44(22), 34(17) and 36(17) μg/h; and iii) rate of fluoride renal clearance was 26.5(9.0), 27.2(30.4), 13.1(20.4) and 18.3(34.9) ml/min. The observed trend of a rise in plasma fluoride concentration and decline in rate of fluoride renal clearance with increasing exercise intensity needs to be investigated in a larger trial. This study, which provides the first data on the effect of exercise with different intensities on fluoride metabolism in humans, informs sample size planning for any subsequent definitive trial, by providing a robust estimate of the variability of the effect.

Fluoride metabolism.

PubMed

Buzalaf, Marília Afonso Rabelo; Whitford, Gary Milton

2011-01-01

Knowledge of all aspects of fluoride metabolism is essential for comprehending the biological effects of this ion in humans as well as to drive the prevention (and treatment) of fluoride toxicity. Several aspects of fluoride metabolism - including gastric absorption, distribution and renal excretion - are pH-dependent because the coefficient of permeability of lipid bilayer membranes to hydrogen fluoride (HF) is 1 million times higher than that of F(-). This means that fluoride readily crosses cell membranes as HF, in response to a pH gradient between adjacent body fluid compartments. After ingestion, plasma fluoride levels increase rapidly due to the rapid absorption from the stomach, an event that is pH-dependent and distinguishes fluoride from other halogens and most other substances. The majority of fluoride not absorbed from the stomach will be absorbed from the small intestine. In this case, absorption is not pH-dependent. Fluoride not absorbed will be excreted in feces. Peak plasma fluoride concentrations are reached within 20-60 min following ingestion. The levels start declining thereafter due to two main reasons: uptake in calcified tissues and excretion in urine. Plasma fluoride levels are not homeostatically regulated and vary according to the levels of intake, deposition in hard tissues and excretion of fluoride. Many factors can modify the metabolism and effects of fluoride in the organism, such as chronic and acute acid-base disturbances, hematocrit, altitude, physical activity, circadian rhythm and hormones, nutritional status, diet, and genetic predisposition. These will be discussed in detail in this review. Copyright © 2011 S. Karger AG, Basel.

Superbugs on Duodenoscopes: the Challenge of Cleaning and Disinfection of Reusable Devices

PubMed Central

McDonnell, Gerald

2015-01-01

Inadequate flexible endoscope reprocessing has been associated with infection outbreaks, most recently caused by carbapenem-resistant Enterobacteriaceae. Lapses in essential device reprocessing steps such as cleaning, disinfection/sterilization, and storage have been reported, but some outbreaks have occurred despite claimed adherence to established guidelines. Recommended changes in these guidelines include the use of sterilization instead of high-level disinfection or the use of routine microbial culturing to monitor efficacy of reprocessing. This review describes the current standards for endoscope reprocessing, associated outbreaks, and the complexities associated with both microbiological culture and sterilization approaches to mitigating the risk of infection associated with endoscopy. PMID:26202125

Framework conditions and requirements to ensure the technical functional safety of reprocessed medical devices.

PubMed

Kraft, Marc

2008-09-03

Testing and restoring technical-functional safety is an essential part of medical device reprocessing. Technical functional tests have to be carried out on the medical device in the course of the validation of reprocessing procedures. These ensure (in addition to the hygiene tests) that the reprocessing procedure is suitable for the medical device. Functional tests are, however, also a part of reprocessing procedures. As a stage in the reprocessing, they ensure for the individual medical device that no damage or other changes limit the performance. When determining which technical-functional tests are to be carried out, the current technological standard has to be taken into account in the form of product-specific and process-oriented norms. Product-specific norms primarily define safety-relevant requirements. The risk management method described in DIN EN ISO 14971 is the basis for recognising hazards; the likelihood of such hazards arising can be minimised through additional technical-functional tests, which may not yet have been standardised. Risk management is part of a quality management system, which must be bindingly certified for manufacturers and processors of critical medical devices with particularly high processing demands by a body accredited by the competent authority.

Framework conditions and requirements to ensure the technical functional safety of reprocessed medical devices

PubMed Central

Kraft, Marc

2008-01-01

Testing and restoring technical-functional safety is an essential part of medical device reprocessing. Technical functional tests have to be carried out on the medical device in the course of the validation of reprocessing procedures. These ensure (in addition to the hygiene tests) that the reprocessing procedure is suitable for the medical device. Functional tests are, however, also a part of reprocessing procedures. As a stage in the reprocessing, they ensure for the individual medical device that no damage or other changes limit the performance. When determining which technical-functional tests are to be carried out, the current technological standard has to be taken into account in the form of product-specific and process-oriented norms. Product-specific norms primarily define safety-relevant requirements. The risk management method described in DIN EN ISO 14971 is the basis for recognising hazards; the likelihood of such hazards arising can be minimised through additional technical-functional tests, which may not yet have been standardised. Risk management is part of a quality management system, which must be bindingly certified for manufacturers and processors of critical medical devices with particularly high processing demands by a body accredited by the competent authority. PMID:20204095

[Fluoridation of drinking water, why is it needed?].

PubMed

Zusman, S P; Natapov, L; Ramon, T

2004-01-01

Dental caries is a widespread disease. It causes irreversible damage, pain and considerable expense. Fluoride is the only known substance that raises the tooth's resistance to acid attack. Natural drinking waters contain fluoride at different concentration. The most effective method of fluoride administration to the community level is by adjustng the fluoride concentration in the drinking water to about 1 part per million. To describe the mode of action of fluoride, methods of administration and to describe water fluoridation, advantages and disadvantages. Fluoridation of drinking water started in 1945 in the world and in 1981 in Israel. Today more then 300 million people in some 60 countries enjoy the defending effect of fluoride in drinking water. This is the most effective method for decreasing incidence of caries, as well as being cost effective. Over the years there were many attempts to 'blame' fluoridation with negative side effects to human health. Till today, none of the allegations passed scientific scrutiny. There is overwhelming scientific support for the Regulations that oblige the Water supplier to adjust fluoride levels to 1 ppm in every town or municipality with more then 5,000 inhabitants.

Community water fluoridation on the Internet and social media.

PubMed

Mertz, Aaron; Allukian, Myron

2014-01-01

In the United States, 95 percent of teens and 85 percent of adults use the Internet. Two social media outlets, Facebook and Twitter, reach more than 150 billion users. This study describes anti-fluoridation activity and dominance on the Internet and social media, both of which are community water fluoridation (CWF) information sources. Monthly website traffic to major fluoridation websites was determined from June 2011 to May 2012. Facebook, Twitter, and YouTube fluoridation activity was categorized as "proCWF" or "anti-CWF." Twitter's anti-CWF tweets were further subcategorized by the argument used against CWF. Anti-CWF website traffic was found to exceed proCWF activity five- to sixty-fold. Searching "fluoride" and "fluoridation" on Facebook resulted in 88 to 100 percent anti-CWF groups and pages; "fluoridation" on Twitter and YouTube resulted in 64 percent anti-CWF tweets and 99 percent anti-CWF videos, respectively. "Cancer, " "useless, " and "poisonous" were the three major arguments used against fluoridation. Anti-fluoridation information significantly dominates the Internet and social media. Thousands of people are being misinformed daily about the safety, health, and economic benefits of fluoridation.

The Impact of Fluoride on Ameloblasts and the Mechanisms of Enamel Fluorosis

PubMed Central

Bronckers, A.L.J.J.; Lyaruu, D.M.; DenBesten, P.K.

2009-01-01

Intake of excess amounts of fluoride during tooth development cause enamel fluorosis, a developmental disturbance that makes enamel more porous. In mild fluorosis, there are white opaque striations across the enamel surface, whereas in more severe cases, the porous regions increase in size, with enamel pitting, and secondary discoloration of the enamel surface. The effects of fluoride on enamel formation suggest that fluoride affects the enamel-forming cells, the ameloblasts. Studies investigating the effects of fluoride on ameloblasts and the mechanisms of fluorosis are based on in vitro cultures as well as animal models. The use of these model systems requires a biologically relevant fluoride dose, and must be carefully interpreted in relation to human tooth formation. Based on these studies, we propose that fluoride can directly affect the ameloblasts, particularly at high fluoride levels, while at lower fluoride levels, the ameloblasts may respond to local effects of fluoride on the mineralizing matrix. A new working model is presented, focused on the assumption that fluoride increases the rate of mineral formation, resulting in a greater release of protons into the forming enamel matrix. PMID:19783795

Assessment of fluoride-induced changes on physicochemical and structural properties of bone and the impact of calcium on its control in rabbits.

PubMed

Gopalakrishnan, Subarayan Bothi; Viswanathan, Gopalan

2012-03-01

Bone deformities caused by the chronic intake of large quantities of fluoride and the beneficial effect of calcium on its control have been studied for many years, but only limited data are available on the quantitative effect of fluoride intake and the beneficial impact of calcium on fluoride-induced changes in bone at the molecular level. It is necessary to determine the degree of fluoride-induced changes in bone at different levels of fluoride intake to evaluate the optimum safe intake level of fluoride for maintaining bone health and quality. The ameliorative effect of calcium at different dose levels on minimizing fluoride-induced changes in bone is important to quantify the amount of calcium intake necessary for reducing fluoride toxicity. Thirty rabbits, 2 months old, were divided into five groups. Group I animals received 1 mg/l fluoride and 0.11% calcium diet; groups II and III received 10 mg/l fluoride and diet with 0.11% or 2.11% calcium, respectively; and groups IV and V received 150 mg/l fluoride and diet with 2.11% or 0.11% calcium, respectively. Analysis of bone density, ash content, fluoride, calcium, phosphorus, and Ca:P molar ratio levels after 6 months of treatment indicated that animals that received high fluoride with low-calcium diet showed significant detrimental changes in physicochemical properties of bone. Animals that received fluoride with high calcium intake showed notable amelioration of the impact of calcium on fluoride-induced changes in bone. The degree of fluoride-induced characteristic changes in structural properties such as crystalline size, crystallinity, and crystallographic "c"-axis length of bone apatite cells was also assessed by X-ray diffraction and Fourier transform infrared studies. X-ray images showed bone deformity changes such as transverse stress growth lines, soft tissue ossification, and calcification in different parts of bones as a result of high fluoride accumulation and the beneficial role of calcium intake on its control.

Water fluoridation: a critical review of the physiological effects of ingested fluoride as a public health intervention.

PubMed

Peckham, Stephen; Awofeso, Niyi

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 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.

Effect of fluoride on growth and acid production by Streptococcus mutans in dental plaque.

PubMed Central

van der Hoeven, J S; Franken, H C

1984-01-01

The aim of this study was to measure the effect of fluoride on the production of organic acids by Streptococcus mutans in dental plaque. The effect was studied in a simplified model of dental plaque with gnotobiotic rats monoinfected with S. mutans Ny341. Adaptation of S. mutans to fluoride was induced by feeding one group of the rats on fluoride-containing diet and drinking water. No difference was found in the accumulation of S. mutans on the teeth between the fluoride-adapted and the control groups. However, there was a significant difference in the amount of lactic acid in metabolically resting plaque between the groups, lactic acid being lower in the fluoride-adapted plaque. At 5 min after a rinse containing 10% sucrose, a high level of lactic acid was found in plaque from animals not exposed to fluoride. Rinses containing 4 or 20 mM fluoride before the sucrose rinse significantly inhibited the lactic acid production in the control group. In the plaque from rats on fluoridated diet and drinking water the sucrose-induced production of lactic acid was not inhibited by a 4 mM fluoride rinse. Moreover, the production of lactic acid in the fluoride-adapted plaque was prolonged. The results indicate that due to fluoride adaptation the inhibition of acid production is unlikely to be important for the caries-preventive action of fluoride. PMID:6746094

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

PubMed Central

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 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. PMID:24719570

Chemico-therapeutic approach to prevention of dental caries. [using stannous fluoride gel

NASA Technical Reports Server (NTRS)

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.

Effects of fluoridated milk on root dentin remineralization.

PubMed

Arnold, Wolfgang H; Heidt, Bastian A; Kuntz, Sebastian; Naumova, Ella A

2014-01-01

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.

Evaluation of salivary fluoride retention from a new high fluoride mouthrinse.

PubMed

Mason, Stephen C; Shirodaria, Soha; Sufi, Farzana; Rees, Gareth D; Birkhed, Dowen

2010-11-01

To evaluate salivary fluoride retention from a new high fluoride daily use mouthrinse over a 120 min period. Sixteen subjects completed a randomised single-blind, four-treatment cross-over trial. Sensodyne® Pronamel® mouthrinse (A) contained 450 ppm fluoride; reference products were Colgate® Fluorigard® (B), Listerine® Total Care (C) and Listerine Softmint Sensation (D) containing 225, 100 and 0 ppm fluoride respectively. Salivary fluoride retention was monitored ex vivo after a single supervised use of test product (10 mL, 60 s). Samples were collected at 0, 1, 3, 5, 15, 30, 60 and 120 min post-rinse, generating fluoride clearance curves from which the area under the curve (AUC) was calculated. Differences in salivary fluoride concentrations for each product were analysed using ANCOVA at each time point using a 5% significance level, as well as lnAUC for the periods 0-120, 0-1, 1-15, 15-60 and 60-120 min. Pairwise comparisons between all treatment groups were performed. Salivary fluoride levels for A-C peaked immediately following use. Fluoride levels were statistically significantly higher for A versus B-D (p≤ 0.004), linear dose responses were apparent. AUC(0-120) was statistically significantly greater for A than for B (p = 0.035), C (p< 0.0001) and D (p< 0.0001). Post-hoc comparisons of lnAUC for the remaining time domains showed fluoride retention from A was statistically significantly greater versus B-D (p< 0.0001). Single-use treatment with the new mouthrinse containing 450 ppm fluoride resulted in statistically significantly higher salivary fluoride levels throughout the 120 min test period. Total fluoride retention (AUC(0-120)) was also statistically significantly greater versus comparator rinse treatments. Copyright © 2010 Elsevier Ltd. All rights reserved.

Fluoride Increase in Saliva and Dental Biofilm due to a Meal Prepared with Fluoridated Water or Salt: A Crossover Clinical Study.

PubMed

Lima, Carolina V; Tenuta, Livia M A; Cury, Jaime A

2018-06-07

Knowledge about fluoride delivery to oral fluids from foods cooked with fluoridated water and salt is scarce, and no study has evaluated fluoride concentrations in saliva or biofilm during meal consumption. In this randomized double-blind crossover study, 12 volunteers ingested meals (rice, beans, meat, and legumes) prepared with nonfluoridated water and salt (control group), fluoridated water (0.70 mg F/L; water group), and fluoridated salt (183.7 mg F/kg; salt group). Whole saliva was collected before meal ingestion, during mastication, and up to 2 h after meal ingestion. Dental biofilm was collected before and immediately after meal ingestion. Fluoride concentrations in saliva and dental biofilm were determined by an ion-specific electrode. The mean (±standard deviation; n = 4) fluoride concentrations in meals prepared for the control, water, and salt groups were 0.039 ± 0.01, 0.43 ± 0.04, and 1.71 ± 0.32 μg F/g, respectively. The three groups had significantly different fluoride concentrations in saliva collected during mastication (p < 0.0001) and after meal ingestion (p < 0.04; salt > water > control). The fluoride concentration in saliva returned to baseline 30 min after meal ingestion in the water group but remained high for up to 2 h in the salt group (p = 0.002). The fluoride concentration in biofilm fluid differed only between the salt and control groups (p = 0.008). The mastication of foods cooked with fluoridated water and salt increases fluoride concentrations in oral fluids and may contribute to the local effect of these community-based fluoride interventions on caries control. © 2018 S. Karger AG, Basel.

Salt fluoridation and oral health.

PubMed

Marthaler, Thomas M

2013-11-01

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 caries-protective 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. 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. Copyright © 2013 by Academy of Sciences and Arts of Bosnia and Herzegovina.

Salt fluoridation--an alternative in automatic prevention of dental caries.

PubMed

Marthaler, T M; Petersen, P E

2005-12-01

Despite great improvements in terms of reduced prevalence and amount of dental caries in populations worldwide, problems still persist particularly among the underprivileged groups of both developed and developing countries. Research and practical experience gained in several countries have demonstrated however, that dental caries can be prevented effectively through establishment of fluoride programmes. Water fluoridation, salt fluoridation, milk fluoridation and use of affordable fluoridated toothpastes play the major roles in public health. The present paper outlines the relevance and some practical aspects in relation to implementation of salt fluoridation programmes. The World Health Organisation Oral Health Programme provides technical assistance to countries in the process of planning, implementing and evaluating salt fluoridation projects.

Fluoride’s Effects on the Formation of Teeth and Bones, and the Influence of Genetics

PubMed Central

Everett, E.T.

2011-01-01

Fluorides are present in the environment. Excessive systemic exposure to fluorides can lead to disturbances of bone homeostasis (skeletal fluorosis) and enamel development (dental/enamel fluorosis). The severity of dental fluorosis is also dependent upon fluoride dose and the timing and duration of fluoride exposure. Fluoride’s actions on bone cells predominate as anabolic effects both in vitro and in vivo. More recently, fluoride has been shown to induce osteoclastogenesis in mice. Fluorides appear to mediate their actions through the MAPK signaling pathway and can lead to changes in gene expression, cell stress, and cell death. Different strains of inbred mice demonstrate differential physiological responses to ingested fluoride. Genetic studies in mice are capable of identifying and characterizing fluoride-responsive genetic variations. Ultimately, this can lead to the identification of at-risk human populations who are susceptible to the unwanted or potentially adverse effects of fluoride action and to the elucidation of fundamental mechanisms by which fluoride affects biomineralization. PMID:20929720

Is the fluoride intake by diet and toothpaste in children living in tropical semi-arid city safe?

PubMed

Oliveira, Priscila Ferreira Torres de; Cury, Jaime Aparecido; Lima, Carolina Veloso; Vale, Glauber Campos; Lima, Marina de Deus Moura de; Moura, Lúcia de Fátima Almeida de Deus; Moura, Marcoeli Silva de

2018-01-01

Data about total fluoride intake in children living in a tropical semi-arid climate city is scarce, thus we conducted this study. Fifty-eight children aged two to five years, living in a Brazilian tropical city with optimally fluoridated water were selected. Dietary samples were collected using the duplicate diet method on two non-consecutive days in the children's home toothpaste was determined by subtracting the amount of fluoride recovered after brushing from the amount placed on the toothbrush. The mean total dose (SD) of fluoride intake was 0.043(0.016) mg F·kg-1·d-1, with the major (60.6%) contribution from water. The factors associated with the ingestion of fluoride from toothpaste were fluoride concentration of the toothpaste (p = 0.03) and the use of kids toothpaste (p = 0.02). The findings suggest that children have a low fluoride intake, measured by at-home meals and use of fluoride toothpaste; drinking water is the main source of fluoride ingestion.

Sodium trimetaphosphate enhances the effect of 250 p.p.m. fluoride toothpaste against enamel demineralization in vitro.

PubMed

Missel, Emilene M C; Cunha, Robson F; Vieira, Ana E M; Cruz, Nathália V S; Castilho, Flavia C N; Delbem, Alberto C B

2016-08-01

This in vitro study investigated the effect of sodium trimetaphosphate (TMP), added to toothpaste containing 250 p.p.m. fluoride, on enamel demineralization. Bovine enamel blocks (n = 96) were subjected to five pH cycles over a 7-d period and treatment with suspensions of toothpastes containing 0, 250, 500, and 1,100 p.p.m. fluoride (as sodium fluoride), as well as with 250 p.p.m. fluoride containing TMP at 0.25, 0.5, 1.0, and 3.0%. Treatment with toothpaste suspensions was performed under agitation twice a day, for 1 min. Surface and cross-sectional hardness, and fluoride firmly bound to enamel, were quantified. Data were subjected to one-way anova, followed by Tukey's test. Low-fluoride toothpastes containing TMP at 0.25-1.0% resulted in enamel mineral loss similar to that seen for the toothpaste containing 1,100 p.p.m. fluoride. Also, the addition of TMP to the toothpaste containing 250 p.p.m. fluoride promoted enamel fluoride concentrations similar to those obtained for the 500 p.p.m. fluoride group. The toothpaste containing 250 p.p.m. fluoride and 0.25% TMP led to the lowest mineral loss among all groups. It was concluded that the addition of as little as 0.25% TMP to a toothpaste containing 250 p.p.m. fluoride can reduce enamel demineralization to levels similar to those seen for a conventional toothpaste containing 1,100 p.p.m. fluoride, in vitro. © 2016 Eur J Oral Sci.

Fluoride concentration in dentine as a biomarker of fluoride intake in European roe deer (Capreolus capreolus) - an electron-microprobe study.

PubMed

Richter, Heiko; Kierdorf, Uwe; Richards, Alan; Melcher, Frank; Kierdorf, Horst

2011-08-01

Fluoride concentration in dentine has been recommended as the best marker for the level of chronic fluoride intake and the most suitable indicator of an individual's total body burden of fluoride. We analysed fluoride concentrations in the dentine of cheek teeth of European roe deer from fluoride-polluted habitats to retrospectively assess the level of fluoride uptake into the tissue. Thereby, we tested the hypothesis of the existence of mechanisms that limit fluoride intake of individuals and fluoride exposure of forming dental hard tissues during the late foetal and early postnatal periods in the species. Using electron-microprobe analysis, fluoride profiles were obtained on sectioned P(4)s, M(1)s, and M(3)s from individuals exhibiting pronounced dental fluorosis. Fluoride concentrations were compared between early formed (peripheral) and late-formed (juxtapulpal) dentine both within single teeth and amongst the three different teeth studied. Peripheral dentine of the M(1), which is formed during the late foetal and early postnatal periods, exhibited markedly lower fluoride concentrations than juxtapulpal dentine of the same tooth and both, peripheral and juxtapulpal dentine of P(4) and M(3) that are formed post-weaning. Our study provides strong support for the hypothesis that in the European roe deer the prenatal and early postnatal (pre-weaning) stages of dental development are (largely) protected against exposure to excess fluoride. This is attributed to the operation of certain protective mechanisms during these periods. Copyright © 2011 Elsevier Ltd. All rights reserved.

Critical factors determining fluoride concentration in tea leaves produced from Anhui province, China.

PubMed

Cai, Huimei; Zhu, Xiaohui; Peng, Chuanyi; Xu, Wei; Li, Daxiang; Wang, Yijun; Fang, Shihui; Li, Yeyun; Hu, Shaode; Wan, Xiaochun

2016-09-01

This study investigated the fluoride present in tea plants (Camellia sinensis (L.) O. Kuntze) and its relationship to soils, varieties, seasons and tea leaf maturity. The study also explored how different manufacturing processes affect the leaching of fluoride into tea beverages. The fluoride concentration in the tea leaves was significantly correlate to the concentration of water-soluble fluoride in the soil. Different tea varieties accumulated different levels of fluoride, with varieties, Anji baicha having the highest and Nongkang zao having the lowest fluoride concentration. In eight different varieties of tea plant harvested over three tea seasons, fluoride concentration were highest in the summer and lowest in the spring in china. The fluoride concentration in tea leaves was directly related to the maturity of the tea leaves at harvest. Importantly, the tea manufacturing process did not introduced fluoride contamination. The leaching of fluoride was 6.8% and 14.1% higher in black and white tea, respectively, than in fresh tea leaves. The manufacturing step most affecting the leaching of fluoride into tea beverage was withering used in white, black and oolong tea rather than rolling or fermentation. The exposure and associated health risks for fluoride concentration in infusions of 115 commercially available teas from Chinese tea markets was determined. The fluoride concentration ranged from 5.0 to 306.0mgkg(-1), with an average of 81.7mgkg(-1). The hazard quotient (HQ) of these teas indicated that there was no risk of fluorosis from drinking tea, based on statistical analysis by Monte Carlo simulation. Copyright © 2016 Elsevier Inc. All rights reserved.

Fluoride exposure and indicators of thyroid functioning in the Canadian population: implications for community water fluoridation

PubMed Central

Barberio, Amanda M; Hosein, F Shaun; Quiñonez, Carlos; McLaren, Lindsay

2017-01-01

Background There are concerns that altered thyroid functioning could be the result of ingesting too much fluoride. Community water fluoridation (CWF) is an important source of fluoride exposure. Our objectives were to examine the association between fluoride exposure and (1) diagnosis of a thyroid condition and (2) indicators of thyroid functioning among a national population-based sample of Canadians. Methods We analysed data from Cycles 2 and 3 of the Canadian Health Measures Survey (CHMS). Logistic regression was used to assess associations between fluoride from urine and tap water samples and the diagnosis of a thyroid condition. Multinomial logistic regression was used to examine the relationship between fluoride exposure and thyroid-stimulating hormone (TSH) level (low/normal/high). Other available variables permitted additional exploratory analyses among the subset of participants for whom we could discern some fluoride exposure from drinking water and/or dental products. Results There was no evidence of a relationship between fluoride exposure (from urine and tap water) and the diagnosis of a thyroid condition. There was no statistically significant association between fluoride exposure and abnormal (low or high) TSH levels relative to normal TSH levels. Rerunning the models with the sample constrained to the subset of participants for whom we could discern some source(s) of fluoride exposure from drinking water and/or dental products revealed no significant associations. Conclusion These analyses suggest that, at the population level, fluoride exposure is not associated with impaired thyroid functioning in a time and place where multiple sources of fluoride exposure, including CWF, exist. PMID:28839078

[Effect of fluoride on human hypothalamus-hypophysis-testis axis hormones].

PubMed

Hao, Pengfei; Ma, Xiaoying; Cheng, Xuemin; Ba, Yue; Zhu, Jingyuan; Cui, Liuxin

2010-01-01

To study of endocrine disturbing effect of fluoride on human hypothalamus-hypophysis-testis axis hormones. Sunying County, Kaifeng City was selected as polluted district which the fluoride in drinking water was 3.89 mg/L, and Shenlilou county was selected as control district which the fluoride was less than 1.0 mg/L. 150 individual lived there more than 5 years were srlected randomly. And investigated by medical examination, then blood and urine sample were collected, and the serum level of gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), testosterone (T) and estradiol (E2) were measured by RIA method, and the urine level of fluoride were measured. Other than that, the concentration of fluoride in the water, food, soil and air were detected by the standard methods. The concentrations of fluoride in the water, food and soil of the fluoride polluted district were significantly higher than those of control district (P < 0.05), and the concentration fluoride in the air of two district were not found. There was no significant difference of serum level of GnRH between fluoride polluted district and control district (P > 0.05). The serum level of LH in men of fluoride polluted district was significantly higher than that of control group (P < 0.05), and the serum level of T in men of fluoride polluted district was significantly less than that of control group (P < 0.05). There was no significant difference of serum level of LH between fluoride polluted district and control district (P > 0.05), and the serum level of T in women of fluoride polluted district was significantly higher than that of control group (P < 0.05). There was no significant difference of serum level of E2 between fluoride polluted district and control district (P > 0.05). Fluoride could effect hormone levels of each layer of the hypothalamus-hypophysis-testis axis, and show the reproductive endocrine disturbing effects. The reproductive endocrine disturbing effects of male maybe more severe than those of female.

49 CFR 173.163 - Hydrogen fluoride.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 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 in...

49 CFR 173.163 - Hydrogen fluoride.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 2 2012-10-01 2012-10-01 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 in...

49 CFR 173.163 - Hydrogen fluoride.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 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 in...

FLUORIDATION CHEMISTRY: EQUILIBRIA AND KINETICS OF FLUORIDE AND FLUORO-COMPLEXES

EPA Science Inventory

The most common fluoridating agents used by major American waterworks are hexafluorosilicic acid (H2SiF6) and sodium hexxafluorosilicate (Na2SiF6). According to the 1992 Water Fluoridation Census where 10,002 utilities responded affirmatively to fluoridating their water, 59
% ...

49 CFR 173.163 - Hydrogen fluoride.

Code of Federal Regulations, 2010 CFR

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 in...

49 CFR 173.163 - Hydrogen fluoride.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 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 in...

Dissolution of bulk specimens of silicon nitride

NASA Technical Reports Server (NTRS)

Davis, W. F.; Merkle, E. J.

1981-01-01

An accurate chemical characterization of silicon nitride has become important in connection with current efforts to incorporate components of this material into advanced heat engines. However, there are problems concerning a chemical analysis of bulk silicon nitride. Current analytical methods require the pulverization of bulk specimens. A pulverization procedure making use of grinding media, on the other hand, will introduce contaminants. A description is given of a dissolution procedure which overcomes these difficulties. It has been found that up to at least 0.6 g solid pieces of various samples of hot pressed and reaction bonded silicon nitride can be decomposed in a mixture of 3 mL hydrofluoric acid and 1 mL nitric acid overnight at 150 C in a Parr bomb. High-purity silicon nitride is completely soluble in nitric acid after treatment in the bomb. Following decomposition, silicon and hydrofluoric acid are volatilized and insoluble fluorides are converted to a soluble form.

Flexible thin-film battery based on solid-like ionic liquid-polymer electrolyte

NASA Astrophysics Data System (ADS)

Li, Qin; Ardebili, Haleh

2016-01-01

The development of high-performance flexible batteries is imperative for several contemporary applications including flexible electronics, wearable sensors and implantable medical devices. However, traditional organic liquid-based electrolytes are not ideal for flexible batteries due to their inherent safety and stability issues. In this study, a non-volatile, non-flammable and safe ionic liquid (IL)-based polymer electrolyte film with solid-like feature is fabricated and incorporated in a flexible lithium ion battery. The ionic liquid is 1-Ethyl-3-methylimidazolium dicyanamide (EMIMDCA) and the polymer is composed of poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP). The electrolyte exhibits good thermal stability (i.e. no weight loss up to 300 °C) and relatively high ionic conductivity (6 × 10-4 S cm-1). The flexible thin-film lithium ion battery based on solid-like electrolyte film is encapsulated using a thermal-lamination process and demonstrates excellent electrochemical performance, in both flat and bent configurations.

Combined orbits and clocks from IGS second reprocessing

NASA Astrophysics Data System (ADS)

Griffiths, Jake

2018-05-01

The Analysis Centers (ACs) of the International GNSS Service (IGS) have reprocessed a large global network of GPS tracking data from 1994.0 until 2014.0 or later. Each AC product time series was extended uniformly till early 2015 using their weekly operational IGS contributions so that the complete combined product set covers GPS weeks 730 through 1831. Three ACs also included GLONASS data from as early as 2002 but that was insufficient to permit combined GLONASS products. The reprocessed terrestrial frame combination procedures and results have been reported already, and those were incorporated into the ITRF2014 multi-technique global frame released in 2016. This paper describes the orbit and clock submissions and their multi-AC combinations and assessments. These were released to users in early 2017 in time for the adoption of IGS14 for generating the operational IGS products. While the reprocessing goal was to enable homogeneous modeling, consistent with the current operational procedures, to be applied retrospectively to the full history of observation data in order to achieve a more suitable reference for geophysical studies, that objective has only been partially achieved. Ongoing AC analysis changes and a lack of full participation limit the consistency and precision of the finished IG2 products. Quantitative internal measures indicate that the reprocessed orbits are somewhat less precise than current operational orbits or even the later orbits from the first IGS reprocessing campaign. That is even more apparent for the clocks where a lack of robust AC participation means that it was only possible to form combined 5-min clocks but not the 30-s satellite clocks published operationally. Therefore, retrospective precise point positioning solutions by users are not recommended using the orbits and clocks. Nevertheless, the orbits do support long-term stable user solutions when used with network processing with either double differencing or explicit clock estimation. Among the main benefits of the reprocessing effort is a more consistent long product set to analyze for sources of systematic error and accuracy. Work to do that is underway but the reprocessing experience already points to a number of ways future IGS performance and reprocessing campaigns can be improved.

Fluoridation and Defluoridation. Training Module 2.230.2.77.

ERIC Educational Resources Information Center

McMullen, L. D.

This document is an instructional module package prepared in objective form for use by an instructor familiar with fluoridation and fluoride feeding equipment. Enclosed are objectives, an instructor guide, student handouts and transparency masters. The module considers the principles and purposes of fluoridation, methods of feeding fluoride,…

21 CFR 355.70 - Testing procedures for fluoride dentifrice drug products.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Testing procedures for fluoride dentifrice drug... Procedures § 355.70 Testing procedures for fluoride dentifrice drug products. (a) A fluoride dentifrice drug... tests: Enamel solubility reduction or fluoride enamel uptake. The testing procedures for these...

21 CFR 355.70 - Testing procedures for fluoride dentifrice drug products.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 5 2011-04-01 2011-04-01 false Testing procedures for fluoride dentifrice drug... Procedures § 355.70 Testing procedures for fluoride dentifrice drug products. (a) A fluoride dentifrice drug... tests: Enamel solubility reduction or fluoride enamel uptake. The testing procedures for these...

Design Manual: Removal of Fluoride from Drinking Water ...

EPA Pesticide Factsheets

This document is an updated version of the Design Manual: Removal of Fluoride from Drinking Water Supplies by Activated Alumina (Rubel, 1984). The manual is an in-depth presentation of the steps required to design and operate a fluoride removal plant using activated alumina (AA), which is a reliable and cost-effective process for treating excess fluoride from drinking water supplies. Design Manual on removing fluoride from drinking water to support the fluoride MCL - manual

Copper Mediated Fluorination of Aryl Iodides

PubMed Central

Fier, Patrick S.; Hartwig, John F.

2012-01-01

The synthesis of aryl fluorides has been a topic of considerable interest because of the importance of aryl fluorides in pharmaceuticals, agrochemicals and materials. The stability, reactivity and biological properties of aryl fluorides can be distinct from those of the corresponding arenes. Methods for the synthesis of aryl fluorides, however, are limited. We report the conversion of a diverse set of aryl iodides to the corresponding aryl fluorides. This reaction occurs with a cationic copper reagent and silver fluoride. Preliminary results suggest this reaction is enabled by a facile reductive elimination from a cationic aryl copper(III) fluoride. PMID:22709145

Fluoride Binding to Dental Biofilm Bacteria: Synergistic Effect with Calcium Questioned.

PubMed

Nóbrega, Diego Figueiredo; Leitão, Tarcísio Jorge; Cury, Jaime Aparecido; Tenuta, Livia Maria Andaló

2018-06-06

It has been suggested that fluoride binding to dental biofilm is enhanced when more bacterial calcium binding sites are available. However, this was only observed at high calcium and fluoride concentrations (i.e., when CaF2 precipitation may have occurred). We assessed fluoride binding to Streptococcus mutans pellets treated with calcium and fluoride at concentrations allowing CaF2 precipitation or not. Increasing calcium concentration resulted in a linear increase (p < 0.01) in fluoride concentration only in the pellets in which CaF2 precipitated. The results suggest that CaF2 precipitation, rather than bacterially bound fluoride, is responsible for the increase in fluoride binding to dental biofilm with the increase in calcium availability. © 2018 S. Karger AG, Basel.

Small Molecule Fluoride Toxicity Agonists

PubMed Central

Nelson1, James W.; Plummer, Mark S.; Blount, Kenneth F.; Ames, Tyler D.; Breaker, Ronald R.

2015-01-01

SUMMARY Fluoride is a ubiquitous anion that inhibits a wide variety of metabolic processes. Here we report the identification of a series of compounds that enhance fluoride toxicity in Escherichia coli and Streptococcus mutans. These molecules were isolated by using a high-throughput screen (HTS) for compounds that increase intracellular fluoride levels as determined via a fluoride riboswitch-reporter fusion construct. A series of derivatives were synthesized to examine structure-activity relationships, leading to the identification of compounds with improved activity. Thus, we demonstrate that small molecule fluoride toxicity agonists can be identified by HTS from existing chemical libraries by exploiting a natural fluoride riboswitch. In addition, our findings suggest that some molecules might be further optimized to function as binary antibacterial agents when combined with fluoride. PMID:25910244

Corrosion Behavior of Titanium Grade 7 in Fluoride-Containing NaCl Brines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lian, T; Whalen, M T; Wong, L

2004-10-25

The effects of fluoride on the corrosion behavior of Titanium Grade 7 (0.12-0.25% Pd) have been investigated. Up to 0.1 mol/L fluoride was added to the NaCl brines at 95 C, and three pH values of 4, 8, and 11 were selected for studying pH dependence of fluoride effects. It was observed that fluoride significantly altered the anodic polarization behavior, at all three pH values of 4, 8, and 11. Under acidic condition fluoride caused active corrosion. The corrosion of Titanium grade 7 was increased by three orders of magnitude when a 0.1 mol/L fluoride was added to the NaClmore » brines at pH 4, and the Pd ennoblement effect was not observed in acidic fluoride-containing environments. The effects of fluoride were reduced significantly when pH was increased to 8 and above.« less

Global water fluoridation: what is holding us back?

PubMed

Botchey, Sally-Ann; Ouyang, Jing; Vivekanantham, Sayinthen

2015-01-01

Artificial water fluoridation was introduced more than 60 y ago as a public health intervention to control dental caries. Despite wide recommendations for its use from the World Health Organization (WHO) and studies showing the benefits of water fluoridation, many countries have opted out. Currently, only 25 countries, including the United Kingdom, the United States, and Australia have schemes for artificial water fluoridation. The issues faced in efforts to promote the global uptake of water fluoridation and the factors that affect the decision to implement it are unique in both developed and developing countries and must be explored. This article addresses the benefits and challenges of artificial water fluoridation. Further, it tackles the complexities faced with uptake of water fluoridation globally, such as ethical and political controversies and the use of alternative fluoride therapies. Potential future strategies to encourage the uptake of artificial water fluoridation are also discussed.

Controlling the fluoride dosage in a patient with compromised salivary function.

PubMed

Eichmiller, Frederick C; Eidelman, Naomi; Carey, Clifton M

2005-01-01

High-concentration topical fluorides are used commonly to with compromised salivary function due to irradiation and chemotherapy. The authors describe a 50-year-old man with previously treated cancer who was using tray-applied topical fluoride gel. He complained of gastric symptoms, difficulty in swallowing, leg muscle soreness and knee joint soreness. A computed tomographic scan revealed thickening of the esophageal walls. An upper endoscopy revealed abnormal motility. The motility test indicated high-amplitude peristalsis and hypertensive lower esophageal sphincter, and urine testing indicated high levels of systemic fluoride. The patient's fluoride regimen was altered, and within a short period his urinary fluoride levels returned to normal and his symptoms resolved. Clinicians prescribing home-applied high-concentration fluorides need to be cognizant of the symptoms of fluoride toxicity, carefully monitor the patient's compliance with the treatment regimen, and adjust the dosage or mode of application to control the total ingested dose of fluoride.

Water fluoridation and oral health.

PubMed

Harding, Máiréad Antoinette; O'Mullane, Denis Martin

2013-11-01

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. 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. Copyright © 2013 by Academy of Sciences and Arts of Bosnia and Herzegovina.

Fluoridation advocacy in Queensland: a long and winding road.

PubMed

Akers, Harry Francis; Foley, Michael Anthony

2012-10-01

By 1977, all Australian states and mainland territories, with the exception of Queensland, had widely implemented adjusted water fluoridation. This disparity in public health policy persisted until 2008. This study analyses the sociopolitical and socioeconomic backgrounds that underpinned the repeal of the Fluoridation of Public Water Supplies Act (1963) and its replacement with the Water Fluoridation Act (2008). The authors used a literature review and historic method. References are in the public domain. The devolution, without funding, of a discretionary local authority power to fluoridate contributed to the perennial low fluoridation status in Queensland. A window of opportunity for fluoridation advocates opened between 2003 and 2008. Now that 87% of Queenslanders have access to optimally fluoridated water, Queensland premier Anna Bligh has largely delivered on a promise made in 2007 to fluoridate water supplies across the state. The implementation of adjusted water fluoridation requires not only political stability and resolve, but also centralised authority. The last of these factors must embrace the decision, the funding and the indemnity. State control over water-related infrastructure and water treatment enhances prospects for fluoridation. The roles of opinion polls, internal advisers and departmental figures are also confirmed. Political repercussions were minimal. © 2012 FDI World Dental Federation.

Fluoride in drinking water and human urine in Southern Haryana, India.

PubMed

Singh, Bhupinder; Gaur, Shalini; Garg, V K

2007-06-01

The objective of this study was to determine the fluoride content in drinking water and urine samples of adolescent males aged 11-16 years living in Southern Haryana, India. A total of 30 drinking water sources in the studied habitations were assessed for fluoride contamination. Fluoride was estimated in the urine of 400 male children randomly selected from these habitations. The fluoride concentration in drinking water and urine samples was determined using USEPA fluoride ion selective electrode method. The mean fluoride concentration in drinking water samples of Pataudi, Haily Mandi and Harsaru villages was 1.68+/-0.35, 3.22+/-1.18 and 1.78+/-0.12 mg/l, respectively. The mean urinary fluoride concentration was 2.26+/-0.024 mg/l at Pataudi, 2.48+/-0.77 mg/l at Haily Mandi and 2.43+/-0.84 mg/l at Harsaru village. The higher fluoride levels in the urine of children may be associated to higher fluoride levels in drinking water. The accuracy of measurements was assessed with known addition method in water and urine. Mean fluoride recovery was 98.0 and 99.1% in water and urine. The levels obtained were reproducible with in +/-3% error limit.

Development of a sustained fluoride delivery system.

PubMed

Baturina, Olga; Tufekci, Eser; Guney-Altay, Ozge; Khan, Shadeed M; Wnek, Gary E; Lindauer, Steven J

2010-11-01

To develop a novel delivery system by which fluoride incorporated into elastomeric rings, such as those used to ligate orthodontic wires, will be released in a controlled and constant manner. Polyethylene co-vinyl acetate (PEVA) was used as the model elastomer. Samples (N = 3) were prepared by incorporating 0.02 to 0.4 g of sodium fluoride (NaF) into previously prepared PEVA solution. Another group of samples prepared in the same manner were additionally dip-coated in PEVA to create an overcoat. Fluoride release studies were conducted in vitro using an ion selective electrode over a period of 45 days. The amount of fluoride released was compared to the optimal therapeutic dose of 0.7 microg F(-)/ring/d. Only coated samples with the highest fluoride content (group D, 0.4 g of NaF) were able to release fluoride at therapeutic levels. When fluoride release from coated and uncoated samples with the same amount of NaF were compared, it was shown that the dip-coating technique resulted in a fluoride release in a controlled manner while eliminating the initial burst effect. This novel fluoride delivery matrix provided fluoride release at a therapeutically effective rate and profile.

