CAN FLUORIDATION AFFECT WATER LEAD (II) LEVELS AND LEAD (II) NEUROTOXICITY?

EPA Science Inventory

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

Raman and Photoluminescence Spectroscopy of Er(3+) Doped Heavy Metal Oxide Glasses

NASA Technical Reports Server (NTRS)

Dyer, Keith; Pan, Zheng-Da; Morgan, Steve

1997-01-01

The potential applications of rare-earth ion doped materials include fiber lasers which can be pumped conveniently by infrared semiconductor laser diodes. The host material systems most widely studied are fluoride crystals and glasses because fluorides have low nonradiative relaxation rates due to their lower phonon energies. However, the mechanical strength, chemical durability and temperature stability of the oxide glasses are generally much better than fluoride glasses. The objective of this research was to investigate the optical and spectroscopic properties of Er(3+)-doped lead-germanate and lead-tellurium-germanate glasses. The maximum vibrational energy of lead-tellurium-germanate glasses are in the range of 740-820/cm, intermediate between those of silicate (1150/cm) and fluoride (530/cm) glasses.

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.

40 CFR 421.114 - Standards of performance for new sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Ammonia (as N) 82.910 36.450 Fluoride 21.770 12.440 Total suspended solids 9.330 7.464 pH (1) (1) 1 Within... concentrate digested Lead 2.592 1.203 Zinc 9.442 3.888 Ammonia (as N) 1,233.000 542.5000 Fluoride 324.000 185... digested Lead .069 .032 Zinc .251 .103 Ammonia (as N) 32.790 14.420 Fluoride 8.610 4.920 Total suspended...

40 CFR 421.114 - Standards of performance for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Ammonia (as N) 82.910 36.450 Fluoride 21.770 12.440 Total suspended solids 9.330 7.464 pH (1) (1) 1 Within... concentrate digested Lead 2.592 1.203 Zinc 9.442 3.888 Ammonia (as N) 1,233.000 542.5000 Fluoride 324.000 185... digested Lead .069 .032 Zinc .251 .103 Ammonia (as N) 32.790 14.420 Fluoride 8.610 4.920 Total suspended...

40 CFR 421.114 - Standards of performance for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Ammonia (as N) 82.910 36.450 Fluoride 21.770 12.440 Total suspended solids 9.330 7.464 pH (1) (1) 1 Within... concentrate digested Lead 2.592 1.203 Zinc 9.442 3.888 Ammonia (as N) 1,233.000 542.5000 Fluoride 324.000 185... digested Lead .069 .032 Zinc .251 .103 Ammonia (as N) 32.790 14.420 Fluoride 8.610 4.920 Total suspended...

40 CFR 421.114 - Standards of performance for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Ammonia (as N) 82.910 36.450 Fluoride 21.770 12.440 Total suspended solids 9.330 7.464 pH (1) (1) 1 Within... concentrate digested Lead 2.592 1.203 Zinc 9.442 3.888 Ammonia (as N) 1,233.000 542.5000 Fluoride 324.000 185... digested Lead .069 .032 Zinc .251 .103 Ammonia (as N) 32.790 14.420 Fluoride 8.610 4.920 Total suspended...

Designing of a fluoride selective receptor through molecular orbital engineering

NASA Astrophysics Data System (ADS)

Mishra, Rakesh K.; Kumar, Virendra; Diwan, Uzra; Upadhyay, K. K.; Roy Chowdhury, P. K.

2012-11-01

The stepwise substitution of appropriate groups over the 3-[(2,4-dinitro-phenyl)-hydrazono]-butyric acid ethyl ester (R3) lead receptor R1 which showed selectivity towards fluoride in DMSO. The UV-vis and 1H NMR titration studies revealed the details of the binding between receptor R1 and fluoride. The receptor R1 also recognized fluoride in a toothpaste solution to as low as 50 ppm. The theoretical simulations of recognition event at Density Functional Theory (DFT) level using B3LYP/6-31G** basis set and polarizable continuum model (PCM) approach lead a semi-quantitative match with the experimental results.

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.

40 CFR 421.112 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2011 CFR

2011-07-01

...-tantalum oxide dried Lead 16.140 7.685 Zinc 56.100 23.440 Ammonia (as N) 5,122.000 2,252.000 Fluoride 1,345... digested Lead 2.612 1.244 Zinc 9.080 3.794 Ammonia (as N) 829.000 364.500 Fluoride 217.700 124.400 Total....851 Zinc 13.520 5.647 Ammonia (as N) 1,233.000 542.500 Fluoride 324.000 185.100 Total Suspended Solids...

40 CFR 421.112 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2010 CFR

2010-07-01

...-tantalum oxide dried Lead 16.140 7.685 Zinc 56.100 23.440 Ammonia (as N) 5,122.000 2,252.000 Fluoride 1,345... digested Lead 2.612 1.244 Zinc 9.080 3.794 Ammonia (as N) 829.000 364.500 Fluoride 217.700 124.400 Total....851 Zinc 13.520 5.647 Ammonia (as N) 1,233.000 542.500 Fluoride 324.000 185.100 Total Suspended Solids...

METHOD OF IMPROVING THE CARRIER PRECIPITATION OF PLUTONIUM

DOEpatents

Kamack, H.J.; Balthis, J.H.

1958-12-01

Plutonium values can be recovered from acidic solutlons by adding lead nitrate, hydrogen fluoride, lantha num nitrate, and sulfurlc acid to the solution to form a carrler preclpitate. The lead sulfate formed improves the separatlon characteristics of the lanthanum fluoride carrier precipitate,

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.

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

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.

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.

Formation and transformation of the radiation-induced nearsurface color centers in sodium and lithium fluorides nanocrystals

NASA Astrophysics Data System (ADS)

Novikov, A. N.; Kalinov, V. S.; Radkevich, A. V.; Runets, L. P.; Stupak, A. P.; Voitovich, A. P.

2017-11-01

Near-surface color centers in sodium fluoride nanocrystals have been formed. At pre-irradiation annealing of sodium and lithium fluorides samples at temperatures of 623 K and above, the near-surface color centers in them have not been found after γ-irradiation. Annealing lithium fluoride nanocrystals with the near-surface defects leads to their transformation into bulk ones of the same composition.

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.

Toxic effects of fluoride on organisms.

PubMed

Zuo, Huan; Chen, Liang; Kong, Ming; Qiu, Lipeng; Lü, Peng; Wu, Peng; Yang, Yanhua; Chen, Keping

2018-04-01

Accumulation of excess fluoride in the environment poses serious health risks to plants, animals, and humans. This endangers human health, affects organism growth and development, and negatively impacts the food chain, thereby affecting ecological balance. In recent years, numerous studies focused on the molecular mechanisms associated with fluoride toxicity. These studies have demonstrated that fluoride can induce oxidative stress, regulate intracellular redox homeostasis, and lead to mitochondrial damage, endoplasmic reticulum stress and alter gene expression. This paper reviews the present research on the potential adverse effects of overdose fluoride on various organisms and aims to improve our understanding of fluoride toxicity. Copyright © 2018 Elsevier Inc. All rights reserved.

PROCESS OF PREPARING A FLUORIDE OF TETRAVLENT URANIUM

DOEpatents

Wheelwright, E.J.

1959-02-17

A method is described for producing a fluoride salt pf tetravalent uranium suitable for bomb reduction to metallic uranium. An aqueous solution of uranyl nitrate is treated with acetic acid and a nitrite-suppressor and then contacted with metallic lead whereby uranium is reduced from the hexavalent to the tetravalent state and soluble lead acetate is formed. Sulfate ions are then added to the solution to precipitate and remove the lead values. Hydrofluoric acid and alkali metal ions are then added causing the formation of an alkali metal uranium double-fluoride in which the uranium is in the tetravalent state. After recovery, this precipitate is suitable for using in the limited production of metallic uranium.

Dentifrice Fluoride

NASA Astrophysics Data System (ADS)

Rakita, Philip E.

2004-05-01

The effectiveness of the fluoride ion in lowering the incidence of dental caries is a major factor in the field of dental health. Observations and research studies in the first half of the 20th century have lead to the widespread adoption of fluoridated water and the use of inorganic fluoride compounds in oral care products, such as toothpaste and dental rinses. This article provides a brief review of the types of compounds used and the chemistry involved.