Fluoride bioaccumulation by hydroponic cultures of camellia (Camellia japonica spp.) and sugar cane (Saccharum officinarum spp.).

PubMed

Camarena-Rangel, Nancy; Rojas Velázquez, Angel Natanael; Santos-Díaz, María del Socorro

2015-10-01

The ability of hydroponic cultures of camellia and sugar cane adult plants to remove fluoride was investigated. Plants were grown in a 50% Steiner nutrient solution. After an adaptation period to hydroponic conditions, plants were exposed to different fluoride concentrations (0, 2.5, 5 and 10 mg L(-1)). Fluoride concentration in the culture medium and in tissues was measured. In sugar cane, fluoride was mainly located in roots, with 86% of it absorbed and 14% adsorbed. Sugar cane plants removed 1000-1200 mg fluoride kg(-1) dry weight. In camellia plants the highest fluoride concentration was found in leaf. Roots accumulated fluoride mainly through absorption, which was 2-5 times higher than adsorption. At the end of the experiment, fluoride accumulation in camellia plants was 1000-1400 mgk g(-1) dry weight. Estimated concentration factors revealed that fluoride bioaccumulation is 74-221-fold in camellia plants and 100-500-fold in sugar cane plants. Thus, the latter appear as a suitable candidate for removing fluoride from water due to their bioaccumulation capacity and vigorous growth rate; therefore, sugar cane might be used for phytoremediation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of Fluoridated Miswak and Toothbrushing with Fluoridated Toothpaste on Plaque Removal and Fluoride Release.

PubMed

Baeshen, Hosam; Salahuddin, Sabin; Dam, Robel; Zawawi, Khalid H; Birkhed, Dowen

2017-04-01

Dental caries and periodontal diseases are all induced by oral biofilm (dental plaque). This study was conducted to evaluate if fluoride-impregnated miswak is as effective in plaque removal and fluoride release as toothbrushing with fluoride toothpaste. This single-blind, randomized, crossover study was conducted at the Department of Cariology, University of Gothenburg, Gothenburg, Sweden, from February 2010 to January 2011. Fifteen healthy subjects participated in this study. The participants were instructed to use the following: (1) 0.5% NaF-impregnated miswak, (2) nonfluoridated miswak, (3) toothbrush with nonfluoride toothpaste, and (4) toothbrush with 1450 ppm fluoride toothpaste. Each method was used twice a day for 1 week after which plaque amount and fluoride concentration in resting saliva were measured. There was a 1-week washout period between each method. No significant difference between miswak and tooth-brushing was found regarding plaque removal on buccal and lingual surfaces. A somewhat higher fluoride concentration in resting saliva was found after using impregnated miswak when compared with toothbrushing with fluoride toothpaste (p < 0.05). Miswak and toothbrushing showed the same plaque removing effect on buccal and lingual surfaces. Miswak impregnated with 0.5% NaF resulted in a higher concentration of fluoride in saliva than brushing with 1450 ppm fluoride toothpaste. Miswak impregnated with 0.5% NaF and toothbrushing results in comparable plaque removal and about the same fluoride concentration in saliva even it was somewhat higher for impregnated miswak.

Effect of fluoride exposure on mRNA expression of cav1.2 and calcium signal pathway apoptosis regulators in PC12 cells.

PubMed

Liao, Qiuxia; Zhang, Rui; Wang, Xiaoyu; Nian, Weiwei; Ke, Lulu; Ouyang, Wei; Zhang, Zigui

2017-09-01

This study investigated the effects of fluoride exposure on the mRNA expression of Cav1.2 calcium signaling pathway and apoptosis regulatory molecules in PC12 cells. The viability of PC12 cell receiving high fluoride (5.0mM) and low fluoride (0.5mM) alone or fluoride combined with L-type calcium channel (LTCC) agonist/inhibitor (5umol/L FPL6417/2umol/L nifedipine) was detected using cell counting kit-8 at different time points (2, 4, 6, 8, 12, 10, and 24h). Changes in the cell configuration were observed after exposing the cells to fluoride for 24h. The expression levels of molecules related to the LTCC were examined, particularly, Cav1.2, c-fos, CAMK II, Bax, and Bcl-2. Fluoride poisoning induced severe cell injuries, such as decreased PC12 cell activity, enhanced cell apoptosis, high c-fos, CAMKII, and Bax mRNA expression levels. Bcl-2 expression level was also reduced. Meanwhile, high fluoride, high fluoride with FPL64176, and low fluoride with FPL64176 enhanced the Cav1.2 expression level. In contrast, low fluoride, high fluoride with nifedipine, and low fluoride with nifedipine reduced the Cav1.2 expression level. Thus, Cav1.2 may be an important molecular target for the fluorosis treatment, and the LTCC inhibitor nifedipine may be an effective drug for fluorosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Study on fluoride emission from soils at high temperature related to brick-making process.

PubMed

Xie, Z M; Wu, W H; Xu, J M

2003-02-01

Characteristics of fluoride emission from 12 soils at temperatures of 400-1,100 degrees C related to the brick-making process were studied. The results obtained in this study indicate that fluoride emission as gaseous HF and SiF4 was related to the firing temperature, soil total fluoride content, soil composition and calcium compounds added to soils. Soils began to release fluoride at temperatures between 500 and 700 degrees C. Marked increases of the average fluoride mission rate from 57.2% to 85.4% of soil total fluoride were noticed as the heating temperature was increased from 700 to 1,100 degrees C. It was found that the major proportion (over 50%) of the soil total fluoride was emitted from soils at approximate 800 degrees C. The amount of fluoride released into the atmosphere when heated depended on the total fluoride contents in the soils. Correlation analysis showed that the soil composition, such as cation exchange capacity, exchangeable calcium and CaCO3, had some influence on fluoride emission below 900 degrees C, but had no influence at temperatures above 900 degrees C. Addition of four calcium compounds (CaO, CaCO3, Ca(OH)2, and CaSO4) at 1.5% by weight raised the temperature at which fluoride began to be released to 700 degrees C. The greatest decrease in fluoride emission among the four calcium compound treatments was found with CaCO3.

Fluoride penetration from toothpastes into incipient enamel erosive lesions investigated using dynamic secondary ion mass spectrometry.

PubMed

Fowler, C E; Gracia, L; Edwards, M I; Brown, A; Rees, G D

2009-01-01

The primary aim of this study was to assess the utility of dynamic secondary ion mass spectrometry (DSIMS) as a convenient and sensitive technique for determining fluoride uptake and distribution into incipient human enamel erosive lesions in vitro. A secondary aim was to correlate the extent of lesion rehardening following treatment with a toothpaste slurry, with relative fluoride uptake determined by DSIMS. The final aim was to compare fluoride uptake by incipient lesions treated with toothpastes containing different sources of fluoride using DSIMS. Relative fluoride uptake into the surface and body of enamel erosive lesions was monitored by DSIMS as a function of fluoride concentration in a series of formulation-matched experimental pastes. Fluoride uptake into lesions that had been subjected to treatment with different toothpaste slurries in a single-treatment enamel lesion rehardening model was also determined, and its relationship with regard to the extent of rehardening and also the fluoride source investigated. Fluoride uptake by incipient erosive lesions treated with toothpastes containing NaF was quantitatively compared by DSIMS and found to be directly proportional to the fluoride concentration over the studied range (0-1400 ppm). Lesion repair observed in a single-treatment lesion rehardening model was positively correlated with the extent of fluoride uptake by the treated lesions. DSIMS was also able to show differences between commercial toothpastes containing different sources of fluoride and their ability to deliver the fluoride into the body of the lesion. The detrimental effect of sodium hexametaphosphate (NaHMP) present in Crest Pro-Health formulations previously reported in the single-treatment lesion rehardening model was also evident from the DSIMS elemental line scans obtained from the lesion cross-sections. DSIMS has been shown to be a powerful selective technique for quantifying relative fluoride uptake into enamel erosive lesions, and determining the extent and depth of lesion penetration. The relative efficacy of toothpastes containing fluoride from a variety of sources in the single-treatment lesion rehardening study is positively correlated with fluoride uptake and penetration determined by DSIMS.

4-phenylbutyrate Mitigates Fluoride-Induced Cytotoxicity in ALC Cells

PubMed Central

Suzuki, Maiko; Everett, Eric T.; Whitford, Gary M.; Bartlett, John D.

2017-01-01

Chronic fluoride over-exposure during pre-eruptive enamel development can cause dental fluorosis. Severe dental fluorosis is characterized by porous, soft enamel that is vulnerable to erosion and decay. The prevalence of dental fluorosis among the population in the USA, India and China is increasing. Other than avoiding excessive intake, treatments to prevent dental fluorosis remain unknown. We previously reported that high-dose fluoride induces endoplasmic reticulum (ER) stress and oxidative stress in ameloblasts. Cell stress induces gene repression, mitochondrial damage and apoptosis. An aromatic fatty acid, 4-phenylbutyrate (4PBA) is a chemical chaperone that interacts with misfolded proteins to prevent ER stress. We hypothesized that 4PBA ameliorates fluoride-induced ER stress in ameloblasts. To determine whether 4PBA protects ameloblasts from fluoride toxicity, we analyzed gene expression of Tgf-β1, Bcl2/Bax ratio and cytochrome-c release in vitro. In vivo, we measured fluorosis levels, enamel hardness and fluoride concentration. Fluoride treated Ameloblast-lineage cells (ALC) had decreased Tgf-β1 expression and this was reversed by 4PBA treatment. The anti-apoptotic Blc2/Bax ratio was significantly increased in ALC cells treated with fluoride/4PBA compared to fluoride treatment alone. Fluoride treatment induced cytochrome-c release from mitochondria into the cytosol and this was inhibited by 4PBA treatment. These results suggest that 4PBA mitigates fluoride-induced gene suppression, apoptosis and mitochondrial damage in vitro. In vivo, C57BL/6J mice were provided fluoridated water for six weeks with either fluoride free control-chow or 4PBA-containing chow (7 g/kg 4PBA). With few exceptions, enamel microhardness, fluorosis levels, and fluoride concentrations of bone and urine did not differ significantly between fluoride treated animals fed with control-chow or 4PBA-chow. Although 4PBA mitigated high-dose fluoride toxicity in vitro, a diet rich in 4PBA did not attenuate dental fluorosis in rodents. Perhaps, not enough intact 4PBA reaches the rodent ameloblasts necessary to reverse the effects of fluoride toxicity. Further studies will be required to optimize protocols for 4PBA administration in vivo in order to evaluate the effect of 4PBA on dental fluorosis. PMID:28553235

4-phenylbutyrate Mitigates Fluoride-Induced Cytotoxicity in ALC Cells.

PubMed

Suzuki, Maiko; Everett, Eric T; Whitford, Gary M; Bartlett, John D

2017-01-01

Chronic fluoride over-exposure during pre-eruptive enamel development can cause dental fluorosis. Severe dental fluorosis is characterized by porous, soft enamel that is vulnerable to erosion and decay. The prevalence of dental fluorosis among the population in the USA, India and China is increasing. Other than avoiding excessive intake, treatments to prevent dental fluorosis remain unknown. We previously reported that high-dose fluoride induces endoplasmic reticulum (ER) stress and oxidative stress in ameloblasts. Cell stress induces gene repression, mitochondrial damage and apoptosis. An aromatic fatty acid, 4-phenylbutyrate (4PBA) is a chemical chaperone that interacts with misfolded proteins to prevent ER stress. We hypothesized that 4PBA ameliorates fluoride-induced ER stress in ameloblasts. To determine whether 4PBA protects ameloblasts from fluoride toxicity, we analyzed gene expression of Tgf -β 1, Bcl2 / Bax ratio and cytochrome-c release in vitro . In vivo , we measured fluorosis levels, enamel hardness and fluoride concentration. Fluoride treated Ameloblast-lineage cells (ALC) had decreased Tgf -β 1 expression and this was reversed by 4PBA treatment. The anti-apoptotic Blc2 / Bax ratio was significantly increased in ALC cells treated with fluoride/4PBA compared to fluoride treatment alone. Fluoride treatment induced cytochrome-c release from mitochondria into the cytosol and this was inhibited by 4PBA treatment. These results suggest that 4PBA mitigates fluoride-induced gene suppression, apoptosis and mitochondrial damage in vitro . In vivo , C57BL/6J mice were provided fluoridated water for six weeks with either fluoride free control-chow or 4PBA-containing chow (7 g/kg 4PBA). With few exceptions, enamel microhardness, fluorosis levels, and fluoride concentrations of bone and urine did not differ significantly between fluoride treated animals fed with control-chow or 4PBA-chow. Although 4PBA mitigated high-dose fluoride toxicity in vitro , a diet rich in 4PBA did not attenuate dental fluorosis in rodents. Perhaps, not enough intact 4PBA reaches the rodent ameloblasts necessary to reverse the effects of fluoride toxicity. Further studies will be required to optimize protocols for 4PBA administration in vivo in order to evaluate the effect of 4PBA on dental fluorosis.

Sirt1 overexpression suppresses fluoride-induced p53 acetylation to alleviate fluoride toxicity in ameloblasts responsible for enamel formation.

PubMed

Suzuki, Maiko; Ikeda, Atsushi; Bartlett, John D

2018-03-01

Low-dose fluoride is an effective caries prophylactic, but high-dose fluoride is an environmental health hazard that causes skeletal and dental fluorosis. Treatments to prevent fluorosis and the molecular pathways responsive to fluoride exposure remain to be elucidated. Previously we showed that fluoride activates SIRT1 as an adaptive response to protect cells. Here, we demonstrate that fluoride induced p53 acetylation (Ac-p53) [Lys379], which is a SIRT1 deacetylation target, in ameloblast-derived LS8 cells in vitro and in enamel organ in vivo. Here we assessed SIRT1 function on fluoride-induced Ac-p53 formation using CRISPR/Cas9-mediated Sirt1 knockout (LS8 Sirt/KO ) cells or CRISPR/dCas9/SAM-mediated Sirt1 overexpressing (LS8 Sirt1/over ) cells. NaF (5 mM) induced Ac-p53 formation and increased cell cycle arrest via Cdkn1a/p21 expression in Wild-type (WT) cells. However, fluoride-induced Ac-p53 was suppressed by the SIRT1 activator resveratrol (50 µM). Without fluoride, Ac-p53 persisted in LS8 Sirt/KO cells, whereas it decreased in LS8 Sirt1/over . Fluoride-induced Ac-p53 formation was also suppressed in LS8 Sirt1/over cells. Compared to WT cells, fluoride-induced Cdkn1a/p21 expression was elevated in LS8 Sirt/KO and these cells were more susceptible to fluoride-induced growth inhibition. In contrast, LS8 Sirt1/over cells were significantly more resistant. In addition, fluoride-induced cytochrome-c release and caspase-3 activation were suppressed in LS8 Sirt1/over cells. Fluoride induced expression of the DNA double strand break marker γH2AX in WT cells and this was augmented in LS8 Sirt1/KO cells, but was attenuated in LS8 Sirt1/over cells. Our results suggest that SIRT1 deacetylates Ac-p53 to mitigate fluoride-induced cell growth inhibition, mitochondrial damage, DNA damage and apoptosis. This is the first report implicating Ac-p53 in fluoride toxicity.

Tuning the thickness of exfoliated quasi-two-dimensional β-Ga2O3 flakes by plasma etching

NASA Astrophysics Data System (ADS)

Kwon, Yongbeom; Lee, Geonyeop; Oh, Sooyeoun; Kim, Jihyun; Pearton, Stephen J.; Ren, Fan

2017-03-01

We demonstrated the thinning of exfoliated quasi-two-dimensional β-Ga2O3 flakes by using a reactive ion etching technique. Mechanical exfoliation of the bulk β-Ga2O3 by using an adhesive tape was followed by plasma etching to tune its thickness. Since β-Ga2O3 is not a van der Waals material, it is challenging to obtain ultra-thin flakes below a thickness of 100 nm. In this study, an etch rate of approximately 16 nm/min was achieved at a power of 200 W with a flow of 50 sccm of SF6, and under these conditions, thinning of β-Ga2O3 flakes from 300 nm down to ˜60 nm was achieved with smooth morphology. We believe that the reaction between SF6 and Ga2O3 results in oxygen and volatile oxygen fluoride compounds, and non-volatile compounds such as GaFX that can be removed by ion bombardment. The opto-electrical properties were also characterized by fabricating solar-blind photodetectors using the plasma-thinned β-Ga2O3 flakes; these detectors showed fast response and decay with excellent responsivity and selectivity. Our results pave the way for tuning the thickness of two-dimensional materials by using this scalable, industry-compatible dry etching technique.

[Chronic combined effects of fluoride and arsenite on the Runx2 and downstream related factors of bone metabolism in rats].

PubMed

Hong, Feng; Zheng, Chong; Xu, De-gan; Qian, Ya-li

2013-09-01

To observe the chronic combined effects of sodium fluoride and sodium arsenite on the Runx2 and downstream related factors of bone metabolism in SD rats. SD rats were divided randomly into nine groups of 6 each by factorial experimental design (half female and half male) , and supplied with the different doses of fluoride, arsenite and fluoride plus arsenite containing in deionized water (untreated control containing 0 mg/kg fluoride and 0 mg/kg arsenite, and low-fluoride and high supplemented with 5 and 20 mg/kg fluoride, and low-arsenite and high supplemented with 2.5 and 10 mg/kg arsenite, and low-fluoride plus low-arsenite, and low-fluoride plus high-arsenite, and high-fluoride plus low-arsenite, and high-fluoride plus high-arsenite, respectively) . After 6 months exposure, the concentration of Runx2, matrix metallopeptidase 9 (MMP-9) ,Osterix, Receptor activator for nuclear factor-κ β ligand (RANKL) were detected by enzyme-linked immunosorbent assay method, respectively. There were no dental fluorosis found in the control group, low-arsenic group and high-arsenic group. There were significant differences in the constituent ratio of dental fluorosis among the rats from low-fluoride and high-fluoride (that is 5 rats out of 6 and 6 rats out of 6) compared with the control group (0 rat out of 6) (χ(2) = 8.57, 12.00, P < 0.05). The bone fluorine level increased with the increase of fluoride dose, the groups without fluoride supply (control group, low-arsenite and high-arsenite group's geometric mean (minimum-maximum) were 0.005 (0.003-0.009), 0.006 (0.003-0.021), 0.003 (0.002-0.100) mg/g, respectively), low-fluorine groups (low-fluoride group, low-fluoride plus low-arsenite, and low-fluoride plus high-arsenite group were 3.395 (2.416-5.871), 3.809 (1.471-7.799), 1.471 (1.473-6.732)mg/g, respectively) , the high-fluorine groups (high-fluoride, high-fluoride plus low-arsenite, and high-fluoride plus high-arsenite group were 70.086 (46.183-131.927), 69.925 (40.503-96.183), 40.503 (52.622-89.487) mg/g, respectively) and the differences between groups was significant (P < 0.05). The bone arsenic level increased with the increase of arsenite dose. The low-arsenic groups (low-arsenite group, low-arsenite plus low-fluoride, and low-arsenite plus high-fluoride group were 7.195 (5.060-9.860), 6.518 (2.960-12.130), 6.970 (3.400-9.730) µg/g, respectively), the high-arsenic groups (high-arsenite, high-arsenite plus low-fluoride, and high-fluoride plus high-arsenite group's geometric mean(minimum-maximum) were 8.823 (5.760-10.840), 9.470 (7.230-12.860), 8.321 (2.420-17.540) µg/g, respectively) were significantly higher than that in the groups without arsenic supply (control group, low-fluoride and high-fluoride group were 1.785 (0.300-3.750), 2.226 (1.410-3.980), 2.030 (1.040-3.850)µg/g, respectively) (P < 0.05). There was no significant difference of the bone arsenic concentration between low-arsenic and high arsenic group. There was significant positive correlation between fluoride concentration and Runx2, MMP-9, Osterix, RANKL level (the correlation coefficient was 0.647, 0.354, 0.582, 0.613 between fluorine gavage concentration and protein level, the correlation coefficient was 0.559,0.387, 0.487, 0.525 between bone fluorine concentration and protein level, respectively, P < 0.01). There was negative correlation between arsenite gavage concentration with Runx2 level (r = -0.527, P < 0.05) and was no correlation between arsenite gavage concentration with MMP-9, RANKL,Osterix level (P > 0.05). There was interaction between fluoride and arsenite to Runx2, MMP-9, RANKL,Osterix (F = 3.88, 15.66, 2.92, 6.42, respectively, P = 0.01, <0.01, 0.031, <0.01, respectively). The combined effects of fluoride and arsenic on the Runx2, MMP-9, RANKL, Osterix of bone metabolism showed antagonistic effects.

Superbugs on Duodenoscopes: the Challenge of Cleaning and Disinfection of Reusable Devices.

PubMed

Humphries, Romney M; McDonnell, Gerald

2015-10-01

Inadequate flexible endoscope reprocessing has been associated with infection outbreaks, most recently caused by carbapenem-resistant Enterobacteriaceae. Lapses in essential device reprocessing steps such as cleaning, disinfection/sterilization, and storage have been reported, but some outbreaks have occurred despite claimed adherence to established guidelines. Recommended changes in these guidelines include the use of sterilization instead of high-level disinfection or the use of routine microbial culturing to monitor efficacy of reprocessing. This review describes the current standards for endoscope reprocessing, associated outbreaks, and the complexities associated with both microbiological culture and sterilization approaches to mitigating the risk of infection associated with endoscopy. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Ion release from, and fluoride recharge of a composite with a fluoride-containing bioactive glass.

PubMed

Davis, Harry B; Gwinner, Fernanda; Mitchell, John C; Ferracane, Jack L

2014-10-01

Materials that are capable of releasing ions such as calcium and fluoride, that are necessary for remineralization of dentin and enamel, have been the topic of intensive research for many years. The source of calcium has most often been some form of calcium phosphate, and that for fluoride has been one of several metal fluoride or hexafluorophosphate salts. Fluoride-containing bioactive glass (BAG) prepared by the sol-gel method acts as a single source of both calcium and fluoride ions in aqueous solutions. The objective of this investigation was to determine if BAG, when added to a composite formulation, can be used as a single source for calcium and fluoride ion release over an extended time period, and to determine if the BAG-containing composite can be recharged upon exposure to a solution of 5000ppm fluoride. BAG 61 (61% Si; 31% Ca; 4% P; 3% F; 1% B) and BAG 81 (81% Si; 11% Ca; 4% P; 3% F; 1% B) were synthesized by the sol-gel method. The composite used was composed of 50/50 Bis-GMA/TEGDMA, 0.8% EDMAB, 0.4% CQ, and 0.05% BHT, combined with a mixture of BAG (15%) and strontium glass (85%) to a total filler load of 72% by weight. Disks were prepared, allowed to age for 24h, abraded, then placed into DI water. Calcium and fluoride release was measured by atomic absorption spectroscopy and fluoride ion selective electrode methods, respectively, after 2, 22, and 222h. The composite samples were then soaked for 5min in an aqueous 5000ppm fluoride solution, after which calcium and fluoride release was again measured at 2, 22, and 222h time points. Prior to fluoride recharge, release of fluoride ions was similar for the BAG 61 and BAG 81 composites after 2h, and also similar after 22h. At the four subsequent time points, one prior to, and three following fluoride recharge, the BAG 81 composite released significantly more fluoride ions (p<0.05). Both composites were recharged by exposure to 5000ppm fluoride, although the BAG 81 composite was recharged more than the BAG 61 composite. The BAG 61 composite released substantially more calcium ions prior to fluoride recharge during each of the 2 and 22h time periods. Thereafter, the release of calcium at the four subsequent time points was not significantly different (p>0.05) for the two composites. These results show that, when added to a composite formulation, fluoride-containing bioactive glass made by the sol-gel route can function as a single source for both calcium and fluoride ions, and that the composite can be readily recharged with fluoride. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Exposure to fluoride in smelter workers in a primary aluminum industry in India.

PubMed

Susheela, A K; Mondal, N K; Singh, A

2013-04-01

Fluoride is used increasingly in a variety of industries in India. Emission of fluoride dust and fumes from the smelters of primary aluminum producing industries is dissipated in the work environment and poses occupational health hazards. To study the prevalence of health complaints and its association with fluoride level in body fluids of smelter workers in a primary aluminum producing industry. In an aluminum industry, health status of 462 smelter workers, 60 supervisors working in the smelter unit, 62 non-smelter workers (control group 1) and 30 administration staff (control group 2) were assessed between 2007 and 2009. Their health complaints were recorded and categorized into 4 groups: 1) gastro-intestinal complaints; 2) non-skeletal manifestations; 3) skeletal symptoms; and (4) respiratory problems. Fluoride level in body fluids, nails, and drinking water was tested by an ion selective electrode; hemoglobin level was tested using HemoCue. The total complaints reported by study groups were significantly higher than the control groups. Smelter workers had a significantly (p<0.001) higher urinary and serum fluoride level than non-smelter workers; the nail fluoride content was also higher in smelter workers than non-smelter workers (p<0.001). The smelter workers with higher hemoglobin level had a significantly (p<0.001) lower urinary fluoride concentration and complained less frequently of health problems. Only 1.4% of the smelter workers were consuming water with high fluoride concentrations. A high percentage of participants was using substances with high fluoride contents. Industrial emission of fluoride is not the only important sources of fluoride exposure--consumption of substance with high levels of fluoride is another important route of entry of fluoride into the body. Measurement of hemoglobin provides a reliable indicator for monitoring the health status of employees at risk of fluorosis.

No calcium-fluoride-like deposits detected in plaque shortly after a sodium fluoride mouthrinse.

PubMed

Vogel, G L; Tenuta, L M A; Schumacher, G E; Chow, L C

2010-01-01

Plaque 'calcium-fluoride-like' (CaF(2)-like) and fluoride deposits held by biological/bacterial calcium fluoride (Ca-F) bonds appear to be the source of cariostatic concentrations of fluoride in plaque fluid. The aim of this study was to quantify the amounts of plaque fluoride held in these reservoirs after a sodium fluoride rinse. 30 and 60 min after a 228 microg/g fluoride rinse, plaque samples were collected from 11 volunteers. Each sample was homogenized, split into 2 aliquots (aliquots 1 and 2), centrifuged, and the recovered plaque fluid combined and analyzed using microelectrodes. The plaque mass from aliquot 1 was retained. The plaque mass from aliquot 2 was extracted several times with a solution having the same fluoride, calcium and pH as the plaque fluid in order to extract the plaque CaF(2)-like deposits. The total fluoride in both aliquots was then determined. In a second experiment, the extraction completeness was examined by applying the above procedure to in vitro precipitates containing known amounts of CaF(2)-like deposits. Nearly identical fluoride concentrations were found in both plaque aliquots. The extraction of the CaF(2)-like precipitates formed in vitro removed more than 80% of these deposits. The results suggest that either CaF(2)-like deposits were not formed in plaque or, if these deposits had been formed, they were rapidly lost. The inability to form persistent amounts of CaF(2)-like deposits in plaque may account for the relatively rapid loss of plaque fluid fluoride after the use of conventional fluoride dentifrices or rinses. (c) 2010 S. Karger AG, Basel.

Child-education program for the reduction of health risks due to fluoride in water sources in the Chiang Mai Basin, Thailand.

PubMed

Takizawa, S; Takeda, T; Wongrueng, A; Wattanachira, S

2010-01-01

Groundwater is the major source of drinking water in Lamphun Province in the Chiang Mai Basin, Thailand. However, groundwater contains high fluoride up to 16 mg F/L, which has caused dental and skeletal fluorosis. Although Thai Government installed RO membrane plants for the removal of fluoride from groundwater; and delivers RO-filtered bottled water that contains less fluoride than the Thai Standard of 0.7 mg F/L, it was found that the urinary fluoride levels are still high among the residents. To find the major sources of fluoride intake, fluoride contents in various water sources, such as village water supply, shallow and deep groundwaters, rain water and bottled water, were measured, and the local people's behavior on water uses was recorded by interview and questionnaire study. As a result, it was found that the highest risk of fluoride ingestion comes from cooking rice with fluoride-containing water because of a lack of knowledge on fluoride sources and fluoride chemistry. To reduce the health risks arising from fluoride intake, a hands-on educational program on the sources and risks of fluoride in water was developed and implemented in the local schools. The participatory educational program promoted active involvement of schoolchildren, but it was found that the effectiveness of education varied depending on the questions we asked. Therefore, it needs to be improved by an iterative and interactive educational program. In conclusion, it was found that the benefits of providing safe drinking water using such advanced technology as RO membrane can be maximized only when it comes along with a participatory educational program on fluoride sources and health risks.

A study to investigate fluoride contamination and fluoride exposure dose assessment in lateritic zones of West Bengal, India.

PubMed

Samal, Alok C; Bhattacharya, Piyal; Mallick, Anusaya; Ali, Md Motakabber; Pyne, Jagadish; Santra, Subhas C

2015-04-01

To assess the status of severity of fluoride contamination in lateritic Bankura and Purulia districts of West Bengal, concentrations of fluoride in different water sources and agricultural field soils were investigated. The fluoride content (mg/l) was observed to differ with aquifer depths: 0.19-0.47 in dug wells, 0.01-0.17 in shallow tube wells, and 0.07-1.6 in deep tube wells. Fluoride within the World Health Organization (WHO) prescribed range (1.0-1.5 mg/l) was estimated only in ~17% of the total collected water samples while ~67% showed <0.7 mg/l fluoride and thus may impede in the production and maintenance of healthy teeth and bones of the residents, especially children. Fluoride in water was found to be significantly correlated (r = 0.63) with pH. The exposure dose of fluoride (mg/kg/day) from drinking water in infants, children, and adults was estimated in the ranges 0.02-0.53, 0.01-0.24, and 0.01-0.14, respectively against the standard value of 0.05. A clear risk of dental fluorosis is apparent in infants and children of the study area. The fluoride in soil (55-399 mg/kg) was detected to be significantly correlated with the fluoride content in deep tube wells and soil pH (r = 0.56 and 0.71, respectively). The relationships of soil fluoride with total hardness and that with phosphate were not significant. There is a high possibility of bioaccumulation of fluoride from contaminated soil and water of the study area to cultivated crops. This will enhance the quantity of fluoride intake into human food chain in addition to drinking water pathway.

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

PubMed

Martín-Pardillos, Ana; Sosa, Cecilia; Millán, Ángel; Sorribas, Víctor

2014-04-06

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 2mM 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 1.5mg/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 calcification in vitro, the WHO's recommended concentrations in drinking water become nephrotoxic to CKD rats, thereby aggravating renal disease and making media vascular calcification significant. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Fluoride exposure and indicators of thyroid functioning in the Canadian population: implications for community water fluoridation.

PubMed

Barberio, Amanda M; Hosein, F Shaun; Quiñonez, Carlos; McLaren, Lindsay

2017-10-01

There are concerns that altered thyroid functioning could be the result of ingesting too much fluoride. Community water fluoridation (CWF) is an important source of fluoride exposure. Our objectives were to examine the association between fluoride exposure and (1) diagnosis of a thyroid condition and (2) indicators of thyroid functioning among a national population-based sample of Canadians. We analysed data from Cycles 2 and 3 of the Canadian Health Measures Survey (CHMS). Logistic regression was used to assess associations between fluoride from urine and tap water samples and the diagnosis of a thyroid condition. Multinomial logistic regression was used to examine the relationship between fluoride exposure and thyroid-stimulating hormone (TSH) level (low/normal/high). Other available variables permitted additional exploratory analyses among the subset of participants for whom we could discern some fluoride exposure from drinking water and/or dental products. There was no evidence of a relationship between fluoride exposure (from urine and tap water) and the diagnosis of a thyroid condition. There was no statistically significant association between fluoride exposure and abnormal (low or high) TSH levels relative to normal TSH levels. Rerunning the models with the sample constrained to the subset of participants for whom we could discern some source(s) of fluoride exposure from drinking water and/or dental products revealed no significant associations. These analyses suggest that, at the population level, fluoride exposure is not associated with impaired thyroid functioning in a time and place where multiple sources of fluoride exposure, including CWF, exist. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

No Calcium-Fluoride-Like Deposits Detected in Plaque Shortly after a Sodium Fluoride Mouthrinse

PubMed Central

Vogel, G.L.; Tenuta, L.M.A.; Schumacher, G.E.; Chow, L.C.

2010-01-01

Plaque ‘calcium-fluoride-like’ (CaF2-like) and fluoride deposits held by biological/bacterial calcium fluoride (Ca-F) bonds appear to be the source of cariostatic concentrations of fluoride in plaque fluid. The aim of this study was to quantify the amounts of plaque fluoride held in these reservoirs after a sodium fluoride rinse. 30 and 60 min after a 228 μg/g fluoride rinse, plaque samples were collected from 11 volunteers. Each sample was homogenized, split into 2 aliquots (aliquots 1 and 2), centrifuged, and the recovered plaque fluid combined and analyzed using microelectrodes. The plaque mass from aliquot 1 was retained. The plaque mass from aliquot 2 was extracted several times with a solution having the same fluoride, calcium and pH as the plaque fluid in order to extract the plaque CaF2-like deposits. The total fluoride in both aliquots was then determined. In a second experiment, the extraction completeness was examined by applying the above procedure to in vitro precipitates containing known amounts of CaF2-like deposits. Nearly identical fluoride concentrations were found in both plaque aliquots. The extraction of the CaF2-like precipitates formed in vitro removed more than 80% of these deposits. The results suggest that either CaF2-like deposits were not formed in plaque or, if these deposits had been formed, they were rapidly lost. The inability to form persistent amounts of CaF2-like deposits in plaque may account for the relatively rapid loss of plaque fluid fluoride after the use of conventional fluoride dentifrices or rinses. PMID:20185917

Validation of a Cariogenic Biofilm Model to Evaluate the Effect of Fluoride on Enamel and Root Dentine Demineralization.

PubMed

Fernández, Constanza E; Tenuta, Livia M A; Cury, Jaime A

2016-01-01

Due to gingival recession both enamel and root dentine are at risk of developing caries. Both tissues are exposed to a similar environment, however there is not a validated model to evaluate the effect of fluoride on these dental substrates simultaneously. Hence, this study aimed to validate a caries model to evaluate the effect of fluoride to prevent demineralization on enamel and root-dentine. Streptococcus mutans UA159 biofilms were formed on saliva-coated bovine enamel and root dentine slabs (n = 12 per group) mounted in the same well of culture plates. The biofilms were exposed 8×/day to 10% sucrose and treated 2×/day with fluoridated solutions containing 0, 150, 450, or 1,350 ppm F; thus, simulating the use of low to high fluoride concentration toothpastes. The pH values of the culture medium was monitored 2×/day as a biofilm acidogenicity indicator. After 96 h, biofilms were collected for fluoride concentration analysis. The percentage of surface hardness loss (%SHL) was calculated for slabs. The fluoride uptake by the enamel and dentine was also determined. The model showed a dose-response because the biofilm and fluoride uptake increased and %SHL decreased at increasing fluoride concentrations (p < 0.05). Fluoride in the biofilm formed on dentine and fluoride uptake by dentine were higher than those for enamel. With the same fluoride concentration treatment, the percentage of reduction of demineralization was lower for dentine than for enamel. In conclusion, the model was validated in terms of a dose-response effect of fluoride on enamel and root dentine. Furthermore, the findings support the clinical data, suggesting that higher fluoride concentrations are necessary to control caries of root dentine than of enamel.

Effects of fluoride emissions on enzyme activity in metabolism of agricultural plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moeri, P.B.

1980-01-01

The effects of fluoride on the activity of malatedehydrogenase (MDH) in rape seed and rye grass have been investigated. Fluoride, which has been absorbed from the air, seems to act differently from fluoride added to the soil. The action of airborne fluoride compounds resorbed by the plant on the activity of MDH significantly correlated with the distance from an aluminum plant, crop yield, and fluoride content. 5 references, 5 figures, 2 tables.

Chemical Ignition of Flame Throwers

DTIC Science & Technology

1944-04-20

fluorinating agents such as fluorine, antimony penta- fluoride, oxygen fluoride or bromine and chlorine trifluoride mixtures be evaluated. The use...0F2), and bromine and chlorine trifluoride mixtures (BrF3-ClF3). Oxygen fluoride, a gas boiling at -l67°C., has the interesting property of being...ShFc), oxygen fluoride (0F2), and bromine and chlorine fluoride mixtures (BrF3-ClFsJ. Oxygen fluoride Is stable In the presence of moisture. 4

Water fluoridation and dental caries in 5- and 12-year-old children from Canterbury and Wellington.

PubMed

Lee, Martin; Dennison, Peter J

2004-03-01

Claims have been made that the effectiveness of water fluoridation has reduced due to the widespread availability of other sources of fluoride. This study examines the differences in the oral health of children living in fluoridated and non-fluoridated areas of Canterbury and Wellington, New Zealand. The data used in this cross-sectional study had been routinely collected into a computerized data-collection system by the School Dental Services in the two study areas. Records of dental status (dmfs/DMFS), fluoridation status, ethnicity, and socio-economic status for 8030 5-year-olds, and 6916 12-year-olds in 1996 were analysed. Caries prevalence and severity was consistently lower for children in the fluoridated area for both age groups, and within all subgroups. Five-year-olds in the fluoridated area had 2.63 dmfs (sd, 5.88), and those in the non-fluoridated area 3.80 dmfs (sd, 6.79). For 12-year-olds the respective figures were 1.39 DMFS (sd, 2.30) and 2.37 DMFS (sd, 3.46). Multivariable analysis confirmed the independent association between water fluoridation and better dental health. This results of this study show children living in a fluoridated area to have significantly better oral health compared to those not in a fluoridated area. These differences are greater for Maori and Pacific children and children of low socio-economic status.

Fluoride Exposure Aggravates the Testicular Damage and Sperm Quality in Diabetic Mice: Protective Role of Ginseng and Banaba.

PubMed

Sm, Saumya; Mahaboob Basha, P

2017-06-01

Fluoride toxicity is known to pose infertility in fluoride-intoxicated animals as well as in people residing in fluoride endemic zones. The present study addresses the degree of impairments caused due to co-exposure of high fluoride toxicity in diabetic mice. Swiss mice, Mus musculus, were subjected to fluoride toxicity by providing fluoride-supplemented drinking water (600 ppm NaF) for a period of 30 days after the confirmation of streptozotocin-induced diabetes(STZ, 50 mg/kgbw). Consequently, aggravated hyperglycemia and tissue fluoride accumulation were witnessed in fluoride-intoxicated diabetic mice; later, these toxicated mice were treated with ginseng extract (GE) and banaba leaf extract, (BLE) at dose of 150 mg/kgbw/day alone and in combination for 15 and 30-day duration to check the efficacy of phytoextracts in reversing the toxicity. The spermatological indices studied, such as sperm density, motility, viability and morphology as well as the testicular biochemical parameters showed enhanced impairment in reproductive status of fluoride-intoxicated diabetic mice. Further, 15-days administration of GE and BLE in combination at a dose of 150 mg/kgbw/day was found to be beneficial in normalizing the alterations observed upon fluoride intoxication to diabetic mice. However, the correlates showed moderate association between blood glucose levels and the spermatological as well as biochemical indices wherein the tissue fluoride levels correlate least.

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

PubMed

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. Copyright © 2016 Elsevier B.V. All rights reserved.

Ameliorative effects of oleanolic acid on fluoride induced metabolic and oxidative dysfunctions in rat brain: Experimental and biochemical studies.

PubMed

Sarkar, Chaitali; Pal, Sudipta; Das, Niranjan; Dinda, Biswanath

2014-04-01

Beneficial effects of oleanolic acid on fluoride-induced oxidative stress and certain metabolic dysfunctions were studied in four regions of rat brain. Male Wistar rats were treated with sodium fluoride at a dose of 20 mg/kg b.w./day (orally) for 30 days. Results indicate marked reduction in acidic, basic and neutral protein contents due to fluoride toxicity in cerebrum, cerebellum, pons and medulla. DNA, RNA contents significantly decreased in those regions after fluoride exposure. Activities of proteolytic enzymes (such as cathepsin, trypsin and pronase) were inhibited by fluoride, whereas transaminase enzyme (GOT and GPT) activities increased significantly in brain tissue. Fluoride appreciably elevated brain malondialdehyde level, free amino acid nitrogen, NO content and free OH radical generation. Additionally, fluoride perturbed GSH content and markedly reduced SOD, GPx, GR and CAT activities in brain tissues. Oral supplementation of oleanolic acid (a plant triterpenoid), at a dose of 5mg/kgb.w./day for last 14 days of fluoride treatment appreciably ameliorated fluoride-induced alteration of brain metabolic functions. Appreciable counteractive effects of oleanolic acid against fluoride-induced changes in protein and nucleic acid contents, proteolytic enzyme activities and other oxidative stress parameters indicate that oleanolic acid has potential antioxidative effects against fluoride-induced oxidative brain damage. Copyright © 2014 Elsevier Ltd. All rights reserved.

Risk Assessment of Fluoride Intake from Tea in the Republic of Ireland and its Implications for Public Health and Water Fluoridation

PubMed Central

Waugh, Declan T.; Potter, William; Limeback, Hardy; Godfrey, Michael

2016-01-01

The Republic of Ireland (RoI) is the only European Country with a mandatory national legislation requiring artificial fluoridation of drinking water and has the highest per capita consumption of black tea in the world. Tea is a hyperaccumulator of fluoride and chronic fluoride intake is associated with multiple negative health outcomes. In this study, fifty four brands of the commercially available black tea bag products were purchased and the fluoride level in tea infusions tested by an ion-selective electrode method. The fluoride content in all brands tested ranged from 1.6 to 6.1 mg/L, with a mean value of 3.3 mg/L. According to our risk assessment it is evident that the general population in the RoI is at a high risk of chronic fluoride exposure and associated adverse health effects based on established reference values. We conclude that the culture of habitual tea drinking in the RoI indicates that the total cumulative dietary fluoride intake in the general population could readily exceed the levels known to cause chronic fluoride intoxication. Evidence suggests that excessive fluoride intake may be contributing to a wide range of adverse health effects. Therefore from a public health perspective, it would seem prudent and sensible that risk reduction measures be implemented to reduce the total body burden of fluoride in the population. PMID:26927146

Risk Assessment of Fluoride Intake from Tea in the Republic of Ireland and its Implications for Public Health and Water Fluoridation.