Mechanochemical synthesis, structure and properties of lead containing alkaline earth metal fluoride solid solutions MxPb1-xF2 (M = Ca, Sr, Ba)

NASA Astrophysics Data System (ADS)

Heise, M.; Scholz, G.; Düvel, A.; Heitjans, P.; Kemnitz, E.

2018-03-01

The paper deals with the mechanochemical synthesis of lead containing alkaline earth metal fluoride solid solutions MxPb1-xF2 (M = Ca, Sr, Ba) by high-energy ball milling. Several metal precursors and fluorinating agents were tested for synthesizing M0.5Pb0.5F2. Metal acetates and ammonium fluoride as precursors show the most promising results and were therefore used for the formation of MxPb1-xF2 with different metal cationic ratios. The characterization of the local fluorine coordination and the crystal structure was performed by 19F MAS NMR spectroscopy and X-ray diffraction. Additional calculations of 19F chemical shifts using the superposition model allow a deeper insight into the local structure of the compounds. The fluoride ion conductivity was followed by temperature dependent DC conductivity measurements. Significantly higher conductivities were found in comparison with those of the corresponding binary fluorides. The highest values were observed for samples with high lead content M0.25Pb0.75F2, bearing in mind the much higher conductivity of PbF2 compared to MF2.

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.

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

40 CFR 421.115 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Ammonia (as N) 82.910 36.450 Fluoride 21.770 12.440 (b) Subpart K—Solvent Extraction Raffinate. PSES... pounds) of concentrate digested Lead 2.592 1.203 Zinc 9.442 3.888 Ammonia (as N) 1,233.000 542.5000... concentrate digested Lead .069 .032 Zinc .251 .103 Ammonia (as N) 32.790 14.420 Fluoride 8.610 4.920 (d...

40 CFR 421.115 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Ammonia (as N) 82.910 36.450 Fluoride 21.770 12.440 (b) Subpart K—Solvent Extraction Raffinate. PSES... pounds) of concentrate digested Lead 2.592 1.203 Zinc 9.442 3.888 Ammonia (as N) 1,233.000 542.5000... concentrate digested Lead .069 .032 Zinc .251 .103 Ammonia (as N) 32.790 14.420 Fluoride 8.610 4.920 (d...

40 CFR 421.115 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Ammonia (as N) 82.910 36.450 Fluoride 21.770 12.440 (b) Subpart K—Solvent Extraction Raffinate. PSES... pounds) of concentrate digested Lead 2.592 1.203 Zinc 9.442 3.888 Ammonia (as N) 1,233.000 542.5000... concentrate digested Lead .069 .032 Zinc .251 .103 Ammonia (as N) 32.790 14.420 Fluoride 8.610 4.920 (d...

40 CFR 421.115 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Ammonia (as N) 82.910 36.450 Fluoride 21.770 12.440 (b) Subpart K—Solvent Extraction Raffinate. PSES... pounds) of concentrate digested Lead 2.592 1.203 Zinc 9.442 3.888 Ammonia (as N) 1,233.000 542.5000... concentrate digested Lead .069 .032 Zinc .251 .103 Ammonia (as N) 32.790 14.420 Fluoride 8.610 4.920 (d...

40 CFR 421.115 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Ammonia (as N) 82.910 36.450 Fluoride 21.770 12.440 (b) Subpart K—Solvent Extraction Raffinate. PSES... pounds) of concentrate digested Lead 2.592 1.203 Zinc 9.442 3.888 Ammonia (as N) 1,233.000 542.5000... concentrate digested Lead .069 .032 Zinc .251 .103 Ammonia (as N) 32.790 14.420 Fluoride 8.610 4.920 (d...

40 CFR 426.113 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2011 CFR

2011-07-01

... applicable to the abrasive polishing and acid polishing waste water streams. Effluent characteristic Effluent... units (g/kkg of furnace pull) Fluoride 120.0 60.0 Lead 0.9 0.45 English units (lb/1,000 lb of furnace pull) Fluoride 0.12 0.06 Lead 0.0009 0.00045 [44 FR 50747, Aug. 29, 1979] ...

40 CFR 426.115 - Standards of performance for new sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (the fluoride and lead limitations are applicable to the abrasive polishing and acid polishing waste water streams while the TSS, oil, and pH limitations are applicable to the entire process waste water... 130.0 Fluoride 120.0 60.0 Lead 30.9 0.45 pH (1) (1) English units (lb/1,000 lb of furnace pull) Oil 0...

40 CFR 426.115 - Standards of performance for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (the fluoride and lead limitations are applicable to the abrasive polishing and acid polishing waste water streams while the TSS, oil, and pH limitations are applicable to the entire process waste water... 130.0 Fluoride 120.0 60.0 Lead 30.9 0.45 pH (1) (1) English units (lb/1,000 lb of furnace pull) Oil 0...

40 CFR 426.115 - Standards of performance for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (the fluoride and lead limitations are applicable to the abrasive polishing and acid polishing waste water streams while the TSS, oil, and pH limitations are applicable to the entire process waste water... 130.0 Fluoride 120.0 60.0 Lead 30.9 0.45 pH (1) (1) English units (lb/1,000 lb of furnace pull) Oil 0...

40 CFR 426.115 - Standards of performance for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (the fluoride and lead limitations are applicable to the abrasive polishing and acid polishing waste water streams while the TSS, oil, and pH limitations are applicable to the entire process waste water... 130.0 Fluoride 120.0 60.0 Lead 30.9 0.45 pH (1) (1) English units (lb/1,000 lb of furnace pull) Oil 0...

40 CFR 426.113 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2010 CFR

2010-07-01

... applicable to the abrasive polishing and acid polishing waste water streams. Effluent characteristic Effluent... units (g/kkg of furnace pull) Fluoride 120.0 60.0 Lead 0.9 0.45 English units (lb/1,000 lb of furnace pull) Fluoride 0.12 0.06 Lead 0.0009 0.00045 [44 FR 50747, Aug. 29, 1979] ...

Fluoride induces oxidative damage and SIRT1/autophagy through ROS-mediated JNK signaling.

PubMed

Suzuki, Maiko; Bandoski, Cheryl; Bartlett, John D

2015-12-01

Fluoride is an effective caries prophylactic, but at high doses can also be an environmental health hazard. Acute or chronic exposure to high fluoride doses can result in dental enamel and skeletal and soft tissue fluorosis. Dental fluorosis is manifested as mottled, discolored, porous enamel that is susceptible to dental caries. Fluoride induces cell stress, including endoplasmic reticulum stress and oxidative stress, which leads to impairment of ameloblasts responsible for dental enamel formation. Recently we reported that fluoride activates SIRT1 and autophagy as an adaptive response to protect cells from stress. However, it still remains unclear how SIRT1/autophagy is regulated in dental fluorosis. In this study, we demonstrate that fluoride exposure generates reactive oxygen species (ROS) and the resulting oxidative damage is counteracted by SIRT1/autophagy induction through c-Jun N-terminal kinase (JNK) signaling in ameloblasts. In the mouse-ameloblast-derived cell line LS8, fluoride induced ROS, mitochondrial damage including cytochrome-c release, up-regulation of UCP2, attenuation of ATP synthesis, and H2AX phosphorylation (γH2AX), which is a marker of DNA damage. We evaluated the effects of the ROS inhibitor N-acetylcysteine (NAC) and the JNK inhibitor SP600125 on fluoride-induced SIRT1/autophagy activation. NAC decreased fluoride-induced ROS generation and attenuated JNK and c-Jun phosphorylation. NAC decreased SIRT1 phosphorylation and formation of the autophagy marker LC3II, which resulted in an increase in the apoptosis mediators γH2AX and cleaved/activated caspase-3. SP600125 attenuated fluoride-induced SIRT1 phosphorylation, indicating that fluoride activates SIRT1/autophagy via the ROS-mediated JNK pathway. In enamel organs from rats or mice treated with 50, 100, or 125 ppm fluoride for 6 weeks, cytochrome-c release and the DNA damage markers 8-oxoguanine, p-ATM, and γH2AX were increased compared to those in controls (0 ppm fluoride). These results suggest that fluoride-induced ROS generation causes mitochondrial damage and DNA damage, which may lead to impairment of ameloblast function. To counteract this impairment, SIRT1/autophagy is induced via JNK signaling to protect cells/ameloblasts from fluoride-induced oxidative damage that may cause dental fluorosis. Copyright © 2015 Elsevier Inc. All rights reserved.

Fluoride induces oxidative damage and SIRT1/autophagy through ROS-mediated JNK signaling

PubMed Central

Suzuki, Maiko; Bandoski, Cheryl; Bartlett, John D.

2015-01-01

Fluoride is an effective caries prophylactic, but at high doses can also be an environmental health hazard. Acute or chronic exposure to high fluoride doses can result in dental enamel and skeletal and soft tissue fluorosis. Dental fluorosis is manifested as mottled, discolored, porous enamel that is susceptible to dental caries. Fluoride induces cell stress, including endoplasmic reticulum stress and oxidative stress, which leads to impairment of ameloblasts responsible for dental enamel formation. Recently we reported that fluoride activates SIRT1 and autophagy as an adaptive response to protect cells from stress. However, it still remains unclear how SIRT1/autophagy is regulated in dental fluorosis. In this study, we demonstrate that fluoride exposure generates reactive oxygen species (ROS) and the resulting oxidative damage is counteracted by SIRT1/autophagy induction through c-Jun N-terminal kinase (JNK) signaling in ameloblasts. In the mouse-ameloblast-derived cell line LS8, fluoride induced ROS, mitochondrial damage including cytochrome-c release, up-regulation of UCP2, attenuation of ATP synthesis, and H2AX phosphorylation (γH2AX), which is a marker of DNA damage. We evaluated the effects of the ROS inhibitor N-acetylcysteine (NAC) and the JNK inhibitor SP600125 on fluoride-induced SIRT1/autophagy activation. NAC decreased fluoride-induced ROS generation and attenuated JNK and c-Jun phosphorylation. NAC decreased SIRT1 phosphorylation and formation of the autophagy marker LC3II, which resulted in an increase in the apoptosis mediators γH2AX and cleaved/activated caspase-3. SP600125 attenuated fluoride-induced SIRT1 phosphorylation, indicating that fluoride activates SIRT1/autophagy via the ROS-mediated JNK pathway. In enamel organs from rats or mice treated with 50, 100, or 125 ppm fluoride for 6 weeks, cytochrome-c release and the DNA damage markers 8-oxoguanine, p-ATM, and γH2AX were increased compared to those in controls (0 ppm fluoride). These results suggest that fluoride-induced ROS generation causes mitochondrial damage and DNA damage, which may lead to impairment of ameloblast function. To counteract this impairment, SIRT1/autophagy is induced via JNK signaling to protect cells/ameloblasts from fluoride-induced oxidative damage that may cause dental fluorosis. PMID:26431905

40 CFR 426.113 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2014 CFR

2014-07-01

... limitations are applicable to the abrasive polishing and acid polishing waste water streams. Effluent... not exceed— Metric units (g/kkg of furnace pull) Fluoride 120.0 60.0 Lead 0.9 0.45 English units (lb/1,000 lb of furnace pull) Fluoride 0.12 0.06 Lead 0.0009 0.00045 [44 FR 50747, Aug. 29, 1979] ...

40 CFR 426.113 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2013 CFR

2013-07-01

... limitations are applicable to the abrasive polishing and acid polishing waste water streams. Effluent... not exceed— Metric units (g/kkg of furnace pull) Fluoride 120.0 60.0 Lead 0.9 0.45 English units (lb/1,000 lb of furnace pull) Fluoride 0.12 0.06 Lead 0.0009 0.00045 [44 FR 50747, Aug. 29, 1979] ...

40 CFR 426.113 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2012 CFR

2012-07-01

... limitations are applicable to the abrasive polishing and acid polishing waste water streams. Effluent... not exceed— Metric units (g/kkg of furnace pull) Fluoride 120.0 60.0 Lead 0.9 0.45 English units (lb/1,000 lb of furnace pull) Fluoride 0.12 0.06 Lead 0.0009 0.00045 [44 FR 50747, Aug. 29, 1979] ...

Proteasome inhibition by new dual warhead containing peptido vinyl sulfonyl fluorides.

PubMed

Brouwer, Arwin J; Herrero Álvarez, Natalia; Ciaffoni, Adriano; van de Langemheen, Helmus; Liskamp, Rob M J

2016-08-15

The success of inhibition of the proteasome by formation of covalent bonds is a major victory over the long held-view that this would lead to binding the wrong targets and undoubtedly lead to toxicity. Great challenges are now found in uncovering ensembles of new moieties capable of forming long lasting ties. We have introduced peptido sulfonyl fluorides for this purpose. Tuning the reactivity of this electrophilic trap may be crucial for modulating the biological action. Here we describe incorporation of a vinyl moiety into a peptido sulfonyl fluoride backbone, which should lead to a combined attack of the proteasome active site threonine on the double bond and the sulfonyl fluoride. Although this led to strong proteasome inhibitors, in vitro studies did not unambiguously demonstrate the formation of the proposed seven-membered ring structure. Possibly, formation of a seven-membered covalent adduct with the proteosomal active site threonine can only be achieved within the context of the enzyme. Nevertheless, this dual warhead concept may provide exclusive possibilities for duration and selectivity of proteasome inhibition. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

The interrelationship between diet and oral health.

PubMed

Moynihan, Paula

2005-11-01

Diet and nutrition impact on many oral diseases, in particular dental caries. Consumption of fluoridated water coupled with a reduction in non-milk extrinsic sugar intake is an effective means of caries prevention. However, studies on the fluoride concentration of bottled waters suggest increased consumption of these waters, in preference to fluoridated tap water, would lead to a marked decrease in caries protection. Concerns have been raised about the bioavailability of fluoride from artificially-fluoridated water compared with naturally-fluoridated water. This issue has been addressed in a human experimental study that has indicated that any differences in fluoride bioavailability are small compared with the naturally-occurring variability in fluoride absorption. Research has unequivocally shown sugars to be the main aetiological factor for dental caries, and information on intakes guides health promotion. Repeat dietary surveys of English children over three decades indicate that levels of sugars intake have remained stable, while sources of sugars have changed considerably, with the contribution from soft drinks more than doubling since 1980. Dental caries eventually leads to tooth loss, which in turn impairs chewing ability causing avoidance of hard and fibrous foods including fruits, vegetables and whole grains. A very low intake (<12 g/d) of NSP and fruit and vegetables has been found in edentulous subjects. Provision of prostheses alone fails to improve diet. However, initial studies indicate that customised dietary advice at the time of denture provision results in increased consumption of fruits and vegetables, and positive movement through the stages of change. Feasible means of integrating dietary counselling into the dental setting warrants further investigation.

40 CFR 426.112 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2010 CFR

2010-07-01

...). (The fluoride and lead limitations are applicable to the abrasive polishing and acid polishing waste water streams while the TSS, oil, and pH limitations are applicable to the entire process waste water... 150.0 Fluoride 140.0 70.0 Lead 39.0 4.5 pH (1) (1) English units (lb/1,000 lb of furnace pull) Oil 0...

40 CFR 426.112 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2011 CFR

2011-07-01

...). (The fluoride and lead limitations are applicable to the abrasive polishing and acid polishing waste water streams while the TSS, oil, and pH limitations are applicable to the entire process waste water... 150.0 Fluoride 140.0 70.0 Lead 39.0 4.5 pH (1) (1) English units (lb/1,000 lb of furnace pull) Oil 0...

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.

Parent Refusal of Topical Fluoride for Their Children: Clinical Strategies and Future Research Priorities to Improve Evidence-Based Pediatric Dental Practice.

PubMed

Chi, Donald L

2017-07-01

A growing number of parents are refusing topical fluoride for their children during preventive dental and medical visits. This nascent clinical and public health problem warrants attention from dental professionals and the scientific community. Clinical and community-based strategies are available to improve fluoride-related communications with parents and the public. In terms of future research priorities, there is a need to develop screening tools to identify parents who are likely to refuse topical fluoride and diagnostic instruments to uncover the reasons for topical fluoride refusal. This knowledge will lead to evidence-based strategies that can be widely disseminated into clinical practice. Copyright © 2017 Elsevier Inc. All rights reserved.