PubMed

Waugh, Declan T; Potter, William; Limeback, Hardy; Godfrey, Michael

2016-02-26

The Republic of Ireland (RoI) is the only European Country with a mandatory national legislation requiring artificial fluoridation of drinking water and has the highest per capita consumption of black tea in the world. Tea is a hyperaccumulator of fluoride and chronic fluoride intake is associated with multiple negative health outcomes. In this study, fifty four brands of the commercially available black tea bag products were purchased and the fluoride level in tea infusions tested by an ion-selective electrode method. The fluoride content in all brands tested ranged from 1.6 to 6.1 mg/L, with a mean value of 3.3 mg/L. According to our risk assessment it is evident that the general population in the RoI is at a high risk of chronic fluoride exposure and associated adverse health effects based on established reference values. We conclude that the culture of habitual tea drinking in the RoI indicates that the total cumulative dietary fluoride intake in the general population could readily exceed the levels known to cause chronic fluoride intoxication. Evidence suggests that excessive fluoride intake may be contributing to a wide range of adverse health effects. Therefore from a public health perspective, it would seem prudent and sensible that risk reduction measures be implemented to reduce the total body burden of fluoride in the population.

Dental caries and dental fluorosis at varying water fluoride concentrations.

PubMed

Heller, K E; Eklund, S A; Burt, B A

1997-01-01

The purpose of this study was to investigate the relationships between caries experience and dental fluorosis at different fluoride concentrations in drinking water. The impact of other fluoride products also was assessed. This study used data from the 1986-87 National Survey of US School-children. Fluoride levels of school water were used as an indicator of the children's water fluoride exposure. The use of fluoride drops, tablets, professional fluoride treatments, and school fluoride rinses were ascertained from caregiver questionnaires. Only children with a single continuous residence (n = 18,755) were included in this analysis. The sharpest declines in dfs and DMFS were associated with increases in water fluoride levels between 0 and 0.7 ppm F, with little additional decline between 0.7 and 1.2 ppm F. Fluorosis prevalence was 13.5 percent, 21.7 percent, 29.9 percent, and 41.4 percent for children who consumed < 0.3, 0.3 to < 0.7, 0.7 to 1.2, and > 1.2 ppm F water. In addition to fluoridated water, the use of fluoride supplements was associated with both lower caries and increased fluorosis. A suitable trade-off between caries and fluorosis appears to occur around 0.7 ppm F. Data from this study suggest that a reconsideration of the policies concerning the most appropriate concentrations for water fluoridation might be appropriate for the United States.

Association of vascular fluoride uptake with vascular calcification and coronary artery disease.

PubMed

Li, Yuxin; Berenji, Gholam R; Shaba, Wisam F; Tafti, Bashir; Yevdayev, Ella; Dadparvar, Simin

2012-01-01

The feasibility of a fluoride positron emission tomography/computed tomography (PET/CT) scan for imaging atherosclerosis has not been well documented. The purpose of this study was to assess fluoride uptake of vascular calcification in various major arteries, including coronary arteries. We retrospectively reviewed the imaging data and cardiovascular history of 61 patients who received whole-body sodium [¹⁸F]fluoride PET/CT studies at our institution from 2009 to 2010. Fluoride uptake and calcification in major arteries, including coronary arteries, were analyzed by both visual assessment and standardized uptake value measurement. Fluoride uptake in vascular walls was demonstrated in 361 sites of 54 (96%) patients, whereas calcification was observed in 317 sites of 49 (88%) patients. Significant correlation between fluoride uptake and calcification was observed in most of the arterial walls, except in those of the abdominal aorta. Fluoride uptake in coronary arteries was demonstrated in 28 (46%) patients and coronary calcifications were observed in 34 (56%) patients. There was significant correlation between history of cardiovascular events and presence of fluoride uptake in coronary arteries. The coronary fluoride uptake value in patients with cardiovascular events was significantly higher than in patients without cardiovascular events. sodium [¹⁸F]fluoride PET/CT might be useful in the evaluation of the atherosclerotic process in major arteries, including coronary arteries. An increased fluoride uptake in coronary arteries may be associated with an increased cardiovascular risk.

Water fluoridation and osteoporotic fracture.

PubMed

Hillier, S; Inskip, H; Coggon, D; Cooper, C

1996-09-01

Osteoporotic fractures constitute a major public health problem. These fractures typically occur at the hip, spine and distal forearm. Their pathogenesis is heterogeneous, with contributions from both bone strength and trauma. Water fluoridation has been widely proposed for its dental health benefits, but concerns have been raised about the balance of skeletal risks and benefits of this measure. Fluoride has potent effects on bone cell function, bone structure and bone strength. These effects are mediated by the incorporation of fluoride ions in bone crystals to form fluoroapatite, and through an increase in osteoblast activity. It is believed that a minimum serum fluoride level of 100 ng/ml must be achieved before osteoblasts will be stimulated. Serum levels associated with drinking water fluoridated to 1 ppm are usually several times lower than this value, but may reach this threshold at concentrations of 4 ppm in the drinking water. Animal studies suggest no effect of low-level (0-3 ppm) fluoride intake on bone strength, but a possible decrease at higher levels. Sodium fluoride has been used to treat established osteoporosis for nearly 30 years. Recent trials of this agent, prescribed at high doses, have suggested that despite a marked increase in bone mineral density, there is no concomitant reduction in vertebral fracture incidence. Furthermore, the increase in bone density at the lumbar spine may be achieved at the expense of bone mineral in the peripheral cortical skeleton. As a consequence, high dose sodium fluoride (80 mg daily) is not currently used to treat osteoporosis. At lower doses, recent trials have suggested a beneficial effect on both bone density and fracture. The majority of epidemiological evidence regarding the effect of fluoridated drinking water on hip fracture incidence is based on ecological comparisons. Although one Finnish study suggested that hip fracture rates in a town with fluoridated water were lower than those in a matching town without fluoride, a later study failed to show differences. Ecological studies from the United States and Great Britain have, if anything, revealed a weak positive association between water fluoride concentration and hip fracture incidence. Two studies examining hip fracture rates before and after fluoridation yielded discordant results, and are complicated by underlying time trends in hip fracture incidence. Only two studies have attempted to examine the relation between water fluoride concentration and fracture risk at an individual level. In one of these, women in a high fluoride community had double the fracture risk of women in a low fluoride community. In the other, there was no relationship between years of fluoride exposure and incidence of spine or non-spine fractures. In conclusion, the epidemiological evidence relating water fluoridation to hip fracture is based upon ecological comparisons and is inconclusive. However, several studies suggest the possibility of a weak adverse effect, which warrants further exploration. Data on the relationship between fluoride intake and hip fracture risk at the individual level, and data relating fluoridation to bone mineral density are required. Until these become available, the burden of evidence suggesting that fluoridation might be a risk factor for hip fracture is weak and not sufficient to retard the progress of the water fluoridation programme.

21 CFR 175.270 - Poly(vinyl fluoride) resins.

Code of Federal Regulations, 2010 CFR

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 the...

21 CFR 175.270 - Poly(vinyl fluoride) resins.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false 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 the...

[Study on the relationship between renal apoptosis and expression of caspase protein in fluoride induced rat].

PubMed

Gao, Jiping; Song, Guohua; Liu, Maolin; Wang, Yu; Yang, Xia

2014-01-01

To study the relationship between death receptor pathway, mitochondrion pathway and fluoride-induced apoptosis of renal cell. Male Sprague-Dawley rats were divided randomly into four groups (control, low-fluoride, medium-fluoride,and high-fluoride) and administered 0, 50, 100, and 200 mg/L of sodium fluoride, respectively, via drinking water for 120 days. The incidence of dental fluorosis were observed, the body weights and urine fluoride levels were measured. Apoptosis was detected by the Flow Cytometry (FCM). The expressions of protein of Caspase-3, Caspase-8, Caspase-9, Cyt C were detectedby immunohistoehemistry. The apoptosis rate in the fluoride exposed low does group,middle dose group and high dose group increased significantly as compared with control group. The average optical density value of Caspase-3, Caspase-8, Caspase-9 and Cyt C were higher in the fluoride exposed middle dose group and high dose group than those in the control group (P < 0.05). Death receptor pathway and mitochondrion pathway may participate in the process of fluoride-induced apoptosis of renal cell.

Histopathological changes of renal tissue following sodium fluoride administration in two consecutive generations of mice. Correlation with the urinary elimination of fluoride.

PubMed

Dimcevici Poesina, Nicoleta; Bălălău, Cristian; Nimigean, Vanda Roxana; Nimigean, Victor; Ion, Ion; Baconi, Daniela; Bârcă, Maria; Băran Poesina, Violeta

2014-01-01

The present study was designed to investigate the toxic effects (evaluated as histopathological changes) of sodium fluoride on the kidney in two consecutive generations of NMRI mice. An attempt to correlate the toxicity with the urinary elimination of fluoride has been made, as urinary fluoride excretion has been widely used as an indicator of fluoride intake and exposure. Six mixed (males and females) animal groups have been constituted by dividing the populations of mice derived from pregnant females (named "mothers" 0.5 mg sodium fluoride) treated with 0.5 mg sodium fluoride by daily gavage and pregnant females (named "mothers" 0.25 mg sodium fluoride) treated with 0.25 mg sodium fluoride by daily gavage; three types of sodium fluoride treatments were administrated: homeopathic, allopathic-homeopathic and allopathic. When the animals reached the adulthood, by randomization, they were selected in pairs for giving birth to the second generation of mice. No treatments were administrated to the second generation of mice; thus, the urinary elimination of fluoride in the second generation is attributed to exposure at sodium fluoride before birth. The administration of sodium fluoride to the first generation (F1) is realized until the mice reached the adulthood. For the first generation, the urine was collected at three times, every three weeks: at the age of four weeks, seven weeks and 11 weeks; single sampling urine, at the age of four weeks, has been conducted for the second generation. The urine samples have been analyzed using the ion selective electrode method for fluoride. For the histopathological examination, the animals were killed by cervical dislocation; the kidneys were collected in a 10% formalin solution. The preparation of samples for optical microscopy was realized with Hematoxylin-Eosin staining. The results indicate that the elimination of fluoride was similar (at the second evaluation, at 7-week-old of the first generation) for the both generations of mice. Histopathological observation of the kidney has revealed granular dystrophy of the renal tubules, necrosis of the endothelial cells and of the mesangial cells of renal glomerulus. The study indicates that different sodium fluoride treatments produce some pathological aspects of the kidneys and influence the urinary elimination of fluoride in two consecutive generations of mice. For the higher doses, the pathological changes of the kidney are more important, and the urinary elimination of fluoride is higher, especially for the allopathic doses.

Automatic flexible endoscope reprocessors.

PubMed

Muscarella, L F

2000-04-01

Reprocessing medical instruments is a complex and controversial discipline. If all instruments were constructed of materials not damaged by heat, pressure, and moisture, instrument reprocessing would be greatly simplified. As the number of novel and complex instruments entering the market continues to increase, periodic review of the health care facility's instrument reprocessing protocols to ensure their safety and effectiveness is important. This article reviews the advantages and the limitations of automatic flexible endoscope reprocessors.

AirMSPI Level 1B2 V003 New and Reprocessed Data

Atmospheric Science Data Center

2013-12-10

AirMSPI Level 1B2 V003 New and Reprocessed Data PODEX Thursday, December 12, ... The V001 & V002 data were reprocessed as V003, as well as new Pacific targets acquired on February 1, 2013. This release also includes both a terrain and an ellipsoid kml file per date/time/target. More details about the PODEX campaign and AirMSPI participation can be ...

RXTE and BeppoSAX Observations of MCG-5-23-16: Reflection From Distant Cold Material

NASA Technical Reports Server (NTRS)

Mattson, B. J.; Weaver, K. A.

2003-01-01

We examine the spectral variability of the Seyfert 1.9 galaxy MCG-5-23-16 using RXTE and BeppoSAX observations spanning 2 years from April 1996 to April 1998. During the first year the X-ray source brightens by a factor of approximately 25% on timescales of days to months. During this time, the reprocessed continuum emission seen with RXTE does not respond measurably to the continuum increase. However, by the end of the second year during the BeppoSAX epoch the X-ray source has faded again. This time, the reprocessed emission has also faded, indicating that the reprocessed flux has responded to the continuum. If these effects are caused by time delays due to the distance between the X-ray source and the reprocessing region, we derive a light crossing time of between approximately 1 light day and approximately 1.5 light years. This corresponds to a distance of 0.001 pc to 0.55 pc, which implies that the reprocessed emission originates between 3 x 10(exp 15) cm and 1.6 x 10(exp l8) cm from the X-ray source. In other words, the reprocessing in MCG-5-23-16 is not dominated by the inner regions of a standard accretion disk.

The antimicrobial effect of Octenidine-dihydrochloride coated polymer tracheotomy tubes on Staphylococcus aureus and Pseudomonas aeruginosa colonisation.

PubMed

Zumtobel, Michaela; Assadian, Ojan; Leonhard, Matthias; Stadler, Maria; Schneider, Berit

2009-07-25

The surface of polymeric tracheotomy tubes is a favourable environment for biofilm formation and therefore represents a potential risk factor for the development of pneumonia after tracheotomy. The aim of this in-vitro study was to develop octenidine-dihydrochloride (OCT) coated polymer tracheotomy tubes and investigate any effects on Staphylococcus (S.) aureus and Pseudomonas (P.) aeruginosa colonization. Additionally the resistance of the OCT coating was tested using reprocessing procedures like brushing, rinsing and disinfection with glutaraldehyde Contamination with S. aureus: Before any reprocessing, OCT coated tracheotomy tubes were colonized with 103 cfu/ml and uncoated tracheotomy tubes with 105 cfu/ml (P = 0.045). After reprocessing, no differences in bacterial concentration between modified and conventional tubes were observed.Contamination with P. aeruginosa: Before reprocessing, OCT coated tubes were colonized with 106 cfu/ml and uncoated tubes with 107 cfu/ml (P = 0.006). After reprocessing, no significant differences were observed. OCT coating initially inhibits S. aureus and P. aeruginosa colonisation on tracheotomy tubes. This effect, however, vanishes quickly after reprocessing of the tubes due to poor adhesive properties of the antimicrobial compound. Despite the known antimicrobial effect of OCT, its use for antimicrobial coating of tracheotomy tubes is limited unless methods are developed to allow sustained attachment to the tube.

Simethicone residue remains inside gastrointestinal endoscopes despite reprocessing.

PubMed

Ofstead, Cori L; Wetzler, Harry P; Johnson, Ellen A; Heymann, Otis L; Maust, Thomas J; Shaw, Michael J

2016-11-01

During a study designed to assess endoscope reprocessing effectiveness, a borescope was used to examine lumens and ports. Cloudy, white, viscous fluid was observed inside fully reprocessed gastroscopes and colonoscopes. This fluid resembled simethicone, which is commonly administered to reduce foam and bubbles that impede visualization during gastrointestinal endoscopy. This article describes methods used to determine whether the observed fluid contained simethicone. Photographs of residual fluid were taken using a borescope. Sterile cotton-tipped swabs were used to collect samples of fluid observed in 3 endoscope ports. Samples were evaluated using Fourier transform infrared spectroscopy (FTIR)-attenuated total reflection analysis. Residual fluid was observed inside 19 of 20 endoscopes. Fluid photographed in 8 endoscopes resembled simethicone solutions. FTIR analysis confirmed the presence of simethicone in 2 endoscopes. Fluid containing simethicone remained inside endoscopes despite reprocessing. Simethicone is an inert, hydrophobic substance that may reduce reprocessing effectiveness. Simethicone solutions commonly contain sugars and thickeners, which may contribute to microbial growth and biofilm development. Studies are needed to assess the prevalence of residual moisture and simethicone in endoscopes and determine the impact on reprocessing effectiveness. We recommend minimizing the use of simethicone pending further research into its safety. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Small molecule fluoride toxicity agonists.

PubMed

Nelson, James W; Plummer, Mark S; Blount, Kenneth F; Ames, Tyler D; Breaker, Ronald R

2015-04-23

Fluoride is a ubiquitous anion that inhibits a wide variety of metabolic processes. Here, we report the identification of a series of compounds that enhance fluoride toxicity in Escherichia coli and Streptococcus mutans. These molecules were isolated by using a high-throughput screen (HTS) for compounds that increase intracellular fluoride levels as determined via a fluoride riboswitch reporter fusion construct. A series of derivatives were synthesized to examine structure-activity relationships, leading to the identification of compounds with improved activity. Thus, we demonstrate that small molecule fluoride toxicity agonists can be identified by HTS from existing chemical libraries by exploiting a natural fluoride riboswitch. In addition, our findings suggest that some molecules might be further optimized to function as binary antibacterial agents when combined with fluoride. Copyright © 2015 Elsevier Ltd. All rights reserved.

New insight on the response of bacteria to fluoride.

PubMed

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 biology, which has implications for a number of issues that are central to the use of fluoride for dental care. Below I provide a summary of our findings, comment on some of the key prospects for expanding our understanding of fluoride's effects on biology, and propose some future uses of this knowledge. Copyright © 2012 S. Karger AG, Basel.

New Insight on the Response of Bacteria to Fluoride

PubMed Central

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 biology, which has implications for a number of issues that are central to the use of fluoride for dental care. Below I provide a summary of our findings, comment on some of the key prospects for expanding our understanding of fluoride's effects on biology, and propose some future uses of this knowledge. PMID:22327376

Dental Fluorosis and Dental Caries Prevalence among 12 and 15-Year-Old School Children in Nalgonda District, Andhra Pradesh, India.

PubMed

Sukhabogi, J R; Parthasarathi, P; Anjum, S; Shekar, Brc; Padma, Cm; Rani, As

2014-09-01

Fluoride is a double edged sword. The assessment of dental caries and fluorosis in endemic fluoride areas will facilitate in assessing the relation between fluoride concentrations in water with dental caries, dental fluorosis simultaneously. The objective of the following study is to assess the dental caries and dental fluorosis prevalence among 12 and 15-year-old school children in Nalgonda district, Andhra Pradesh, India. This was a cross-sectional study. Two stage cluster sampling technique was employed to select 20 schools from Nalgonda district. The oral examination of available 12 and 15-year-old children fulfilling the inclusion and exclusion criteria was carried out to assess dental caries and fluorosis. The examination was conducted by a single trained and calibrated examiner using the mouth mirror and community periodontal index probe under natural daylight. These areas were divided into four categories, low, medium, high and very high fluoride areas based on the fluoride concentration at the time of statistical analysis. The data was analyzed using Statistical Package for the Social Sciences version 16 (IBM, Chicago, USA). The caries prevalence was less among 12-year-old children (39.9% [369/924]) compared with 15-years-old children (46.7% [444/951]). The prevalence was more among females (50.4% [492/977]) than males (35.8% [321/898]). The prevalence was more in low fluoride area (60.5% [300/496]) followed by very high fluoride area (54.8% [201/367]), high fluoride area (32.4% [293/904]) and medium fluoride area (17.6% [19/108]) in the descending order. The fluorosis prevalence increased with increasing fluoride concentration with no difference in gender and age distribution. Low fluoride areas require fluoridation or alternate sources of fluoride, whereas high fluoride areas require defluoridation. Defluoridation of water is an immediate requirement in areas with fluoride concentration of 4 parts per million and above as dental fluorosis is a public health problem in these areas with 100% prevalence.

Tooth quality in dental fluorosis genetic and environmental factors.

PubMed

Vieira, A P G F; Hanocock, R; Eggertsson, H; Everett, E T; Grynpas, M D

2005-01-01

Dental fluorosis (DF) affects the appearance and structure of tooth enamel and can occur following ingestion of excess fluoride during critical periods of amelogenesis. This tooth malformation may, depending on its severity, influence enamel and dentin microhardness and dentin mineralization. Poor correlation between tooth fluoride (F) concentration and DF severity was shown in some studies, but even when a correlation was present, tooth fluoride concentration explained very little of DF severity. This fact calls into question the generally accepted hypothesis that the main factor responsible for DF severity is tooth fluoride concentration. It has been shown previously that genetic factors (susceptibility to DF) play an important role in DF severity although DF severity relates to individual susceptibility to fluoride exposure (genetics), tooth fluoride concentration relates to fluoride ingestion (environmental). The objective of this study was to investigate the correlation between tooth fluoride concentration, DF severity, and tooth mechanical and materials properties. Three strains of mice (previously shown to have different susceptibility to DF) at weaning were treated with four different levels of F in their water (0, 25, 50, and 100 ppm) for 6 weeks. Mice teeth were tested for fluoride by instrumental neutron activation analysis (INAA), DF severity determined by quantitative light-induced fluorescence [QLF], and tooth quality (enamel and dentin microhardness and dentin mineralization). Tooth fluoride concentration (environment factor) correlated positively with DF severity (QLF) (rs=0.608), fluoride treatment group (rs=0.952). However, tooth fluoride concentration correlated negatively with enamel microhardness (rs=-0.587), dentin microhardness (rs=-0.268) and dentin mineralization (rs=-0.245). Dental fluorosis (genetic factor) severity (QLF) correlated positively with fluoride treatment (rs=0.608) and tooth fluoride concentration (rs=0.583). DF severity correlated negatively with enamel microhardness (rs=-0.564) and dentin microhardness (rs=-0.356). Genetic factors (DF severity) and the environmental factor (fluoride concentration in tooth structure) have similar influence on tooth biomechanical properties, whereas only the environmental factor has an influence on tooth material property (mineralization).

Urinary fluoride levels and prevalence of dental fluorosis in three Brazilian cities with different fluoride concentrations in the drinking water.

PubMed

Heintze, S D; Bastos, J R; Bastos, R

1998-10-01

Urine samples from three daytime periods were collected from 545 5-50-year-old residents of three different Brazilian cities: Garça had fluoridated drinking water since 1973, Bauru since 1975 and Itápolis was not fluoridated. Dental fluorosis was examined in 985 5-24-year-olds using the Thylstrup-Fejerskov index (TF). The subjects were asked to estimate their daily intake of liquids and frequency of beverage consumption. The analysis of 94 water samples showed high variations in the fluoride content of the drinking water. The mean fluoride concentration of the water samples in Garça was 0.9 mg/L (range 0.75-1.2), in Bauru 0.64 mg/L (range 0.01-1.3), and in Itápolis 0.02 mg/L. Mean urinary fluoride concentration was 1.31 mg/L (s 0.61) in Garça, 0.88 mg/L (s 0.49) in Bauru, and 0.39 mg/L (s 0.21) in Itápolis. Self-reported daily liquid intake was not related to urinary fluoride concentration. The mean prevalence of fluorosis was 13.3% in Garça, 6.8% in Bauru, and 1.7% in Itápolis, with mainly categories TF 1 and TF 2 being recorded. Subjects with dental fluorosis tended to show a higher mean urinary fluoride concentration but the difference was not statistically significant. The study showed that fluoride exposure measured by urinary fluoride excretion was within the range expected for the level of fluoride concentration in the drinking water. However, enamel fluorosis tended to be markedly lower than expected. This study revealed that fluoride levels in the two cities with fluoridated drinking water were variable. To optimise anticaries benefits and minimise the risk of fluorosis greater control of the fluoride dosing of the drinking water is required.

An in vitro evaluation of a novel high fluoride daily mouthrinse using a combination of microindentation, 3D profilometry and DSIMS.

PubMed

Gracia, Louise H; Rees, Gareth D; Brown, Alan; Fowler, Christabel E

2010-11-01

Firstly, to evaluate the in vitro anti-erosion efficacy of a new mouthrinse formulation containing 450 ppm fluoride using profilometry and microindentation. Secondly, to compare fluoride uptake by erosive lesions from two mouthrinses containing different fluoride sources using dynamic secondary ion mass spectrometry (DSIMS). Sound human enamel was treated (60s) with mouthrinses containing different fluoride concentrations, then immersed in 1.0% citric acid pH 3.8 for either 300 s or 30 min (Studies 1 & 2 respectively). Surface roughness and erosion depth were determined profilometrically in Study 1, and surface microhardness monitored as a function of time in Study 2. Lesion rehardening was monitored following a 60 s rinse and immersion in artificial saliva for 48 h (Study 3), whilst Study 4 employed DSIMS to quantify fluoride uptake by lesions treated (60s) with rinses containing either sodium fluoride (NaF) or a NaF/Olaflur/stannous chloride combination. The test rinse (450 ppm fluoride) suppressed surface roughening and bulk tissue loss versus all comparators (p< 0.0001), except in the latter measure for the rinse containing 112 ppm fluoride. The test rinse significantly inhibited enamel surface softening versus the three rinses containing ≤112 ppm fluoride (as NaF) at 30 min (p<0.05), but was not statistically significantly different from the 225 ppm fluoride rinse. The test rinse conferred statistically superior lesion rehardening versus all comparators at both 24 and 48 h (p< 0.0001). DSIMS demonstrated statistically significantly higher fluoride uptake by incipient erosive lesions treated with the test rinse versus the NaF/Olaflur/stannous rinse. Anti-erosion efficacy was positively correlated with fluoride concentration. DSIMS showed significantly higher levels of fluoride uptake by incipient erosive lesions treated with the 450 ppm fluoride rinse versus the NaF/Olaflur/stannous rinse. Copyright © 2010 Elsevier Ltd. All rights reserved.

Utility of check dams in dilution of fluoride concentration in ground water and the resultant analysis of blood serum and urine of villagers, Anantapur District, Andhra Pradesh, India.

PubMed

Bhagavan, S V B K; Raghu, V

2005-02-01

High levels of fluoride (beyond 1.5 ppm) in ground water as source of drinking water are common in many parts of Andhra Pradesh, India, causing fluorosis. The study carried out in endemic Nalgonda District, Andhra Pradesh, has indicated that the fluoride-rich ground water present in the wells located down stream and close to the surface water bodies is getting diluted by the low-fluoride surface water. Encouraged by this result, check dams were constructed upstream of the identified marginally high fluoride bearing ground water zones in Anantapur District to reduce fluoride levels as an alternate solution for safe drinking water. In this paper, an attempt is made to study the utility and effect of these check dams in dilution of fluoride concentration in drinking water and its resultant impact on the health aspects of certain villagers of Anantapur District through the analysis of their blood serum and urine. Ground water samples from three fluoride-affected villages, blood and urine of males and females from the same villages were collected and analyzed for fluoride using ion selective electrode method. The results indicated that the fluoride levels in blood serum and urine of males in the age group of 5-11 years are found to be the highest. The concentration of fluoride in ground water is directly proportional to the concentration of fluoride in blood serum and urine. The concentration of fluoride in ground water with depth of the aquifer is a function of lithology, amount and duration of rainfall, rate of infiltration, level of ground water exploitation in the area etc. The construction of check dams upstream of the identified marginally high fluoride waters will not only cause additional recharge of ground water but also reduces the fluoride concentration eventually improving the health of the villagers.

Monitoring of endoscope reprocessing with an adenosine triphosphate (ATP) bioluminescence method.

PubMed

Parohl, Nina; Stiefenhöfer, Doris; Heiligtag, Sabine; Reuter, Henning; Dopadlik, Dana; Mosel, Frank; Gerken, Guido; Dechêne, Alexander; Heintschel von Heinegg, Evelyn; Jochum, Christoph; Buer, Jan; Popp, Walter

2017-01-01

Background: The arising challenges over endoscope reprocessing quality proposes to look for possibilities to measure and control the process of endoscope reprocessing. Aim: The goal of this study was to evaluate the feasibility of monitoring endoscope reprocessing with an adenosine triphosphate (ATP) based bioluminescence system. Methods: 60 samples of eight gastroscopes have been assessed from routine clinical use in a major university hospital in Germany. Endoscopes have been assessed with an ATP system and microbial cultures at different timepoints during the reprocessing. Findings: After the bedside flush the mean ATP level in relative light units (RLU) was 19,437 RLU, after the manual cleaning 667 RLU and after the automated endoscope reprocessor (AER) 227 RLU. After the manual cleaning the mean total viable count (TVC) per endoscope was 15.3 CFU/10 ml, and after the AER 5.7 CFU/10 ml. Our results show that there are reprocessing cycles which are not able to clean a patient used endoscope. Conclusion: Our data suggest that monitoring of flexible endoscope with ATP can identify a number of different influence factors, like the endoscope condition and the endoscopic procedure, or especially the quality of the bedside flush and manual cleaning before the AER. More process control is one option to identify and improve influence factors to finally increase the overall reprocessing quality, best of all by different methods. ATP measurement seems to be a valid technique that allows an immediate repeat of the manual cleaning if the ATP results after manual cleaning exceed the established cutoff of 200 RLU.

Optimizing Endoscope Reprocessing Resources Via Process Flow Queuing Analysis.

PubMed

Seelen, Mark T; Friend, Tynan H; Levine, Wilton C

2018-05-04

The Massachusetts General Hospital (MGH) is merging its older endoscope processing facilities into a single new facility that will enable high-level disinfection of endoscopes for both the ORs and Endoscopy Suite, leveraging economies of scale for improved patient care and optimal use of resources. Finalized resource planning was necessary for the merging of facilities to optimize staffing and make final equipment selections to support the nearly 33,000 annual endoscopy cases. To accomplish this, we employed operations management methodologies, analyzing the physical process flow of scopes throughout the existing Endoscopy Suite and ORs and mapping the future state capacity of the new reprocessing facility. Further, our analysis required the incorporation of historical case and reprocessing volumes in a multi-server queuing model to identify any potential wait times as a result of the new reprocessing cycle. We also performed sensitivity analysis to understand the impact of future case volume growth. We found that our future-state reprocessing facility, given planned capital expenditures for automated endoscope reprocessors (AERs) and pre-processing sinks, could easily accommodate current scope volume well within the necessary pre-cleaning-to-sink reprocessing time limit recommended by manufacturers. Further, in its current planned state, our model suggested that the future endoscope reprocessing suite at MGH could support an increase in volume of at least 90% over the next several years. Our work suggests that with simple mathematical analysis of historic case data, significant changes to a complex perioperative environment can be made with ease while keeping patient safety as the top priority.

Widespread genetic switches and toxicity resistance proteins for fluoride.

PubMed

Baker, Jenny L; Sudarsan, Narasimhan; Weinberg, Zasha; Roth, Adam; Stockbridge, Randy B; Breaker, Ronald R

2012-01-13

Most riboswitches are metabolite-binding RNA structures located in bacterial messenger RNAs where they control gene expression. We have discovered a riboswitch class in many bacterial and archaeal species whose members are selectively triggered by fluoride but reject other small anions, including chloride. These fluoride riboswitches activate expression of genes that encode putative fluoride transporters, enzymes that are known to be inhibited by fluoride, and additional proteins of unknown function. Our findings indicate that most organisms are naturally exposed to toxic levels of fluoride and that many species use fluoride-sensing RNAs to control the expression of proteins that alleviate the deleterious effects of this anion.

Widespread Genetic Switches and Toxicity Resistance Proteins for Fluoride

PubMed Central

Weinberg, Zasha; Roth, Adam; Stockbridge, Randy B.; Breaker, Ronald R.

2014-01-01

Most riboswitches are metabolite-binding RNA structures located in bacterial messenger RNAs where they control gene expression. We have discovered a riboswitch class in many bacterial and archaeal species whose members are selectively triggered by fluoride but reject other small anions, including chloride. These fluoride riboswitches activate expression of genes that encode putative fluoride transporters, enzymes that are known to be inhibited by fluoride, and additional proteins of unknown function. Our findings indicate that most organisms are naturally exposed to toxic levels of fluoride and that many species use fluoride-sensing RNAs to control the expression of proteins that alleviate the deleterious effects of this anion. PMID:22194412

Probability of foliar injury for Acer sp. based on foliar fluoride concentrations.

PubMed

McDonough, Andrew M; Dixon, Murray J; Terry, Debbie T; Todd, Aaron K; Luciani, Michael A; Williamson, Michele L; Roszak, Danuta S; Farias, Kim A

2016-12-01

Fluoride is considered one of the most phytotoxic elements to plants, and indicative fluoride injury has been associated over a wide range of foliar fluoride concentrations. The aim of this study was to determine the probability of indicative foliar fluoride injury based on Acer sp. foliar fluoride concentrations using a logistic regression model. Foliage from Acer nedundo, Acer saccharinum, Acer saccharum and Acer platanoides was collected along a distance gradient from three separate brick manufacturing facilities in southern Ontario as part of a long-term monitoring programme between 1995 and 2014. Hydrogen fluoride is the major emission source associated with the manufacturing facilities resulting with highly elevated foliar fluoride close to the facilities and decreasing with distance. Consistent with other studies, indicative fluoride injury was observed over a wide range of foliar concentrations (9.9-480.0 μg F -  g -1 ). The logistic regression model was statistically significant for the Acer sp. group, A. negundo and A. saccharinum; consequently, A. negundo being the most sensitive species among the group. In addition, A. saccharum and A. platanoides were not statistically significant within the model. We are unaware of published foliar fluoride values for Acer sp. within Canada, and this research provides policy maker and scientist with probabilities of indicative foliar injury for common urban Acer sp. trees that can help guide decisions about emissions controls. Further research should focus on mechanisms driving indicative fluoride injury over wide ranging foliar fluoride concentrations and help determine foliar fluoride thresholds for damage.

Fluoride in drinking water and diet: the causative factor of chronic kidney diseases in the North Central Province of Sri Lanka.

PubMed

Dharmaratne, Ranjith W

2015-07-01

A significant number of people in the North Central Province of Sri Lanka suffer from chronic kidney diseases (CKD), and the author revisits existing literature related to CKD to find its causative factor. There is a direct connection between high fluoride levels in drinking water and kidney disease, and there are unhealthy levels of fluoride in the groundwater in Sri Lanka's CKD-affected areas. Based on the following observations, the author believes with confidence that excess fluoride in drinking water and in the locally grown food in the affected areas are the culprits of CKD in Sri Lanka. Fluoride excretion rate is considerably lower in children than adults, leading to renal damage of children living in areas with high fluoride. Adults who had renal damage due to fluoride in childhood are vulnerable to CKD with continued consumption of water from the same source. Patients with chronic renal insufficiency are at an increased risk of chronic fluoride toxicity. High content of fluoride in groundwater paves the way to excess fluoride in local food crops, consequently adding more fluoride to the systems of the consumers. People who work outdoors for prolonged periods consume excess water and tea, and are subjected to additional doses of fluoride in their system. In the mid-1980s, the increase in water table levels of the affected areas due to new irrigation projects paved the way to adding more fluorides to their system through drinking water and locally grown foods.

The Impact of Selected Fluoridated Toothpastes on Dental Erosion in Profilometric Measurement.

PubMed

Fita, Katarzyna; Kaczmarek, Urszula

2016-01-01

Some fluoridated toothpastes, available commercially, are described to have a protective effect against dental erosion. To evaluate the influence of the selected marketed toothpastes on the human enamel exposed to acid beverages. Enamel specimens from extracted human teeth were prepared (n = 40). Specimens were randomly divided into 10 experimental groups, 4 specimens each, which were subjected to acid challenge for 10 min using orange juice (pH 3.79) or Pepsi Cola (pH 2.58) and then immersed for 2 min into a slurry of five marketed toothpastes with distilled water (1 : 3 w/w). The tested toothpastes contained 1450 or 5000 ppm fluoride, CPP-ACP with 900 ppm fluoride, 1450 ppm fluoride with potassium nitrate 5%, all of them as sodium fluoride, and 700 ppm fluoride as amine and sodium fluoride with 3500 ppm SnCl2. Enamel roughness (Ra parameter) by contact profilometer at baseline and after exposure onto soft drinks and slurry was measured. Exposure to both beverages caused a similar increase of enamel surface roughness. After the specimens immersion into slurries of toothpastes with 1450 or 5000 ppm fluoride, 1450 ppm fluoride with potassium nitrate 5% and CPP-ACP with 900 ppm fluoride the significant decrease of Ra values were found, reaching the baseline values. However, toothpaste with 700 ppm fluoride and 3500 ppm SnCl2 did not cause any fall in Ra value, probably due to other mechanism of action. Within the limitation of the study we can conclude that the sodium fluoride toothpastes are able to restore the surface profile of enamel exposed shortly to acidic soft drinks.

Fluoride and Oral Health.

PubMed

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.

Patterns of dental caries following the cessation of water fluoridation.

PubMed

Maupomé, G; Clark, D C; Levy, S M; Berkowitz, J

2001-02-01

To compare prevalence and incidence of caries between fluoridation-ended and still-fluoridated communities in British Columbia, Canada, from a baseline survey and after three years. At the baseline (1993/4 academic year) and follow-up (1996/7) surveys, children were examined at their schools. Data were collected on snacking, oral hygiene, exposure to fluoride technologies, and socio-economic level. These variables were used together with D1D2MFS indices in multiple regression models. The prevalence of caries (assessed in 5,927 children, grades 2, 3, 8, 9) decreased over time in the fluoridation-ended community while remaining unchanged in the fluoridated community. While numbers of filled surfaces did not vary between surveys, sealed surfaces increased at both study sites. Caries incidence (assessed in 2,994 life-long residents, grades 5, 6, 11, 12) expressed in terms of D1D2MFS was not different between the still-fluoridating and fluoridation-ended communities. There were, however, differences in caries experienced when D1D2MFS components and surfaces at risk were investigated in detail. Regression models did not identify specific variables markedly affecting changes in the incidence of dental decay. Our results suggest a complicated pattern of disease following cessation of fluoridation. Multiple sources of fluoride besides water fluoridation have made it more difficult to detect changes in the epidemiological profile of a population with generally low caries experience, and living in an affluent setting with widely accessible dental services. There are, however, subtle differences in caries and caries treatment experience between children living in fluoridated and fluoridation-ended areas.

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

PubMed

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fluoride Penetration and Clearance Are Higher in Exopolysaccharide-Containing Bacterial Pellets.

PubMed

Spinola, Manuela S; Nóbrega, Diego Figueiredo; Del Bel Cury, Altair Antoninha; Ricomini Filho, Antonio Pedro; Cury, Jaime Aparecido; Tenuta, Livia Maria Andaló

2018-06-06

Extracellular polysaccharides (EPS) could increase the penetration of fluoride through dental biofilm, reducing its cariogenicity. We measured the concentration of fluoride in EPS-containing (EPS+) or not-containing (EPS-) Streptococcus mutans bacterial pellets resembling test biofilms, before and up to 60 min after a 0.05% NaF rinse in situ. Fluoride penetration and clearance were higher in EPS+ bacterial pellets. The data suggest that EPS enhances fluoride penetration, but also accelerates fluoride clearance from dental biofilms. © 2018 S. Karger AG, Basel.

Fungus hyphae-supported alumina: An efficient and reclaimable adsorbent for fluoride removal from water.

PubMed

Yang, Weichun; Tian, Shunqi; Tang, Qiongzhi; Chai, Liyuan; Wang, Haiying

2017-06-15

A reclaimable adsorbent of fungus hyphae-supported alumina (FHSA) bio-nanocomposites was developed, characterized and applied in fluoride removal from water. This adsorbent can be fast assembled and disassemble reversibly, promising efficient reclamation and high accessible surface area for fluoride adsorption. Adsorption experiments demonstrate that the FHSA performed well over a considerable wide pH range of 3-10 with high fluoride removal efficiencies (>66.3%). The adsorption capacity was 105.60mgg -1 for FHSA, much higher than that for the alumina nanoparticles (50.55mgg -1 ) and pure fungus hyphae (22.47mgg -1 ). The adsorption capacity calculated by the pure content of alumina in the FHSA is 340.27mgg -1 of alumina. Kinetics data reveal that the fluoride adsorption process on the FHSA was fast, nearly 90% fluoride adsorption can be achieved within 40min. The fluoride adsorption on the FHSA is mainly due to the surface complexes formation of fluoride with AlOH and the attraction between protonated NH 2 and fluoride through hydrogen bonding. Findings demonstrate that the FHSA has potential applicability in fluoride removal due to its strong fluoride adsorbility and the easy reclamation by its fast reversible assembly and disassembly feature. Copyright © 2017 Elsevier Inc. All rights reserved.

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

PubMed Central

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). However, the additives had no significant effect on the fluoride release into the infusions (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

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

PubMed

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). However, the additives had no significant effect on the fluoride release into the infusions (P > 0.05). Finally, drinking of the studied green teas cannot make a significant contribution to the daily dietary intake of F for consumers.

Tissue distributions of fluoride and its toxicity in the gills of a freshwater teleost, Cyprinus carpio.

PubMed

Cao, Jinling; Chen, Jianjie; Wang, Jundong; Wu, Xiangtian; Li, Yundong; Xie, Lingtian

2013-04-15

Fish take up fluoride directly from water and are susceptible to fluoride contamination of their environment. In this study, we examined the tissue distributions of fluoride and its toxicity in the gills of the common carp (Cyprinus carpio) chronically exposed to fluoride. Carp were exposed to a range of aqueous fluoride (35-124 mg/L) and sampled at 30, 60 and 90 days. The accumulation of fluoride in the tissues increased with the level and duration of exposure. Steady state was not achieved under the experimental conditions. The gills accumulated the highest levels of fluoride followed by the liver>brain>kidney>muscle>intestine. A dose-dependent inhibition was observed for the enzyme activities of Na(+)-K(+)-ATPase and Ca(2+)-ATPase in the gills after the fish were exposed for 90 days. Also, accumulation of fluoride was associated with the inhibition of superoxide dismutase (SOD) activities and a dose-dependent stimulation of malondialdehyde (MDA) levels in the gill tissues, suggesting that fluoride promoted oxidative stress in the fish. Microscopic examinations revealed injuries to gill tissues and chloride cells, with the severity of injury increasing with exposure concentration. These results suggest that chronic exposure to elevated concentrations of fluoride may induce toxicity in the common carp. Copyright © 2012 Elsevier B.V. All rights reserved.

Toxicity of fluoride to microorganisms in biological wastewater treatment systems.

PubMed

Ochoa-Herrera, Valeria; Banihani, Qais; León, Glendy; Khatri, Chandra; Field, James A; Sierra-Alvarez, Reyes

2009-07-01

Fluoride is a common contaminant in a variety of industrial wastewaters. Available information on the potential toxicity of fluoride to microorganisms implicated in biological wastewater treatment is very limited. The objective of this study was to evaluate the inhibitory effect of fluoride towards the main microbial populations responsible for the removal of organic constituents and nutrients in wastewater treatment processes. The results of short-term batch bioassays indicated that the toxicity of sodium fluoride varied widely depending on the microbial population. Anaerobic microorganisms involved in various metabolic steps of anaerobic digestion processes were found to be very sensitive to the presence of fluoride. The concentrations of fluoride causing 50% metabolic inhibition (IC(50)) of propionate- and butyrate-degrading microorganisms as well as mesophilic and thermophilic acetate-utilizing methanogens ranged from 18 to 43 mg/L. Fluoride was also inhibitory to nitrification, albeit at relatively high levels (IC(50)=149 mg/L). Nitrifying bacteria appeared to adapt rapidly to fluoride, and a near complete recovery of their metabolic activity was observed after only 4d of exposure to high fluoride levels (up to 500 mg/L). All other microbial populations evaluated in this study, i.e., glucose fermenters, aerobic glucose-degrading heterotrophs, denitrifying bacteria, and H(2)-utilizing methanogens, tolerated fluoride at very high concentrations (>500 mg/L).

[The effects of topical fluoridation of Ketac Molar Aplicap glass-ionomer material on the growth of cariogenic bacteria contained in the dental plaque].

PubMed

Płuciennik-Stronias, Małgorzata; Zarzycka, Beata; Bołtacz-Rzepkowska, Elzbieta

2013-01-01

Dental caries is a bacterial disease. The most important element used in caries prevention is fluoride, which is derived from the air, diet or fluoride-containing preparations and materials, e.g. glass-ionomer restorations. Modern fluoride-containing restorative materials are capable of releasing fluoride to the environment. Fluoride can be also accumulated in glass-ionomer cements, thus an attempt was made to saturate these materials with fluoride. The aim of the study was to evaluate the effect of topical fluoridation of Ketac Molar Aplicap glass-ionomer cement on the growth of Lactobacillus spp. in the dental plaque. The study was carried out in 15 patients with good oral hygiene, in whom 35 fillings with conventional glass-ionomer material, Ketac Molar Aplicap, were performed. After 6 months, three-day dental plaque from these fillings was examined. Next, fluoride was rubbed on the glass-ionomer surface and the examination of three-day dental plaque was repeated. No statistically significant differences (p = 0.143) in the amounts of Lactobacillus spp. in the plaque collected prior to and after topical fluoridation were revealed. Fluoride rubbed in the conventional glass-ionomer cement, Ketac Molar Aplicap, did not affect the amount of Lactobacillus spp. in the dental plaque growing on this material.

Fluoride content of clay minerals and argillaceous earth materials

USGS Publications Warehouse

Thomas, Josephus; 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 <2-µm fractions of marine and nonmarine 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.

Associations between exposure to fluoridated drinking water and dental caries experience among children in two Australian states.

PubMed

Slade, G D; Davies, M J; Spencer, A J; Stewart, J F

1995-01-01

This study assessed associations between exposure to fluoride in water and dental caries experience among children in two Australian states. Cross-sectional data were obtained from 9,690 South Australian children aged 5-15 years and 10,195 Queensland children aged 5-12 years. School dental service practitioners recorded DMFS and dmfs data. A questionnaire to parents gained information about residential history that was used to calculate children's percent of lifetime exposed to fluoridated water. Greater exposure to fluoride in water was associated with lower dmfs and DMFS in both states (P < .01), although in South Australia the effect for DMFS was statistically significant only after controlling for extent of unknown fluoridation exposure and for fluoride supplements. Caries-fluoridation associations were stronger for dmfs compared with DMFS and for Queensland (5% of population fluoridated) compared with South Australia (70% of population fluoridated). Effects for DMFS persisted after controlling for socioeconomic factors. Fluoridation was associated with lower caries experience. The weaker association with DMFS in South Australia may be due to less caries and more fissure sealants in that state, and is consistent with a "diffusion" effect, whereby a high proportion of the population exposed to fluoridation diminishes differences among exposure groups.

Effects of different amine fluoride concentrations on enamel remineralization.

PubMed

Naumova, E A; Niemann, N; Aretz, L; Arnold, W H

2012-09-01

The aim of this study was to investigate the effects of decreasing fluoride concentrations on repeated demineralizing challenges on human enamel. In 24 teeth, 3mm×3mm windows were prepared on the buccal and lingual sides and treated in a cycling demineralization-remineralization model. Remineralization was achieved with 100, 10 and 0.1 ppm fluoride from anime fluoride. Coronal sections were cut through the artificial lesions, and three sections per tooth were investigated using polarized light microscopy and scanning electron microscopy with quantitative element analysis. The morphology of the lesions was studied, and the extensions of the superficial layer and the body of the lesion were measured. Using element analysis, the Ca, P and F content were determined. The body of the lesion appeared remineralized after application of 100 ppm fluoride, while remineralization of the lesion was less successful after application of 10 and 0.1 ppm fluoride. The thickness of the superficial layer increased with decreasing fluoride concentrations, and also the extension of the body of the lesion increased. Ca and P content increased with increasing fluoride concentrations. The effectiveness of fluoride in enamel remineralization increased with increasing fluoride concentration. A consistently higher level of fluoride in saliva should be a goal in caries prevention. Copyright © 2012 Elsevier Ltd. All rights reserved.

Modelling of fluoride removal via batch monopolar electrocoagulation process using aluminium electrodes

NASA Astrophysics Data System (ADS)

Amri, N.; Hashim, M. I.; Ismail, N.; Rohman, F. S.; Bashah, N. A. A.

2017-09-01

Electrocoagulation (EC) is a promising technology that extensively used to remove fluoride ions efficiently from industrial wastewater. However, it has received very little consideration and understanding on mechanism and factors that affecting the fluoride removal process. In order to determine the efficiency of fluoride removal in EC process, the effect of operating parameters such as voltage and electrolysis time were investigated in this study. A batch experiment with monopolar aluminium electrodes was conducted to identify the model of fluoride removal using empirical model equation. The EC process was investigated using several parameters which include voltage (3 - 12 V) and electrolysis time (0 - 60 minutes) at a constant initial fluoride concentration of 25 mg/L. The result shows that the fluoride removal efficiency increased steadily with increasing voltage and electrolysis time. The best fluoride removal efficiency was obtained with 94.8 % removal at 25 mg/L initial fluoride concentration, voltage of 12 V and 60 minutes electrolysis time. The results indicated that the rate constant, k and number of order, n decreased as the voltage increased. The rate of fluoride removal model was developed based on the empirical model equation using the correlation of k and n. Overall, the result showed that EC process can be considered as a potential alternative technology for fluoride removal in wastewater.

Laboratory investigations into the potential anticaries efficacy of fluoride varnishes.

PubMed

Lippert, Frank; Hara, Anderson Takeo; Martinez-Mier, Esperanza Angeles; Zero, Domenick T

2014-01-01

The purpose of this study was to investigate the potential anticaries efficacy of fluoride varnishes (FVs) by studying their ability to reharden and deliver fluoride to carious lesions and to release fluoride into saliva. Enamel carious lesions were created and allocated to 24 groups (11 FVs with two FV incubation times and two control groups) based on Knoop microhardness test values. FVs were applied to lesions, which were incubated in artificial saliva for two or six hours, with saliva being renewed hourly. FV was removed and lesions were remineralized in artificial saliva for 22 hours. Microhardness was measured and enamel fluoride uptake (EFU) was determined. Saliva samples (six-hour groups) were analyzed to determine fluoride release characteristics. Data were analyzed using analysis of variance. FVs differed considerably in their ability to reharden and deliver fluoride to carious lesions and in their fluoride release characteristics. Little consistency was found between investigated study variables for virtually all tested FVs. For example, a particular FV showed the highest EFU and fluoride release values but the lowest rehardening value. A longer FV contact time led to increased EFU for five of the 11 FVs. Some FVs delivered more fluoride to lesions in two hours than others did in six hours. Fluoride varnishes differ greatly in their in vitro anticaries efficacy.

Changing risk factors for fluorosis among South Australian children.

PubMed

Spencer, A John; Do, Loc G

2008-06-01

Research in the last decade has shown changing exposure patterns to discretionary fluorides and declining prevalence of fluorosis among South Australian children, raising the question of how risk factors for fluorosis have changed. To examine and compare risk factors for fluorosis among representative samples of South Australian children in 1992/1993 and 2002/2003. Similar sampling strategies and data collection methods were employed in the Child Fluoride Study (CFS) Marks 1 (1992/1993) and 2 (2002/2003). Participants in each CFS round were examined for fluorosis using the Thylstrup and Fejerskov (TF) Index. Exposure history was collected for fluoride in water, toothpaste, fluoride supplements and infant formula, allowing for a fluorosis risk assessment analysis. Data were re-weighted to represent the child population at each time. Changes in prevalence of fluorosis, defined as having a TF score of 1+ on maxillary central incisors, fluoride exposure and risk factors between the two rounds were evaluated. A total of 375 and 677 children participated in the 1992/1993 and 2002/2003 rounds respectively. Prevalence of fluorosis declined significantly from 45.3% to 25.9%. Reduced use of fluoride supplements and increased use of 400-550-ppm children F toothpaste were the most substantial fluoride exposure changes. Early toothpaste use, residence in fluoridated areas and fluoride supplement use were the risk factors in 1992/1993. Early toothpaste use and fluoride supplement use were not risk factors, leaving fluoridated water as the only risk factor among the common variables in 2002/2003. In an analysis stratified by the type of fluoridated toothpaste in 2002/2003, the large amount of toothpaste used was a risk factor in those who used 1000-ppm fluoridated toothpaste, and eating/licking toothpaste when toothpaste use started was a risk factor among children who used either 1000-ppm or 400-550-ppm fluoridated toothpaste. Introduction of the 400-550-ppm F toothpaste and use of smaller amount of toothpaste restricted risk associated with early toothpaste use. Less use and possibly a stricter fluoride supplements regimen also restricted fluorosis risk. Periodic monitoring of risk of fluorosis is required to adjust guidelines for fluoride use in caries prevention.

Fluoride Programs in the School Setting: Preventive Dental Health.

ERIC Educational Resources Information Center

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)

High School Forum.

ERIC Educational Resources Information Center

Herron, J. Dudley, Ed.

1980-01-01

Presents questions and answers about the fluoridation of water regarding the compounds added to drinking water in the fluoridation process, how raw water is tested for fluoride content, and how fluoride reacts with tooth enamel. (CS)

Mitigation of Fluorosis - A Review

PubMed Central

Dodamani, Arun S.; Jadhav, Harish C.; Naik, Rahul G.; Deshmukh, Manjiri A.

2015-01-01

Fluoride is required for normal development and growth of the body. It is found in plentiful quantity in environment and fluoride content in drinking water is largest contributor to the daily fluoride intake. The behaviour of fluoride ions in the human organism can be regarded as that of “double-edged sword”. Fluoride is beneficial in small amounts but toxic in large amounts. Excessive consumption of fluorides in various forms leads to development of fluorosis. Fluorosis is major health problem in 24 countries, including India, which lies in the geographical fluoride belt. Various technologies are being used to remove fluoride from water but still the problem has not been rooted out. The purpose of this paper is to review the available treatment modalities for fluorosis, available technologies for fluoride removal from water and ongoing fluorosis mitigation programs based on literature survey. Medline was the primary database used in the literature search. Other databases included: PubMed, Web of Science, Google Scholar, WHO, Ebscohost, Science Direct, Google Search Engine, etc. PMID:26266235

Total and Free Fluoride Concentration in Various Brands of Toothpaste Marketed in India

PubMed Central

Siddanna, Sunitha

2015-01-01

Background For fluoridated toothpaste to be effective in controlling dental caries, an adequate concentration of soluble fluoride must be available in the oral cavity. Aim To determine the total and free fluoride concentration in various brands of toothpaste marketed in India. Materials and Methods Three samples of 12 different toothpastes were purchased from supermarkets in Mysore city, Karnataka, India. Toothpastes were analysed in duplicate using a fluoride ion-specific electrode. The concentration of total fluoride (TF) and total soluble fluoride (TSF) were determined. Results Measured TF was consistent with that declared by the manufacturer in five products. Four toothpastes showed lower TF and two higher TF than declared. Most toothpastes exhibited TSF concentrations similar to the TF content except four samples that displayed considerably lower TSF than TF. Conclusion The measurement of total and free fluoride concentrations of toothpastes available in India showed inhomogenities. Therefore there is a need for stringent regulatory control measures for the determination of fluoride content in toothpastes in developing country like India. PMID:26557607

Fluoride Increases Superoxide Production and Impairs the Respiratory Chain in ROS 17/2.8 Osteoblastic Cells

PubMed Central

Fina, Brenda Lorena; Lombarte, Mercedes; Rigalli, Juan Pablo; Rigalli, Alfredo

2014-01-01

It is known that fluoride produces oxidative stress. Inflammation in bone tissue and an impairment of the respiratory chain of liver have been described in treatments with fluoride. Whether the impairment of the respiratory chain and oxidative stress are related is not known. The aim of this work was to study the effects of fluoride on the production of superoxide radical, the function of the respiratory chain and the increase in oxidative stress in ROS 17/2.8 osteoblastic cells. We measured the effect of fluoride (100 µM) on superoxide production, oxygen consumption, lipid peroxidation and antioxidant enzymes activities of cultured cells following the treatment with fluoride. Fluoride decreased oxygen consumption and increased superoxide production immediately after its addition. Furthermore, chronic treatment with fluoride increased oxidative stress status in osteoblastic cells. These results indicate that fluoride could damage bone tissue by inhibiting the respiratory chain, increasing the production of superoxide radicals and thus of the others reactive oxygen species. PMID:24964137

Effect of fluoride mouthwash on tensile strength of stainless steel orthodontic archwires

NASA Astrophysics Data System (ADS)

Fatimah, D. I.; Anggani, H. S.; Ismah, N.

2017-08-01

Patients with orthodontic treatment are commonly recommended to use a fluoride mouthwash for maintaining their oral hygiene and preventing dental caries. However, fluoride may affect the characteristics of stainless steel orthodontic archwires used during treatment. The effect of fluoride mouthwash on the tensile strength of stainless steel orthodontic archwires is still unknown. The purpose of this study is to know the effect of fluoride mouthwash on the tensile strength of stainless steel orthodontic archwires. Examine the tensile strength of 0.016 inch stainless steel orthodontic archwires after immersion in 0.05%, 100 ml fluoride mouthwash for 30, 60, and 90 min. There is no statistically significant difference in the tensile strength of stainless steel orthodontic archwires after immersed in fluoride mouthwash. The p-values on immersion fluoride mouthwash for 30, 60, and 90 min consecutively are 0.790; 0.742; and 0.085 (p > 0.05). The use of fluoride mouthwash did not have an effect on the tensile strength of stainless Steel orthodontic archwires.

The effects of sodium fluoride and stannous fluoride on the surface roughness of intraoral magnet systems.

PubMed

Obatake, R M; Collard, S M; Martin, J; Ladd, G D

1991-10-01

Four types of intraoral magnets used for retention of overdentures and maxillofacial prostheses were exposed in vitro to SnF2 and NaF to determine the effects of fluoride rinses on surface roughness. The surface roughness (Ra) was measured, after simulated 1, 2, and 5 years' clinical exposure to fluoride (31, 62, and 155 hours). The mean change in Ra was calculated for each period of simulated exposure to fluoride for each magnet type. Two-way ANOVA was used to compare mean change in Ra between magnets within fluorides, and between fluorides within magnets. Paired t tests were used to compare mean change in Ra within fluorides within magnets. The mean change in Ra increased for all magnets after simulated 1, 2, and 5 years of exposure to SnF2 and NaF (p less than 0.03). Using the change in Ra as an indicator for corrosion, PdCo encapsulated SmCo5 magnets and their keepers demonstrated the least corrosion with either fluoride.

Fluoride and Water (For Parents)

MedlinePlus

... the label. The Controversy Over Fluoride Opponents of water fluoridation have questioned its safety and effectiveness; however, there has been little evidence to support these concerns. Scientific research continues to show the benefits of fluoride when ...

FLUORIDE CONTENT OF COMMERCIALLY AVAILABLE SOY MILK PRODUCTS IN THAILAND.

PubMed

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.

Risk perception, psychological heuristics and the water fluoridation controversy.

PubMed

Perrella, Andrea M L; Kiss, Simon J

2015-04-29

Increasingly, support for water fluoridation has come under attack. We seek an explanation, focusing on the case of Waterloo, Ontario, where a 2010 referendum overturned its water fluoridation program. In particular, we test whether individuals perceive the risks of water fluoridation based not on 'hard' scientific evidence but on heuristics and cultural norms. A sample of 376 residents in Waterloo were surveyed in June 2012 using random digit dialing. We use factor analysis, OLS regression, as well as t-tests to evaluate a survey experiment to test the credibility hypothesis. Perceptions of fluoride as a risk are lower among those who perceive fluoride's benefits (B = .473, p < 0.001) and those whose cultural view is 'egalitarian' (B = .156, p < 0.05). The experiment shows a lower level of perception of fluoride's benefits among respondents who are told that water fluoridation is opposed by a national advocacy group (Group A) compared to those who are told that the government and the World Health Organization support fluoridation (Group B) (t = 1.6547, p < 0.05), as well as compared to the control group (t = 1.8913, p < 0.05). There is no difference between Group B and the control, possibly because people's already general support for fluoridation is less prone to change when told that other public organizations also support fluoridation. Public health officials should take into account cultural norms and perceptions when individuals in a community appear to rise up against water fluoridation, with implications for other public health controversies.

Bioavailability of fluoride in drinking water: a human experimental study.

PubMed

Maguire, A; Zohouri, F V; Mathers, J C; Steen, I N; Hindmarch, P N; Moynihan, P J

2005-11-01

It has been suggested that systemic fluoride absorption from drinking water may be influenced by the type of fluoride compound in the water and by water hardness. Using a human double-blind cross-over trial, we conducted this study to measure c(max), T(max), and Area Under the Curve (AUC) for plasma F concentration against time, following the ingestion of naturally fluoridated hard and soft waters, artificially fluoridated hard and soft waters, and a reference water. Mean AUC over 0 to 8 hours was 1330, 1440, 1679, 1566, and 1328 ng F.min.mL(-1) for naturally fluoridated soft, naturally fluoridated hard, artificially fluoridated soft, artificially fluoridated hard, and reference waters, respectively, with no statistically significant differences among waters for AUC, c(max), or T(max). Any differences in fluoride bioavailability between drinking waters in which fluoride is present naturally or added artificially, or the waters are hard or soft, were small compared with large within- and between-subject variations in F absorption. Abbreviations used: F, fluoride; AUC, Area under the Curve for plasma F concentration against time; AUC(0-3), Area under the Curve for plasma F concentration against time for 0 to 3 hours following water ingestion; AUC(0-8), Area under the Curve for plasma F concentration against time for 0 to 8 hours following water ingestion; c(max), maximum plasma F concentration corrected for baseline plasma F and dose (i.e., F concentration of individual waters); T(max), time of c(max).

Influence of uncertainties of isotopic composition of the reprocessed uranium on effectiveness of its enrichment in gas centrifuge cascades

NASA Astrophysics Data System (ADS)

Smirnov, A. Yu; Mustafin, A. R.; Nevinitsa, V. A.; Sulaberidze, G. A.; Dudnikov, A. A.; Gusev, V. E.

2017-01-01

The effect of the uncertainties of the isotopic composition of the reprocessed uranium on its enrichment process in gas centrifuge cascades while diluting it by adding low-enriched uranium (LEU) and waste uranium. It is shown that changing the content of 232U and 236U isotopes in the initial reprocessed uranium within 15% (rel.) can significantly change natural uranium consumption and separative work (up to 2-3%). However, even in case of increase of these parameters is possible to find the ratio of diluents, where the cascade with three feed flows (depleted uranium, LEU and reprocessed uranium) will be more effective than ordinary separation cascade with one feed point for producing LEU from natural uranium.

Reconfigurable and Reprocessable Thermoset Shape Memory Polymer with Synergetic Triple Dynamic Covalent Bonds.

PubMed

Wang, Yongwei; Pan, Yi; Zheng, Zhaohui; Ding, Xiaobin

2018-04-20

Degradable shape memory polymers (SMPs), especially for polyurethane-based SMPs, have shown great potential for biomedical applications. How to reasonably fabricate SMPs with the ideal combination of degradability, shape reconfigurability, and reprocessability is a critical issue and remains a challenge for medical disposable materials. Herein, a shape memory poly(urethane-urea) with synergetic triple dynamic covalent bonds is reported via embedding polycaprolactone unit into poly(urethane-urea) with the hindered urea dynamic bond. The single polymer network is biodegradable, thermadapt, and reprocessable, without sacrificing the outstanding shape memory performance. Such a shape memory network with plasticity and reprocessability is expected to have significant and positive impact on the medical device industry. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Is there a need of extra fluoride in children?

PubMed

Gupta, Sunil Kumar; Gupta, R C; Gupta, A B

2009-09-01

The issues related to fluoridation of water or fortification of tooth paste with compounds of fluorides are controversial. Fluoride is stored mainly in the bones, where it increases the density and changes the internal architecture, makes it osteoporotic and more prone to fractures. Fluoride consumption by human beings increases the general cancer death rate, disrupts the synthesis of collagen and leads to the breakdown of collagen in bone, tendon, muscle, skin, cartilage, lungs, kidney and trachea, causing disruptive effect on various tissues in the body. It inhibits antibody formation, disturbs immune system and makes the child prone to malignancy. Fluoride has been categorized as a protoplasmic poison and any additional ingestion of fluoride by children is undesirable.

SEPARATION OF PROTACTINIUM FROM MOLTEN SALT REACTOR FUEL COMPOSITIONS

DOEpatents

Shaffer, J.H.; Strain, J.E.; Cuneo, D.R.; Kelly, M.J.

1963-11-12

A method for selectively precipitating protactinium from a neutron- irradiated fused fluoride salt composition comprising at least one metal fluoride selected from the group consisting of an alkali metal fluoride and an alkaline earth metal fluoride containing dissolved thorium-232 values is presented. An inorganic metal oxide corresponding to any of the metal fluorides of the composition is also added. (AEC)

[Geographical distribution of fluoride in the public water supply in the province of Tucumán, Argentina].

PubMed

Durán, Raúl Alberto; Durán, Estela Liliana; Ojeda, Graciela de Jesús; Castellanos, Walter Alfredo

2017-01-01

This work studied the geographical distribution of fluoride content in the public water supply in the province of Tucumán, Argentina. A total of 1,210 samples were collected in 190 localities of the 17 departments of the province during the 2008-2012 period. The analytical determination was performed using the SPADNS method and QGis 2.16 was used for processing the information. The fluoride content requirements in the studied localities were determined according to the Argentine Food Code. The results showed that 94% of population studied consumed water with fluoride concentrations below the recommended limits, 5% were exposed to fluoride concentrations above the required maximum limit and 1% consumed water at optimal fluoride concentrations. The maps showed a heterogeneous geographical distribution of fluorides, in which areas with deficit, excess and recommended values of fluorides can be differentiated; in some departments an inverse relationship between the density of the hydrological network and fluoride concentration can be observed. In the capital of the province, the average value found was 0.32 mg/l, presenting a homogeneous geographical distribution. The information obtained is indispensable for the proper management of fluoride, so as to improve public health through policy.

Reducing Exposure to High Fluoride Drinking Water in Estonia—A Countrywide Study

PubMed Central

Indermitte, Ene; Saava, Astrid; Karro, Enn

2014-01-01

Fluoride is a naturally occurring contaminant in groundwater in Estonia. There are several regions in Estonia with fluoride contents in public water supplies as high as 7 mg/L. Long-term exposure to high-fluoride drinking water may have several adverse health effects, primarily dental fluorosis. The opportunities for exposure reduction rely highly on water treatment technologies. Since 2004 public water suppliers in Estonia have made efforts to diminish fluoride content in drinking water systems. A follow-up study on a country level was carried out in 2004–2012 to analyze the changes in population exposure to excessive (over 1.5 mg/L) fluoride in drinking water and to get information about the reduction methods applied by public water supplies (PWS) to optimize the fluoride levels in public water system. The results showed that bigger PWS have been more effective in fluoride reduction measures than small PWS. The main methods used to lower the fluoride content were reverse osmosis technology and replacement of water sources with new ones (new drilled wells). As a result of all the measures taken the overall high-fluoride exposure has been reduced substantially (82%). PMID:24637908

Characterization of a fluoride-resistant bacterium Acinetobacter sp. RH5 towards assessment of its water defluoridation capability

NASA Astrophysics Data System (ADS)

Mukherjee, Shraboni; Yadav, Vaibhav; Mondal, Madhumanti; Banerjee, Soumya; Halder, Gopinath

2017-07-01

The present study investigates the defluoridation capability of fluoride-resistant bacteria from contaminated groundwater collected from Asanjola and Madhabpur, West Bengal, India. Seven strains of fluoride-resistant bacteria were isolated employing culture media containing 10-250 mg/L of fluoride to evaluate their ability in reducing fluoride concentration in water. Five isolates exhibited significant amount of reduction in fluoride. Isolate RH5 achieved a maximum fluoride removal of 25.7 % from the media at 30 °C and pH 7 after 8 days of incubation. Based on morphological, physiological characteristics and analysis of 16S rDNA gene sequence, isolate RH5 was identified as Acinetobacter sp. RH5. Growth of RH5 was analysed at a diverse pH range, and it could thrive at pH 5-10. The present investigation revealed that the selective pressure of fluoride results in growth of fluoride-resistant bacteria capable of secreting high-affinity anion-binding compounds. This bacterium played a dominant bioremediative role by concentrating the anions so that they become less available. Hence, the fluoride-resistant bacteria, Acinetobacter sp. RH5, could be used as a promising strain for application in water defluoridation from contaminated sites.

Reducing exposure to high fluoride drinking water in Estonia-a countrywide study.

PubMed

Indermitte, Ene; Saava, Astrid; Karro, Enn

2014-03-14

Fluoride is a naturally occurring contaminant in groundwater in Estonia. There are several regions in Estonia with fluoride contents in public water supplies as high as 7 mg/L. Long-term exposure to high-fluoride drinking water may have several adverse health effects, primarily dental fluorosis. The opportunities for exposure reduction rely highly on water treatment technologies. Since 2004 public water suppliers in Estonia have made efforts to diminish fluoride content in drinking water systems. A follow-up study on a country level was carried out in 2004-2012 to analyze the changes in population exposure to excessive (over 1.5 mg/L) fluoride in drinking water and to get information about the reduction methods applied by public water supplies (PWS) to optimize the fluoride levels in public water system. The results showed that bigger PWS have been more effective in fluoride reduction measures than small PWS. The main methods used to lower the fluoride content were reverse osmosis technology and replacement of water sources with new ones (new drilled wells). As a result of all the measures taken the overall high-fluoride exposure has been reduced substantially (82%).

Geographical mapping of fluoride levels in drinking water sources in Nigeria.

PubMed

Akpata, Enosakhare S; Danfillo, I S; Otoh, E C; Mafeni, J O

2009-12-01

Knowledge of fluoride levels in drinking water is of importance in dental public health, yet this information is lacking, at national level, in Nigeria. To map out fluoride levels in drinking water sources in Nigeria. Fluoride levels in drinking water sources from 109 randomly selected Local Government Areas (LGAs) in the 6 Nigerian geopolitical zones were determined. From the results, maps showing LGAs with fluoride concentrations exceeding 0.3 ppm, were drawn. ANOVA and t-test were used to determine the significance of the differences between the fluoride levels in the drinking water sources. Fluoride levels were low in most parts of the country, being 0.3 ppm or less in 62% of the LGAs. Fluoride concentrations were generally higher in North Central geopolitical zone, than the other zones in the country (p<0.05). In a few drinking water sources, fluoride concentrations exceeded 1.5 ppm, but was as high as 6.7 ppm in one well. Only 9% of the water sources were from waterworks. Most of the water sources in Nigeria contained low fluoride levels; but few had excessive concentrations and need to be partially defluoridated, or else alternative sources of drinking water provided for the community.

The influence of age on the distribution, metabolism and excretion of methoxyflurane in Fischer 344 rats: a possible relationship to nephrotoxicity.

PubMed

Bell, L E; Hitt, B A; Mazze, R I

1975-10-01

Age as a factor in methoxyflurane nephrotoxicity was evaluated in Fischer 344 rats of various ages by determination of: 1) serum inorganic fluoride and methoxyflurane concentrations, and urinary inorganic fluoride excretion in methoxyflurane-exposed rats; 2) liver microsomal methoxyflurane defluorinase activity; and 3) distribution of injected sodium fluoride. Only rats in the youngest age group (6 weeks) did not develop nephrotoxicity after anesthesia. Older rats had a biphasic rather than a monophasic decay in serum methoxyflurane concentration and also had increased serum inorganic fluoride concentration and urinary inorganic fluoride excretion. Older rats also excreted a greater proportion of an injected dose of sodium fluoride compared to young rats. Microsomal methoxyflurane defluorinase specific activity was similar among rats of all ages. It is likely that increased availability of methoxyflurane due to its greater storage in fat led to more inorganic fluoride production in older compared to younger rats. Bone sequestration of inorganic fluoride in younger rats probably accounts for decreased serum inorganic fluoride levels in that group. Both factors cause significant differences in renal exposure to inorganic fluoride; thus the risk of nephrotoxicity is less in younger animals.

FLUORIDE CONCENTRATIONS IN INDUSTRIALIZED BEVERAGES CONSUMED BY CHILDREN IN THE CITY OF BAURU, BRAZIL

PubMed Central

Lodi, Carolina Simonetti; Ramires, Irene; Pessan, Juliano Pelim; Neves, Lucimara Teixeira das; Buzalaf, Marília Afonso Rabelo

2007-01-01

The increasing consumption of juices, soft drinks and teas among children has increased significantly fluoride ingestion at the age range of risk for development of dental fluorosis. Objective: The purpose of this study was to evaluate fluoride concentrations in some brands of industrialized beverages consumed by children in the city of Bauru, SP, Brazil. Material and Methods: 98 brands of beverages were analyzed, divided into 3 lots, comprising 36, 32 and 30 brands, respectively, for the first, second and third lots. Fluoride concentrations were determined by HMDS-facilitated diffusion, using a fluoride ion-specific electrode (Orion 9409). Results: Fluoride concentrations ranged between 0.04 and 1.76 μg F/mL. It was observed a wide variation in fluoride concentrations among the different brands, as well as the different lots of the same brand. There was no information on fluoride concentrations on the labels of any product. Conclusions: Some of the products analyzed could contribute significantly to the total fluoride intake and, thus, be important risk factors for development of dental fluorosis, which indicates the need of controlling the production of these beverages with respect to fluoride concentration. PMID:19089131

The dentist’s role in promoting community water fluoridation

PubMed Central

Melbye, Molly L.R.; Armfield, Jason M.

2013-01-01

Background and Overview Community water fluoridation is an important public health intervention that reduces oral health disparities and increases the health of the population. Promotion of its safety and effectiveness is critical to maintaining its widespread acceptance and ensuring its continued use. Dentists are a potentially important source of knowledge regarding the oral health benefits and safety of water fluoridation. However, few dentists regularly discuss fluorides, and water fluoridation in particular, with patients. The authors aim to describe and discuss the role and importance of dentists’ promotion of public water fluoridation, barriers to dentists’ involvement and some approaches that might influence dentists to promote water fluoridation more actively. Conclusions and Practice Implications Ongoing promotion of fluoridation by dentists is a key factor in ensuring sustained municipal water fluoridation. However, current undergraduate dental curricula do not adequately prepare dentists for this role, and continuing dental education may be insufficient to change clinical practice. Although smoking-cessation literature can shed some light on how to proceed, changing dentists’ practice behavior remains a largely unstudied topic. Dental associations are a key resource for dentists, providing information that can assist them in becoming advocates for water fluoridation. PMID:23283928

[Influence of different concentrations of fluoride in the water on epidemiologic indicators of oral health/disease].

PubMed

de Carvalho, Raquel Baroni; Medeiros, Urubatan Vieira de; dos Santos, Karina Tonini; Pacheco Filho, Antônio Carlos

2011-08-01

The scope of this study was to evaluate access to fluoride sources and oral health hygiene of 237 schoolchildren aged nine to sixteen, from three locations with different fluoride concentrations in the water. The fluoride level in the water of each area was analyzed by the selective electrode technique for the fluoride ion and the prevalence of dental caries and fluorosis were evaluated, respectively, by the DMFT and TSIF index, revealing a statistically significant difference (ANOVA; p <0,05) in the three locations: area without artificial fluoridation (DMTF 5.32 ± 3.49) and 16% of dental fluorosis; area with artificial fluoridation of 0.8 ppmF (DMTF 1.88 ± 2.22) and 94% of dental fluorosis; area with natural fluoridation of 2.54 ppmF (DMTF 3.96 ± 2.38) and 100% of dental fluorosis. The findings suggest that the epidemiologic indicators of oral health/disease are influenced by the presence of fluoride in the water supply and that supervision and orientation are fundamental in the correct use of fluoridated compositions, taking advantage of the maximum benefit in the control of dental caries with minimum risk of the occurrence of dental fluorosis.

Isolation and identification of Trichoderma harzianum from groundwater: An effective biosorbent for defluoridation of groundwater.

PubMed

Koshle, Shalini; Mahesh, S; Swamy, S Nanjunda

2016-01-01

The ability of non-viable form of Trichoderma harzianum, isolated from fluoride rich groundwater, was investigated as biosorbent for defluoridation of groundwater. Biosorption experiments were carried out at laboratory scale for removal of fluoride from groundwater. Significant effect of operational parameters on fluoride biosorption using Trichoderma harzianum as biosorbent was evaluated by varying operational parameters such as: initial fluoride concentration (2-8 mgl(-1)), biosorbent dose (0.4-1.6g/100ml), groundwater pH (6-10), temperature (30-50 degrees C) and biosorption time (30-120 min). The fluoride adsorption isotherms were modeled by Langmuir and Freundlich isotherms. Our result showed that fluoride biosorption, significantly increased with increase in groundwater pH, biosorbent dose, temperature and biosorption time, whereas increase in initial fluoride concentration reduced fluoride removal. The fluoride biosorption was rapid and maximum fluoride uptake was attained with 1.6g 100ml(-1) biosorbent within 60 min. Optimal pH 10 and temperature 50 degrees C gave maximum defluoridation efficiency. Freundlich isotherm fits well for defluoridation of groundwater using Trichoderma harzianum as biosorbent which indicated that biosorbent surface sites were heterogeneous in nature and fitted into heterogeneous site binding model.

Natural fluoride levels in the drinking water, water fluoridation and estimated risk of dental fluorosis in a tropical region of Brazil.

PubMed

Sampaio, Fábio Correia; Silva, Fábia Danielle; Silva, Andréa Cristina; Machado, Ana Thereza; de Araújo, Demétrius Antônio; de Sousa, Erik Melo

2010-01-01

The aim of the present study was to determine the natural fluoride levels in the drinking water supplies of a tropical area of Brazil to identify the cities at risk of high prevalence of dental fluorosis and to provide data for future water fluoridation projects in the region. The present study was carried out in Paraíba, in the north-eastern region of Brazil. A total of 223 cities were selected, and local health workers were instructed to collect three samples of drinking water: one from the main public water supply and the other two from a public or residential tap with the same water source. Fluoride analyses were carried out in duplicate using a fluoride-specific electrode coupled to an ion analyser. A total of 167 cities (75%) provided water samples for analysis. Fluoride levels ranged from 0.1 to 1.0 ppm (mg/l). Samples from most of the cities (n = 163, 73%) presented low levels of fluoride (< 0.5 mg/l). Samples from three cities (a total estimate of 28,222 inhabitants exposed) presented 'optimum' fluoride levels (0.6 to 0.8 mg/l). Samples from one city (16,724 inhabitants) with 1.0 mg/l of fluoride in the water were above the recommended level (0.7 mg/l) for the local temperature. It can be concluded that the cities in this area of Brazil presented low natural fluoride levels in the drinking water and could implement controlled water fluoridation projects when technical requirements are accomplished. A high or a moderate prevalence of dental fluorosis due to the intake of natural fluoride in the drinking water is likely to take place in one city only.

Fluoride gastrointestinal absorption from Na2FPO3/CaCO3- and NaF/SiO2-based toothpastes.

PubMed

Falcão, A; Tenuta, L M A; Cury, J A

2013-01-01

Depending on toothpaste formulation, part of the fluoride is insoluble and would not be totally absorbable in the gastrointestinal tract, thus changing dental fluorosis risk estimation. This hypothesis was tested with formulations with either all fluoride in a soluble form (NaF/SiO2-based toothpaste, 1,100 µg F/g as labeled, 1,129.7 ± 49.4 µg F/g soluble fluoride as analyzed) or with around 20% of insoluble fluoride (Na2FPO3/CaCO3-based toothpaste, 1,450 µg F/g as labeled, 1,122.4 ± 76.4 µg F/g soluble fluoride as analyzed). Toothpastes were evaluated either fresh or after accelerated aging, which increased insoluble fluoride to 40% in the Na2FPO3/CaCO3-based toothpaste. In a blind, crossover clinical trial conducted in five legs, 20 adult volunteers ingested 49.5 µg of total fluoride/kg body weight from each formulation or purified water (control). Whole saliva and urine were collected as bioavailability indicators, and pharmacokinetics parameters calculated showed significantly (p < 0.05) lower fluoride bioavailability for Na2FPO3/CaCO3 toothpaste, which was reduced further after aging. A significant correlation between the amount of soluble fluoride ingested, but not total fluoride, and fluoride bioavailability was found (r = 0.57, p < 0.0001). The findings suggest that the estimated fluorosis risk as a result of ingestion of Na2FPO3/CaCO3-based toothpastes should be calculated based on the toothpaste's soluble rather than total fluoride concentration. Copyright © 2012 S. Karger AG, Basel.

Antibacterial Effect of Silver Diamine Fluoride on Cariogenic Organisms.

PubMed

Lou, Yali; Darvell, Brain W; Botelho, Michael G

2018-05-01

To screen the possible antimicrobial activity of a range of clinically used, silver-based compounds on cariogenic organisms: silver diamine fluoride (SDF), silver fluoride, and silver nitrate. Preliminary screening disk-diffusion susceptibility tests were conducted on Mueller-Hinton agar plates inoculated with Streptococcus mutans, Lactobacillus acidophilus, and Actinomyces naeslundii, organisms known to be cariogenic. In order to identify which component of the silver compounds was responsible for any antibacterial (AB) effect, and to provide controls, the following were also investigated at high and low concentrations: sodium fluoride, ammonium fluoride, ammonium chloride, sodium fluoride, sodium chloride, and sodium nitrate, as well as deionized water as control. A volume of 10 pL of a test solution was dispensed onto a paper disk resting on the inoculated agar surface, and the plate incubated anaerobically at 37°C for 48 hours. The zones of inhibition were then measured. Silver diamine fluoride, silver fluoride, silver nitrate, and ammonium fluoride had significant AB effect (p < 0.05) on all three test organisms, although ammonium fluoride had no effect at low concentration; the remaining other compounds had no effect. Silver ions appear to be the principal AB agent at both high and low concentration; fluoride ions only have an AB effect at high concentration, while ammonium, nitrate, chloride and sodium ions have none. The anticaries effect of topical silver solutions appears restricted to that of the silver ions. Silver compounds, such as SDF, silver fluoride, and silver nitrate have AB effect against cariogenic organisms and these may have clinical impact in arresting or preventing dental decay. Sodium fluoride did not have AB effect under the conditions tested.

A cross-sectional study to assess the intelligence quotient (IQ) of school going children aged 10-12 years in villages of Mysore district, India with different fluoride levels.

PubMed

Sebastian, Shibu Thomas; Sunitha, S

2015-01-01

Besides dental and skeletal fluorosis, excessive fluoride intake can also affect the central nervous system without first causing the physical deformities associated with skeletal fluorosis. With the existence of widespread endemic fluorosis in India, the possible adverse effect of elevated fluoride in drinking water on the Intelligence Quotient (IQ) level of children is a potentially serious public health problem. This study assessed the Intelligence Quotient (IQ) of school going children aged 10-12 years in villages of Mysore district with different fluoride levels. In this cross-sectional study, 405 school children aged 10-12 years were selected from three villages in Mysore district with normal fluoride (1.20 mg F/l), low fluoride (0.40 mg F/l) and high fluoride (2.20 mg F/l) in their water supplies. A pre designed questionnaire was used to collect the required data for the survey which included socio demographic details, oral hygiene practices, diet history, body mass index and dental fluorosis. Intelligence Quotient was assessed using Raven's colored Progressive Matrices Test. In bivariate analysis, significant relationships were found between water fluoride levels and Intelligence Quotient of school children (P < 0.05). In the high fluoride village, the proportion of children with IQ below 90, i.e. below average IQ was larger compared to normal and low fluoride village. Age, gender, parent education level and family income had no significant association with IQ. School children residing in area with higher than normal water fluoride level demonstrated more impaired development of intelligence when compared to school children residing in areas with normal and low water fluoride levels. Thus, children's intelligence can be affected by high water fluoride levels.

Sirtuin1 and autophagy protect cells from fluoride-induced cell stress.