A new polymerizable fluorescent PET chemosensor of fluoride (F-) based on naphthalimide-thiourea dye.

PubMed

Alaei, Parvaneh; Rouhani, Shohre; Gharanjig, Kamaladin; Ghasemi, Jahanbakhsh

2012-05-01

A novel N-allyl-4-amino-substituted 1,8-naphthalimide dye, containing thiourea functional group with intense yellow-green fluorescence was successfully synthesized. Copolymerization was done with styrene. The photophysical characteristics of dye and its copolymer in solution and solid film were investigated in the presence of halide ions. The results reveal that the fluorescence emissions of the monomer dye and also its polymer were 'switched off' in the presence of fluoride ions. The dye showed spectral shifts and intensity changes in the presence of more fluoride ions which lead to detect certain fluoride concentrations of 10-150 mM at visible wavelengths. By adding the fluoride ions, green-yellow to purple color changes occurs and the green fluorescence emission quenches, all of which easily observed by naked eyes. These phenomena are essential for producing a dual responsive chemosensor for fluoride ions. The polymeric sensor, in the film state exhibited a fast response to the fluoride ions. Copyright © 2012 Elsevier B.V. All rights reserved.

Risk assessment of fluoride exposure in drinking water of Tunisia.

PubMed

Guissouma, Wiem; Hakami, Othman; Al-Rajab, Abdul Jabbar; Tarhouni, Jamila

2017-06-01

The presence of fluoride in drinking water is known to reduce dental cavities among consumers, but an excessive intake of this anion might leads to dental and skeletal fluorosis. This study reports a complete survey of the fluoridated tap water taken from 100 water consumption points in Tunisia. The fluoride concentrations in tap water were between 0 and 2.4 mg L -1 . Risk assessment of Fluoride exposure was assessed depending on the age of consumers using a four-step method: hazard identification, toxicity reference values selection (TRVs), daily exposure assessment, and risk characterization. Our findings suggest that approximately 75% of the Tunisian population is at risk for dental decay, 25% have a potential dental fluorosis risk, and 20% might have a skeletal fluorosis risk according to the limits of fluoride in drinking water recommended by WHO. More investigations are recommended to assess the exposure risk of fluoride in other sources of drinking water such as bottled water. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fluoride enrichment in groundwater of semi-arid urban area: Khan Younis City, southern Gaza Strip (Palestine)

NASA Astrophysics Data System (ADS)

Abu Jabal, Mohamed Shaban; Abustan, Ismail; Rozaimy, Mohd Remy; Al-Najar, Hussam

2014-12-01

The aim of this study is to determine fluoride enhancement in the groundwater of semi-arid urban area of Khan Younis City, southern Gaza Strip. Physicochemical data for a total of 200 groundwater samples were analyzed. The fluoride concentrations were varied from 0.3 to 6.45 mg/L with average value of 2.87 mg/L. Correlations between fluorides with other measured ions were relatively observed, negative correlation with calcium and the positive correlation with pH, bicarbonate and sodium increase the dissolution/solubility of fluoride bearing minerals, leading to fluoride leaching into the groundwater. Fluoride enrichment in the groundwater of the area is due to water hydrochemistry, mineral-water interaction (mainly calcite and fluorite), fluorite resulted from fluorapatite dissolution. The saturation indexes evaluation indicated that 42% of the samples are over saturated with respect to calcite and 35.5% under saturated with respect to fluorite, while 40.5% approached equilibrium with respect to both calcite and fluorite. At fluoride concentrations of less than 2.2 mg/L fluorite saturation indexes show under-saturation condition for fluorite and at higher fluoride concentrations show near saturation condition.

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

Fluoride-induced modulation of ionic transport in asymmetric nanopores functionalized with "caged" fluorescein moieties.

PubMed

Ali, Mubarak; Ahmed, Ishtiaq; Ramirez, Patricio; Nasir, Saima; Cervera, Javier; Niemeyer, Christof M; Ensinger, Wolfgang

2016-04-28

We demonstrate experimentally and theoretically a nanofluidic fluoride sensing device based on a single conical pore functionalized with "caged" fluorescein moieties. The nanopore functionalization is based on an amine-terminated fluorescein whose phenolic hydroxyl groups are protected with tert-butyldiphenylsilyl (TBDPS) moieties. The protected fluorescein (Fcn-TBDPS-NH2) molecules are then immobilized on the nanopore surface via carbodiimide coupling chemistry. Exposure to fluoride ions removes the uncharged TBDPS moieties due to the fluoride-promoted cleavage of the silicon-oxygen bond, leading to the generation of negatively charged groups on the fluorescein moieties immobilized onto the pore surface. The asymmetrical distribution of these groups along the conical nanopore leads to the electrical rectification observed in the current-voltage (I-V) curve. On the contrary, other halides and anions are not able to induce any significant ionic rectification in the asymmetric pore. In each case, the success of the chemical functionalization and deprotection reactions is monitored through the changes observed in the I-V curves before and after the specified reaction step. The theoretical results based on the Nernst-Planck and Poisson equations further demonstrate the validity of an experimental approach to fluoride-induced modulation of nanopore current rectification behaviour.

Quality of our groundwater resources: Arsenic and fluoride

USGS Publications Warehouse

Nordstrom, D. Kirk

2011-01-01

Groundwater often contains arsenic or fluoride concentrations too high for drinking or cooking. These constituents, often naturally occurring, are not easy to remove. The right combination of natural or manmade conditions can lead to elevated arsenic or fluoride which includes continental source rocks, high alkalinity and pH, reducing conditions for arsenic, high phosphate, high temperature and high silica. Agencies responsible for safe drinking water should be aware of these conditions, be prepared to monitor, and treat if necessary.

Tuning the Colors of the Dark Isomers of Photochromic Boron Compounds with Fluoride Ions: Four-State Color Switching.

PubMed

Mellerup, Soren K; Rao, Ying-Li; Amarne, Hazem; Wang, Suning

2016-09-02

Combining a three-coordinated boron (BMes2) moiety with a four-coordinated photochromic organoboron unit leads to a series of new diboron compounds that undergo four-state reversible color switching in response to stimuli of light, heat, and fluoride ions. Thus, these hybrid diboron systems allow both convenient color tuning/switching of such photochromic systems, as well as visual fluoride sensing by color or fluorescent emission color change.

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

Choi, Sungho, E-mail: shochoi@krict.re.kr; Park, Byung-Yoon; Jung, Ha-Kyun

Highlights: {yields} Systematic study of the fluorides doped solution-processed ZnO thin films via the luminescence and electrical behaviors. {yields} Defect-related visible emission bands are affected by annealing ambient and fluoride addition. {yields} Adding lithium fluoride followed by annealing in oxygen ambient leads to a controlled defect density with proper TFT performance. -- Abstract: To develop an efficient channel layer for thin film transistors (TFTs), understanding the defect-related luminescence and electrical property is crucial for solution-processed ZnO thin films. Film growth with the fluorides addition, especially using LiF, followed by the oxygen ambient post-annealing leads to decreased defect-related emission as wellmore » as enhanced switching property. The saturation mobility and current on/off ratio are 0.31 cm{sup 2} V{sup -1} s{sup -1} and 1.04 x 10{sup 3}. Consequently, we can visualize an optimized process condition and characterization method for solution-processed TFT based on the fluorine-doped ZnO film channel layer by considering the overall emission behavior.« less

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.

40 CFR 471.62 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 0.059 Lead 0.205 0.098 Zinc 0.713 0.298 Ammonia 65.1 28.6 Fluoride 29.1 12.90 (c) Drawing spent neat....030 0.015 Zinc 0.105 0.044 Ammonia 9.59 4.22 Fluoride 4.28 1.90 (f) Extrusion press hydraulic fluid... Zinc 0.260 0.109 Ammonia 23.7 10.5 Fluoride 10.6 4.70 (g) Forging spent lubricants—Subpart F—BAT. There...

40 CFR 471.62 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 0.059 Lead 0.205 0.098 Zinc 0.713 0.298 Ammonia 65.1 28.6 Fluoride 29.1 12.90 (c) Drawing spent neat....030 0.015 Zinc 0.105 0.044 Ammonia 9.59 4.22 Fluoride 4.28 1.90 (f) Extrusion press hydraulic fluid... Zinc 0.260 0.109 Ammonia 23.7 10.5 Fluoride 10.6 4.70 (g) Forging spent lubricants—subpart F—BAT. There...

40 CFR 471.62 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2014 CFR

2014-07-01

... Cyanide 0.142 0.059 Lead 0.205 0.098 Zinc 0.713 0.298 Ammonia 65.1 28.6 Fluoride 29.1 12.90 (c) Drawing....030 0.015 Zinc 0.105 0.044 Ammonia 9.59 4.22 Fluoride 4.28 1.90 (f) Extrusion press hydraulic fluid... Zinc 0.260 0.109 Ammonia 23.7 10.5 Fluoride 10.6 4.70 (g) Forging spent lubricants—subpart F—BAT. There...

40 CFR 471.62 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2012 CFR

2012-07-01

... Cyanide 0.142 0.059 Lead 0.205 0.098 Zinc 0.713 0.298 Ammonia 65.1 28.6 Fluoride 29.1 12.90 (c) Drawing....030 0.015 Zinc 0.105 0.044 Ammonia 9.59 4.22 Fluoride 4.28 1.90 (f) Extrusion press hydraulic fluid... Zinc 0.260 0.109 Ammonia 23.7 10.5 Fluoride 10.6 4.70 (g) Forging spent lubricants—subpart F—BAT. There...

A core-substituted naphthalene diimide fluoride sensor.

PubMed

Bhosale, Sheshanath V; Bhosale, Sidhanath V; Kalyankar, Mohan B; Langford, Steven J

2009-12-03

The synthesis and characterization of a highly fluorescent core-substituted naphthalene diimide sensor (varphi = 0.34) bearing a bis-sulfonamide group is described. The compound shows a unique selectivity and reactivity for the fluoride ion over other anions in CHCl(3) by a two-stage deprotonation process leading to a colorimetric response. In DMSO solution, the sensor is shown to be highly selective for fluoride (K(a) approximately 10(6) M(-1)) over other anions with more pronounced changes in absorption characteristics.

Crystallization, Optical and Chemical Properties of Fluoride Glasses

NASA Technical Reports Server (NTRS)

Doremus, R. H.

1985-01-01

Fluoride glasses have great promise as infrared optical components, especially fibers, because they are transparent to 8 micrometers and higher. In order to optimize properties, different glass compositions are needed. Some are hard to form in a container, and may possibly be formable in a containerless furnace. Understanding of crystallization with and without a container could lead to glasses with optimum properties. Chemical durability (attack by water) can limit or extend the applicability of fluoride glasses. Progress to date is given.

Ultrasonic Determination of Combinations of Third-Order Elastic Constants of Small Cubic Single Crystals

DTIC Science & Technology

1981-05-01

crystals Cesium cadmium fluoride Ultrasonic wave propagation Potassium zinc fluoride Nonlinear acoustics 20. A’?S1 RACT (Continue on reverse side If...is the stray capacitance of the detector, L is the inductance of the wire leading from the banana jack to the BNC connector (shown in Figure 111-2). Z...The samples on which measurements were made included [lO0] and [1111 copper samples, a sample of potassium zinc fluoride (KZnF 3 ) and a sample of

Defluoridation by Bacteriogenic Iron Oxides: Sorption Studies

NASA Astrophysics Data System (ADS)

Evans, K.; Ferris, F.

2009-05-01

At concentrations above 1 mg/L, fluoride in drinking water can lead to dental and skeletal fluorosis, a disease that causes mottling of the teeth, calcification of ligaments, crippling bone deformities and many other physiological disorders that can, ultimately, lead to death. Conservative estimates are that fluorosis afflicts tens of millions of people worldwide. As there is no treatment for fluorosis, prevention is the only means of controlling the disease. While numerous defluoridation techniques have been explored, no single method has been found to be both effective and inexpensive enough to implement widely. Our research began in India, with a large-scale geochemical study of the groundwater in a fluoride-contaminated region of Orissa. Having developed a better understanding of the geochemical relationships that exist between fluoride and other parameters present in an affected area, as well as the complex relationships that arise among those parameters that can impact the presence of fluoride, we began investigating certain remediation scenarios involving iron oxides. A common approach to remediation involves the partitioning of fluoride from groundwater by sorption onto a variety of materials, one of the most effective of which is iron oxide whose surface area acts as a scavenger for fluoride. In the presence of iron oxidizing bacteria, the oxidation rate of iron has been shown to be ˜6 times greater than in their absence; fluoride should, therefore, be removed from an aqueous environment by bacteriogenic iron oxides (BIOS) much more quickly than by abiotic iron oxides. Most recently, sorption studies have been conducted using both BIOS and synthetic hydrous ferric oxides in order to compare the behavior between biotic and abiotic sorbents. These studies have provided sorption isotherms that allow comparison of fluoride removed by sorption to BIOS versus synthetic iron oxides. Sorption affinity constants have also been determined, which allow for the prediction of fluoride removal in a wide variety of groundwater systems. Sorption isotherms and affinity constants show the use of BIOS to be a promising technique for the remediation of fluoride in groundwater.

Organoboron compounds as Lewis acid receptors of fluoride ions in polymeric membranes.

PubMed

Jańczyk, Martyna; Adamczyk-Woźniak, Agnieszka; Sporzyński, Andrzej; Wróblewski, Wojciech

2012-07-06

Newly synthesized organoboron compounds - 4-octyloxyphenylboronic acid (OPBA) and pinacol ester of 2,4,6-trifluorophenylboronic acid (PE-PBA) - were applied as Lewis acid receptors of fluoride anions. Despite enhanced selectivity, the polymer membrane electrodes containing the lipophilic receptor OPBA exhibited non-Nernstian slopes of the responses toward fluoride ions in acidic conditions. Such behavior was explained by the lability of the B-O bond in the boronic acids, and the OH(-)/F(-) exchange at higher fluoride content in the sample solution. In consequence, the stoichiometry of the OPBA-fluoride complexes in the membrane could vary during the calibration, changing the equilibrium concentration of the primary anion in membrane and providing super-Nernstian responses. The proposed mechanism was supported by (19)F NMR studies, which indicated that the fluoride complexation proceeds more effectively in acidic solution leading mainly to PhBF(3)(-) species. Finally, the performances of the membranes based on the phenylboronic acid pinacol ester, with a more stable B-O bond, were tested. As it was expected, Nernstian fluoride responses were recorded for such membranes with worsened fluoride selectivity. Copyright © 2012 Elsevier B.V. All rights reserved.

Excessive fluoride consumption increases haematological alteration in subjects with iron deficiency, thalassaemia, and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency.

PubMed

Pornprasert, Sakorn; Wanachantararak, Phenphichar; Kantawong, Fahsai; Chamnanprai, Supoj; Kongpan, Chatpat; Pienthai, Nattasit; Yanola, Jintana; Duangmano, Suwit; Prasannarong, Mujalin

2017-08-01

Excessive fluoride consumption leads to accelerated red blood cell death and anaemia. Whether that increases the haematological alteration in subjects with haematological disorders (iron deficiency, thalassaemia, and G-6-PD deficiency) is still unclear. The fluoride in serum and urine and haematological parameters of students at Mae Tuen School (fluoride endemic area) were analysed and compared to those of students at Baan Yang Poa and Baan Mai Schools (control areas). Iron deficiency, thalassaemia, and G-6-PD deficiency were also diagnosed in these students. The students at Mae Tuen School had significantly (P < 0.001) higher levels of mean fluoride in the serum and urine than those in control areas. In both control and fluoride endemic areas, students with haematological disorders had significantly lower levels of Hb, Hct, MCV, MCH, and MCHC than those without haematological disorders. Moreover, the lowest levels of Hb, MCH, and MCHC were observed in the students with haematological disorders who live in the fluoride endemic area. Thus, the excessive fluoride consumption increased haematological alteration in subjects with iron deficiency, thalassaemia, and G-6-PD deficiency and that may increase the risk of anaemia in these subjects.