PubMed

Suzuki, Maiko; Bartlett, John D

2014-02-01

Sirtuin1 (SIRT1) is a nicotinamide adenine dinucleotide (NAD(+))-dependent deacetylase functioning in the regulation of metabolism, cell survival and organismal lifespan. Active SIRT1 regulates autophagy during cell stress, including calorie restriction, endoplasmic reticulum (ER) stress and oxidative stress. Previously, we reported that fluoride induces ER-stress in ameloblasts responsible for enamel formation, suggesting that ER-stress plays a role in dental fluorosis. However, the molecular mechanism of how cells respond to fluoride-induced cell stress is unclear. Here, we demonstrate that fluoride activates SIRT1 and initiates autophagy to protect cells from fluoride exposure. Fluoride treatment of ameloblast-derived cells (LS8) significantly increased Sirt1 expression and induced SIRT1 phosphorylation resulting in the augmentation of SIRT1 deacetylase activity. To demonstrate that fluoride exposure initiates autophagy, we characterized the expression of autophagy related genes (Atg); Atg5, Atg7 and Atg8/LC3 and showed that both their transcript and protein levels were significantly increased following fluoride treatment. To confirm that SIRT1 plays a protective role in fluoride toxicity, we used resveratrol (RES) to augment SIRT1 activity in fluoride treated LS8 cells. RES increased autophagy, inhibited apoptosis, and decreased fluoride cytotoxicity. Rats treated with fluoride (0, 50, 100 and 125ppm) in drinking water for 6weeks had significantly elevated expression levels of Sirt1, Atg5, Atg7 and Atg8/LC3 in their maturation stage enamel organs. Increased protein levels of p-SIRT1, ATG5 and ATG8/LC3 were present in fluoride-treated rat maturation stage ameloblasts. Therefore, the SIRT1/autophagy pathway may play a critical role as a protective response to help prevent dental fluorosis. Copyright © 2013 Elsevier B.V. All rights reserved.

The Role of Calcium in Ameliorating the Oxidative Stress of Fluoride in Rats.

PubMed

Mohamed, N E

2016-03-01

The present study was carried out to investigate the effects of fluoride toxicity on some biochemical, hormonal, and histological parameters of female rats and the protective role of calcium against such effects. Adult female albino rats were divided into five groups; control group received distilled water for 60 days, calcium group received calcium carbonate with dose of 50 mg/kg three times per week for 60 days, fluoride group received sodium fluoride with dose of 20 mg/kg three times per week for 60 days, calcium + fluoride group received calcium carbonate (50 mg/kg) then after 2 h received sodium fluoride (20 mg/kg) three times per week for 60 days, and fluoride + calcium group received sodium fluoride (20 mg/kg) three times per week for 30 days then received calcium carbonate (50 mg/kg) three times per week for another 30 days. The results showed that the levels of thiobarbituric acid reactive substances, urea, creatinine, alkaline phosphatase, triiodothyronine, thyroxine, parathormone, phosphorous, magnesium, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and gamma glutamyl transferase were significantly increased in rats treated with fluoride while serum estradiol, calcium, and organ glutathione were significantly decreased. The histological examination of the femur bone revealed that fluoride treatment induced thinning of bone trabeculae with wilding of marrow space, demineralization, and loss of trabeculae interconnections. Also, the histological examination of hepatic and renal tissues of fluoride-treated rats showed some damages in these tissues while administration of calcium carbonate for 30 or 60 days during fluoride treatment minimized such damages. It could be concluded that administration of calcium to female rats can ameliorate the hazardous effects of fluoride observed in the biochemical, hormonal, and histological parameters.

Sirtuin1 and autophagy protect cells from fluoride-induced cell stress

PubMed Central

Suzuki, Maiko; Bartlett, John D.

2014-01-01

Sirtuin1 (SIRT1) is an (NAD+)-dependent deacetylase functioning in the regulation of metabolism, cell survival and organismal lifespan. Active SIRT1 regulates autophagy during cell stress, including calorie restriction, endoplasmic reticulum stress and oxidative stress. Previously, we reported that fluoride induces endoplasmic reticulum (ER) stress in ameloblasts responsible for enamel formation, suggesting that ER-stress plays a role in dental fluorosis. However, the molecular mechanism of how cells respond to fluoride-induced cell stress is unclear. Here, we demonstrate that fluoride activates SIRT1 and initiates autophagy to protect cells from fluoride exposure. Fluoride treatment of ameloblast-derived cells (LS8) significantly increased Sirt1 expression and induced SIRT1 phosphorylation resulting in the augmentation of SIRT1 deacetylase activity. To demonstrate that fluoride exposure initiates autophagy, we characterized the expression of autophagy related genes (Atg); Atg5, Atg7 and Atg8/LC3 and showed that both their transcript and protein levels were significantly increased following fluoride treatment. To confirm that SIRT1 plays a protective role in fluoride toxicity, we used resveratrol (RES) to augmented SIRT1 activity in fluoride treated LS8 cells. RES increased autophagy, inhibited apoptosis, and decreased fluoride cytotoxicity. Rats treated with fluoride (0, 50 and 100 ppm) in drinking water for 6 weeks had significantly elevated expression levels of Sirt1, Atg5, Atg7 and Atg8/LC3 in their maturation stage enamel organs. Increased protein levels of p-SIRT1, ATG5 and ATG8/LC3 were present in fluoride-treated rat maturation stage ameloblasts. Therefore, the SIRT1/autophagy pathway may play a critical role as a protective response to help prevent dental fluorosis. PMID:24296261

Fluoride bioaccumulation and toxic effects on the survival and behavior of the endangered white-clawed crayfish Austropotamobius pallipes (Lereboullet).

PubMed

Aguirre-Sierra, Arantxa; Alonso, Alvaro; Camargo, Julio A

2013-08-01

Laboratory experiments were performed to examine the toxic effects of fluoride (F(-)) on the survival and behavior of white-clawed crayfish (Austropotamobius pallipes). Body fluoride contents (bioaccumulation) of test crayfish were also examined. No significant differences between male and female crayfish regarding mortality, escape (tail-flip) response, and fluoride bioaccumulation were detected. For mortality, 48-, 72-, 96-, 120-, 144-, 168-, and 192-h median lethal concentrations (LC50) were estimated to be 93.0, 55.3, 42.7, 36.5, 32.9, 30.6, and 28.9 mg F(-)/l, respectively. For the escape response, 48-, 72-, 96-, 120-, 144-, 168- and 192-h median effective concentrations (EC50) were estimated to be 18.4, 11.1, 8.6, 7.4, 6.7, 6.2 and 5.9 mg F(-)/l, respectively. Average food consumption in test crayfish tended to decrease with increasing water fluoride concentration with a 192-h lowest-observed effect concentration of 10.7 mg F(-)/l. These results indicate that the escape response was the most sensitive end point to fluoride toxicity followed by food consumption and mortality. Fluoride bioaccumulation in test crayfish increased with increasing water fluoride concentration and exposure time. The exoskeleton accumulated more fluoride than muscle. A comparison of the obtained results with previous data for other freshwater invertebrates shows that white-clawed crayfish are relatively tolerant to fluoride toxicity. We conclude that fluoride pollution in freshwater ecosystems should not be viewed as an important risk factor contributing to the catastrophic decrease of A. pallipes in many European countries. Our results indicate that fluoride bioaccumulation in A. pallipes might be used as a bioindicator of fluoride pollution in freshwater ecosystems where it is present.

Sub-chronic exposure to fluoride impacts the response to a subsequent nephrotoxic treatment with gentamicin.

PubMed

Cárdenas-González, Mariana; Jacobo Estrada, Tania; Rodríguez-Muñoz, Rafael; Barrera-Chimal, Jonatan; Bobadilla, Norma A; Barbier, Olivier C; Del Razo, Luz M

2016-02-01

Fluoride is an important groundwater contaminant, and more than 200 million people are exposed to high fluoride levels in drinking water, the major source of fluoride exposure. Exposure above 2 ppm of fluoride is associated with renal impairment in humans. In rats, moderate levels of fluoride induce kidney injury at early stages in which the glomerular filtration rate (GFR) is not altered. In the present study, we investigated if sub-nephrotoxic stimulus induced by fluoride might impact the response to a subsequent nephrotoxic treatment with gentamicin. Male Wistar rats (~21 days) were exposed to 0, 15 or 50 ppm of fluoride through drinking water during 40 days. Afer that, rats were co-exposed to gentamicin (40 mg kg(-1) day(-1), 7 days). Gentamicin induced a marked decrease in the GFR and an increase in urinary levels as well as the protein and mRNA expression of biomarkers of early kidney injury, such as Kim-1. Interestingly, gentamicin nephrotoxicity was less pronounced in groups previously exposed to fluoride than in the group only treated with gentamicin. Fluoride induced Hsp72, a cytoprotective molecule, which might have improved the response against gentamicin. Moreover, fluoride decreased the expression of megalin, a molecule necessary for internalization of gentamicin into the proximal tubule, potentially reducing gentamicin accumulation. The present results suggest that fluoride reduced gentamicin-induced nephrotoxicity by inducing a compensatory response carried out by Hsp72 and by decreasing gentamicin accumulation. These findings should not be interpreted to suggest that fluoride is a protective agent as megalin deficiency could lead to serious adverse effects on the kidney physiology. Copyright © 2015 John Wiley & Sons, Ltd.

Effect of long-term exposure to fluoride in drinking water on risks of bone fractures.

PubMed

Li, Y; Liang, C; Slemenda, C W; Ji, R; Sun, S; Cao, J; Emsley, C L; Ma, F; Wu, Y; Ying, P; Zhang, Y; Gao, S; Zhang, W; Katz, B P; Niu, S; Cao, S; Johnston, C C

2001-05-01

Findings on the risk of bone fractures associated with long-term fluoride exposure from drinking water have been contradictory. The purpose of this study was to determine the prevalence of bone fracture, including hip fracture, in six Chinese populations with water fluoride concentrations ranging from 0.25 to 7.97 parts per million (ppm). A total of 8266 male and female subjects > or =50 years of age were enrolled. Parameters evaluated included fluoride exposure, prevalence of bone fractures, demographics, medical history, physical activity, cigarette smoking, and alcohol consumption. The results confirmed that drinking water was the only major source of fluoride exposure in the study populations. A U-shaped pattern was detected for the relationship between the prevalence of bone fracture and water fluoride level. The prevalence of overall bone fracture was lowest in the population of 1.00-1.06 ppm fluoride in drinking water, which was significantly lower (p < 0.05) than that of the groups exposed to water fluoride levels > or =4.32 and < or =0.34 ppm. The prevalence of hip fractures was highest in the group with the highest water fluoride (4.32-7.97 ppm). The value is significantly higher than the population with 1.00-1.06 ppm water fluoride, which had the lowest prevalence rate. It is concluded that long-term fluoride exposure from drinking water containing > or =4.32 ppm increases the risk of overall fractures as well as hip fractures. Water fluoride levels at 1.00-1.06 ppm decrease the risk of overall fractures relative to negligible fluoride in water; however, there does not appear to be similar protective benefits for the risk of hip fractures.

Hospitalizations for dental infections: optimally versus nonoptimally fluoridated areas in Israel.

PubMed

Klivitsky, Amir; Tasher, Diana; Stein, Michal; Gavron, Etan; Somekh, Eli

2015-03-01

Odontogenic infections may result in local, systemic, and even potentially life-threatening complications. The authors investigated whether water fluoridation was associated with reduction in rates of hospitalizations due to odontogenic infections. The authors included cities in Israel that had fluoride concentrations of either 0.7 milligrams per liter or more (optimally fluoridated) or 0.5 mg/L or less (nonoptimally fluoridated) and that had a public water fluoride concentration consistent for the last decade. The authors compared hospitalization rates (per 10,000 children) for odontogenic infections in children younger than 18 years in each socioeconomic group between optimally and nonoptimally fluoridated cities. The authors included 1,413 hospitalizations between January 2005 and December 2011 of children residing in the 38 studied municipalities. The cities with the higher fluoride concentration reported a lower hospitalization rate (2.0 versus 4.3 for cities with a lower fluoride concentration; relative risk [RR]: 2.16; P < .001). When the authors divided cities into 3 socioeconomic groups, a large difference in hospitalization rates was seen in the lowest socioeconomic group (10.1 versus 2.6; RR: 3.79; P < .001) and the middle socioeconomic group (3.6 versus 1.9; RR: 2.35; P < .001) in optimally and nonoptimally fluoridated cities, respectively. No significant difference in hospitalization rates was apparent between the 2 fluoridation groups in the higher socioeconomic level. These results clearly indicate that there is an association between adequacy of water fluoridation and hospitalization due to dental infections among children and adolescents. This effect is more prominent in populations of lower socioeconomic status. Water fluoridation is associated with reduction in dental health disparity. Copyright © 2015 American Dental Association. Published by Elsevier Inc. All rights reserved.

Keep Your Mouth Healthy: Oral Care for Older Adults

MedlinePlus

... decay and gum disease by brushing daily with fluoride toothpaste and flossing. Also visit the dentist regularly ... Your Mouth Healthy Drink fluoridated water and use fluoride toothpaste. Fluoride protects against dental decay at all ...

Effect of fluoride ion on the stability of DNA hairpin

NASA Astrophysics Data System (ADS)

Liu, Chao; Zhai, Weili; Gong, Hongling; Liu, Yanhui; Chen, Hu

2017-06-01

Fluoride prevents tooth decay as an additive in oral hygiene products, while high dose intake of fluoride from contaminated drinking water leads to fluorosis. Here we studied the effect of fluoride ion on the stability of DNA double helix using magnetic tweezers. The equilibrium critical force decreases with increasing concentration of fluoride in the range from 1 mM to 100 mM. Our results give the first quantitative measurement of DNA stability in the presence of fluoride ion, which might disturb DNA-related biological processes to cause fluorosis.

PROCESS FOR THE PRODUCTION OF AMMONIUM URANIUM FLUORIDE

DOEpatents

Ellis, A.S.; Mooney, R.B.

1953-08-25

This patent relates to the preparation of ammonium uranium fluoride. The process comprises adding a water soluble fluoride to an aqueous solution of a uranous compound containing an ammonium salt, and isolating the resulting precipitate. This patent relates to the manufacture of uranium tetnafluoride from ammonium uranium fluoride, NH/sub 4/UF/sub 5/. Uranium tetrafluoride is prepared by heating the ammonium uranium fluoride to a temperature at which dissociation occurs with liberation of ammonium fluoride. Preferably the process is carried out under reduced pressure, or in a current of an inert gas.

Improving Dental Health of DOD Related Persons Assigned to Okinawa by Using Fluoridated Salt in Lieu of Water Fluoridation: A Comparative Analysis

DTIC Science & Technology

1999-04-01

1994-1997). During this time, the 18th Medical Group (MDG) set fluoridating the base water supply as a goal to prevent dental caries – a noble and...related personnel. Supplemental fluoride may be an effective method of improving oral health by reducing dental caries . Water and salt fluoridation ...372-5,381. 9 Colonel Canning and Mr. Noorda, “Talking Paper on Fluoridation of Kadena AB Drinking Water ,” 26 Apr 1995. 5 Chapter 2 Dental Caries The

[Influence of natural fluoride concentration in drinking water on dental health of first class pupils in an area with enhanced fluoride content at the beginning of the 21st century].

PubMed

Steinmeyer, R

2011-08-01

Since the end of the first half of the 20 (th) century it is well-known that fluoride concentrations in drinking water of about 1 ppm reduce the prevalence of dental caries by about 40-60%. This knowledge led to the fluoridation of drinking water during the second half of the 20 (th) century in many countries, including East Germany. Although the natural F (-) content in drinking water in Germany is usually very low, the eastern Eifel is one of the few larger areas in Germany with (nearly) optimal (0.7-1.0 ppm) or moderately enhanced (0.3-0.7 ppm) natural fluoride concentrations in drinking water. 30 years ago, in 1977, the caries prevalence of children of various age groups in the fluoride-rich areas of the eastern Eifel was established by Einwag to be about 40% lower than in adjacent fluoride-poor regions (0.1 ppm). Meanwhile fluoride has become available from many different sources for children of any age: e. g., toothpaste (with 500 ppm fluoride even for very young children who just got the first tooth), fluoridated salt, professional fluoride applications (paid by health insurances), the rising consumption of mineral waters (many of which have a fluoride content >0.3 ppm). This poses the question of the current influence of enhanced natural drinking water fluoride concentrations on caries prevalence in children. The results of the dental examinations of 9 555 pupils (6 or 7 years old) of the first classes of all 63 primary schools in the Landkreis Mayen-Koblenz from 5 years (2004/2005-2008/2009) are compared to the fluoride content of the drinking water. The data show no obvious correlation between dental health and fluoride concentration for any of the dental health parameters investigated. However, in spite of the low geographic resolution of social parameters, there was a notable connection between dental health status and sociodemographic indicators for the respective region. 30 years after the study by Einwag in the same region, the natural fluoride content of drinking water either had no influence on dental health at all, or this influence is so diminutive that it is exceeded by far by sociodemographic factors. Obviously there is much more fluoride available from other sources nowadays compared to 30 years ago. The results may also have implications for the administration of fluoride tablets and support the recommendations of the DGZMK (Deutsche Gesellschaft für Zahn-, Mund- und Kieferheilkunde) from the year 2000, restricting the administration of fluoride tablets to special situations following an individual anamnesis of fluoride uptake. © Georg Thieme Verlag KG Stuttgart · New York.

Fluoride release, recharge and mechanical property stability of various fluoride-containing resin composites.

PubMed

Naoum, S; Ellakwa, A; Martin, F; Swain, M

2011-01-01

To determine the fluoride release and recharge of three fluoride-containing resin composites when aged in deionized water (pH 6.5) and lactic acid (pH 4.0) and to assess mechanical properties of these composites following aging. Three fluoride-containing resin composites were analyzed in this study; a new giomer material named Beautifil II, Gradia Direct X, and Tetric EvoCeram. A glass ionomer cement, Fuji IX Extra, was also analyzed for comparison. Specimens were fabricated for two test groups: group 1 included 10 disc specimens initially aged 43 days in deionized water (five specimens) and lactic acid (five specimens). The fluoride release from these specimens was measured using a fluoride-specific electrode on nine specific test days during the aging period. Following 49 days of aging, each specimen was recharged in 5000 ppm neutral sodium fluoride solution for 5 minutes. Specimen recharge was then repeated on a weekly basis for 3 weeks. The subsequent fluoride rerelease was measured at 1, 3, and 7 days after each recharge episode. Group 2 included six disc specimens aged for 3 months in deionized water (three specimens) and lactic acid (three specimens). The hardness and elastic modulus of each specimen was measured using nano-indentation at intervals of 24 hours, 1 month, and 3 months after fabrication. Two-way factorial analysis of variance (ANOVA) and post-hoc (Tukey) testing was used to assess the influence of storage media (two levels) and composite type (three levels) on the fluoride release, fluoride rerelease, hardness, and elastic modulus of the assessed materials. The level of significance was set at p=0.05. All three composites demonstrated fluoride release and recharge when aged in both deionized water and lactic acid. The cumulative fluoride released from Beautifil II into both media was substantially greater than the fluoride released from Gradia Direct X and Tetric EvoCeram after 43 days aging and was significantly (p<0.05, ANOVA, Tukey test) greater during several analysis periods. Beautifil II demonstrated the greatest recharge ability of the three composites over the 3-week recharge period in both media. Fuji IX Extra demonstrated a significantly (p<0.05) greater fluoride release and recharge compared with the three resin composites. The elastic modulus and hardness of the three composites did not decrease significantly (p<0.05) with fluoride release or fluid uptake over the 3-month aging period, in either media. The three composites in the present study demonstrated fluoride release (Beautiful II > Gradia Direct X > Tetric EvoCeram) and fluoride recharge (Beautiful II > Gradia Direct X > Tetric EvoCeram). This capability raises the possibility of fluoride-containing composites exhibiting a lower incidence of recurrent caries than non fluoride–containing composites. The mechanical properties of each composite did not diminish with aging and fluoride release over the testing period.

Evaluation and comparison of quantity and pattern of fluoride release from orthodontic adhesives: an in vitro study.

PubMed

Regalla, Ravindra Reddy; Jadav, Chandulal; Babu, Devatha Ashok; Sriram, Roopa Rani S; Sriram, Sanjay Krishna; Kattimani, Vivekanand S

2014-01-01

Orthodontic treatment has gained popularity since beginning of era of dentistry. Now a day, everyone is conscious about their appearance, smile and function. During orthodontic treatment use of brackets and adhesives are common. The bonding of brackets will cause demineralization which requires the fluoridation. So the study has been under- taken to analyze the pattern of fluoride release by commercially available adhesive bonding material for the prevention of demineralization. To evaluate and compare the clinical significance of quantity and pattern of fluoride release from three commercially available adhesives. To assess the pattern of fluoride release and quantity, to reduce the decalcification of enamel around orthodontic brackets and bands during treatment and to prevent further use of topical fluoride both office and self-use agents for prevention of demineralization/for remineralization. The comparison of quantity and pattern of fluoride release study involved commercially available bonding adhesives. They are: Group I--resin reinforced glass Ionomer light cure material (OrthoLC), Group II--fluoride releasing composite resin material (Excel) and Group III--conventional composite (Relay-a-bond) evaluated on 78 freshly extracted premolar teeth divided into three groups consisting 26 specimens in each group. The prepared specimens were stored in artificial saliva at 37°C in an incubator for subsequent fluoride analysis using ORION ion selective electrode coupled with ionalyzer 901. Fluoride analysis made at 24 hours intervals for first 3 consecutive days and thereafter at the end of 10th, 17th, 24th and 31st day of bonding. The data obtained were tabulated and interpreted by statistical analysis using 't' test and one-way analysis of variance (ANOVA). The quantity of fluoride release in groups I and II was significant even at the end of 31st day. The one-way AVOVA showed intra and inter group significance in the quantity of fluoride release. But group III with zero fluoride release with significant decalcification on enamel which requires external use of topical fluorides. The pattern of fluoride released was 3.06 ppm for group I and 2.01 ppm for group II and was declined sharply after 24 hours; and continued to decline in subsequent weeks. Mean quantity of fluoride release by group I was 15.08 ppm were as group II was 9.02 ppm over the test period of 31 days. At the end of 31st day the group I bonding adhesive was releasing considerable amount of fluoride compared to group II whereas group III was nil. At all the periods inter and intra group mean values were highly significant. And group III acted as base line or control group as it was non-fluoride releasing material. Both the fluoride releasing adhesive bond material are useful to reduce the risk of demineralization and further prevent the usage of topical fluoride application and reduce cost and clinical visiting time for both patient and clinician.

EOS Data Products Latency and Reprocessing Evaluation

NASA Astrophysics Data System (ADS)

Ramapriyan, H. K.; Wanchoo, L.

2012-12-01

NASA's Earth Observing System (EOS) Data and Information System (EOSDIS) program has been processing, archiving, and distributing EOS data since the launch of Terra platform in 1999. The EOSDIS Distributed Active Archive Centers (DAACs) and Science-Investigator-led Processing Systems (SIPSs) are generating over 5000 unique products with a daily average volume of 1.7 Petabytes. Initially EOSDIS had requirements to make process data products within 24 hours of receiving all inputs needed for generating them. Thus, generally, the latency would be slightly over 24 and 48 hours after satellite data acquisition, respectively, for Level 1 and Level 2 products. Due to budgetary constraints these requirements were relaxed, with the requirement being to avoid a growing backlog of unprocessed data. However, the data providers have been generating these products in as timely a manner as possible. The reduction in costs of computing hardware has helped considerably. It is of interest to analyze the actual latencies achieved over the past several years in processing and inserting the data products into the EOSDIS archives for the users to support various scientific studies such as land processes, oceanography, hydrology, atmospheric science, cryospheric science, etc. The instrument science teams have continuously evaluated the data products since the launches of EOS satellites and improved the science algorithms to provide high quality products. Data providers have periodically reprocessed the previously acquired data with these improved algorithms. The reprocessing campaigns run for an extended time period in parallel with forward processing, since all data starting from the beginning of the mission need to be reprocessed. Each reprocessing activity involves more data than the previous reprocessing. The historical record of the reprocessing times would be of interest to future missions, especially those involving large volumes of data and/or computational loads due to complexity of algorithms. Evaluation of latency and reprocessing times requires some of the product metadata information, such as the beginning and ending time of data acquisition, processing date, and version number. This information for each product is made available by data providers to the ESDIS Metrics System (EMS). The EMS replaced the earlier ESDIS Data Gathering and Reporting System (EDGRS) in FY2005. Since then it has collected information about data products' ingest, archive, and distribution. The analysis of latencies and reprocessing times will provide an insight to the data provider process and identify potential areas of weakness in providing timely data to the user community. Delays may be caused by events such as system unavailability, disk failures, delay in level 0 data delivery, availability of input data, network problems, and power failures. Analysis of metrics will highlight areas for focused examination of root causes for delays. The purposes of this study are to: 1) perform a detailed analysis of latency of selected instrument products for last 6 years; 2) analyze the reprocessed data from various data providers to determine the times taken for reprocessing campaigns; 3) identify potential reasons for any anomalies in these metrics.

A 4-year assessment of a new water-fluoridation scheme in New South Wales, Australia.

PubMed

Blinkhorn, Anthony S; Byun, Roy; Mehta, Pathik; Kay, Meredith

2015-06-01

To monitor the changes in dental caries prevalence of 5- to 7-year-old children living in a fluoridated area, a newly fluoridated area and in an area without water fluoridation, in NSW, Australia. Dental caries prevalence was recorded for 5- to 7-year-old children, living in the three study locations, by six trained and calibrated examiners in 2008, 2010 and 2012. A questionnaire recorded demographic data, toothbrushing behaviour and sugary drink consumption. Caries experience was measured using the decayed, missing, and filled teeth (dmft) index for primary teeth, the percentage of children who were caries free and the significant caries index. Univariate analysis was undertaken to determine independent predictors of caries. The caries prevalence changed over time. In 2008, the mean dmft index was 1.40 for the fluoridated area, 2.02 for the area about to fluoridate and 2.09 for the unfluoridated control. By 2012, these mean dmft scores were 0.69, 0.72 and 1.21, respectively. In the two areas where children received fluoridated water, the significant caries index was 2.30 for the fluoridated area and 2.40 for the newly fluoridated area. The significant caries score for children in the unfluoridated location was 3.93. Multivariate analysis showed that over time the differences in dental caries prevalence between the established fluoride area and the newly fluoridated area diminished. However, children in the unfluoridated control area continued to demonstrate significant differences in the mean number of decayed teeth compared with children in the fluoridated comparator sites, and the proportions of children free from decay were significantly higher in the fluoridated areas than in the unfluoridated area. Fluoridation of public water supplies in Gosford and Wyong offers young children better dental health than those children who do not have access to this public health measure. © 2015 FDI World Dental Federation.

Prevalence of dental caries and dental fluorosis among 12 and 15 years old school children in relation to fluoride concentration in drinking water in an endemic fluoride belt of Andhra Pradesh.

PubMed

Shekar, Chandra; Cheluvaiah, Manjunath Bhadravathi; Namile, Dinesh

2012-01-01

The published literature on the prevalence and severity of dental caries and dental fluorosis among school going children in Nalgonda district - An Endemic Fluoride belt was lacking . To assess the prevalence and severity of dental fluorosis and dental caries among 12 and 15 years old children in relation to fluoride concentration in drinking water . It was a cross-sectional study, done in Nalgonda district of Andhra Pradesh, India (endemic fluoride belt) . 5 of the 59 mandals in the district of Nalgonda were selected by simple random sampling. Then, 3 schools from each of these selected mandals were chosen at random. All the eligible 6 th and 9 th standard children were considered for final analysis. The demographic and other relevant information was collected by 3 trained and calibrated dentists, using a structured questionnaire. Dental caries were recorded using dentition status and treatment needs and fluorosis were recorded by Dean's fluorosis index. The statistical analysis was done using SPSS version 16. The prevalence of dental caries among children was 56.3% with the highest in below optimal fluoride area (71.3%) and lowest in optimal fluoride area (24.3%). The prevalence of dental fluorosis was 71.5%. The prevalence was 39.7% in below optimal fluoride area and 100% in high and very fluoride areas. The prevalence and severity of fluorosis increased with increasing fluoride concentration. The caries experience was more among boys than girls. There was a negative correlation between dental caries and fluoride concentration for the entire study population. However, in high fluoride areas, there was a positive correlation between fluoride concentration and dental caries. Water defluoridation on an urgent basis is a priority here than water fluoridation, because the prevalence and severity of dental flurorosis is very high.

Associations between fluorosis of permanent incisors and fluoride intake from infant formula, other dietary sources and dentifrice during early childhood

PubMed Central

Levy, Steven M.; Broffitt, Barbara; Marshall, Teresa A.; Eichenberger-Gilmore, Julie M.; Warren, John J.

2017-01-01

Objectives The authors describe associations between dental fluorosis and fluoride intakes, with an emphasis on intake from fluoride in infant formula. Methods The authors administered periodic questionnaires to parents to assess early fluoride intake sources from beverages, selected foods, dentifrice and supplements. They assessed relationships between fluorosis of the permanent maxillary incisors and fluoride intake from beverages and other sources, both for individual time points and cumulatively using area-under-the-curve (AUC) estimates. The authors determined effects associated with fluoride in reconstituted powdered infant formulas, along with risks associated with intake of fluoride from dentifrice and other sources. Results Considering only fluoride intake from age 3 to 9 months, the authors found that participants with fluorosis (97 percent of which was mild) had significantly greater cumulative fluoride intake (AUC) from reconstituted powdered infant formula, other beverages with added water or a combination of these than did those without fluorosis. For participants aged 16 to 36 months, participants with fluorosis had significantly higher fluoride intake from water by itself, dentifrice or a combination of these than did those without fluorosis. In a model combining both the 3- to 9-month and 16- to 36-months age groups, the significant variables were fluoride intake from reconstituted powder concentrate formula (by participants aged 3–9 months), other beverages with added water (also by participants aged 3–9 months) and dentifrice (by participants aged 16–36 months). Conclusions Greater fluoride intakes from reconstituted powdered formulas (when participants were aged 3–9 months) and other water-added beverages (when participants were aged 3–9 months) increased fluorosis risk as did higher dentifrice intake by participants when aged 16 to 36 months. Clinical Implications Results suggest that prevalence of mild dental fluorosis could be reduced by avoiding ingestion of large quantities of fluoride from reconstituted powdered concentrate infant formula and fluoridated dentifrice. PMID:20884921

Fluoride releasing and enamel demineralization around orthodontic brackets by fluoride-releasing composite containing nanoparticles.

PubMed

Melo, Mary A S; Morais, Weslanny A; Passos, Vanara F; Lima, Juliana P M; Rodrigues, Lidiany K A

2014-05-01

Fluoride-containing materials have been suggested to control enamel demineralization around orthodontic brackets during the treatment with fixed appliances. The improvement of their properties has been made through innovations, such as the application of nanotechnology by incorporation of nanofillers. This in vitro study evaluated the capacity of fluoride releasing and enamel demineralization inhibition of fluoride-releasing nanofilled cement around orthodontic brackets using an artificial caries biofilm model. Forty bovine enamel discs were selected by evaluating surface microhardness and randomized into four groups (n = 10): non-fluoride-releasing microfilled composite, fluoride-releasing microfilled composite, resin-modified glass ionomer cement (RMGI), and fluoride-releasing nanofilled composite (FN). After brackets bonding in each disc, the specimens were subjected to a cariogenic challenge through a Streptococcus mutans biofilm model. After the experimental period, the biofilm formed around the brackets was collected for fluoride analysis and the mineral loss around the brackets was determined by integrated demineralization via cross-sectional microhardness measurement at 20 and 70 μm from the bracket margin. Additionally, samples of each group were subjected to energy-dispersive X-ray spectroscopy (EDX) analysis examined under a scanning electron microscopy (SEM). ANOVA followed by Tukey test were applied for fluoride concentration and mineral loss data, respectively. At both distances, only RMGI statistically differed from the other groups presenting the lowest demineralization, although there was a trend to a lower demineralization of enamel around brackets in FN group. Similar condition was found to fluoride concentration and EDX/SEM analysis. Under the cariogenic exposure condition of this study, the fluoride-releasing nanofilled material had similar performance to fluoride-releasing microfilled materials. The presence of nanofillers in the fluoride-releasing materials studied did not promote further benefits against caries lesion development around brackets and presented inferior demineralization inhibition than the resin-modified glass ionomer material.

Performance of novel hydroxyapatite nanowires in treatment of fluoride contaminated water.

PubMed

He, Junyong; Zhang, Kaisheng; Wu, Shibiao; Cai, Xingguo; Chen, Kai; Li, Yulian; Sun, Bai; Jia, Yong; Meng, Fanli; Jin, Zhen; Kong, Lingtao; Liu, Jinhuai

2016-02-13

Novel ultralong hydroxyapatite (HAP) nanowires were successfully prepared for fluoride removal for the first time. The fluoride adsorption on the HAP nanowires was studied on a batch mode. The results revealed that the adsorption data could be well described by the Freundlich model, and the adsorption kinetic followed the pseudo-second-order model. The maximum of adsorption capacity was 40.65 mg/g at pH 7.0 when the fluoride concentration is 200mg/L. The thermodynamic parameters suggested that the adsorption of fluoride was a spontaneous endothermic process. The FT-IR, XPS and Zeta potential analysis revealed that both anion exchange and electrostatic interactions were involved in the adsorption of fluoride. Furthermore, the HAP nanowires were made into HAP membrane through a simple process of suction filtration. Membrane filtration experiments revealed that the fluoride removal capabilities depended on the membrane thickness, flow rate and initial concentration of fluoride. The as-prepared membrane could remove fluoride efficiently through continues filtration. The filtered water amount could reach 350, 192, and 64 L/m(2) when the fluoride concentrations were 4, 5 and 8 ppm, respectively, using the HAP membrane with only 150 μm thickness. The as-synthesized ultralong HAP nanowires were thus demonstrated to be very effective and biocompatible adsorbents for fluoride removal from contaminated water. Copyright © 2015 Elsevier B.V. All rights reserved.

Association between water fluoride and the level of children's intelligence: a dose-response meta-analysis.

PubMed

Duan, Q; Jiao, J; Chen, X; Wang, X

2018-01-01

Higher fluoride concentrations in water have inconsistently been associated with the levels of intelligence in children. The following study summarizes the available evidence regarding the strength of association between fluoridated water and children's intelligence. Meta-analysis. PubMed, Embase, and Cochrane Library databases were systematically analyzed from November 2016. Observational studies that have reported on intelligence levels in relation to high and low water fluoride contents, with 95% confidence intervals (CIs) were included. Further, the results were pooled using inverse variance methods. The correlation between water fluoride concentration and intelligence level was assessed by a dose-response meta-analysis. Twenty-six studies reporting data on 7258 children were included. The summary results indicated that high water fluoride exposure was associated with lower intelligence levels (standardized mean difference : -0.52; 95% CI: -0.62 to -0.42; P < 0.001). The findings from subgroup analyses were consistent with those from overall analysis. The dose-response meta-analysis suggested a significant association between water fluoride dosage and intelligence (P < 0.001), while increased water fluoride exposure was associated with reduced intelligence levels. Greater exposure to high levels of fluoride in water was significantly associated with reduced levels of intelligence in children. Therefore, water quality and exposure to fluoride in water should be controlled in areas with high fluoride levels in water. Copyright © 2017. Published by Elsevier Ltd.

Protective effect of ascorbic acid and Ginkgo biloba against learning and memory deficits caused by fluoride.

PubMed

Jetti, Raghu; Raghuveer, C V; Mallikarjuna, Rao C

2016-01-01

Fluoride is present in the ground water, World Health Organization permitted level of fluoride in the ground water is 0.5 ppm. Tooth pastes, mouth washes, tea and sea fish are the sources of fluoride. Exposure to these multiple sources results in several adverse effects in addition to the fluorosis. The present study aimed to test the effect of vitamin C and Ginkgo biloba against the behavioural deficits caused by fluoride. Rats were divided into five groups with six animals in each group (n = 6). Control group received ordinary tap water with 0.5 ppm of fluoride, the remaining groups received 100 ppm of fluoride for 30 days prior to fluoride exposure. Two groups of animals received 100 mg/kg body weight of vitamin C and G. biloba for 15 days prior to fluoride exposure. After 45 days, behavioural studies (T-Maze, passive avoidance) were conducted on the experimental animals. The results of the present study showed no behavioural deficits in the control group of animals however, the rats that received fluoride water exhibited impairment in their spatial learning and memory deficits. The deficits are not marked in the vitamin C and G. biloba groups. To conclude chronic exposure to high levels of fluoride causes severe impairment in the spatial learning and memory, these deficits can be ameliorated with the vitamin C and G. biloba. © The Author(s) 2013.

Sustainable approach for recycling waste lamb and chicken bones for fluoride removal from water followed by reusing fluoride-bearing waste in concrete.

PubMed

Ismail, Zainab Z; AbdelKareem, Hala N

2015-11-01

Sustainable management of waste materials is an attractive approach for modern societies. In this study, recycling of raw waste lamb and chicken bones for defluoridation of water has been estimated. The effects of several experimental parameters including contact time, pH, bone dose, fluoride initial concentration, bone grains size, agitation rate, and the effect of co-existing anions in actual samples of wastewater were studied for fluoride removal from aqueous solutions. Results indicated excellent fluoride removal efficiency up to 99.4% and 99.8% using lamb and chicken bones, respectively at fluoride initial concentration of 10 mg F/L and 120 min contact time. Maximum fluoride uptake was obtained at neutral pH range 6-7. Fluoride removal kinetic was well described by the pseudo-second order kinetic model. Both, Langmuir and Freundlich isotherm models could fit the experimental data well with correlation coefficient values >0.99 suggesting favorable conditions of the process. Furthermore, for complete sustainable management of waste bones, the resulted fluoride-bearing sludge was reused in concrete mixes to partially replace sand. Tests of the mechanical properties of fluoride sludge-modified concrete mixes indicated a potential environmentally friendly approach to dispose fluoride sludge in concrete and simultaneously enhance concrete properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

The status of community water fluoridation in the United States.

PubMed Central

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, ethnicity, religion, educational status, or socioeconomic level. Despite the obvious benefits associated with this proven public health measure, slow progress has been made toward achieving the 1990 national fluoridation objectives as listed in "Promoting Health/Preventing Disease: Objectives for the Nation." This paper documents the lagging pace of community fluoridation by reviewing and analyzing data reported in "Fluoridation Census, 1985," a document published in late 1988 by the Public Health Service's Centers for Disease Control. Failure to attain the 1990 objectives is attributable to a combination of circumstances, including their low priority within many local, State, and Federal health agencies, inadequate funding at all levels of government, lack of a coordinated and focused national fluoridation effort, failure of most States to require fluoridation, lack of Federal legislation mandating fluoridation, general apathy of most health professional organizations toward fluoridation, misconceptions by the public about effectiveness and safety and, finally, unrelenting opposition by a highly vocal minority of the lay public.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2116635

Prior fluoridation in childhood affects dental caries and tooth wear in a south east Queensland population.

PubMed

Teo, C; Young, W G; Daley, T J; Sauer, H

1997-04-01

Fluoride exposure in early life has an effect on dental caries experience, but does it affect tooth wear in later life? Ninety-six South East Queensland subjects were studied. Their histories revealed three groups; a fluoride (F-) in water supply, a F- by supplement, and a non-fluoridated (non F-) group. Significantly higher caries experience was found in the non-F- group compared with F- in water group and the F- supplement group. No statistically significant difference in caries experience was found between the F- in water and F- supplement groups. Overall, tooth wear affected more sextants of the dentitions of non-fluoridated, high-caries subjects than of fluoridated low-caries subjects. Comparisons of wear patterns on sextants of the dentitions, between the fluoridated and non-fluoridated groups, revealed that in sextants where attrition was present no marked differences were discernible between the two groups. However, in most sextants where incisal, palatal, occlusal or non-occlusal erosion was found, this type of wear was commoner in non-fluoridated subjects. The exceptions were the mandibular molar sextants, where prior fluoride-exposure did not appear to protect against occlusal erosion patterns. This study showed that fluoride exposure during the first 12 years of life, which reduced dental caries in this population, may also protect teeth from wear to some extent.

Comparative cost-efficiency of the EVOTECH endoscope cleaner and reprocessor versus manual cleaning plus automated endoscope reprocessing in a real-world Canadian hospital endoscopy setting

PubMed Central

2011-01-01

Background Reprocessing of endoscopes generally requires labour-intensive manual cleaning followed by high-level disinfection in an automated endoscope reprocessor (AER). EVOTECH Endoscope Cleaner and Reprocessor (ECR) is approved for fully automated cleaning and disinfection whereas AERs require manual cleaning prior to the high-level disinfection procedure. The purpose of this economic evaluation was to determine the cost-efficiency of the ECR versus AER methods of endoscopy reprocessing in an actual practice setting. Methods A time and motion study was conducted at a Canadian hospital to collect data on the personnel resources and consumable supplies costs associated with the use of EVOTECH ECR versus manual cleaning followed by AER with Medivators DSD-201. Reprocessing of all endoscopes was observed and timed for both reprocessor types over three days. Laboratory staff members were interviewed regarding the consumption and cost of all disposable supplies and equipment. Exact Wilcoxon rank sum test was used for assessing differences in total cycle reprocessing time. Results Endoscope reprocessing was significantly shorter with the ECR than with manual cleaning followed by AER. The differences in median time were 12.46 minutes per colonoscope (p < 0.0001), 6.31 minutes per gastroscope (p < 0.0001), and 5.66 minutes per bronchoscope (p = 0.0040). Almost 2 hours of direct labour time was saved daily with the ECR. The total per cycle cost of consumables and labour for maintenance was slightly higher for EVOTECH ECR versus manual cleaning followed by AER ($8.91 versus $8.31, respectively). Including the cost of direct labour time consumed in reprocessing scopes, the per cycle and annual costs of using the EVOTECH ECR was less than the cost of manual cleaning followed by AER disinfection ($11.50 versus $11.88). Conclusions The EVOTECH ECR was more efficient and less costly to use for the reprocessing of endoscopes than manual cleaning followed by AER disinfection. Although the cost of consumable supplies required to reprocess endoscopes with EVOTECH ECR was slightly higher, the value of the labour time saved with EVOTECH ECR more than offset the additional consumables cost. The increased efficiency with EVOTECH ECR could lead to even further cost-savings by shifting endoscopy laboratory personnel responsibilities but further study is required. PMID:21967345

Comparative cost-efficiency of the EVOTECH endoscope cleaner and reprocessor versus manual cleaning plus automated endoscope reprocessing in a real-world Canadian hospital endoscopy setting.