NIOSH Manual of Analytical Methods (third edition). Fourth supplement

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

Not Available

1990-08-15

The NIOSH Manual of Analytical Methods, 3rd edition, was updated for the following chemicals: allyl-glycidyl-ether, 2-aminopyridine, aspartame, bromine, chlorine, n-butylamine, n-butyl-glycidyl-ether, carbon-dioxide, carbon-monoxide, chlorinated-camphene, chloroacetaldehyde, p-chlorophenol, crotonaldehyde, 1,1-dimethylhydrazine, dinitro-o-cresol, ethyl-acetate, ethyl-formate, ethylenimine, sodium-fluoride, hydrogen-fluoride, cryolite, sodium-hexafluoroaluminate, formic-acid, hexachlorobutadiene, hydrogen-cyanide, hydrogen-sulfide, isopropyl-acetate, isopropyl-ether, isopropyl-glycidyl-ether, lead, lead-oxide, maleic-anhydride, methyl-acetate, methyl-acrylate, methyl-tert-butyl ether, methyl-cellosolve-acetate, methylcyclohexanol, 4,4'-methylenedianiline, monomethylaniline, monomethylhydrazine, nitric-oxide, p-nitroaniline, phenyl-ether, phenyl-ether-biphenyl mixture, phenyl-glycidyl-ether, phenylhydrazine, phosphine, ronnel, sulfuryl-fluoride, talc, tributyl-phosphate, 1,1,2-trichloro-1,2,2-trifluoroethane, trimellitic-anhydride, triorthocresyl-phosphate, triphenyl-phosphate, and vinyl-acetate.

Antidotal activity of Averrhoa carambola (Star fruit) on fluoride induced toxicity in rats

PubMed Central

Vasant, Rupal A.

2014-01-01

Consumption of fluoride leads to several physiological disturbances in carbohydrate, lipid and antioxidant metabolisms. Averrhoa carambola L. fruit (Star fruit) is a commonly consumed fruit in tropical countries and is an ingredient in folklore medicines. As the fruits have high polyphenolic and antioxidant contents, the present study was undertaken to investigate the potential of star fruit as a dietary supplement in attenuating the fluoride induced hyperglycemia, hypercholesterolemia and oxidative stress in laboratory rats. A four-week exposure to fluoride caused sustained hyperglycemia, hyperlipidemia and oxidative stress and, when the diet was supplemented with star fruit powder, carbohydrate, lipid and antioxidant profiles were restored significantly. It is surmised that the antihyperglycemic, antihypercholesterolemic and antioxidant activities of star fruit in fluoride exposed rats could be due to the presence of polyphenols, flavonoids, saponins, phytosterols, ascorbic acid and fibers in the fruit, which are all well known regulators of carbohydrate, lipid and antioxidant metabolisms. These findings suggest that star fruit can be used as a dietary supplement in fluoride endemic regions to contain fluoride induced hyperglycemia, hyperlipidemia and oxidative stress. PMID:26109886

Antidotal activity of Averrhoa carambola (Star fruit) on fluoride induced toxicity in rats.

PubMed

Vasant, Rupal A; Narasimhacharya, A V R L

2014-06-01

Consumption of fluoride leads to several physiological disturbances in carbohydrate, lipid and antioxidant metabolisms. Averrhoa carambola L. fruit (Star fruit) is a commonly consumed fruit in tropical countries and is an ingredient in folklore medicines. As the fruits have high polyphenolic and antioxidant contents, the present study was undertaken to investigate the potential of star fruit as a dietary supplement in attenuating the fluoride induced hyperglycemia, hypercholesterolemia and oxidative stress in laboratory rats. A four-week exposure to fluoride caused sustained hyperglycemia, hyperlipidemia and oxidative stress and, when the diet was supplemented with star fruit powder, carbohydrate, lipid and antioxidant profiles were restored significantly. It is surmised that the antihyperglycemic, antihypercholesterolemic and antioxidant activities of star fruit in fluoride exposed rats could be due to the presence of polyphenols, flavonoids, saponins, phytosterols, ascorbic acid and fibers in the fruit, which are all well known regulators of carbohydrate, lipid and antioxidant metabolisms. These findings suggest that star fruit can be used as a dietary supplement in fluoride endemic regions to contain fluoride induced hyperglycemia, hyperlipidemia and oxidative stress.

Curcumin based optical sensing of fluoride in organo-aqueous media using irradiation technique

NASA Astrophysics Data System (ADS)

Venkataraj, Roopa; Radhakrishnan, P.; Kailasnath, M.

2017-06-01

The present work describes the degradation of natural dye Curcumin in organic-aqueous media upon irradiation by a multi-wavelength source of light like mercury lamp. The presence of anions in the solution leads to degradation of Curcumin and this degradation is especially enhanced in the case of fluoride ion. The degradation of Curcumin is investigated by studying the change in its absorption and fluorescence characteristics in organoaqueous solution upon irradiation. A broad detection range of fluoride ranging from 2.3×10-6-2.22×10-3 M points to the potential of the method of visible light irradiation enabling aqueous based sensing of fluoride using Curcumin.

Fluoride exposure regulates the elongation phase of protein synthesis in cultured Bergmann glia cells.

PubMed

Flores-Méndez, Marco; Ramírez, Diana; Alamillo, Nely; Hernández-Kelly, Luisa C; Del Razo, Luz María; Ortega, Arturo

2014-08-17

Fluoride is an environmental pollutant present in dental products, food, pesticides and water. The latter, is the greatest source of exposure to this contaminant. Structural and functional damages to the central nervous system are present in exposed population. An established consequence of the neuronal is the release of a substantial amount of glutamate to the extracellular space, leading to an excitotoxic insult. Glutamate exerts its actions through the activation of specific plasma membrane receptors and transporters present in neurons and in glia cells and it is the over-activation of glutamate receptors and transporters, the biochemical hallmark of neuronal and oligodendrocyte cell death. In this context, taking into consideration that fluoride leads to degeneration of cerebellar cells, we took the advantage of the well-established model of cerebellar Bergmann glia cultures to gain insight into the molecular mechanisms inherent to fluoride neurotoxicity that might be triggered in glia cells. We could establish that fluoride decreases [(35)S]-methionine incorporation into newly synthesized polypeptides, in a time-dependent manner, and that this halt in protein synthesis is the result of a decrease in the elongation phase of translation, mediated by an augmentation of eukaryotic elongation factor 2 phosphorylation. These results favor the notion of glial cells as targets of fluoride toxicity and strengthen the idea of a critical involvement of glia cells in the function and dysfunction of the brain. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

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.

A newly developed highly selective ratiometric fluoride ion sensor: spectroscopic, NMR and density functional studies.

PubMed

Mallick, Arabinda; Roy, Ujjal Kanti; Haldar, Basudeb; Pratihar, Sanjay

2012-03-07

A new easy-to-synthesize chemosensor, 3,3'-bis(indolyl)-4-chlorophenylmethane (hereafter S), was designed, synthesized and employed as a selective optical chemosensor for fluoride ions.(1)H NMR and density functional studies on the system have been carried out to determine the nature of the interaction between S and X(-) (X = inorganic anions) responsible for the significant fluoride-induced changes in the absorption properties of S. The experimental results reveal that abstraction of an acidic proton of S by the fluoride ion, leading to the formation of anionic species, is responsible for the spectral changes. These changes allow signaling for the fluoride ion to detect and estimate the concentration of fluoride ion present even at the submicromolar level, accurate up to 2 μM. Calculations of the transition energies of S, S(-), and S···F(-) (hydrogen bonded complex) show that only S(-) is responsible for the long-wavelength absorption band in the presence of F(-).

Cost-effectiveness of extending the coverage of water supply fluoridation for the prevention of dental caries in Australia.

PubMed

Cobiac, Linda J; Vos, Theo

2012-08-01

Fluoride was first added to the Australian water supply in 1953, and by 2003, 69% of Australia's population was receiving the minimum recommended dose. Extending coverage of fluoridation to all remaining communities of at least 1000 people is a key strategy of Australia's National Oral Health Plan 2004-2013. We evaluate the cost-effectiveness of this strategy from an Australian health sector perspective. Health gains from the prevention of caries in the Australian population are modelled over the average 15-year lifespan of a treatment plant. Taking capital and on-going operational costs of fluoridation into account, as well as costs of caries treatment, we determine the dollars per disability-adjusted life years (DALY) averted from extending coverage of fluoridation to all large (≥ 1000 people) and small (<1000 people) communities in Australia. Extending coverage of fluoridation to all communities of at least 1000 people will lead to improved population health (3700 DALYs, 95% uncertainty interval: 2200-5700 DALYs), with a dominant cost-effectiveness ratio and 100% probability of cost-savings. Extending coverage to smaller communities leads to 60% more health gains, but is not cost-effective, with a median cost-effectiveness ratio of A$92 000/DALY and only 10% probability of being under a cost-effectiveness threshold of A$50 000/DALY. Extension of fluoridation coverage under the National Oral Health Plan is highly recommended, but given the substantial dental health disparities and inequalities in access to dental care that currently exist for more regional and remote communities, there may be good justification for extending coverage to include all Australians, regardless of where they live, despite less favourable cost-effectiveness. © 2012 John Wiley & Sons A/S.

Chronic fluoride exposure exacerbates headkidney pathology and causes immune commotion in Clarias gariepinus.

PubMed

Singh, Rashmi; Hussain, Md Arafat; Kumar, Jai; Kumar, Manmohan; Kumari, Usha; Mazumder, Shibnath

2017-11-01

The current study was aimed to understand the effects of chronic fluoride exposure on fish immune system. African sharp tooth catfish (Clarias gariepinus) were exposed to 73.45mg/L of fluoride corresponding to 1/10 96h LC 50 for 30 d and the effects on general fish health and several immune parameters were studied. Chronic fluoride exposure led to significant alteration in serum biochemical parameters including alkaline phosphatase, alanine transaminase, aspartate transaminase, triglycerides, cholesterol and blood urea nitrogen levels revealing the detrimental effect of fluoride on general fish health. Upregulation in cytochrome P450 1A expression, both at mRNA and protein level suggested that fluoride activates the detoxification machinery in headkidney (HK) of C. gariepinus. Histopathological analysis of HK from exposed fish further revealed fluoride-induced hypertrophy, increase in melano-macrophage centers (MMCs) and the development of cell-depleted regions. Fluoride reduced headkidney somatic index (HKSI) and the phagocytic potential of headkidney macrophages (HKM). It induced caspase-3-dependent headkidney leukocyte (HKL) apoptosis, elevated superoxide generation and production of pro-inflammatory cytokine TNF-α besides suppressed T-cell proliferation in the exposed fish. We surmise the elevation in superoxide levels coupled with increased TNF-α production to be plausible causes of fluoride-induced HKL apoptosis. It is concluded that chronic fluoride exposure induces structure-function alterations in HK, the primary lymphoid organ in fish leading to impairment in immune responses. Copyright © 2017. Published by Elsevier B.V.

Effects of fluoride on growth, body composition, and serum biochemical profile in a freshwater teleost, Cyprinus carpio.

PubMed

Chen, Jianjie; Cao, Jinling; Wang, Jundong; Jia, Ruhui; Xue, Wenjuan; Li, Yundong; Luo, Yongju; Xie, Lingtian

2013-10-01

Fluoride is ubiquitously distributed in natural waters. Elevated fluoride may cause histopathological changes and induce oxidative stress in the gills of the common carp (Cyprinus carpio). The present study further evaluates the effects of fluoride on growth performance, body composition, and biochemical measurements of C. carpio. The results showed that food intake, growth, serum osmolality, body composition, and biochemical measures in the blood were affected by fluoride. Weight gain rate and specific growth rate in the exposed fish decreased compared with those of the control fish. Levels of crude protein and crude lipids were reduced in the fluoride-exposed fish. The major ion levels in the sera of fluoride-exposed fish were severely disturbed, resulting in a lower osmolality. All the biochemical parameters measured in the blood were affected by the exposure to fluoride. Total protein, albumin, globulin, and glucose in fish exposed to 63.6 mg/L, 77.7 mg/L, and 124.4 mg/L were lower than those in the control fish. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were markedly increased in exposed fish compared with control. Taken together, the data showed that exposure to fluoride caused a suite of detrimental effects in C. carpio, which might lead to a decrease in growth and food utilization efficiency. The results of the present study indicated that high levels of fluoride could pose a threat to carp in the field. © 2013 SETAC.

Topographic assessment of human enamel surface treated with different topical sodium fluoride agents: Scanning electron microscope consideration.

PubMed

Brar, Gurlal Singh; Arora, Amandeep Singh; Khinda, Vineet Inder Singh; Kallar, Shiminder; Arora, Karuna

2017-01-01

Continuous balanced demineralization and remineralization are natural dynamic processes in enamel. If the balance is interrupted and demineralization process dominates, it may eventually lead to the development of carious lesions in enamel and dentine. Fluoride helps control decay by enhancing remineralization and altering the structure of the tooth, making the surface less soluble. One hundred and twenty sound human permanent incisors randomly and equally distributed into six groups as follows: Group I - Control, II - Sodium fluoride solution, III - Sodium fluoride gel, IV - Sodium fluoride varnish, V - Clinpro Tooth Crème (3M ESPE), and VI-GC Tooth Mousse Plus or MI Paste Plus. The samples were kept in artificial saliva for 12 months, and the topical fluoride agents were applied to the respective sample groups as per the manufacturer instructions. Scanning electron microscope (SEM) evaluation of all the samples after 6 and 12 months was made. Morphological changes on the enamel surface after application of fluoride in SEM revealed the presence of globular precipitate in all treated samples. Amorphous, globular, and crystalline structures were seen on the enamel surface of the treated samples. Clear differences were observed between the treated and untreated samples. Globular structures consisting of amorphous CaF2precipitates, which acted as a fluoride reservoir, were observed on the enamel surface after action of different sodium fluoride agents. CPP-ACPF (Tooth Mousse) and Tricalcium phosphate with fluoride (Clinpro tooth crème) are excellent delivery vehicles available in a slow release amorphous form to localize fluoride at the tooth surface.

Evaluation of fluoride levels in bottled water and their contribution to health and teeth problems in the United Arab Emirates.

PubMed

Abouleish, Mohamed Yehia Z

2016-10-01

Fluoride is needed for better health, yet if ingested at higher levels it may lead to health problems. Fluoride can be obtained from different sources, with drinking water being a major contributor. In the United Arab Emirates (UAE), bottled water is the major source for drinking. The aim of this research is to measure fluoride levels in different bottled water brands sold in UAE, to determine whether fluoride contributes to better health or health problems. The results were compared to international and local standards. Fluoride was present in seven out of 23 brands. One brand exhibited high fluoride levels, which exceeded all standards, suggesting it may pose health problems. Other brands were either below or above standards, suggesting either contribution to better health or health problems, depending on ingested amount. A risk assessment suggested a potential for non-cancer effects from some brands. The results were compared to fluoride levels in bottled water sold in UAE and neighboring countries (e.g. Saudi Arabia, Qatar, Kuwait, and Bahrain), over 24 years, to reflect on changes in fluoride levels in bottled water in this region. The research presents the need for creating, stricter regulations that require careful fluoride monitoring and new regulations that require listing fluoride level on the bottled water label, internationally and regionally. The research will have local and global health impact, as bottled water sold in UAE and neighboring countries, is produced locally and imported from international countries, e.g. Switzerland, the USA, France, Italy, New Zealand, and Fiji.

Fluoride effects: the two faces of janus.