PubMed

Forte, Lindy; Shum, Cynthia

2011-10-03

Reprocessing of endoscopes generally requires labour-intensive manual cleaning followed by high-level disinfection in an automated endoscope reprocessor (AER). EVOTECH Endoscope Cleaner and Reprocessor (ECR) is approved for fully automated cleaning and disinfection whereas AERs require manual cleaning prior to the high-level disinfection procedure. The purpose of this economic evaluation was to determine the cost-efficiency of the ECR versus AER methods of endoscopy reprocessing in an actual practice setting. A time and motion study was conducted at a Canadian hospital to collect data on the personnel resources and consumable supplies costs associated with the use of EVOTECH ECR versus manual cleaning followed by AER with Medivators DSD-201. Reprocessing of all endoscopes was observed and timed for both reprocessor types over three days. Laboratory staff members were interviewed regarding the consumption and cost of all disposable supplies and equipment. Exact Wilcoxon rank sum test was used for assessing differences in total cycle reprocessing time. Endoscope reprocessing was significantly shorter with the ECR than with manual cleaning followed by AER. The differences in median time were 12.46 minutes per colonoscope (p < 0.0001), 6.31 minutes per gastroscope (p < 0.0001), and 5.66 minutes per bronchoscope (p = 0.0040). Almost 2 hours of direct labour time was saved daily with the ECR. The total per cycle cost of consumables and labour for maintenance was slightly higher for EVOTECH ECR versus manual cleaning followed by AER ($8.91 versus $8.31, respectively). Including the cost of direct labour time consumed in reprocessing scopes, the per cycle and annual costs of using the EVOTECH ECR was less than the cost of manual cleaning followed by AER disinfection ($11.50 versus $11.88). The EVOTECH ECR was more efficient and less costly to use for the reprocessing of endoscopes than manual cleaning followed by AER disinfection. Although the cost of consumable supplies required to reprocess endoscopes with EVOTECH ECR was slightly higher, the value of the labour time saved with EVOTECH ECR more than offset the additional consumables cost. The increased efficiency with EVOTECH ECR could lead to even further cost-savings by shifting endoscopy laboratory personnel responsibilities but further study is required.

Novel fluorogenic probe for fluoride ion based on the fluoride-induced cleavage of tert-butyldimethylsilyl ether

NASA Astrophysics Data System (ADS)

Yang, Xiao-Feng

2007-06-01

A highly sensitive and selective fluorogenic probe for fluoride ion, 4-methylumbelliferyl tert-butyldimethylsilyl ether (4-MUTBS), was designed and synthesized. 4-MUTBS was a weakly fluorescent compound and was synthesized via the one-step reaction of 4-MU with tert-butyldimethylsilyl chloride. Upon incubation with fluoride ion in acetone-water solution (7:3, v/v), the Si-O bond of 4-MUTBS was cleaved and highly fluorescent 4-methylumbelliferone (4-MU) was released, hence leading to the fluorescence increase of the reaction solution. The fluorescence increase is linearly with fluoride concentration in the range 50-8000 nmol l -1 with a detection limit of 19 nmol l -1 (3 σ). Because of the high affinity of silicon toward fluoride ion, the proposed probe shows excellent selectivity toward fluoride ion over other anions. The method has been successfully applied to the fluoride determination in toothpaste and tap water samples.

Zirconium fluoride glass - Surface crystals formed by reaction with water

NASA Technical Reports Server (NTRS)

Doremus, R. H.; Bansal, N. P.; Bradner, T.; Murphy, D.

1984-01-01

The hydrated surfaces of a zirconium barium fluoride glass, which has potential for application in optical fibers and other optical elements, were observed by scanning electron microscopy. Crystalline zirconium fluoride was identified by analysis of X-ray diffraction patterns of the surface crystals and found to be the main constituent of the surface material. It was also found that hydrated zirconium fluorides form only in highly acidic fluoride solutions. It is possible that the zirconium fluoride crystals form directly on the glass surface as a result of its depletion of other ions. The solubility of zirconium fluoride is suggested to be probably much lower than that of barium fluoride (0.16 g/100 cu cm at 18 C). Dissolution was determined to be the predominant process in the initial stages of the reaction of the glass with water. Penetration of water into the glass has little effect.

Effect of fluoride prophylactic agents on the surface topography of NiTi and CuNiTi wires.

PubMed

Mane, Pratap P; Pawar, Renuka; Ganiger, Chanamallappa; Phaphe, Sandesh

2012-05-01

The aim of this study was to see the effect of topical fluoride on surface texture on nickel-titanium and copper-nickel-titanium orthodontic archwires. Preformed rectangular NiTi and CuNiTi wires were immersed in in fluoride solution and artificial saliva (control) for 90 minutes at 37°C. after immersion optical microscope was used to see the fluoride effect on the wire topography. The acidulated fluoride agents appeared to cause greater corrosive effects as compared to the neutral fluoride agents. The result suggest that using topical fluoride agents leads to corrosion of surface topography indirectly affecting the mechanical properties of the wire that will lead to prolonged orthodontic treatment. The use of topical fluoride agents has to be limited in patients with prolonged orthodontic treatment as it causes the corrosion of the NiTi and CuNiTi wires.

Tribological properties of self-lubricating fluoride-metal composites to 900 C (1650 F): A review and some new developments

NASA Technical Reports Server (NTRS)

Sliney, H. E.; Graham, J. W.

1974-01-01

The friction and wear behavior of some fluoride-metal, self-lubricating composites are summarized. Fluoride-infiltrated sintered nickel alloy composites and plasma-sprayed, co-deposited fluoride-nickel alloy composites are described. The importance of proper surface-conditioning of the composites is stressed. Performance of fluoride-metal composites in some machine application evaluation is discussed.

Highly selective optical fluoride ion sensor with submicromolar detection limit based on aluminum(III) octaethylporphyrin in thin polymeric film.

PubMed

Badr, Ibrahim H A; Meyerhoff, Mark E

2005-04-20

A highly selective, sensitive, and reversible fluoride optical sensing film based on aluminum(III)octaethylporphyrin as a fluoride ionophore and a lipophilic pH indicator as the optical transducer is described. The fluoride optical sensing films exhibit a submicromolar detection limit and high discrimination for fluoride over several lipophilic anions such as nitrate, perchlorate, and thiocyanate.

Dental Fluorosis and Dental Caries Prevalence among 12 and 15-Year-Old School Children in Nalgonda District, Andhra Pradesh, India

PubMed Central

Sukhabogi, JR; Parthasarathi, P; Anjum, S; Shekar, BRC; Padma, CM; Rani, AS

2014-01-01

Background: Fluoride is a double edged sword. The assessment of dental caries and fluorosis in endemic fluoride areas will facilitate in assessing the relation between fluoride concentrations in water with dental caries, dental fluorosis simultaneously. Aim: The objective of the following study is to assess the dental caries and dental fluorosis prevalence among 12 and 15-year-old school children in Nalgonda district, Andhra Pradesh, India. Subjects and Methods: This was a cross-sectional study. Two stage cluster sampling technique was employed to select 20 schools from Nalgonda district. The oral examination of available 12 and 15-year-old children fulfilling the inclusion and exclusion criteria was carried out to assess dental caries and fluorosis. The examination was conducted by a single trained and calibrated examiner using the mouth mirror and community periodontal index probe under natural daylight. These areas were divided into four categories, low, medium, high and very high fluoride areas based on the fluoride concentration at the time of statistical analysis. The data was analyzed using Statistical Package for the Social Sciences version 16 (IBM, Chicago, USA). Results: The caries prevalence was less among 12-year-old children (39.9% [369/924]) compared with 15-years-old children (46.7% [444/951]). The prevalence was more among females (50.4% [492/977]) than males (35.8% [321/898]). The prevalence was more in low fluoride area (60.5% [300/496]) followed by very high fluoride area (54.8% [201/367]), high fluoride area (32.4% [293/904]) and medium fluoride area (17.6% [19/108]) in the descending order. The fluorosis prevalence increased with increasing fluoride concentration with no difference in gender and age distribution. Conclusion: Low fluoride areas require fluoridation or alternate sources of fluoride, whereas high fluoride areas require defluoridation. Defluoridation of water is an immediate requirement in areas with fluoride concentration of 4 parts per million and above as dental fluorosis is a public health problem in these areas with 100% prevalence. PMID:25364597

Fluoride and Arsenic Exposure Impairs Learning and Memory and Decreases mGluR5 Expression in the Hippocampus and Cortex in Rats

PubMed Central

Jiang, Shoufang; Su, Jing; Yao, Sanqiao; Zhang, Yanshu; Cao, Fuyuan; Wang, Fei; Wang, Huihui; Li, Jun; Xi, Shuhua

2014-01-01

Fluoride and arsenic are two common inorganic contaminants in drinking water that are associated with impairment in child development and retarded intelligence. The present study was conducted to explore the effects on spatial learning, memory, glutamate levels, and group I metabotropic glutamate receptors (mGluRs) expression in the hippocampus and cortex after subchronic exposure to fluoride, arsenic, and a fluoride and arsenic combination in rats. Weaned male Sprague-Dawley rats were assigned to four groups. The control rats drank tap water. Rats in the three exposure groups drank water with sodium fluoride (120 mg/L), sodium arsenite (70 mg/L), and a sodium fluoride (120 mg/L) and sodium arsenite (70 mg/L) combination for 3 months. Spatial learning and memory was measured in Morris water maze. mGluR1 and mGluR5 mRNA and protein expression in the hippocampus and cortex was detected using RT-PCR and Western blot, respectively. Compared with controls, learning and memory ability declined in rats that were exposed to fluoride and arsenic both alone and combined. Combined fluoride and arsenic exposure did not have a more pronounced effect on spatial learning and memory compared with arsenic and fluoride exposure alone. Compared with controls, glutamate levels decreased in the hippocampus and cortex of rats exposed to fluoride and combined fluoride and arsenic, and in cortex of arsenic-exposed rats. mGluR5 mRNA and protein expressions in the hippocampus and mGluR5 protein expression in the cortex decreased in rats exposed to arsenic alone. Interestingly, compared with fluoride and arsenic exposure alone, fluoride and arsenic combination decreased mGluR5 mRNA expression in the cortex and protein expression in the hippocampus, suggesting a synergistic effect of fluoride and arsenic. These data indicate that fluoride and arsenic, either alone or combined, can decrease learning and memory ability in rats. The mechanism may be associated with changes of glutamate level and mGluR5 expression in cortex and hippocampus. PMID:24759735

The influence of lifelong exposure to environmental fluoride on bone quality in humans

NASA Astrophysics Data System (ADS)

Chachra, Debbie

The objective of this study was to determine if lifelong exposure to environmental sources of fluoride (including fluoridated water) had an effect on bone quality in humans. Ninety-two femoral heads were obtained from individuals undergoing total hip arthroplasty in regions with and without fluoridated water (Toronto and Montreal, respectively), so that the donors would have had a wide range of fluoride exposure. As the samples were obtained at surgery, the femoral heads were affected by osteoarthritis (75), osteoporosis (9) and other diseases. The fluoride content of cancellous bone was assessed by instrumental neutron activation analysis. A number of contributors to bone quality were assessed. The compressive and torsional mechanical properties were measured for cancellous cores excised from the centre of the femoral head. The architecture was assessed by image analysis of an x-ray of a 5 mm thick coronal section of the femoral head, as well as of histological sections taken from the superior (weightbearing) and the inferior (nonweightbearing) surface of the femoral head. The degree of mineralization was measured using backscattered electron imaging and microhardness, again at the superior and the inferior surface. Femoral heads from Toronto donors had a greater mean fluoride content than those from Montreal donors (1033 +/- 438 ppm vs. 643 +/- 220 ppm). However, the fluoride content of the Toronto donors ranged approximately twelve-fold (192--2264 ppm) and entirely contained the range of Montreal donors. Therefore, fluoridated water exposure is not the only determinant of fluoride content. The logarithm of the bone fluoride content increased with age. No substantive effect of fluoride, independent of age, was observed for the mechanical properties. Similarly, at the inferior surface, the architecture was affected by age but not by fluoride incorporation but the degree of mineralization was not affected by either. However, the degree of mineralization (measured by both backscattered electron imaging and microhardness) at the superior surface increased linearly with the fluoride content. As osteoarthritis results in a reduced degree of mineralization at the superior surface, this suggests that the presence of fluoride (which increases the degree of mineralization in osteoarthritis-affected bone) may aid in preventing this loss.

Fluoride exposure in public drinking water and childhood and adolescent osteosarcoma in Texas.

PubMed

Archer, Natalie P; Napier, Thomas S; Villanacci, John F

2016-07-01

The purpose of this study was to examine the association between fluoride levels in public drinking water and childhood and adolescent osteosarcoma in Texas; to date, studies examining this relationship have been equivocal. Using areas with high and low naturally occurring fluoride, as well as areas with optimal fluoridation, we examined a wide range of fluoride levels in public drinking water. This was a population-based case-control study, with both cases and controls obtained from the Texas Cancer Registry. Eligible cases were Texas children and adolescents <20 years old diagnosed with osteosarcoma between 1996 and 2006. Controls were sampled from children and adolescents diagnosed with either central nervous system (CNS) tumors or leukemia during the same time frame. Using geocoded patient addresses at the time of diagnosis, we estimated patients' drinking water fluoride exposure levels based on the fluoride levels of their residence's public water system (PWS). Unconditional logistic regression models were used to assess the association between osteosarcoma and public drinking water fluoride level, adjusting for several demographic risk factors. Three hundred and eight osteosarcoma cases, 598 leukemia controls, and 604 CNS tumor controls met selection criteria and were assigned a corresponding PWS fluoride level. PWS fluoride level was not associated with osteosarcoma, either in a univariable analysis or after adjusting for age, sex, race, and poverty index. Stratified analyses by sex were conducted; no association between PWS fluoride level and osteosarcoma was observed among either males or females. No relationship was found between fluoride levels in public drinking water and childhood/adolescent osteosarcoma in Texas.

Mechanisms of action of fluoride for caries control.

PubMed

Buzalaf, Marília Afonso Rabelo; Pessan, Juliano Pelim; Honório, Heitor Marques; ten Cate, Jacob Martien

2011-01-01

Fluoride was introduced into dentistry over 70 years ago, and it is now recognized as the main factor responsible for the dramatic decline in caries prevalence that has been observed worldwide. However, excessive fluoride intake during the period of tooth development can cause dental fluorosis. In order that the maximum benefits of fluoride for caries control can be achieved with the minimum risk of side effects, it is necessary to have a profound understanding of the mechanisms by which fluoride promotes caries control. In the 1980s, it was established that fluoride controls caries mainly through its topical effect. Fluoride present in low, sustained concentrations (sub-ppm range) in the oral fluids during an acidic challenge is able to absorb to the surface of the apatite crystals, inhibiting demineralization. When the pH is re-established, traces of fluoride in solution will make it highly supersaturated with respect to fluorhydroxyapatite, which will speed up the process of remineralization. The mineral formed under the nucleating action of the partially dissolved minerals will then preferentially include fluoride and exclude carbonate, rendering the enamel more resistant to future acidic challenges. Topical fluoride can also provide antimicrobial action. Fluoride concentrations as found in dental plaque have biological activity on critical virulence factors of S. mutans in vitro, such as acid production and glucan synthesis, but the in vivo implications of this are still not clear. Evidence also supports fluoride's systemic mechanism of caries inhibition in pit and fissure surfaces of permanent first molars when it is incorporated into these teeth pre-eruptively. Copyright © 2011 S. Karger AG, Basel.

[Effects of long-term fluoride in drinking water on risks of hip fracture of the elderly: an ecologic study based on database of hospitalization episodes].

PubMed

Park, Eun Young; Hwang, Seung Sik; Kim, Jai Yong; Cho, Soo Hun

2008-05-01

Fluoridation of drinking water is known to decrease dental caries, particularly in children. However, the effects of fluoridated water on bone over several decades are still in controversy. To assess the risk of hip fracture related to water fluoridation, we evaluated the hip fracture-related hospitalizations of the elderly between a fluoridated city and non-fluoridated cities in Korea. Cheongju as a fluoridated area and Chungju, Chuncheon, Suwon, Wonju as non-fluoridated areas were chosen for the study. We established a database of hip fracture hospitalization episode based on the claims data submitted to the Health Insurance Review Agency from January 1995 to December 2002. The hip fracture hospitalization episodes that satisfied the conditions were those that occurred in patients over 65 years old, the injuries had a hip fracture code (ICD-9 820, ICD-10 S72) and the patients were hospitalized for at least 7days. A total of 80,558 cases of hip fracture hospitalization episodes were analyzed. The admission rates for hip fracture increased with the age of the men and women in both a fluoridated city and the non-fluoridated cities (p<0.01). The relative risk of hip fracture increased significantly both for men and women as their age increased. However, any difference in the hip fracture admission rates was not consistently observed between the fluoridated city and the nonfluoridated cities. We cannot conclude that fluoridation of drinking water increases the risk of hip fracture in the elderly.

Investing in professional advocacy: a case study of a successful fluoridation campaign in rural New South Wales, Australia.

PubMed

Sivaneswaran, S; Chong, G T F

2011-09-01

In New South Wales (NSW), Australia, the responsibility to implement water fluoridation rests with local government Councils, partly accounting for the hindrance in its statewide implementation. Since 2003, the NSW Health Department has been actively promoting water fluoridation to the remaining unfluoridated rural communities. To describe the community education and consultation strategies which led to the implementation of fluoridation in two rural NSW towns. In February 2005, the Mid-Western Regional Council and the NSW Health Department undertook a comprehensive community education process followed by a consultation process. The education process included the organization of public forums; distribution of fluoridation information packs; building rapport with the local media; and the use of local disease and treatment data to demonstrate oral health disparities with neighbouring fluoridated towns. The consultation process to determine support for fluoridation included seeking written submissions from the community and conducting interviews on a random sample of households by an independent research organization. A total of 502 (N = 1,012) interviews to determine support for fluoridation were completed, achieving a response rate of 49.6%. 54% of respondents wanted their water supplies fluoridated, 25% did not and the remaining 21% were unsure. In June 2005, the Mid-Western Regional Council resolved to implement water fluoridation and fluoride was added to the towns' water supplies in November 2007. This case study demonstrates that it is possible to garner community support for water fluoridation with the use of a multifaceted approach in educating and consulting communities and stakeholders.

Curse of Fluorosis.

PubMed

Patil, M M; Lakhkar, Bhavana B; Patil, Shailaja S

2018-05-01

Fluoride was identified to have caries preventive properties and was widely used for fluoridation of water since 1940, especially in developed countries. After this there was sudden increase in the use of fluorides in food items and in oral medicinal products like toothpastes and mouth washes. Inadvertent use of above has lead to increase in fluorosis as a public health problem. In many places high fluorides are naturally present in earth crust leading to high water fluoride content increasing the risk of fluorosis. Maintaining a fine balance of fluorides in the body is mandatory for exploiting its advantages. World Health Organization (WHO) has fixed permissible limit of fluorides in water to 1.5 mg/L as a preventive step to contain fluorosis. Fluorosis has three clinical components: Dental, Skeletal and Non-Skeletal Fluorosis. It occurs with increasing level of fluorides in the body. Acute toxicity due to fluorides is also known and occurs as a result of sudden exposure to high levels of fluorides, usually by ingestion. Once fluorosis occurs it is irreversible without any cure. Only symptomatic and supportive management is possible. Hence prevention is the mainstay of management. Prevention is by using alternative sources of water or its de-fluoridation. National Program for Prevention and Control of Fluorosis (NPPCF) was launched in 2008-9 to identify areas with high fluoride content of water, manage the water bodies, screen schools and community for fluorosis and comprehensive management of cases. Improving quality of drinking water as per standards and improving nutritional status of children are also important components of prevention of fluorosis.

Status of industrial fluoride pollution and its diverse adverse health effects in man and domestic animals in India.

PubMed

Choubisa, Shanti Lal; Choubisa, Darshana

2016-04-01

Hydrofluorosis in humans and domestic animals is a worldwide health problem and caused by a prolonged period of fluoride exposure through drinking of fluoride contaminated water. But in recent years, due to rapid industrialization in India, diverse serious health problems among industrial workers and residents and domestic animals living in the industrial areas due to fluoride pollution are on the rise. A number of coal-burning and industrial activities such as power-generating stations, welding operations and the manufacturing or production of steel, iron, aluminum, zinc, phosphorus, chemical fertilizers, bricks, glass, plastic, cement, and hydrofluoric acid are generally discharging fluoride in both gaseous and particulate/dust forms into surrounding environments which create a industrial fluoride pollution and are an important cause of occupational exposure to fluoride in several countries including India. An industrial emitted fluoride contaminates not only surrounding soil, air, and water but also vegetation, crops and many other biotic communities on which man and animals are generally dependants for food. Long- time of inhalation or ingestion of industrial fluoride also causes serious health problems in the forms of industrial and neighborhood fluorosis. In India, whatever research works conducted so far on the chronic industrial fluoride intoxication or poisoning (industrial and neighborhood fluorosis) in man and various species of domestic animals due to a prolonged period of industrial fluoride exposure or pollution (contamination) are critically reviewed in the present communication. Simultaneously, we are also focused the various bio-indicators and bio-markers for chronic industrial fluoride intoxication or pollution.

Prevalence of dental fluorosis & dental caries in association with high levels of drinking water fluoride content in a district of Gujarat, India.

PubMed

Kotecha, P V; Patel, S V; Bhalani, K D; Shah, D; Shah, V S; Mehta, K G

2012-06-01

Endemic fluorosis resulting from high fluoride concentration in groundwater is a major public health problem in India. This study was carried out to measure and compare the prevalence of dental fluorosis and dental caries in the population residing in high and normal level of fluoride in their drinking water in Vadodara district, Gujarat, India. A cross-sectional study was conducted in Vadodara district, six of the 261 villages with high fluoride level and five of 1490 with normal fluoride level in drinking water were selected. The data collection was made by house-to-house visits twice during the study period. The dental fluorosis prevalence in high fluoride area was 59.31 per cent while in normal fluoride area it was 39.21 per cent. The prevalence of dental caries in high fluoride area was 39.53 per cent and in normal fluoride area was 48.21 per cent with CI 6.16 to 11.18. Dental fluorosis prevalence was more among males as compared to females. Highest prevalence of dental fluorosis was seen in 12-24 yr age group. The risk of dental fluorosis was higher in the areas showing more fluoride content in drinking water and to a lesser degree of dental caries in the same area. High fluoride content is a risk factor for dental fluorosis and problem of dental fluorosis increased with passage of time suggesting that the fluoride content in the water has perhaps increased over time. Longitudinal studies should be conducted to confirm the findings.

Fluoride therapy for osteoporosis: characterization of the skeletal response by serial measurements of serum alkaline phosphatase activity.

PubMed

Farley, S M; Wergedal, J E; Smith, L C; Lundy, M W; Farley, J R; Baylink, D J

1987-03-01

Optimum use of fluoride therapy for osteoporosis requires a sensitive and convenient index of the skeletal response to fluoride. Since previous studies had shown that serum alkaline phosphatase activity (SALP) was increased in response to fluoride therapy, we examined serial measurements of SALP in 53 osteoporotics treated with 66 to 110 mg of sodium fluoride (NaF) for 12 to 91 months. SALP was increased in 87% of the subjects during therapy with fluoride. The increase in SALP was thought to reflect the osteogenic action of fluoride based on the findings that SALP correlated with both trabecular bone area (r = .81, P less than .001) and osteoid length (r = .67, P less than .01) in iliac crest biopsies, predicted increased bone density on spinal radiographs in response to fluoride therapy with an 87% accuracy, and predicted decreased back pain in response to fluoride with a 91% accuracy. In addition, the SALP response to fluoride was seen earlier than other therapeutic responses as indicated by the findings that the tau 1/2 for the SALP response (ie, time for 1/2 of the patients to show a significant response) was significantly less (1.2 +/- 0.3 yr) than that for the pain response (1.6 +/- 0.3 yr, P less than .05) or that for the radiographic response (3.7 +/- 0.5 yr, P less than .001). Although most patients responded to fluoride with an increase in SALP, evaluation of the kinetics of the SALP response to fluoride revealed marked interpatient variation.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of Methods for Decladding LWR Fuel for a Pyroprocessing-Based Reprocessing Plant

DTIC Science & Technology

1992-10-01

oAD-A275 326 ORN.rFM-1121o04 OAK RIDGE NATIONAL LABORATORY Evaluation of Methods for Decladding _LWR Fuel for a Pyroprocessing -Based Reprocessing...Dist. Category UC-526 EVALUATION OF METHODS FOR DECLADDING LWR FUEL FOR A PYROPROCESSING -BASED REPROCESSING PLANT W. D. Bond J. C. Mailen G. E...decladding technologies has been performed to identify candidate decladding processes suitable for LWR fuel and compatible with downstream pyroprocesses

The antimicrobial effect of Octenidine-dihydrochloride coated polymer tracheotomy tubes on Staphylococcus aureus and Pseudomonas aeruginosa colonisation

PubMed Central

2009-01-01

Background The surface of polymeric tracheotomy tubes is a favourable environment for biofilm formation and therefore represents a potential risk factor for the development of pneumonia after tracheotomy. The aim of this in-vitro study was to develop octenidine-dihydrochloride (OCT) coated polymer tracheotomy tubes and investigate any effects on Staphylococcus (S.) aureus and Pseudomonas (P.) aeruginosa colonization. Additionally the resistance of the OCT coating was tested using reprocessing procedures like brushing, rinsing and disinfection with glutaraldehyde Results Contamination with S. aureus: Before any reprocessing, OCT coated tracheotomy tubes were colonized with 103 cfu/ml and uncoated tracheotomy tubes with 105 cfu/ml (P = 0.045). After reprocessing, no differences in bacterial concentration between modified and conventional tubes were observed. Contamination with P. aeruginosa: Before reprocessing, OCT coated tubes were colonized with 106 cfu/ml and uncoated tubes with 107 cfu/ml (P = 0.006). After reprocessing, no significant differences were observed. Conclusion OCT coating initially inhibits S. aureus and P. aeruginosa colonisation on tracheotomy tubes. This effect, however, vanishes quickly after reprocessing of the tubes due to poor adhesive properties of the antimicrobial compound. Despite the known antimicrobial effect of OCT, its use for antimicrobial coating of tracheotomy tubes is limited unless methods are developed to allow sustained attachment to the tube. PMID:19630994

1-Bromoethene-1-sulfonyl fluoride (BESF) is another good connective hub for SuFEx click chemistry.

PubMed

Smedley, Christopher J; Giel, Marie-Claire; Molino, Andrew; Barrow, Andrew S; Wilson, David J D; Moses, John E

2018-05-25

We demonstrate 1,2-dibromoethane-1-sulfonyl fluoride (DESF) as a bench-stable and readily accessible precursor to the robust SuFEx connector, 1-bromoethene-1-sulfonyl fluoride (BESF). The in situ generation of BESF from DESF opens up several new reaction profiles, including application in the syntheses of unprecedented 3-substituted isoxazole-5-sulfonyl fluorides, 1-substituted-1H-1,2,3-triazole-4-sulfonyl fluorides, 2-amino-1-bromoethane-1-sulfonyl fluorides and 4-bromo-β-sultams in good to excellent yields. These new modules comprise a pendant sulfonyl fluoride handle, which further undergoes facile and selective SuFEx reactions with a selection of aryl silyl ethers to generate stable and useful sulfonate connections.

Assessment of fluoride contaminations in groundwater of hard rock aquifers in Madurai district, Tamil Nadu (India)

NASA Astrophysics Data System (ADS)

Thivya, C.; Chidambaram, S.; Rao, M. S.; Thilagavathi, R.; Prasanna, M. V.; Manikandan, S.

2017-05-01

The fluoride contamination in drinking water is already gone to the alarming level and it needs the immediate involvement and attention of all people to solve this problem. Fluoride problem is higher in hard rock terrains in worldwide and Madurai is such type of hard rock region. Totally 54 samples were collected from the Madurai district of Tamilnadu with respect to lithology. The samples collected were analysed for major cations and anions using standard procedures. The higher concentration of fluoride is noted in the Charnockite rock types of northern part of the study area. 20 % of samples are below 0.5 ppm and 6 % of samples are above 1.5 ppm exceeding the permissible limit. The affinity between the pH and fluoride ions in groundwater suggests that dissolution of fluoride bearing minerals in groundwater. The higher concentration of fluoride ions are observed in the lower EC concentration. The isotopic study suggests that fluoride is geogenic in nature. In factor scores, fluoride is noted in association with pH which indicates the dissolution process.

Is water fluoridation effective in reducing inequalities in dental caries distribution in developing countries? Recent findings from Brazil.

PubMed

Peres, Marco Aurélio; Antunes, José Leopoldo Fereira; Peres, Karen Glazer

2006-01-01

To assess socioeconomic differences between towns with and without water fluoridation, and to compare dental caries levels among socioeconomic strata in fluoridated and non-fluoridated areas. A countrywide survey of oral health performed in 2002-03 and comprising 34,550 children aged 12 years provided information about dental caries levels in 249 Brazilian towns. Socioeconomic indices, the coverage and the fluoride status of the water supply network of participating towns were also appraised. Multivariate regression models fitted the adjustment of dental caries levels and covariates to socioeconomic status and water supply. Inequalities in dental outcomes were compared in towns with and without fluoridated tap water. Better-off towns tended to present a higher coverage by the water supply network, and were more inclined to add fluoride. Fluoridated tap water was associated with an overall improved profile of caries, concurrent with an expressively larger inequality in the distribution of dental disease. Suppressing inequalities in the distribution of dental caries requires an expanded access to fluoridated tap water; a strategy that can be effective to foster further reductions in caries indices.

Removal of fluoride from drinking water using aluminum hydroxide coated activated carbon prepared from bark of Morinda tinctoria

NASA Astrophysics Data System (ADS)

Amalraj, Augustine; Pius, Anitha

2017-10-01

The aim of this study is to design and develop a novel cost effective method for fluoride removal, applicable to rural areas of developing countries. Adsorption is widely considered as one of the appropriate technologies for water defluoridation. This study investigates the feasibility of using low-cost biomass based activated carbon from the bark of Morinda tinctoria coated with aluminum hydroxide (AHAC) for water defluoridation, at neutral pH range. Characterization of AHAC was done through IR, SEM with EDAX studies before and after fluoride treatment. The fluoride adsorption capacity of AHAC as a function of contact time, pH and initial fluoride concentration was investigated. The role of co-existing interfering ions also was studied. The isotherm and kinetic models were used to understand the nature of the fluoride adsorption onto AHAC. Freundlich isotherm and intra-particle diffusion were the best-fitting models for the adsorption of fluoride on AHAC. Fluoride adsorption kinetics well fitted with pseudo-second order model. The results showed excellent fluoride adsorption capacity was found to be 26.03 mg g-1 at neutral pH.

Comparison of storage stability of odorous VOCs in polyester aluminum and polyvinyl fluoride Tedlar® bags.

PubMed

Kim, Yong-Hyun; Kim, Ki-Hyun; Jo, Sang-Hee; Jeon, Eui-Chan; Sohn, Jong Ryeul; Parker, David B

2012-01-27

Whole air sampling using containers such as flexible bags or rigid canisters is commonly used to collect samples of volatile organic compounds (VOC) in air. The objective of this study was to compare the stability of polyester aluminum (PEA) and polyvinyl fluoride (PVF, brand name Tedlar(®)) bags for gaseous VOC sampling. Eight VOC standards (benzene, toluene, p-xylene, styrene, methyl ethyl ketone, methyl isobutyl ketone, butyl acetate, and isobutyl alcohol) were placed into each bag at storage times of 0, 2, and 3 days prior to analyses by gas chromatography/mass spectrometry (GC/MS). From each bag representing each storage day, samples of 3 different mass loadings were withdrawn and analyzed to derive response factors (RF) of each chemical between the slope of the GC response (y-axis) vs. loaded mass (x-axis). The relative recoveries (RR) of VOC, if derived by dividing RF value of a given storage day by that of 0 day, varied by time, bag type, and VOC type. If the RR values after three days are compared, those of methyl isobutyl ketone were the highest with 96 (PVF) and 99% (PEA); however, the results of isobutyl alcohol were highly contrasting between the two bags with 31 and 94%, respectively. Differences in RR values between the two bag types increased with storage time, such that RR of PEA bags (88±10%) were superior to those of PVF bags (73±22%) after three days, demonstrating that VOC in PEA bags were more stable than in PVF bags. Copyright © 2011 Elsevier B.V. All rights reserved.

Anaerobic digestion of citrus waste using two-stage membrane bioreactor

NASA Astrophysics Data System (ADS)

Millati, Ria; Lukitawesa; Dwi Permanasari, Ervina; Wulan Sari, Kartika; Nur Cahyanto, Muhammad; Niklasson, Claes; Taherzadeh, Mohammad J.

2018-03-01

Anaerobic digestion is a promising method to treat citrus waste. However, the presence of limonene in citrus waste inhibits anaerobic digestion process. Limonene is an antimicrobial compound and could inhibit methane forming bacteria that takes a longer time to recover than the injured acid forming bacteria. Hence, volatile fatty acids will be accumulated and methane production will be decreased. One way to solve this problem is by conducting anaerobic digestion process into two stages. The first step is aimed for hydrolysis, acidogenesis, and acetogenesis reactions and the second stage is aimed for methanogenesis reaction. The separation of the system would further allow each stage in their optimum conditions making the process more stable. In this research, anaerobic digestion was carried out in batch operations using 120 ml-glass bottle bioreactors in 2 stages. The first stage was performed in free-cells bioreactor, whereas the second stage was performed in both bioreactor of free cells and membrane bioreactor. In the first stage, the reactor was set into ‘anaerobic’ and ‘semi-aerobic’ conditions to examine the effect of oxygen on facultative anaerobic bacteria in acid production. In the second stage, the protection of membrane towards the cells against limonene was tested. For the first stage, the basal medium was prepared with 1.5 g VS of inoculum and 4.5 g VS of citrus waste. The digestion process was carried out at 55°C for four days. For the second stage, the membrane bioreactor was prepared with 3 g of cells that were encased and sealed in a 3×6 cm2 polyvinylidene fluoride membrane. The medium contained 40 ml basal medium and 10 ml liquid from the first stage. The bioreactors were incubated at 55°C for 2 days under anaerobic condition. The results from the first stage showed that the maximum total sugar under ‘anaerobic’ and ‘semi-aerobic’ conditions was 294.3 g/l and 244.7 g/l, respectively. The corresponding values for total volatile fatty acids were 3.8 g/l and 2.9 g/l, respectively. Methane production of citrus waste taken from the first stage under ‘anaerobic’ condition in membrane and free-cells bioreactors was 11.2 Nml and 7.2 Nml, respectively. Whereas, methane production of citrus waste taken from the first stage under ‘semi-aerobic’ condition in membrane and free-cells bioreactors was 8.8 Nml and 5.7 Nml, respectively. It can be seen from the results of the first stage that volatile fatty acids from ‘anaerobic’ condition was higher than that of ‘semi-aerobic’ condition. The absence of oxygen provides the optimal condition for growth and metabolism of facultative and obligatorily anaerobic bacteria in the first stage. Furthermore, polyvinylidene fluoride membrane was able to protect the cells from antimicrobial compounds.

Microbial Populations Growing in the Presence of Fluoride at Low pH Isolated from Dental Plaque of Children Living in an Area with Fluoridated Water

PubMed Central

Bowden, G. H. W.; Odlum, O.; Nolette, N.; Hamilton, I. R.

1982-01-01

Longitudinal microbiological examinations have been made of dental plaque from a site approximal to the upper central incisors of 10 8-year-old children living in an area with water fluoridation. Differential counts of viable bacteria, made using a selective medium containing various levels of fluoride (0 to 100 μg/ml) at pH levels of 7.0 to 5.5, demonstrated an effect of both pH and fluoride on the numbers and types of bacteria isolated. Strains of Streptococcus and Neisseria grew after only 16 h of incubation at pH levels as low as 6.0 with fluoride levels up to 50 μg/ml. The most commonly isolated streptococci were Streptococcus mitior and S. salivarius. S. mutans was isolated less frequently and was inhibited by 20 and 50 μg of fluoride per ml at pH 6.0 and 6.5, respectively. Veillonella strains were the most resistant isolates, being isolated after 16 h of incubation on media at pH 6.0 with 100 μg of fluoride per ml. Despite their known fluoride resistance, Actinomyces spp. were often only detected on the selective media after 72 h of incubation. The pH of the medium had a definite selective effect, as the number of colonies growing on the fluoride-free basal media at pH 6.0 was only 30% of that at pH 7.0. Representative strains of S. mutans, S. mitior, S. sanguis, and S. milleri were tested for their ability to utilize glucose at the pH and fluoride levels of the medium on which they were initially isolated. Fluoride reduced the initial glycolytic rate of the cells, but in 5 of the 13 strains tested the final amount of glucose used after 2 h of incubation was the same in the presence or absence of fluoride. The isolation of bacteria capable of growth in the presence of fluoride over a significant portion of the pH range that occurs in plaque in vivo could explain in part the finding that fluoride does not have a dramatic effect on the plaque community. Fluoride in plaque may reduce the ecological advantage afforded to aciduric S. mutans strains by carbohydrate substances. In the in vivo situation this could mean that, even with high carbohydrate intake, fluoride may permit S. mitior to compete with S. mutans within the plaque ecosystem. PMID:7076297

The Effect of Fluoride in Osteoporosis.

ERIC Educational Resources Information Center

Hedlund, L. R.; Gallagher, J. C.

1987-01-01

This article discusses the effect of fluoride on bone tissue and the possible role of fluoride in the treatment of osteoporosis. At present, fluoride treatment should be restricted to clinical trials until its risks and benefits have been further evaluated. (Author/MT)

METHOD FOR DISSOLVING LANTHANUM FLUORIDE CARRIER FOR PLUTONIUM

DOEpatents

Koshland, D.E. Jr.; Willard, J.E.

1961-08-01

A method is described for dissolving lanthanum fluoride precipitates which is applicable to lanthanum fluoride carrier precipitation processes for recovery of plutonium values from aqueous solutions. The lanthanum fluoride precipitate is contacted with an aqueous acidic solution containing dissolved zirconium in the tetravalent oxidation state. The presence of the zirconium increases the lanthanum fluoride dissolved and makes any tetravalent plutonium present more readily oxidizable to the hexavalent state. (AEC)

Fluoride: a risk factor for inflammatory bowel disease?

PubMed

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.

The effects of an anchovy (stolephorus insularis) substrate application on the level of fluor intrusion on Sprague Dawley rat teeth (in vivo)

NASA Astrophysics Data System (ADS)

Sakinah, N. R.; Gunawan, H. A.; Puspitawati, R.

2017-08-01

Fluoride intrusion is one of the efficacy parameters of fluoridation. Anchovy (Stolephorus insularis), which contains a high fluoride concentration in the CaF2compound, can be used as a fluoridative agent which is affordable and easily obtained. The aim of this study is to prove the effectiveness of the application of an anchovy substrate (Stolephorus insularis), either by a feeding method or a topical method, for tooth fluoridation based on the depth of fluoride intrusion on the enamel. An in vivo experimental laboratory method was used. The subjects were 14 Sprague Dawley rats divided into five groups. The groups included a baseline control, a feeding negative control, a topical negative control, an anchovy feeding method, and a topical solution anchovy method. After 15 days of treatment, the teeth were cut transversely with a 0.5 mm thickness then processed to test for fluoride intrusion using fluorescence microscopy. There was increased fluor intrusion on the enamel of the experimental groups compared to the negative control groups (p<0.05).Fluoride intrusion using the topical fluoride method is higher than with the feeding method (p <0.05). Thus, the application of an anchovy substrate, either by chewing or smearing, increases fluoride intrusion on the enamel.

Evaluating the impact of municipal water fluoridation on the aquatic environment.

PubMed Central

Osterman, J W

1990-01-01

Although highly beneficial for dental health, low concentrations of fluoride in environmental waters may be toxic to several organisms. In an era of heightened public awareness about the environment, this may lead city officials to withhold implementing water fluoridation for environmental reasons. This paper presents a mass balance approach to evaluate this perceived risk. Generally speaking, fluoridated water loss during use, dilution of sewage by rain and ground water infiltrate, fluoride removal during secondary sewage treatment, and diffusion dynamics at effluent outfall combine to eliminate fluoridation-related environmental effects. In Montreal, water fluoridation would raise average aquatic fluoride levels in the waste water plume immediately below effluent outfall by only 0.05-0.09 mg/l. Downstream, these changes would be only 0.02-0.05 mg/l at 1 km, and 0.01-0.03 mg/l at 2 km below outfall. Overall river fluoride concentrations theoretically would be raised by 0.001-0.002 mg/l, a value not measurable by current analytical techniques. All resulting concentrations would be well below those recommended for environmental safety and would not exceed natural levels found elsewhere in Quebec. A literature review did not reveal any examples of municipal water fluoridation causing recommended environmental concentrations to be exceeded, although excesses occurred in several cases of severe industrial water pollution. PMID:2400035

Preparation and characterization of γ-AlOOH @CS magnetic nanoparticle as a novel adsorbent for removing fluoride from drinking water.

PubMed

Wan, Zhen; Chen, Wei; Liu, Cheng; Liu, Yu; Dong, Changlong

2015-04-01

For this study, a novel adsorbent of γ-AlOOH @CS (pseudoboehmite and chitosan shell) magnetic nanoparticles (ACMN) with magnetic separation capabilities was developed to remove fluoride from drinking water. The adsorbent was first characterized, and then its performance in removing fluoride was evaluated. Kinetic data demonstrated rapid fluoride adsorption with more than 80% fluoride adsorption within the initial 20 min and equilibrium reached in 60 min. Based on the results of kinetic and isotherm models, the fluoride adsorption process on the ACMN's surface was a monolayer adsorption on a homogeneous surface. Thermodynamic parameters presented that the adsorption process is spontaneous and endothermic in nature. The mechanism for the adsorption involved electrostatic interaction and hydrogen bonding. Moreover, the calculated adsorption capacity of the ACMN for fluoride using the Langmuir model was 67.5 mg/g (20°C, pH=7.0±0.1), higher than other fluoride removal adsorbents. This nanoadsorbent performed well over a pH range of 4-10. The study found that PO4(3-) was the co-existing anion most able to hinder the nanoparticle's fluoride adsorption, followed by NO3(-) then Cl(-). Experimental results suggest that ACMN is a promising adsorbent for treating fluoride-contaminated water. Copyright © 2014 Elsevier Inc. All rights reserved.

Synthesis and characterization of antibacterial dental monomers and composites

PubMed Central

Xu, Xiaoming; Wang, Yapin; Liao, Sumei; Wen, Zezhang T.; Fan, Yuwei

2012-01-01

The objective of this study is to synthesize antibacterial methacrylate and methacrylamide monomers and formulate antibacterial fluoride-releasing dental composites. Three antibacterial methacrylate or methacrylamide monomers containing long-chain quaternary ammonium fluoride, 1,2-methacrylamido-N,N,N-trimethyldodecan-1-aminium fluoride (monomer I), N-benzyl-11-(methacryloyloxy)-N,N-dimethylundecan-1-aminium fluoride (monomer II), and methacryloxyldecylpyridinium fluoride (monomer III) have been synthesized and analyzed by nuclear magnetic resonance (NMR) and mass spectrometry (MS). The cytotoxicity test and bactericidal test against Streptococcus mutans indicate that antibacterial monomer II is superior to monomers I and III. A series of dental composites containing 0–6% of antibacterial monomer II have been formulated and tested for degree of conversion (DC), flexure strength, water sorption, solubility, and inhibition of S. mutans biofilms. An antibacterial fluoride-releasing dental composite has also been formulated and tested for flexure strength and fluoride release. The dental composite containing 3% of monomer II has a significant effect against S. mutans biofilm formation without major adverse effects on its physical and mechanical properties. The new antibacterial monomers can be used together with the fluoride-releasing monomers containing a ternary zirconiun- fluoride chelate to formulate a new antibacterial fluoride- releasing dental composite. Such a new dental composite is expected to have higher anticaries efficacy and longer service life. PMID:22447582

Trends in dental fluorosis and dental caries prevalences in Newburgh and Kingston, NY.

PubMed Central

Kumar, J V; Green, E L; Wallace, W; Carnahan, T

1989-01-01

A study was undertaken in New York State to determine the changes in dental fluorosis prevalence from 1955 to 1986 in fluoridated Newburgh and non-fluoridated Kingston children. The frequency and severity of dental fluorosis among 884 7-14-year-old children were measured by two dentists utilizing Dean's Index. Data regarding residential and fluoride history were obtained from the parents of participants. Among the Newburgh residents, the prevalence of dental fluorosis (very mild to moderate) varied from a low of 5 per cent for the 9-10-year-old group to a high of 9.4 per cent for 11-12-year-olds. Except for the 13-14-year-old group, children in non-fluoridated Kingston had the lowest dental fluorosis prevalence rates. A comparison of Dean's Community Fluorosis Indices to the 1955 baseline data obtained from studies conducted after 10 years of fluoridation in Newburgh revealed no changes of consequence among Newburgh residents. However, the changes are apparent for Kingston residents, indicating the availability of fluorides in non-fluoridated areas. The increased risk for dental fluorosis for Kingston residents appears to be from the use of fluoride tablets. An analysis of dental caries data revealed that caries prevalence declined substantially in both fluoridated and non-fluoridated areas. PMID:2705588

Analysis of Phone Calls Regarding Fluoride Exposure made to New Jersey Poison Control Center from 2010 to 2012.

PubMed

Shah, Sneha; Quek, Samuel; Ruck, Bruce

2016-02-01

The American Association of Poison Control Center's annual reports demonstrate that acute fluoride exposure is not an uncommon occurrence. Despite its prevalence, there has been little published research on the topic in the last 10 years. The purpose of this study was to calculate the incidence of acute fluoride toxicity and lethality as it occurs in New Jersey and provide a descriptive epidemiology of acute fluoride exposures. The study design was retrospective in nature. Records of phone calls made by individuals reporting excessive fluoride exposure (in an amount greater than directed/prescribed) to New Jersey's poison control center, known as Poison Information and Education System from the years 2010 through 2012, were extracted from Toxicall® (Computer Automatic Systems, Inc.) database. A total of 2,476 human-only exposure records met the inclusion criteria and were analyzed. Incidence rates were calculated, and population characteristics, circumstances and medical outcomes of acute fluoride exposure cases were assessed and categorized. A total of 2,476 phone call records met the inclusion criteria. The fluoride exposures reported were from toothpaste with fluoride (49%, n=1,214), mouth rinse with fluoride (21.6%, n=536), multivitamin with fluoride (21.4%, n=530) and pure fluoride (0.08%, n=199). Medically speaking, 94.75% of calls were asymptomatic cases (n=2,346), 4.24% were symptomatic (n=105) and 1.01% were informational inquiries (n=25). Adverse symptoms reported were mostly minor (83.9% of symptomatic cases, n=88) and moderate (16.1% of symptomatic cases, n=17). The age group 18 months to 3 years of age showed the highest incidence of acute fluoride exposure (53.2%, n=1,317). There was a slightly higher incidence of acute fluoride exposures among males (n=1,317) vs. females (n=1,159). Most incidences occurred in the home (93.1% of records, n=2,305) and occurred unintentionally (96.7%, n=2,394). Calls were mainly made by the subject's mother (67.5%, n=1,671). Based on the data, there were no reports of lethality or toxicity due to acute fluoride exposure in New Jersey from 2010 through 2012. Symptomatic reports and informational inquiries were few. All adverse outcomes due to excessive fluoride intake were remedied with calcium as the antidote. Dental hygienists should educate patients on safety measures of fluoride-containing products and evaluate overall fluoride exposure prior to making recommendations. However, findings in this study suggest that levels of fluoride in available commercial products will not produce life-threatening events, even if taken in doses higher than recommended. Copyright © 2016 The American Dental Hygienists’ Association.

Contribution of chloride channel permease to fluoride resistance in Streptococcus mutans.

PubMed

Murata, Takatoshi; Hanada, Nobuhiro

2016-06-01

Genes encoding fluoride transporters have been identified in bacterial and archaeal species. The genome sequence of the cariogenic Streptococcus mutans bacteria suggests the presence of a putative fluoride transporter, which is referred to as a chloride channel permease. Two homologues of this gene (GenBank locus tags SMU_1290c and SMU_1289c) reside in tandem in the genome of S. mutans The aim of this study was to determine whether the chloride channel permeases contribute to fluoride resistance. We constructed SMU_1290c- and SMU_1289c-knockout S. mutans UA159 strains. We also constructed a double-knockout strain lacking both genes. SMU_1290c or SMU_1289c was transformed into a fluoride transporter- disrupted Escherichia coli strain. All bacterial strains were cultured under appropriate conditions with or without sodium fluoride, and fluoride resistance was evaluated. All three gene-knockout S. mutans strains showed lower resistance to sodium fluoride than did the wild-type strain. No significant changes in resistance to other sodium halides were recognized between the wild-type and double-knockout strains. Both SMU_1290c and SMU_1289c transformation rescued fluoride transporter-disrupted E. coli cell from fluoride toxicity. We conclude that the chloride channel permeases contribute to fluoride resistance in S. mutans. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Sustained antibacterial actions of a new stabilized stannous fluoride dentifrice containing sodium hexametaphosphate.

PubMed

Ramji, Nivedita; Baig, Arif; He, Tao; Lawless, Michelle A; Saletta, Lisa; Suszcynsky-Meister, Elaine; Coggan, John

2005-09-01

Stannous fluoride has been used as a chemotherapeutic agent for years to improve oral health. The benefits of stannous fluoride in controlling caries, plaque, and gingivitis are directly associated with its antimicrobial actions. Recently, a novel dentifrice was developed that combines stannous fluoride with an anticalculus agent, sodium hexa. metaphosphate. A series of independent evaluations were conducted to assess the long-lasting antimicrobial activity of stannous fluoride in the new stannous fluoride/sodium hexametaphosphate dentifrice: an in vitro Live/Dead assay; an in vivo Plaque Glycolysis and Regrowth Model study; a rapid in vitro salivary bacteria metabolic activity study; and a 12-hour in vivo tin-retention study. In the Live/Dead study, the new stannous fluoride/sodium hexametaphosphate dentifrice killed approximately 90% to 99% of the salivary microbes 16 hours after a single exposure. Similarly, the stannous fluoride dentifrice produced statistically significant reductions in plaque acid production and plaque regrowth activity compared to plaque treated with a standard fluoride dentifrice at all time intervals measured after product exposure (15 and 45 minutes). Results from the final two studies collectively demonstrated the presence of total soluble tin, which serves as a marker for the active stannous fluoride, at levels above the minimum concentration for inhibition of salivary bacteria metabolic activity 12 hours posttreatment. These findings confirm the long-lasting antibacterial action of the new stannous fluoride dentifrice, which serves as a basis for its therapeutic benefits.

Effects of Excess Fluoride and Iodide on Thyroid Function and Morphology.

PubMed

Jiang, Yaqiu; Guo, Xiujuan; Sun, Qiuyan; Shan, Zhongyan; Teng, Weiping

2016-04-01

Exposure to high levels of iodide in Cangzhou, Shandong Province, China has been associated with increased incidence of thyroid disease; however, whether fluoride can affect the thyroid remains controversial. To investigate the effects of excess fluoride, we evaluated thyroid gland structure and function in rats exposed to fluoride and iodide, either alone or in combination. Five-week-old Wistar rats (n = 160 total) were randomly divided into eight groups: three groups that were given excess fluoride (15, 30, or 60 ppm F); one group given excess iodide (1200 μg/L I); three groups given excess iodide plus fluoride (1200 μg/L I plus 15, 30, or 60 ppm F); and one control group. The serum concentrations of the thyroid hormones TT3 and TT4 on day 150 were significantly reduced for certain fluoride groups; however, no significant differences were observed in concentrations for the pituitary hormone TSH among any groups. Hematoxylin and eosin staining revealed that iodide causes an increase in the areas of the colloid lumens and a decrease in the diameters of epithelial cells and nuclei; however, fluoride causes an increase in nuclear diameters. The damage to follicular epithelial cells upon fluoride or iodide treatment was easily observed by transmission electron microscopy, but the effects were most dramatic upon treatment with both fluoride and iodide. These results suggest that iodide causes the most damage but that fluoride can promote specific changes in the function and morphology of the thyroid, either alone or in combination with iodide.

Topical fluoride for caries prevention

PubMed Central

Weyant, Robert J.; Tracy, Sharon L.; Anselmo, Theresa (Tracy); Beltrán-Aguilar, Eugenio D.; Donly, Kevin J.; Frese, William A.; Hujoel, Philippe P.; Iafolla, Timothy; Kohn, William; Kumar, Jayanth; Levy, Steven M.; Tinanoff, Norman; Wright, J. Timothy; Zero, Domenick; Aravamudhan, Krishna; Frantsve-Hawley, Julie; Meyer, Daniel M.

2015-01-01

Background A panel of experts convened by the American Dental Association (ADA) Council on Scientific Affairs presents evidence-based clinical recommendations regarding professionally applied and prescription-strength, home-use topical fluoride agents for caries prevention. These recommendations are an update of the 2006 ADA recommendations regarding professionally applied topical fluoride and were developed by using a new process that includes conducting a systematic review of primary studies. Types of Studies Reviewed The authors conducted a search of MEDLINE and the Cochrane Library for clinical trials of professionally applied and prescription-strength topical fluoride agents—including mouthrinses, varnishes, gels, foams and pastes—with caries increment outcomes published in English through October 2012. Results The panel included 71 trials from 82 articles in its review and assessed the efficacy of various topical fluoride caries-preventive agents. The panel makes recommendations for further research. Practical Implications The panel recommends the following for people at risk of developing dental caries: 2.26 percent fluoride varnish or 1.23 percent fluoride (acidulated phosphate fluoride) gel, or a prescription-strength, home-use 0.5 percent fluoride gel or paste or 0.09 percent fluoride mouthrinse for patients 6 years or older. Only 2.26 percent fluoride varnish is recommended for children younger than 6 years. The strengths of the recommendations for the recommended products varied from “in favor” to “expert opinion for.” As part of the evidence-based approach to care, these clinical recommendations should be integrated with the practitioner's professional judgment and the patient's needs and preferences. PMID:24177407

Caries prevention through the fluoridation of milk. A review.

PubMed

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.

Are fluoride releasing dental materials clinically effective on caries control?

PubMed

Cury, Jaime Aparecido; de Oliveira, Branca Heloisa; dos Santos, Ana Paula Pires; Tenuta, Livia Maria Andaló

2016-03-01

(1) To describe caries lesions development and the role of fluoride in controlling disease progression; (2) to evaluate whether the use of fluoride-releasing pit and fissure sealants, bonding orthodontic agents and restorative materials, in comparison to a non-fluoride releasing material, reduces caries incidence in children or adults, and (3) to discuss how the anti-caries properties of these materials have been evaluated in vitro and in situ. The search was performed on the Cochrane Database of Systematic Reviews and on Medline via Pubmed. Caries is a biofilm-sugar dependent disease and as such it provokes progressive destruction of mineral structure of any dental surface - intact, sealed or restored - where biofilm remains accumulated and is regularly exposed to sugar. The mechanism of action of fluoride released from dental materials on caries is similar to that of fluoride found in dentifrices or other vehicles of fluoride delivery. Fluoride-releasing materials are unable to interfere with the formation of biofilm on dental surfaces adjacent to them or to inhibit acid production by dental biofilms. However, the fluoride released slows down the progression of caries lesions in tooth surfaces adjacent to dental materials. This effect has been clearly shown by in vitro and in situ studies but not in randomized clinical trials. The anti-caries effect of fluoride releasing materials is still not based on clinical evidence, and, in addition, it can be overwhelmed by fluoride delivered from dentifrices. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Physiology and toxicity of fluoride.

PubMed

Dhar, Vineet; Bhatnagar, Maheep

2009-01-01

Fluoride has been described as an essential element needed for normal development and growth of animals and extremely useful for human beings. Fluoride is abundant in the environment and the main source of fluoride to humans is drinking water. It has been proved to be beneficial in recommended doses, and at the same time its toxicity at higher levels has also been well established. Fluoride gets accumulated in hard tissues of the body and has been know to play an important role in mineralization of bone and teeth. At high levels it has been known to cause dental and skeletal fluorosis. There are suggested effects of very high levels of fluoride on various body organs and genetic material. The purpose of this paper is to review the various aspects of fluoride and its importance in human life.

Rare earth fluoride nano-/microstructures: hydrothermal synthesis, luminescent properties and applications.

PubMed

Zhao, Qian; Xu, Zhenhe; Sun, Yaguang

2014-02-01

Rare earth fluoride materials have attracted wide interest and come to the forefront in nanophotonics due to their distinct electrical, optical and magnetic properties as well as their potential applications in diverse fields such as optical telecommunication, lasers, biochemical probes, infrared quantum counters, and medical diagnostics. This review presents a comprehensive overview of the flourishing field of rare earth fluorides materials in the past decade. We summarize the recent research progress on the preparation, morphology, luminescent properties and application of rare earth fluoride-based luminescent materials by hydrothermal systems. Various rare earth fluoride materials are obtained by fine-tuning of experimental conditions, such as capping agents, fluoride source, acidity, temperature and reaction time. The controlled morphology, luminescent properties and application of the rare earth fluorides are briefly discussed with typical examples.

[Study on ecological risk assessment technology of fluoride pollution from arid oasis soil].

PubMed

Xue, Su-Yin; Li, Ping; Wang, Sheng-Li; Nan, Zhong-Ren

2014-03-01

According to translocation regulation of fluoride in the typical oasis soil-plant system under field, an ecological risk assessment model of fluoride was established, and this model was used to assess ecological risk to fluoride pollution from suburban oasis soils in Baiyin City, which was specifically expressed with the potential ecological risk of bioavailability (ER(bc)) model to assess ecological risk of fluoride pollution in oasis regions. Results showed that the ecological risk indices of fluoride pollution from this region were 1.37-24.81, the level of risk at most sites was high to very high, the average ecological risk index was 11.28, belonged to very high risk. This indicated that in the suburb soil of Baiyin City needs to be concerned about the remediation of fluoride pollution.

Simple One-Pot Syntheses and Characterizations of Free Fluoride- and Bifluoride-Containing Polymers Soluble in Non-Aqueous Solvents

PubMed Central

Steinle, Dominik; Friedrich, Laura; Bevilacqua, Nico; von Hauff, Elizabeth; Gschwind, Fabienne

2016-01-01

One of the problems that arise with bifluoride- or fluoride-containing compounds is their poor solubility in non-aqueous solvents. We report herein a facile one-pot synthesis and the chemical analysis of fluoride/bifluoride-containing polymers, which are soluble in MeCN. Different polymers, such as Polyvinylacetate or Polyethylene imine and saccharides, such as maltodextrin, were complexed with ammonium (bi)fluoride using hydrogen bonds to form the desired (bi)fluoride-containing compounds. The newly formed hydrogen bonding (bi)fluoride-doped polymer matrices were analyzed using infrared and nuclear magnetic resonance spectroscopies, and X-ray diffraction. The promising materials also underwent impedance spectroscopy, conductivity measurements and preliminary tests as electrolytes for room temperature fluoride ion batteries along with an analysis of their performance. PMID:28774092

Availability analysis of an HTGR fuel recycle facility. Summary report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharmahd, J.N.

1979-11-01

An availability analysis of reprocessing systems in a high-temperature gas-cooled reactor (HTGR) fuel recycle facility was completed. This report summarizes work done to date to define and determine reprocessing system availability for a previously planned HTGR recycle reference facility (HRRF). Schedules and procedures for further work during reprocessing development and for HRRF design and construction are proposed in this report. Probable failure rates, transfer times, and repair times are estimated for major system components. Unscheduled down times are summarized.

Laser-enhanced chemical reactions and the liquid state. II. Possible applications to nuclear fuel reprocessing

DOE Office of Scientific and Technical Information (OSTI.GOV)

DePoorter, G.L.; Rofer-DePoorter, C.K.

1976-01-01

Laser photochemistry is surveyed as a possible improvement upon the Purex process for reprocessing spent nuclear fuel. Most of the components of spent nuclear fuel are photochemically active, and lasers can be used to selectively excite individual chemical species. The great variety of chemical species present and the degree of separation that must be achieved present difficulties in reprocessing. Lasers may be able to improve the necessary separations by photochemical reaction or effects on rates and equilibria of reactions. (auth)

"Borderline" fluorotic region in Serbia: correlations among fluoride in drinking water, biomarkers of exposure and dental fluorosis in schoolchildren.

PubMed

Antonijevic, Evica; Mandinic, Zoran; Curcic, Marijana; Djukic-Cosic, Danijela; Milicevic, Nemanja; Ivanovic, Mirjana; Carevic, Momir; Antonijevic, Biljana

2016-06-01

This study explores relation between dental fluorosis occurrence in schoolchildren, residents of Ritopek, a small local community near Belgrade, and fluoride exposure via drinking water. Additionally, fluoride levels were determined in children's urine and hair samples, and efforts were made to correlate them with dental fluorosis. Dental fluorosis and caries prevalence were examined in a total of 52 schoolchildren aged 7-15 years (29 boys and 23 girls). Fluoride levels in three types of samples were analyzed using composite fluoride ion-selective electrode. Results showed high prevalence of dental fluorosis (34.6 %) and low prevalence of dental caries (23.1 %, mean DMFT 0.96) among children exposed to wide range of water fluoride levels (0.11-4.14 mg/L, n = 27). About 11 % of water samples exceeded 1.5 mg/L, a drinking-water quality guideline value for fluoride given by the World Health Organization (2006). Fluoride levels in urine and hair samples ranged between 0.07-2.59 (n = 48) and 1.07-19.83 mg/L (n = 33), respectively. Severity of dental fluorosis was positively and linearly correlated with fluoride levels in drinking water (r = 0.79). Fluoride levels in urine and hair were strongly and positively correlated with levels in drinking water (r = 0.92 and 0.94, respectively). Fluoride levels in hair samples appeared to be a potentially promising biomarker of fluoride intake via drinking water on one hand, and severity of dental fluorosis on the other hand. Based on community fluorosis index value of 0.58, dental fluorosis revealed in Ritopek can be considered as "borderline" public health issue.

[The effect of fluoride-containing tooth paste on dental plaque and on fluoride level in the mouth].

PubMed

Oomori, H

1989-01-01

Various kinds of fluoride have been used for a long time and there are many reports concerning fluorides and their effects. Recently, the caries-inhibiting action of fluoride-containing tooth paste has been given much attention. In this study, I tried to clarify the residual time and amount of fluoride derived from the fluoride-containing tooth paste in the mouth, as well as to assess possible variation in bacterial composition in the dental plaque bacteriologically and biochemically. In the study on the fluoride clearance from the mouth, both 1.0 g and 0.5 g of paste showed the same reduction rates; and about an 80% reduction was recognized between the value at 3 minutes and that at 30 minutes, and about a 40% reduction from the 30-minute to the 60-minute interval. Next, a study on the variation in plaque bacteria was carried out. The total number of the CFU on each plate was not different between samples obtained before and after the use of the tooth paste; moreover, no difference was noted between aerobic and anaerobic culture. However, when plaque before and after brushing with fluoride-containing tooth paste were cultured in 10% sucrose solution, the differences of acid production such as lactic acid, acetic acid, and formic acid were demonstrated. Namely, these acid productions were inhibited after the use of fluoride, especially lactic acid was strongly inhibited. On the other hand, when Str. mutans from the plaque obtained after the use of fluoride-containing tooth paste was cultured in fluoride-free BHI broth, the inhibition of acid from carbohydrates was not shown clearly.(ABSTRACT TRUNCATED AT 250 WORDS)

Periodontal health status among permanent residents of low, optimum and high fluoride areas in Kolar District, India.

PubMed

Megalamanegowdru, Jayachandra; Ankola, Anil V; Vathar, Jagadishchandra; Vishwakarma, Prashanthkumar; Dhanappa, Kirankumar B; Balappanavar, Aswini Y

2012-01-01

To assess and compare the periodontal health status among permanent residents of low, optimum and high fluoride areas in Kolar District, India. A house-to-house survey was conducted in a population consisting of 925 permanent residents aged 35 to 44 years in three villages having different levels of fluoride concentrations in the drinking water. The fluoride concentrations in selected villages were 0.48 ppm (low), 1.03 ppm (optimum) and 3.21 ppm (high). The ion selective electrode method was used to estimate the fluoride concentration in the drinking water. Periodontal status was assessed using the Community Periodontal Index (CPI) and loss of attachment (LOA). Results were analysed using the chi-square test and logistic regression. The chi-square test was used to find the group differences and logistic regression to find association between the variables. The overall prevalence of periodontitis was 72.9%; specifically, prevalences were 95.4%, 76.3% and 45.7% in low, optimum and high fluoride areas, respectively. The number of sextants with shallow or deep pockets decreased (shallow pockets: 525, 438, 217; deep pockets: 183, 81, 34) from low to high fluoride areas (odds ratio: 71.3). The low fluoride area had a 7.9-fold higher risk of periodontitis than the optimum fluoride area and a 30-fold higher risk than the high fluoride area, which was highly significant (χ2 = 53.5, P < 0.0001 and χ2 = 192.8, P < 0.001, respectively). The severity of periodontal disease is inversely associated with the fluoride concentrations in drinking water. This relation can provide an approach to fluoride treatments to reduce the prevalence or incidence of this disease.

In situ study of the anticariogenic potential of fluoride varnish combined with CO2 laser on enamel.

PubMed

Souza-Gabriel, Aline Evangelista; Turssi, Cecília Pedroso; Colucci, Vivian; Tenuta, Lívia Maria Andaló; Serra, Mônica Campos; Corona, Silmara Aparecida Milori

2015-06-01

This in situ study evaluated the effect of fluoride varnish combined with CO2 laser in controlling enamel demineralization caused by cariogenic challenges. In a crossover study conducted in 2 phases of 14 days each, 14 volunteers (n = 14) wore palatal appliances with bovine enamel slabs treated with fluoride varnish + CO2 laser (FV + CO2), fluoride varnish (FV), nonfluoride placebo varnish (PV) and nonfluoride placebo varnish + CO2 laser (PV + CO2). Drops of sucrose solution were dripped onto enamel slabs allowing the accumulation of biofilm. At the first phase, half of the volunteers received 4 enamel slabs treated with FV while the remainders received slabs exposed to the PV with and without CO2 laser. In the second phase, the vonlunteers were reversed treatments. The slabs were evaluated for cross-sectional microhardness (CSMH) and the concentration of loosely bound fluoride (CaF2) and firmly bound fluoride (FAp). The concentration of fluoride in biofilm were also determined. Two-way ANOVA showed that the CSMH values were higher in laser-irradiated enamel, regardless of the fluoride varnish. Friedman test showed that FV group presented significantly larger amount of fluoride in biofilm (P < 0.05). In the enamel, the largest amount of fluoride was found in the groups FV + CO2, which was not different from FV (P > 0.05). The synergistic effect of fluoride varnish and CO2 laser on enamel demineralization was not observed, however, CO2 laser reduces enamel demineralization. CO2 laser might reduce the demineralization of subsurface enamel, although its association with a high concentrated fluoride therapy may not result in a positive synergistic interaction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Drinking water fluoridation and bone.

PubMed

Allolio, B; Lehmann, R

1999-01-01

Drinking water fluoridation has an established role in the prevention of dental caries, but may also positively or negatively affect bone. In bone fluoride is incorporated into hydroxylapatite to form the less soluble fluoroapatite. In higher concentrations fluoride stimulates osteoblast activity leading to an increase in cancellous bone mass. As optimal drinking water fluoridation (1 mg/l) is widely used, it is of great interest, whether long-term exposition to artificial water fluoridation has any impact on bone strength, bone mass, and -- most importantly -- fracture rate. Animal studies suggest a biphasic pattern of the effect of drinking water fluoridation on bone strength with a peak strength at a bone fluoride content of 1200 ppm followed by a decline at higher concentrations eventually leading to impaired bone quality. These changes are not paralleled by changes in bone mass suggesting that fluoride concentrations remain below the threshold level required for activation of osteoblast activity. Accordingly, in most epidemiological studies in humans bone mass was not altered by optimal drinking water fluoridation. In contrast, studies on the effect on hip fracture rate gave conflicting results ranging from an increased fracture incidence to no effect, and to a decreased fracture rate. As only ecological studies have been performed, they may be biased by unknown confounding factors -- the so-called ecological fallacy. However, the combined results of these studies indicate that any increase or decrease in fracture rate is likely to be small. It has been calculated that appropriately designed cohort studies to solve the problem require a sample size of >400,000 subjects. Such studies will not be performed in the foreseeable future. Future investigations in humans should, therefore, concentrate on the effect of long-term drinking water fluoridation on bone fluoride content and bone strength.

Geochemical evaluation of fluoride contamination of groundwater in the Thoothukudi District of Tamilnadu, India

NASA Astrophysics Data System (ADS)

Singaraja, C.; Chidambaram, S.; Anandhan, P.; Prasanna, M. V.; Thivya, C.; Thilagavathi, R.; Sarathidasan, J.

2014-09-01

Fluoride is a chemical element that has been shown to cause significant effects on human health through drinking water. Different forms of fluoride exposure are of importance and have shown to affect the body's fluoride content and thus increasing the risks of fluoride-prone diseases. Fluoride has beneficial effects on teeth; however, low concentrations of fluoride intensify the risk of tooth decay. Fluoride can also be quite detrimental at higher concentrations at skeletal fluorosis. The Thoothukudi District is a hard rock and alluvial plain marked as one of the Fluoride-increase area in Tamilnadu due to occurrence of various rock types including fluoride-bearing minerals. The F- content of groundwater can thus originate from the dissolution of Fluoride-bearing minerals in the bed rock. Hundred representative groundwater samples from Thoothukudi District were collected during two different seasons. Samples were analysed for F-, other major cations and anions. The study area is chiefly composed of hornblende biotite gneiss, charnockite, alluvio marine, fluvial marine and granite with small patches of quartzite and sandstone. Higher concentration of fluoride is observed during pre-monsoon (3.3 mg l-1) compared to the post-monsoon (2.4 mg l-1) due to the dilution effect. Spatial distribution and factor score show that higher concentrations of F- are noted in the north and central part of the study area owing to lithology. Bicarbonate is well correlated with F- which explains that both ions were derived from the weathering. While F- has a very weak correlation with pH which may be due to the increase of alkalinity resulting from the increase of carbonate and bicarbonate ions.

Spatial and temporal variability of fluoride concentrations in groundwater resources of Larestan and Gerash regions in Iran from 2003 to 2010.

PubMed

Amini, Hassan; Haghighat, Gholam Ali; Yunesian, Masud; Nabizadeh, Ramin; Mahvi, Amir Hossein; Dehghani, Mohammad Hadi; Davani, Rahim; Aminian, Abd-Rasool; Shamsipour, Mansour; Hassanzadeh, Naser; Faramarzi, Hossein; Mesdaghinia, Alireza

2016-02-01

There is discrepancy about intervals of fluoride monitoring in groundwater resources by Iranian authorities. Spatial and temporal variability of fluoride in groundwater resources of Larestan and Gerash regions in Iran were analyzed from 2003 to 2010 using a geospatial information system and the Mann-Kendall trend test. The mean concentrations of fluoride for the 8-year period in the eight cities and 31 villages were 1.6 and 2.0 mg/l, respectively; the maximum values were 2.4 and 3.8 mg/l, respectively. Spatial, temporal, and spatiotemporal variability of fluoride in overall groundwater resources were relatively constant over the years. However, results of the Mann-Kendall trend test revealed a monotonic trend in the time series of one city and 11 villages for the 8-year period. Specifically, one city and three villages showed positive significant Kendall's Tau values, suggesting an upward trend in fluoride concentrations over the 8-year period. In contrast, seven villages displayed negative significant Kendall's Tau values, arguing for a downward trend in fluoride concentrations over the years. From 2003 to 2010, approximately 52 % of the Larestan and Gerash areas have had fluoride concentrations above the maximum permissible Iranian drinking water standard fluoride level (1.4 mg/l), and about 116,000 people were exposed to such excess amounts. Therefore, our study supports for a close monitoring of fluoride concentrations from health authorities in monthly intervals, especially in villages and cities that showed positive trend in fluoride concentrations. Moreover, we recommend simultaneous implementation of cost-effective protective measures or interventions until a standard fluoride level is achieved.

Fluorescent Sensing of Fluoride in Cellular System

PubMed Central

Jiao, Yang; Zhu, Baocun; Chen, Jihua; Duan, Xiaohong

2015-01-01

Fluoride ions have the important roles in a lot of physiological activities related with biological and medical system, such as water fluoridation, caries treatment, and bone disease treatment. Great efforts have been made to develop new methods and strategies for F- detection in the past decades. Traditional methods for the detection of F- including ion chromatography, ion-selective electrodes, and spectroscopic techniques have the limitations in the biomedicine research. The fluorescent probes for F- are very promising that overcome some drawbacks of traditional fluoride detection methods. These probes exhibit high selectivity, high sensitivity as well as quick response to the detection of fluoride anions. The review commences with a brief description of photophysical mechanisms for fluorescent probes for fluoride, including photo induced electron transfer (PET), intramolecular charge transfer (ICT), fluorescence resonance energy transfer (FRET), and excited-state intramolecular proton transfer (ESIPT). Followed by a discussion about common dyes for fluorescent fluoride probes, such as anthracene, naphalimide, pyrene, BODIPY, fluorescein, rhodamine, resorufin, coumarin, cyanine, and near-infrared (NIR) dyes. We divide the fluorescent probes for fluoride in cellular application systems into nine groups, for example, type of hydrogen bonds, type of cleavage of Si-O bonds, type of Si-O bond cleavage and cylization reactions, etc. We also review the recent reported carriers in the delivery of fluorescent fluoride probes. Seventy-four typical fluorescent fluoride probes are listed and compared in detail, including quantum yield, reaction medium, excitation and emission wavelengths, linear detection range, selectivity for F-, mechanism, and analytical applications. Finally, we discuss the future challenges of the application of fluorescent fluoride probes in cellular system and in vivo. We wish that more and more excellent fluorescent fluoride probes will be developed and applied in the biomedicine field in the future. PMID:25553106

Fate of over 480 million inhabitants living in arsenic and fluoride endemic Indian districts: Magnitude, health, socio-economic effects and mitigation approaches.

PubMed

Chakraborti, Dipankar; Rahman, Mohammad Mahmudur; Chatterjee, Amit; Das, Dipankar; Das, Bhaskar; Nayak, Biswajit; Pal, Arup; Chowdhury, Uttam Kumar; Ahmed, Sad; Biswas, Bhajan Kumar; Sengupta, Mrinal Kumar; Lodh, Dilip; Samanta, Gautam; Chakraborty, Sanjana; Roy, M M; Dutta, Rathindra Nath; Saha, Khitish Chandra; Mukherjee, Subhas Chandra; Pati, Shyamapada; Kar, Probir Bijoy

2016-12-01

During our last 27 years of field survey in India, we have studied the magnitude of groundwater arsenic and fluoride contamination and its resulting health effects from numerous states. India is the worst groundwater fluoride and arsenic affected country in the world. Fluoride results the most prevalent groundwater related diseases in India. Out of a total 29 states in India, groundwater of 20 states is fluoride affected. Total population of fluoride endemic 201 districts of India is 411 million (40% of Indian population) and more than 66 million people are estimated to be suffering from fluorosis including 6 million children below 14 years of age. Fluoride may cause a crippling disease. In 6 states of the Ganga-Brahmaputra Plain (GB-Plain), 70.4 million people are potentially at risk from groundwater arsenic toxicity. Three additional states in the non GB-Plain are mildly arsenic affected. For arsenic with substantial cumulative exposure can aggravate the risk of cancers along with various other diseases. Clinical effects of fluoride includes abnormal tooth enamel in children; adults had joint pain and deformity of the limbs, spine etc. The affected population chronically exposed to arsenic and fluoride from groundwater is in danger and there is no available medicine for those suffering from the toxicity. Arsenic and fluoride safe water and nutritious food are suggested to prevent further aggravation of toxicity. The World Health Organization (WHO) points out that social problems arising from arsenic and fluoride toxicity eventually create pressure on the economy of the affected areas. In arsenic and fluoride affected areas in India, crisis is not always having too little safe water to satisfy our need, it is the crisis of managing the water. Copyright © 2016 Elsevier GmbH. All rights reserved.

Fluoride in the diet of 2-years-old children.

PubMed

Martinez-Mier, E A; Spencer, Kathryn L; Sanders, Brian J; Jones, James E; Soto-Rojas, Armando E; Tomlin, Angela M; Vinson, LaQuia A; Weddell, James A; Eckert, George J

2017-06-01

This study aimed to calculate the fluoride concentrations of commonly consumed foods and beverages for 2-years-old children utilizing market basket information for the US Midwest region. Total Diet Study food lists were cross-referenced with National Health and Nutrition Examination Survey-What We Eat in America data to determine the foods and beverages to be included. Fluoride concentrations were determined using a modification of the hexamethyldisiloxane microdiffusion technique. Fluoride concentrations were summarized for each of the food categories. Daily dietary fluoride intake was estimated using a simulation analysis. Food and beverage fluoride concentrations varied widely, ranging from nondetectable for some oils and dairy products to more than 3.0 μgF/g food for some processed meats, fish and fruits. The estimated mean (±SD) daily dietary fluoride intake, excluding dentifrice and supplements, was 412±114 μgF/d. The estimated average ingestion for a 2-years-old weighing 12.24 kg was 0.034±0.009 mg/kg/d. A diet based on foods and beverages in the fifth percentile of fluoride intake distribution for an average child would result in 247 μgF/d or 0.020 mg/kg/d, while a diet with foods and beverages in the 95th percentile would result in a total intake of 622 μgF/d or 0.051 mg/kg/d. The fluoride concentrations of foods and beverages vary widely, and, if items in the 95th percentile of fluoride intake distribution are ingested, children could consume more fluoride than the recommended 0.05 mg/kg/d. Fluoride intake calculated in this study was higher than historically reported dietary levels. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Prevalence of dental fluorosis & dental caries in association with high levels of drinking water fluoride content in a district of Gujarat, India

PubMed Central

Kotecha, P.V.; Patel, S.V.; Bhalani, K.D.; Shah, D.; Shah, V.S.; Mehta, K.G.

2012-01-01

Background & objectives: Endemic fluorosis resulting from high fluoride concentration in groundwater is a major public health problem in India. This study was carried out to measure and compare the prevalence of dental fluorosis and dental caries in the population residing in high and normal level of fluoride in their drinking water in Vadodara district, Gujarat, India. Methods: A cross-sectional study was conducted in Vadodara district, six of the 261 villages with high fluoride level and five of 1490 with normal fluoride level in drinking water were selected. The data collection was made by house-to-house visits twice during the study period. Results: The dental fluorosis prevalence in high fluoride area was 59.31 per cent while in normal fluoride area it was 39.21 per cent. The prevalence of dental caries in high fluoride area was 39.53 per cent and in normal fluoride area was 48.21 per cent with CI 6.16 to 11.18. Dental fluorosis prevalence was more among males as compared to females. Highest prevalence of dental fluorosis was seen in 12-24 yr age group. Interpretation & conclusions: The risk of dental fluorosis was higher in the areas showing more fluoride content in drinking water and to a lesser degree of dental caries in the same area. High fluoride content is a risk factor for dental fluorosis and problem of dental fluorosis increased with passage of time suggesting that the fluoride content in the water has perhaps increased over time. Longitudinal studies should be conducted to confirm the findings. PMID:22825606

Fluoride release and recharge behavior of a nano-filled resin-modified glass ionomer compared with that of other fluoride releasing materials.

PubMed

Mitra, Sumita B; Oxman, Joe D; Falsafi, Afshin; Ton, Tiffany T

2011-12-01

To compare the long-term fluoride release kinetics of a novel nano-filled two-paste resin-modified glass-ionomer (RMGI), Ketac Nano (KN) with that of two powder-liquid resin-modified glass-ionomers, Fuji II LC (FLC) and Vitremer (VT) and one conventional glass-ionomer, Fuji IX (FIX). Fluoride release was measured in vitro using ion-selective electrodes. Kinetic analysis was done using regression analysis and compared with existing models for GIs and compomers. In a separate experiment the samples of KN and two conventional glass-ionomers, FIX and Ketac Molar (KM) were subjected to a treatment with external fluoride source (Oral-B Neutra-Foam) after 3 months of fluoride release and the recharge behavior studied for an additional 7-day period. The cumulative amount of fluoride released from KN, VT and FLC and the release profiles were statistically similar but greater than that for FIX at P < 0.05. All four materials, including KN, showed a burst of fluoride ions at shorter times (t) and an overall rate dependence on t1/2 typical for glass-ionomers. The coating of KN with its primer and of DY with its adhesive did not significantly alter the fluoride release behavior of the respective materials. The overall rate for KN was significantly higher than for the compomer DY. DY showed a linear rate of release vs. t and no burst effect as expected for compomers. The nanoionomer KN showed fluoride recharge behavior similar to the conventional glass ionomers FIX and KM. Thus, it was concluded that the new RMGI KN exhibits fluoride ion release behavior similar to typical conventional and RMGIs and that the primer does not impede the release of fluoride.

Mus musculus bone fluoride concentration as a useful biomarker for risk assessment of skeletal fluorosis in volcanic areas.

PubMed

Linhares, Diana; Camarinho, Ricardo; Garcia, Patrícia Ventura; Rodrigues, Armindo Dos Santos

2018-08-01

Fluoride is often found in elevated concentrations in volcanic areas due to the release of magmatic fluorine as hydrogen fluorine through volcanic degassing. The exposure to high levels of fluoride can affect the processes of bone formation and resorption causing skeletal fluorosis, a pathology that can easily be mistaken for other skeletal diseases. In this study, we aimed to determine if fluoride concentration in the femoral bone of wild populations of the house mouse (Mus musculus) is a good biomarker of exposure to active volcanic environments naturally enriched in fluoride, allowing their use in biomonitoring programs. The fluoride concentration of the whole femoral bone of 9 mice from Furnas (5 males and 4 females) and 33 mice from Rabo de Peixe (16 males and 17 females) was measured by the potentiometric method with a fluoride ion selective electrode. Fluoride in bones was significantly higher in the mice from Furnas when compared with the mice from Rabo de Peixe (616.5 ± 129.3 μg F/g vs. 253.8 ± 10.5 μg F/g). Accumulation rates were also significantly higher in the mice collected in Furnas when compared with Rabo de Peixe individuals (3.84 ± 0.52 μg F/day vs. 1.22 ± 0.06 μg F/day). The results demonstrate a significant association between exposure to fluoride in the active volcanic environment and fluoride content in bone, revealing that bone fluoride concentration is a suitable biomarker of chronic environmental exposure to fluoride. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dental caries and enamel fluorosis among the fluoridated population in the Republic of Ireland and non fluoridated population in Northern Ireland in 2002.

PubMed

Whelton, H; Crowley, E; O'Mullane, D; Donaldson, M; Cronin, M; Kelleher, V

2006-03-01

An all Ireland/North South survey of Oral Health was carried out in 2001/2002. To compare levels of dental caries and enamel fluorosis among children and adolescents in the fluoridated Republic of Ireland (RoI) with those in the non fluoridated North of Ireland (NI). Cross sectional oral health survey of a representative, random, stratified sample of 5-, 8-, 12- and 15-year-olds in Rol and in NI (N = 19,950). WHO examination criteria with the addition of visible, non cavitated dentine caries were used for recording caries. Fluorosis was measured using Dean's Index. In the RoI, the mean d(3c)mft / D(3c)MFT for 5-, 8-, 12-, and 15-year-olds with full domestic water fluoridation (n = 9,975), was 1.0, 0.3, 1.1 and 2.1 respectively. The corresponding means in non fluoridated NI (n = 1,475) were 1.8, 0.3, 1.5 and 3.6 respectively. (p < 0.0001, NS, p < 0.0005 and p < 0.0001). The prevalence of enamel fluorosis has increased in RoI since 1984, 23% and 36% of 8- and 15-year olds respectively in fluoridated areas had Dean's Index scores at the questionable or greater level in 2002 compared with 6% and 5% respectively in 1984. In 2002 apart from 8-year-olds, caries levels were lower amongst children resident in fluoridated communities in RoI than amongst corresponding age groups in non-fluoridated NI. Caries has declined in fluoridated and non fluoridated groups in both jurisdictions since the early 1960s. In RoI fluorosis levels were higher amongst lifetime residents of fluoridated communities and have increased since 1984.

Effect of eliminating the residual fluoride gel on titanium bracket corrosion.

PubMed

Khoury, Elie S; Abboud, Maher; Bassil-Nassif, Nayla; Bouserhal, Joseph

2011-09-01

Fluoride ions, in long-term applications on titanium brackets, cause their corrosion. Fluoride gel used for caries prevention during orthodontic treatment has a very high concentration in fluoride ions, and therefore has the potential for causing bracket corrosion. The main aim of this study was to determine the effect of eliminating the residual fluoride gel, by rinsing it, on the corrosion of titanium brackets. The secondary aim was to evaluate the corrosion of titanium brackets in the presence of fluoride gel. One hundred titanium brackets were divided into five groups of 20 brackets each. Group 1 being the control group, the rest of the groups were immersed in fluoride gel: Group 2 for 4 minutes and kept for 30 minutes with the residual fluoride gel on; Group 3 for 4 minutes followed by immediate water rinsing; Group 4 for 12 minutes and kept for 90 minutes with the residual fluoride gel on and Group 5 for 12 minutes followed by immediate water rinsing. All groups were rinsed then dried, for 20 hours, using Silica gel in a desiccator maintained at 37°C before testing. Gravimetrical results and SEM analysis showed no significant difference between Groups 2, 3 and 5 compared to each other and to the control group. Only Group 4 showed significant weight loss and pitting corrosion in four of the 20 brackets. In sliding resistance, no significant difference was detected between any of the groups. Short time applications of fluoride gel do not affect sliding resistance of titanium brackets. No titanium corrosion was detected for one application of concentrated fluoride gel and some brackets showed pitting corrosion for three applications. The rinsing of residual fluoride gel eliminates completely the risk of bracket corrosion. Copyright © 2011 CEO. Published by Elsevier Masson SAS. All rights reserved.

Fluoride varnishes containing calcium glycerophosphate: fluoride uptake and the effect on in vitro enamel erosion.

PubMed

Carvalho, Thiago S; Bönecker, Marcelo; Altenburger, Markus J; Buzalaf, Marília A R; Sampaio, Fabio C; Lussi, Adrian

2015-07-01

Calcium glycerophosphate (CaGP) was added to fluoride varnishes to analyze their preventive effect on initial enamel erosion and fluoride uptake: potassium hydroxide (KOH)-soluble and KOH-insoluble fluoride bound to enamel. This study was carried out in two parts. Part 1: 108 enamel samples were randomly distributed into six varnish groups: base varnish (no active ingredients); Duraphat® (2.26%NaF); Duofluorid® (5.63%NaF/CaF2); experimental varnish 1 (1%CaGP/5.63 NaF/CaF2); experimental varnish 2 (5%CaGP/5.63%NaF/CaF2); and no varnish. Cyclic demineralization (90 s; citric acid, pH = 3.6) and remineralization (4 h) was made once a day, for 3 days. Change in surface microhardness (SMH) was measured. Part 2: 60 enamel samples were cut in half and received no varnish (control) or a layer of varnish: Duraphat®, Duofluorid®, experimental varnishes 1 and 2. Then, KOH-soluble and KOH-insoluble fluoride were analyzed using an electrode. After cyclic demineralization, SMH decreased in all samples, but Duraphat® caused less hardness loss. No difference was observed between varnishes containing CaGP and the other varnishes. Similar amounts of KOH-soluble and insoluble fluoride was found in experimental varnish 1 and Duofluorid®, while lower values were found for experimental varnish 2 and Duraphat®. The addition of CaGP to fluoride varnishes did not increase fluoride bound to enamel and did not enhance their protection against initial enamel erosion. We observe that the fluoride varnishes containing CaGP do not promote greater amounts of fluoride bound to enamel and that fluoride bound to enamel may not be closely related to erosion prevention.

Influence of Growth Mode and Sucrose on Susceptibility of Streptococcus sanguis to Amine Fluorides and Amine Fluoride-Inorganic Fluoride Combinations

PubMed Central

Embleton, J. V.; Newman, H. N.; Wilson, M.

1998-01-01

This study evaluated the susceptibility to amine fluorides (AmFs) of planktonic and biofilm cultures of Streptococcus sanguis grown with and without sucrose. Cultures were incubated with AmFs (250 mg of fluoride liter−1) for 1 min. The susceptibility of biofilms was less than that of the planktonic form and was further decreased by growth in the presence of sucrose. PMID:9726905

MOLTEN FLUORIDE NUCLEAR REACTOR FUEL

DOEpatents

Barton, C.J.; Grimes, W.R.

1960-01-01

Molten-salt reactor fuel compositions consisting of mixtures of fluoride salts are reported. In its broadest form, the composition contains an alkali fluoride such as sodium fluoride, zirconium tetrafluoride, and a uranium fluoride, the latter being the tetrafluoride or trifluoride or a mixture of the two. An outstanding property of these fuel compositions is a high coeffieient of thermal expansion which provides a negative temperature coefficient of reactivity in reactors in which they are used.

Effect of high fluoride and high fat on serum lipid levels and oxidative stress in rabbits.

PubMed

Sun, Liyan; Gao, Yanhui; Zhang, Wei; Liu, Hui; Sun, Dianjun

2014-11-01

The purpose of this study was to explore the effects of high fluoride and high fat on triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), total antioxidant capacity (T-AOC), lipid peroxide (LPO) and malondialdehyde (MDA) in rabbits. A factorial experimental design was used, with two factors (fluoride and fat) and three levels. Seventy-two male rabbits were randomly assigned into nine groups according to initial weight and serum lipid levels. The rabbits were fed with basic feed, moderate fat feed or high fat feed and drank tap water, fluoridated water at levels of 50 and 100mgfluorion/L freely. Biological materials were collected after 5 months, and serum lipid, T-AOC, LPO, and MDA levels were then measured. Using these data, the separate and interactive effects of high fluoride and high fat were analyzed. High fluoride and high fat both increased serum levels of TC, HDL-C and LDL-C significantly (P<0.05), and there was also a synergistic effect between high fluoride and high fat (P<0.05). High fluoride and high fat had different effects on TG levels: high fat significantly increased TG levels (P<0.01) whereas high fluoride had nothing to do with TG levels (P>0.05). High fat significantly elevated LPO and MDA levels and lowered T-AOC levels in serum (P<0.05). Similarly, high fluoride significantly increased LPO and MDA levels in serum (P<0.05). However, there was no interactive effect between high fat and high fluoride on these indexes. In summary, high fluoride and high fat increased serum TC and LDL-C levels individually and synergistically, and this would cause and aggravate hypercholesterolemia in rabbits. At the same time, high fluoride and high fat both made the accumulation of product of oxidative stress in experimental animals. Copyright © 2014 Elsevier B.V. All rights reserved.

Successes and drawbacks in the caries-preventive use of fluorides--lessons to be learnt from history.

PubMed

Marthaler, T M

2003-01-01

Water fluoridation was the first breakthrough in the practice of preventive cariology on a community level and has remained one of the cornerstones of prevention in dentistry. The concepts regarding the mechanisms of the caries-inhibitory effect, however, have changed in several respects. Today there is general agreement that topical effects on the erupted enamel are most important. The contention that there is no pre-eruptive effect whatsoever has created confusion; there is in fact evidence for a minor pre-eruptive protective effect. Around 1980 many experts believed that fluorides should not be used in high concentrations, for instance above those in dentifrices, because this could block remineralisation in the body of pre-cavity lesions. However, it is now known that such undesirable effects are negligible or non-existent. In the fifties and sixties, fluoride tablets were widely used in Europe and helped to make the concept of caries prevention popular. From 1980 onwards, fluoride dentifrices were found to have a much greater impact and were recognized as being able to lead to a decline of caries prevalence in entire countries, and fluoride tablets gradually lost their importance. Antifluoridationists were unable to delay or hinder the widespread use of fluoride toothpastes but in many cases have successfully opposed public health measures such as fluoridation of water or of salt. The spread of these methods, beneficial for all social strata, might have been more rapid if some of the experts had not propounded the erroneous supposition that fluoride dentifrice will be sufficient for caries prevention. Sale of fluoridated salt has been authorized in several countries on a nationwide scale. However, only Latin American countries have introduced salt fluoridation for entire populations. In Central and Eastern Europe where caries prevalence continues to be high and where the level of usage of topical fluorides including dentifrices will presumably remain at a low level for many years, salt fluoridation would be beneficial.

Feasibility and costs of water fluoridation in remote Australian Aboriginal communities

PubMed Central

Ehsani, Jonathon P; Bailie, Ross

2007-01-01

Background Fluoridation of public water supplies remains the key potential strategy for prevention of dental caries. The water supplies of many remote Indigenous communities do not contain adequate levels of natural fluoride. The small and dispersed nature of communities presents challenges for the provision of fluoridation infrastructure and until recently smaller settlements were considered unfavourable for cost-effective water fluoridation. Technological advances in water treatment and fluoridation are resulting in new and more cost-effective water fluoridation options and recent cost analyses support water fluoridation for communities of less than 1,000 people. Methods Small scale fluoridation plants were installed in two remote Northern Territory communities in early 2004. Fluoride levels in community water supplies were expected to be monitored by local staff and by a remote electronic system. Site visits were undertaken by project investigators at commissioning and approximately two years later. Interviews were conducted with key informants and documentation pertaining to costs of the plants and operational reports were reviewed. Results The fluoridation plants were operational for about 80% of the trial period. A number of technical features that interfered with plant operation were identified and addressed though redesign. Management systems and the attitudes and capacity of operational staff also impacted on the effective functioning of the plants. Capital costs for the wider implementation of these plants in remote communities is estimated at about $US94,000 with recurrent annual costs of $US11,800 per unit. Conclusion Operational issues during the trial indicate the need for effective management systems, including policy and funding responsibility. Reliable manufacturers and suppliers of equipment should be identified and contractual agreements should provide for ongoing technical assistance. Water fluoridation units should be considered as a potential priority component of health related infrastructure in at least the larger remote Indigenous communities which have inadequate levels of natural fluoride and high levels of dental caries. PMID:17555604

Fluoride-dependent formation of mineralized layers in bovine dentin during demineralization in vitro.

PubMed

Damen, J J; Buijs, M J; ten Cate, J M

1998-01-01

Demineralization of dentin in the presence of fluoride produces lesions with a mineralized surface layer which becomes thicker and more mineralized with higher fluoride concentrations whereas the lesion depth is hardly affected. The aim of this study was to investigate the effects of the time of fluoride treatment and the amount of fluoride taken up on the properties of the mineralized layer. Discs of bovine dentin embedded in methylmethacrylate with one surface exposed were demineralized in 50 mM acetic acid, 2.2 mM CaCl2, 2.2 mM KH2PO4, pH 5.0. At the start and/or later during the demineralization period, the specimens were incubated individually for 1 or 2 days in 10 ml of the same demineralization solution supplemented with 0.5, 2.0 or 5.0 ppm fluoride, which was then assessed for changes in calcium and fluoride concentrations. After 2, 5 and 8 days, specimens were sectioned for microradiographic analysis so as to follow development of the lesions and the mineralized layers. The results were the following: While demineralization with fluoride present at the first day led to the formation of a surface layer, fluoride present only at a later day produced a subsurface layer, not at the lesion front but closer to the surface. This layer resulted from (re)precipitation and not from preservation of the original mineral. The 'integrated mineral content' of the surface layer increased linearly with the uptake of fluoride, which resulted in an apparent fluorapatite content of about 20 vol%. The profiles of the surface layers remained unchanged during continued demineralization in the absence of fluoride. It was concluded that in the presence of fluoride mineral loss is reduced as a result of the reprecipitation of dissolved mineral ions as a layer of fluoride-enriched apatite. This layer does not offer protection of underlying dentin against continued demineralization.

Influence of the Relative Enamel Abrasivity (REA) of Toothpastes on the Uptake of KOH-soluble and Structurally Bound Fluoride.

PubMed

Elmazi, Valbona; Sener, Beatrice; Attin, Thomas; Imfeld, Thomas; Wegehaupt, Florian J

2015-01-01

To determine the influence of the relative enamel abrasivity (REA) of fluoridated toothpaste on the uptake of KOH-soluble and structurally bound fluoride into enamel. Bovine enamel samples were randomly allocated to 6 groups (n=36 per group). Groups A to C were treated with sodium fluoride (NaF) toothpastes and groups D to F with amine fluoride (AmF) toothpastes (1500 ppm F each). The REA in groups A and D was 2, in groups B and E it was 6 and in groups C and F it was 9. Twice a day, 18 samples of each group were immersed for 2 min in a slurry (toothpaste:artificial saliva=1:3), while the remaining samples were brushed with the respective slurry (2.5 N force; 60 strokes/min; 2 min). All samples were stored at 37°C and 100% humidity. After five days, the amount of KOH-soluble and structurally bound fluoride was determined and statistically compared by Scheffe's post-hoc tests. REA value and mode of application (immersion or brushing) had no significant influence on the amount of either kind of fluoride from NaF toothpastes. Only for the NaF toothpaste with REA 6 was the amount of KOH-soluble fluoride significantly higher after brushing. With AmF toothpastes, KOH-soluble and structurally bound fluoride concentrations were significantly higher when the samples were brushed. Furthermore, in the REA-2 group, the amounts of KOH-soluble fluoride (brushed or immersed) and structurally bound fluoride (brushed) were significantly higher than in the other groups. The REA dependency of KOH-soluble and structurally bound fluoride was found only for the AmF toothpastes. Using AmF toothpaste, the mode of application influenced the uptake of KOH-soluble and structurally bound fluoride into enamel.

A hybrid approach for treating fluorided water and biogeophysical monitoring of treatment processes

NASA Astrophysics Data System (ADS)

Singh, K. P.

2016-12-01

A laboratory experiment has been conducted for investigating the possibility of development of novel techniques for treating fluoride contamination and monitoring of physico-chemical alterations caused by biogeochemical processes in the media. In the present study, high adsorption capacity and ion-exchange property of natural zeolites have been utilized in treating fluoride contamination. The preset goals are achieved by designing and constructing experimental setup consisting of three columns, first one is filled with 450 ppm fluorided water prepared by dissolving sodium fluoride in deionized water, the second is filled with zeolite and fluorided water, and the third is filled with zeolite, fluorided water, sodium lactate and the bacterial seed. The first and the second columns were poisoned with sodium azide for preventing the growth of microorganisms. The self-potential (SP) signals associated with physico-chemical alterations in natural zeolite induced by biogeochemical processes are measured by using Cu-CuSO4 gel electrodes. Liquid-phase analysis of samples from column two and three show the reduced concentrations of fluoride and aluminum and it indicates the possibility of precipitation of insoluble aluminum fluoride. This is further confirmed by the presence of fluoride and aluminum in the solid samples as detected by energy dispersive X-ray analysis. The distinct SP of the order of -50 mV and 200 mV have been associated with biostimulated fluoride remediation and geochemical fluoride remediation processes respectively. Thus, there is a possibility of non-invasive monitoring of fluoride remediation processes driven by both microbes and chemical processes. It is found that after thirty-day nitrate and sulfate is introduced in column two due chemical interaction between water and natural zeolite. Furthermore, this study demonstrates that a hybrid approach, a combination of ion exchange and adsorption properties of natural zeolite and the bioremediation is more effective and less expensive than the chemical methodologies.

Effect of CO2 Laser and Fluoride Varnish Application on Microhardness of Enamel Surface Around Orthodontic Brackets

PubMed Central

Mahmoudzadeh, Majid; Rezaei-Soufi, Loghman; Farhadian, Nasrin; Jamalian, Seyed Farzad; Akbarzadeh, Mahdi; Momeni, Mohammadali; Basamtabar, Masome

2018-01-01

Introduction: Orthodontic treatment has many advantages such as esthetic improvement and self-esteem enhancement; yet it has some disadvantages such as increasing the risk of formation of white spot lesions, because it makes oral hygiene more difficult. It is rational to implement procedures to prevent these lesions. The present study was aimed to assess the effect of CO2 laser and fluoride varnish on the surface of the enamel surface microhardness around the orthodontic braces. Methods: Eighty extracted premolar teeth were selected, scaled, polished with nonfluoridated pumic and metal brackets were bonded to them. Then, they were randomly allocated to 5 groups: control (neither fluoride nor laser is used on enamel surfaces), fluoride (4 minutes fluoride varnish treatment of the enamel surfaces), CO2 laser (10.6 µm CO2 laser irradiation of the teeth), laserfluoride (fluoride application after laser irradiation) and fluoride-laser (fluoride was applied and then teeth were irradiated with laser). After surface treatment around brackets on enamel, the samples were stored in 0.1% thymol for less than 5 days and then they were exposed to a 10-day microbiological caries model. Microhardness values of enamel were evaluated with Vickers test. One sample of each group (5 teeth from 80 samples) was prepared for SEM (scanning electron microscopy) and the data from 75 remaining teeth were analyzed with analysis of variance (ANOVA) and chi-square tests (α =0.05). Results: Microhardness mean values from high to low were as follow: fluoride-laser, laser-fluoride, laser, fluoride and control. Microhardness in fluoride-laser group was significantly higher compared with that of the control group. Distribution adhesive remnant index (ARI) scores were significantly different between groups and most of bond failures occurred at the enamel-adhesive interface in groups 2 to 5 and at the adhesive-bracket interface in the control group. Conclusion: Combination of fluoride varnish and CO2 laser irradiation can reduce enamel demineralization around orthodontic brackets. PMID:29399311

Effect of CO2 Laser and Fluoride Varnish Application on Microhardness of Enamel Surface Around Orthodontic Brackets.

PubMed

Mahmoudzadeh, Majid; Rezaei-Soufi, Loghman; Farhadian, Nasrin; Jamalian, Seyed Farzad; Akbarzadeh, Mahdi; Momeni, Mohammadali; Basamtabar, Masome

2018-01-01

Introduction: Orthodontic treatment has many advantages such as esthetic improvement and self-esteem enhancement; yet it has some disadvantages such as increasing the risk of formation of white spot lesions, because it makes oral hygiene more difficult. It is rational to implement procedures to prevent these lesions. The present study was aimed to assess the effect of CO 2 laser and fluoride varnish on the surface of the enamel surface microhardness around the orthodontic braces. Methods: Eighty extracted premolar teeth were selected, scaled, polished with nonfluoridated pumic and metal brackets were bonded to them. Then, they were randomly allocated to 5 groups: control (neither fluoride nor laser is used on enamel surfaces), fluoride (4 minutes fluoride varnish treatment of the enamel surfaces), CO 2 laser (10.6 µm CO 2 laser irradiation of the teeth), laserfluoride (fluoride application after laser irradiation) and fluoride-laser (fluoride was applied and then teeth were irradiated with laser). After surface treatment around brackets on enamel, the samples were stored in 0.1% thymol for less than 5 days and then they were exposed to a 10-day microbiological caries model. Microhardness values of enamel were evaluated with Vickers test. One sample of each group (5 teeth from 80 samples) was prepared for SEM (scanning electron microscopy) and the data from 75 remaining teeth were analyzed with analysis of variance (ANOVA) and chi-square tests (α =0.05). Results: Microhardness mean values from high to low were as follow: fluoride-laser, laser-fluoride, laser, fluoride and control. Microhardness in fluoride-laser group was significantly higher compared with that of the control group. Distribution adhesive remnant index (ARI) scores were significantly different between groups and most of bond failures occurred at the enamel-adhesive interface in groups 2 to 5 and at the adhesive-bracket interface in the control group. Conclusion: Combination of fluoride varnish and CO2 laser irradiation can reduce enamel demineralization around orthodontic brackets.

Sulfate-doped Fe3O4/Al2O3 nanoparticles as a novel adsorbent for fluoride removal from drinking water.

PubMed

Chai, Liyuan; Wang, Yunyan; Zhao, Na; Yang, Weichun; You, Xiangyu

2013-08-01

A novel adsorbent of sulfate-doped Fe3O4/Al2O3 nanoparticles with magnetic separability was developed for fluoride removal from drinking water. The nanosized adsorbent was characterized and its performance in fluoride removal was evaluated. Kinetic data reveal that the fluoride adsorption was rapid in the beginning followed by a slower adsorption process, nearly 90% adsorption can be achieved within 20 min and only 10-15% additional removal occurred in the following 8 h. The fluoride adsorption isotherm was well described by Elovich model. The calculated adsorption capacity of this nanoadsorbent for fluoride by two-site Langmuir model was 70.4 mg/g at pH 7.0. Moreover, this nanoadsorbent performed well over a considerable wide pH range of 4-10, and the fluoride removal efficiencies reached up to 90% and 70% throughout the pH range of 4-10 with initial fluoride concentrations of 10 mg/L and 50 mg/L, respectively. The observed sulfate-fluoride displacement and decreased sulfur content on the adsorbent surface reveal that anion exchange process was an important mechanism for fluoride adsorption by the sulfate-doped Fe3O4/Al2O3 nanoparticles. Moreover, a shift of the pH of zero point charge (pHPZC) of the nanoparticles and surface analysis based on X-ray photoelectron spectroscopy (XPS) suggest the formation of inner-sphere fluoride complex at the aluminum center as another adsorption mechanism. With the exception of PO4(3-), other co-existing anions (NO3(-), Cl(-) and SO4(2-)) did not evidently inhibit fluoride removal by the nanoparticles. Findings of this study demonstrate the potential utility of the nanoparticles as an effective adsorbent for fluoride removal from drinking water. Copyright © 2013 Elsevier Ltd. All rights reserved.

[CHRONIC FLUORIDE INTOXICATION AS A RISK FACTOR FOR THE DEVELOPMENT OF ATHEROSCLEROSIS].

PubMed

Korotenko, O Yu; Panev, N I; Zakharenkov, V V; Filimonov, S N; Semenova, E A; Panev, R N

2015-01-01

In workers employed in the aluminum industry, the main harmful production factor is exposure to fluoride salts, which can cause chronic fluoride intoxication. For the assessment of the impact of chronic fluoride intoxication on the development of atherosclerosis, we conducted a comprehensive survey of 87 aluminum-metal makers with chronic fluoride intoxication and 43 aluminum-metal makers without occupational diseases, mean age--52.1 ± 0.4 years. There were considered the presence and severity of atherosclerosis of brachiocephalic arteries, and the arteries of the lower extremities in the studied group, there was evaluated the effect of other risk factors for atherosclerosis (smoking, presence of hypertension, diabetes, dyslipidemia). With the use of Doppler ultrasound of the arteries it was revealed that in metallurgists with chronic fluoride intoxication atherosclerosis was detected in 73.6% versus 55.8% in persons of the comparison group. The performed analysis of the prevalence of main risk factors for atherosclerosis showed that in metal makers with chronic fluoride intoxication in combination with atherosclerosis hypertension is more common (in 54.7%) than in metallurgists with chronic fluoride intoxication without atherosclerosis--only 26.1%. According to the frequency of occurrence of smoking, diabetes mellitus, hypercholesterolemia, and hypertriglyceridemia, there were no significant differences between the metallurgists with chronic fluoride intoxication, with and without atherosclerosis, and the control group, the increase in LDL cholesterol occurs significantly more often in metal-makers with chronic fluoride intoxication in combination with atherosclerosis if compared to workers without occupational diseases. Thus, chronic fluoride intoxication acts as a risk factor in the development of atherosclerosis: atherosclerosis in metal-makers with chronic fluoride intoxication occurs more frequently than in workers who do not have professional pathology. Hypertension and elevated levels of LDL cholesterol were established to increase the relative risk of developing atherosclerosis in metallurgists with chronic fluoride intoxication. At that there are no significant differences in the prevalence of common risk factors for atherosclerosis (smoking, diabetes, hypercholesterolemia, hypertriglyceridemia).

Fluoride in weathered rock aquifers of southern India: Managed Aquifer Recharge for mitigation.

PubMed

Brindha, K; Jagadeshan, G; Kalpana, L; Elango, L

2016-05-01

Climatic condition, geology, and geochemical processes in an area play a major role on groundwater quality. Impact of these on the fluoride content of groundwater was studied in three regions-part of Nalgonda district in Telangana, Pambar River basin, and Vaniyar River basin in Tamil Nadu, southern India, which experience semi-arid climate and are predominantly made of Precambrian rocks. High concentration of fluoride in groundwater above 4 mg/l was recorded. Human exposure dose for fluoride through groundwater was higher in Nalgonda than the other areas. With evaporation and rainfall being one of the major contributors for high fluoride apart from the weathering of fluoride rich minerals from rocks, the effect of increase in groundwater level on fluoride concentration was studied. This study reveals that groundwater in shallow environment of all three regions shows dilution effect due to rainfall recharge. Suitable managed aquifer recharge (MAR) methods can be adopted to dilute the fluoride rich groundwater in such regions which is explained with two case studies. However, in deep groundwater, increase in fluoride concentration with increase in groundwater level due to leaching of fluoride rich salts from the unsaturated zone was observed. Occurrence of fluoride above 1.5 mg/l was more in areas with deeper groundwater environment. Hence, practicing MAR in these regions will increase the fluoride content in groundwater and so physical or chemical treatment has to be adopted. This study brought out the fact that MAR cannot be practiced in all regions for dilution of ions in groundwater and that it is essential to analyze the fluctuation in groundwater level and the fluoride content before suggesting it as a suitable solution. Also, this study emphasizes that long-term monitoring of these factors is an important criterion for choosing the recharge areas.

Fluoride: A naturally-occurring health hazard in drinking-water resources of Northern Thailand.

PubMed

Chuah, C Joon; Lye, Han Rui; Ziegler, Alan D; Wood, Spencer H; Kongpun, Chatpat; Rajchagool, Sunsanee

2016-03-01

In Northern Thailand, incidences of fluorosis resulting from the consumption of high-fluoride drinking-water have been documented. In this study, we mapped the high-fluoride endemic areas and described the relevant transport processes of fluoride in enriched waters in the provinces of Chiang Mai and Lamphun. Over one thousand surface and sub-surface water samples including a total of 995 collected from shallow (depth: ≤ 30 m) and deep (> 30 m) wells were analysed from two unconnected high-fluoride endemic areas. At the Chiang Mai site, 31% of the shallow wells contained hazardous levels (≥ 1.5 mg/L) of fluoride, compared with the 18% observed in the deep wells. However, at the Lamphun site, more deep wells (35%) contained water with at least 1.5mg/L fluoride compared with the shallow wells (7%). At the Chiang Mai site, the high-fluoride waters originate from a nearby geothermal field. Fluoride-rich geothermal waters are distributed across the area following natural hydrological pathways of surface and sub-surface water flow. At the Lamphun site, a well-defined, curvilinear high-fluoride anomalous zone, resembling that of the nearby conspicuous Mae Tha Fault, was identified. This similarity provides evidence of the existence of an unmapped, blind fault as well as its likely association to a geogenic source (biotite-granite) of fluoride related to the faulted zone. Excessive abstraction of ground water resources may also have affected the distribution and concentration of fluoride at both sites. The distribution of these high-fluoride waters is influenced by a myriad of complex natural and anthropogenic processes which thus created a challenge for the management of water resources for safe consumption in affected areas. The notion of clean and safe drinking water can be found in deeper aquifers is not necessarily true. Groundwater at any depth should always be tested before the construction of wells. Copyright © 2015 Elsevier B.V. All rights reserved.

Acceptability of Salt Fluoridation in a Rural Latino Community in the United States: An Ethnographic Study

PubMed Central

Barker, Judith C.; Hoeft, Kristin S.

2016-01-01

Compared to other population groups in the United States, caries (tooth decay) is a disproportionately prevalent disease among Latino populations, especially among low-income and rural sub-groups and children under five years of age. Fluoride is a primary preventive for caries. While water fluoridation is a major and effective public health means for delivering fluoride on a mass scale, it does not reach many rural areas or population groups such as Latinos who eschew drinking water from municipal sources. This study examines the acceptability to such groups of salt fluoridation, an alternate means of delivering fluoride long used on a global scale. An ethnographic study in California’s rural Central Valley was performed. Thirty individual interviews and 5 focus groups (N = 61) were conducted in Spanish to investigate low-income Latino migrant caregivers’ experiences, views and understandings of domestic salt, oral health, caries prevention and fluoride. Audio data were transcribed, translated, coded and thematically analyzed. Table salt was readily available and frequently consumed. Both adult and child daily sodium consumption was high. Despite a general feeling that it was good, and present in dentifrices or dietary supplements, most participants had little knowledge about fluoride. Concerns were raised about cardio-vascular and other possibly deleterious effects if an increase in salt consumption occurred because fluoridated salt was viewed as having ‘extra’ benefits. Once informed about fluoride’s safety and role in caries prevention, most participants expressed willingness to use fluoridated salt, especially if it benefitted children. Reassurance about its safety and benefits, and demonstration of its taste, were important aspects of acceptance. Taste was paramount. Participants would not consume more fluoridated salt than their current salt as that would result in unpleasant changes in food flavor and taste. While salt fluoridation is acceptable, the feasibility of producing and distributing fluoridated salt in the United States is, however, complex and challenging. PMID:27391112

Anhydrous hydrogen fluoride electrolyte battery. [Patent application

DOEpatents

Not Available

1972-06-26

It is an object of the invention to provide a primary cell or battery using ammonium fluoride--anhydrous hydrogen fluoride electrolyte having improved current and power production capabilities at low temperatures. It is operable at temperatures substantially above the boiling point of hydrogen fluoride. (GRA)

40 CFR 415.230 - Applicability; description of the aluminum fluoride production subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... aluminum fluoride production subcategory. 415.230 Section 415.230 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Fluoride Production Subcategory § 415.230 Applicability; description of the aluminum fluoride production subcategory. This subpart applies to discharges to waters of the United States...

The Economic Value of Teeth

ERIC Educational Resources Information Center

Glied, Sherry; Neidell, Matthew

2010-01-01

This paper examines the effect of oral health on labor market outcomes by exploiting variation in fluoridated water exposure during childhood. The politics surrounding the adoption of water fluoridation by local governments suggests exposure to fluoride is exogenous to other factors affecting earnings. Exposure to fluoridated water increases…

40 CFR 415.230 - Applicability; description of the aluminum fluoride production subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... aluminum fluoride production subcategory. 415.230 Section 415.230 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Fluoride Production Subcategory § 415.230 Applicability; description of the aluminum fluoride production subcategory. This subpart applies to discharges to waters of the United States...

Use of abstraction regime and knowledge of hydrogeological conditions to control high-fluoride concentration in abstracted groundwater: San Luis Potosí basin, Mexico

NASA Astrophysics Data System (ADS)

Carrillo-Rivera, J. J.; Cardona, A.; Edmunds, W. M.

2002-04-01

Significant amounts of fluoride are found in the abstracted groundwater of San Luis Potosí. This groundwater withdrawal induces a cold, low-fluoride flow as well as deeper thermal fluoride-rich flow in various proportions. Flow mixing takes place depending on the abstraction regime, local hydrogeology, and borehole construction design and operation. Fluoride concentrations (≈3.7 mg l -1) could become higher still, in time and space, if the input of regional fluoride-rich water to the abstraction boreholes is enhanced. It is suggested that by controlling the abstraction well-head water temperature at 28-30 °C, a pumped water mixture with a fluoride content close to the maximum drinking water standard of 1.5 mg l -1 will be produced. Further, new boreholes and those already operating could take advantage of fluoride solubility controls to reduce the F concentration in the abstracted water by considering lithology and borehole construction design in order to regulate groundwater flow conditions.

Fluoride concentration in urine after silver diamine fluoride application on tooth enamel

NASA Astrophysics Data System (ADS)

Sari, D. L.; Bahar, A.; Gunawan, H. A.; Adiatman, M.; Rahardjo, A.; Maharani, D. A.; Toptanci, I. R.; Yavuz, I.

2017-08-01

Silver Diammine Fluoride (SDF), which contains fluoride, is known to inhibit tooth enamel demineralization and increase fluoride concentrations in saliva and urine. The aim of this study is to analyze the fluoride concentration in urine after application of SDF on tooth enamel. Urine from four subjects was collected prior to, 30 minutes after, and two and three hours after the application of SDF, and an ion-selective electrode was used to measure the fluoride concentrations. There was no significant difference between time 1 and time 2, time 1 and time 3, time 1 and time 4, time 2 and 3 (p > 0.05), and there was a significant difference between time 2 and time 4 as well as time 3 and time 4 (p < 0.05). There was a decrease in the concentration of fluoride ions in urine from the baseline to 30 minutes after application, and an increase from baseline to two and three hours after the application of SDF.

Removal of fluoride ion by bone char produced from animal biomass.

PubMed

Kawasaki, Naohito; Ogata, Fumihiko; Tominaga, Hisato; Yamaguchi, Isao

2009-01-01

Bone char (BC) was prepared by carbonizing four types of animal biomass, and the adsorption of fluoride ions and elution of phosphate ions were investigated. It was found that the BC yield decreased as carbonization temperature increased, and that carbonization temperature had no significant effect on surface pH, base or acid consumptions. Fluoride ion adsorption was increased in BC produced at a low carbonization temperature. The adsorption mechanism of fluoride ion on BCs might be monolayer adsorption. BC can potentially be used to remove fluoride ions in drinking water. However, it was found that phosphate ions from BC are eluted due to adsorption of fluoride ions, and that ingestion of large amounts of phosphate ions inhibits reabsorption of calcium in the human body. Thus there is a need to study the elution behavior of phosphate ions. The adsorption mechanisms of fluoride ions onto BC would be a physical adsorption onto BC and phosphate ion in BC is exchanged to fluoride ion.

Influence of fluoride on the bacterial composition of a dual-species biofilm composed of Streptococcus mutans and Streptococcus oralis.

PubMed

Jung, Ji-Eun; Cai, Jian-Na; Cho, Sung-Dae; Song, Kwang-Yeob; Jeon, Jae-Gyu

2016-10-01

Despite the widespread use of fluoride for the prevention of dental caries, few studies have demonstrated the effects of fluoride on the bacterial composition of dental biofilms. This study investigated whether fluoride affects the proportion of Streptococcus mutans and S. oralis in mono- and dual-species biofilm models, via microbiological, biochemical, and confocal fluorescence microscope studies. Fluoride did not affect the bacterial count and bio-volume of S. mutans and S. oralis in mono-species biofilms, except for the 24-h-old S. mutans biofilms. However, fluoride reduced the proportion and bio-volume of S. mutans but did not decrease those of S. oralis during both S. oralis and S. mutans dual-species biofilm formation, which may be related to the decrease in extracellular polysaccharide formation by fluoride. These results suggest that fluoride may prevent the shift in the microbial proportion to cariogenic bacteria in dental biofilms, subsequently inhibiting the cariogenic bacteria dominant biofilm formation.

Comparison of the toxicity of fluoridation compounds in the nematode Caenorhabditis elegans.

PubMed

Rice, Julie R; Boyd, Windy A; Chandra, Dave; Smith, Marjolein V; Den Besten, Pamela K; Freedman, Jonathan H

2014-01-01

Fluorides are commonly added to drinking water in the United States to decrease the incidence of dental caries. Silicofluorides, such as sodium hexafluorosilicate (Na2 SiF6 ) and fluorosilicic acid (H2 SiF6 ), are mainly used for fluoridation, although fluoride salts such as sodium fluoride (NaF) are also used. Interestingly, only the toxicity of NaF has been examined and not that of the more often used silicofluorides. In the present study, the toxicities of NaF, Na2 SiF6 , and H2 SiF6 were compared. The toxicity of these fluorides on the growth, feeding, and reproduction in the alternative toxicological testing organism Caenorhabditis elegans was examined. Exposure to these compounds produced classic concentration-response toxicity profiles. Although the effects of the fluoride compounds varied among the 3 biological endpoints, no differences were found between the 3 compounds, relative to the fluoride ion concentration, in any of the assays. This suggests that silicofluorides have similar toxicity to NaF. © 2013 SETAC.

Geological sources of fluoride and acceptable intake of fluoride in an endemic fluorosis area, southern Iran.

PubMed

Battaleb-Looie, Sedigheh; Moore, Farid; Jacks, Gunnar; Ketabdari, Mohammad Reza

2012-10-01

The present study is the first attempt to put forward possible source(s) of fluoride in the Dashtestan area, Bushehr Province, southern Iran. In response to reports on the high incidence of dental fluorosis, 35 surface and groundwater samples were collected and analysed for fluoride. The results indicate that dissolved fluoride in the study area is above the maximum permissible limit recommended by the World Health Organization (WHO). An additional 35 soil and rock samples were also collected and analysed for fluoride, and rock samples were subjected to petrographic investigations and X-ray diffraction. The results of these analyses show that the most likely source for fluoride in the groundwater is from clay minerals (chlorite) and micas (muscovite, sericite, and biotite) in the soils and rocks in the area. We also note that due to the high average temperatures all year round and excessive water consumption in the area, the optimum fluoride dose level should be lower than that recommended by the WHO.

Insights into the fluoride-resistant regulation mechanism of Acidithiobacillus ferrooxidans ATCC 23270 based on whole genome microarrays.

PubMed

Ma, Liyuan; Li, Qian; Shen, Li; Feng, Xue; Xiao, Yunhua; Tao, Jiemeng; Liang, Yili; Yin, Huaqun; Liu, Xueduan

2016-10-01

Acidophilic microorganisms involved in uranium bioleaching are usually suppressed by dissolved fluoride ions, eventually leading to reduced leaching efficiency. However, little is known about the regulation mechanisms of microbial resistance to fluoride. In this study, the resistance of Acidithiobacillus ferrooxidans ATCC 23270 to fluoride was investigated by detecting bacterial growth fluctuations and ferrous or sulfur oxidation. To explore the regulation mechanism, a whole genome microarray was used to profile the genome-wide expression. The fluoride tolerance of A. ferrooxidans cultured in the presence of FeSO4 was better than that cultured with the S(0) substrate. The differentially expressed gene categories closely related to fluoride tolerance included those involved in energy metabolism, cellular processes, protein synthesis, transport, the cell envelope, and binding proteins. This study highlights that the cellular ferrous oxidation ability was enhanced at the lower fluoride concentrations. An overview of the cellular regulation mechanisms of extremophiles to fluoride resistance is discussed.

A review of slow-release fluoride devices.

PubMed

Toumba, K J; Al-Ibrahim, N S; Curzon, M E J

2009-09-01

Fluoride has been used to combat dental caries using a number of different clinical approaches. An exciting relatively new development is fluoride slow-releasing devices that consistently elevate intra-oral fluoride levels of plaque and saliva for prolonged periods of up to two years. The literature on the use of slow-releasing fluoride devices in dentistry were reviewed. A Medline search on key words was carried out. All papers in English were individually reviewed. Slow-releasing fluoride devices have been shown to be effective in elevating salivary fluoride levels in both animals and human studies and to enhance the remineralisation of dental enamel. They have been demonstrated to be safe to use and without the risk of fluoride toxicity. A double blind randomised clinical trial demonstrated 76% fewer new carious surface increment in high caries-risk children after two years. These devices have a number of potential uses in dentistry and in particular have great potential for caries prevention of non-compliant high caries-risk groups.

Effects of combined oleic acid and fluoride at sub-MIC levels on EPS formation and viability of Streptococcus mutans UA159 biofilms.

PubMed

Cai, Jian-Na; Kim, Mi-A; Jung, Ji-Eun; Pandit, Santosh; Song, Kwang-Yeob; Jeon, Jae-Gyu

2015-01-01

Despite the widespread use of fluoride, dental caries, a biofilm-related disease, remains an important health problem. This study investigated whether oleic acid, a monounsaturated fatty acid, can enhance the effect of fluoride on extracellular polysaccharide (EPS) formation by Streptococcus mutans UA159 biofilms at sub-minimum inhibitory concentration levels, via microbiological and biochemical methods, confocal fluorescence microscopy, and real-time PCR. The combination of oleic acid with fluoride inhibited EPS formation more strongly than did fluoride or oleic acid alone. The superior inhibition of EPS formation was due to the combination of the inhibitory effects of oleic acid and fluoride against glucosyltransferases (GTFs) and GTF-related gene (gtfB, gtfC, and gtfD) expression, respectively. In addition, the combination of oleic acid with fluoride altered the bacterial biovolume of the biofilms without bactericidal activity. These results suggest that oleic acid may be useful for enhancing fluoride inhibition of EPS formation by S. mutans biofilms, without killing the bacterium.

Natural fluoride levels in some springs and streams from the late Maastrichtian Ajali formation in Ohafia-Arochukwu area of south eastern Nigeria.

PubMed

Ibe, K K; Adlegbembo, A O; Mafeni, J O; Danfillo, I S

1999-09-01

The aim of this study was to provide baseline data on the fluoride levels in waters associated with the late Maastrichtian Ajali formation in Ohafia-Arochukwu area of South Eastern Nigeria. Water samples from 14 artesian, perched springs and eight streams from the formation were collected with plastic containers. Fluoride analysis was carried out with inductively coupled plasma Atomic Emission Spectrometry (ICP-AES) equipment at the laboratories of the Department of Earth Science, University of Leeds, United Kingdom. The results showed that fluoride occurred in only one of the 14 spring water samples. Fluoride level in the sample was 0.03 ppm. The spring water, which contained some fluoride, was possibly associated with another rock formation: namely, the limestone bearing Nsukka formation, which overlies the Ajali formation. No fluoride was observed in all the stream water samples. This study reported the absence of fluoride in spring and stream waters associated with the late Maastrichtian formations in Nigeria.

[The effects of topical fluoridation of enamel on the growth of cariogenic bacteria contained in the dental plaque].

PubMed

Płuciennik-Stronias, Małgorzata; Zarzycka, Beata; Bołtacz-Rzepkowska, Elzbieta

2013-01-01

Dental caries is a bacterial disease. The most important element used in caries prevention is fluoride, which is derived from the air, diet or fluoride-containing preparations and materials, e.g. glass-ionomer restorations. Fluoride can inhibit metabolism and bacterial growth in the dental plaque. The aim of the study was to evaluate the effect of topical fluoridation of the enamel on the growth of Lactobacillus spp. in the dental plaque. The study was carried out in 15 patients with good oral hygiene, in whom three-day dental plaque from the enamel was examined. Next, fluoride was rubbed on the same surface and the examination of three-day dental plaque was repeated. No statistically significant differences (p = 0.475) in the amounts of Lactobacillus spp. in the plaque collected prior to and after the topical fluoridation were revealed. Fluoride rubbed in the enamel, did not affect the amount of Lactobacillus spp. in the dental plaque growing on this material.