PubMed

Gazzano, E; Bergandi, L; Riganti, C; Aldieri, E; Doublier, S; Costamagna, C; Bosia, A; Ghigo, D

2010-01-01

The behavior of fluoride ions in the human organism is a classic example of double-edged sword. On the one hand the daily supplementation with fluoride is undoubtedly an important preventing factor in protecting teeth from caries, and, as an important mitogenic stimulus for osteoblasts, it may enhance mineral deposition in bone, but on the other hand fluoride, above a threshold concentration, has been demonstrated to be toxic. We present here a brief review of fluoride metabolism and exposure, its use in caries prevention and its effects on bone, followed by an updating about the main hypotheses concerning its mechanism of action and toxicity. The effects of fluoride have been related mainly to its ability to evoke the activation of G proteins and the inhibition of phosphotyrosine phosphatases, leading to an intracellular increase of tyrosine phosphorylation and activation of the mitogen-activated protein kinase pathway, and its capacity to cause generation of reactive oxygen species. We present also a unifying hypothesis accounting for these apparently different effects, although the available experimental models and conditions are highly variable in the literature. A lot of experiments still need to be performed to clarify the positive and negative effects of fluoride. Finding the mechanisms accounting for fluoride toxicity is an important point: indeed, the use of fluoride has been proposed in the preparation of new biomaterials to be inserted in the bone, in order to improve their stable and safe integration.

Minimally invasive monitoring of skeletal muscle hypermetabolism induced by the phosphodiesterase-III-inhibitor milrinone and sodium fluoride.

PubMed

Schuster, Frank; Johannsen, Stephan; Roewer, Norbert; Anetseder, Martin

2013-04-01

We hypothesized that the phosphodiesterase-III-inhibitor milrinone and the non-specific G-protein activator sodium fluoride increase the skeletal muscular lactate levels as a sign of a hypermetabolic response. With approval of the local animal care committee Sprague-Dawley rats were killed and artificially perfused either with Ringer's solution or sodium fluoride 110 mM, while milrinone 1.32 mM or Ringer's solution at 1 μl/min was applied via microdialysis probes in both hind limbs. Lactate was measured spectrophotometrically in the dialysate. Baseline lactate levels before drug application did not differ between hind limbs. Local infusion of milrinone via microdialysis did not significantly increase intramuscular lactate concentrations compared with the Ringer control group. Muscular perfusion with sodium fluoride resulted in a significant increase of lactate and was potentiated by combination with local milrinone. Phosphodiesterase-III-inhibition alone does not significantly influence the lactate levels in skeletal muscle of sacrificed rats. Sodium fluoride infusion leads to an intramuscular lactate increase, which was further potentiated by local inhibition of phosphodiesterase-III. The fluoride-mediated hypermetabolic response following sodium fluoride could be a possible explanation for the observed myotoxic adverse effects in individuals treated by fluoride-containing agents. © 2012 The Authors. JPP © 2012. Royal Pharmaceutical Society.

High electric breakdown strength and energy density in vinylidene fluoride oligomer/poly(vinylidene fluoride) blend thin films

NASA Astrophysics Data System (ADS)

Rahimabady, Mojtaba; Chen, Shuting; Yao, Kui; Eng Hock Tay, Francis; Lu, Li

2011-10-01

Dense α-phase blend films of vinylidene fluoride (VDF) oligomer and poly(vinylidene fluoride) (PVDF) of various compositions were prepared from chemical solution deposition. The dielectric constant of the films was unexpectedly lower, and the mechanical strength was higher than either of the two components, leading to high electromechanical dielectric breakdown strength (>850 MV/m vs. 300˜500 MV/m for typical PVDF-based films). The properties were attributed to the unique blend structure with high crystallinity and densely packed rigid amorphous phase incorporating long and short chains. A maximum polarization of 162 mC/m2 and a large electric energy density up to 27.3 J/cm3 were obtained.

Practice-tailored facilitation to improve pediatric preventive care delivery: a randomized trial.

PubMed

Meropol, Sharon B; Schiltz, Nicholas K; Sattar, Abdus; Stange, Kurt C; Nevar, Ann H; Davey, Christina; Ferretti, Gerald A; Howell, Diana E; Strosaker, Robyn; Vavrek, Pamela; Bader, Samantha; Ruhe, Mary C; Cuttler, Leona

2014-06-01

Evolving primary care models require methods to help practices achieve quality standards. This study assessed the effectiveness of a Practice-Tailored Facilitation Intervention for improving delivery of 3 pediatric preventive services. In this cluster-randomized trial, a practice facilitator implemented practice-tailored rapid-cycle feedback/change strategies for improving obesity screening/counseling, lead screening, and dental fluoride varnish application. Thirty practices were randomized to Early or Late Intervention, and outcomes assessed for 16 419 well-child visits. A multidisciplinary team characterized facilitation processes by using comparative case study methods. Baseline performance was as follows: for Obesity: 3.5% successful performance in Early and 6.3% in Late practices, P = .74; Lead: 62.2% and 77.8% success, respectively, P = .11; and Fluoride: <0.1% success for all practices. Four months after randomization, performance rose in Early practices, to 82.8% for Obesity, 86.3% for Lead, and 89.1% for Fluoride, all P < .001 for improvement compared with Late practices' control time. During the full 6-month intervention, care improved versus baseline in all practices, for Obesity for Early practices to 86.5%, and for Late practices 88.9%; for Lead for Early practices to 87.5% and Late practices 94.5%; and for Fluoride, for Early practices to 78.9% and Late practices 81.9%, all P < .001 compared with baseline. Improvements were sustained 2 months after intervention. Successful facilitation involved multidisciplinary support, rapid-cycle problem solving feedback, and ongoing relationship-building, allowing individualizing facilitation approach and intensity based on 3 levels of practice need. Practice-tailored Facilitation Intervention can lead to substantial, simultaneous, and sustained improvements in 3 domains, and holds promise as a broad-based method to advance pediatric preventive care. Copyright © 2014 by the American Academy of Pediatrics.

Practice-Tailored Facilitation to Improve Pediatric Preventive Care Delivery: A Randomized Trial

PubMed Central

Schiltz, Nicholas K.; Sattar, Abdus; Stange, Kurt C.; Nevar, Ann H.; Davey, Christina; Ferretti, Gerald A.; Howell, Diana E.; Strosaker, Robyn; Vavrek, Pamela; Bader, Samantha; Ruhe, Mary C.; Cuttler, Leona

2014-01-01

OBJECTIVE: Evolving primary care models require methods to help practices achieve quality standards. This study assessed the effectiveness of a Practice-Tailored Facilitation Intervention for improving delivery of 3 pediatric preventive services. METHODS: In this cluster-randomized trial, a practice facilitator implemented practice-tailored rapid-cycle feedback/change strategies for improving obesity screening/counseling, lead screening, and dental fluoride varnish application. Thirty practices were randomized to Early or Late Intervention, and outcomes assessed for 16 419 well-child visits. A multidisciplinary team characterized facilitation processes by using comparative case study methods. RESULTS: Baseline performance was as follows: for Obesity: 3.5% successful performance in Early and 6.3% in Late practices, P = .74; Lead: 62.2% and 77.8% success, respectively, P = .11; and Fluoride: <0.1% success for all practices. Four months after randomization, performance rose in Early practices, to 82.8% for Obesity, 86.3% for Lead, and 89.1% for Fluoride, all P < .001 for improvement compared with Late practices’ control time. During the full 6-month intervention, care improved versus baseline in all practices, for Obesity for Early practices to 86.5%, and for Late practices 88.9%; for Lead for Early practices to 87.5% and Late practices 94.5%; and for Fluoride, for Early practices to 78.9% and Late practices 81.9%, all P < .001 compared with baseline. Improvements were sustained 2 months after intervention. Successful facilitation involved multidisciplinary support, rapid-cycle problem solving feedback, and ongoing relationship-building, allowing individualizing facilitation approach and intensity based on 3 levels of practice need. CONCLUSIONS: Practice-tailored Facilitation Intervention can lead to substantial, simultaneous, and sustained improvements in 3 domains, and holds promise as a broad-based method to advance pediatric preventive care. PMID:24799539

Energy dispersive X-ray spectrometry study of the protective effects of fluoride varnish and gel on enamel erosion.

PubMed

De Carvalho Filho, Antonio Carlos Belfort; Sanches, Roberto Pizarro; Martin, Airton Abrahão; Do Espírito Santo, Ana Maria; Soares, Luís Eduardo Silva

2011-09-01

Dental erosion is a risk factor for dental health, introduced by today's lifestyle. Topical fluoride applications in the form of varnishes and gel may lead to deposition of fluoride on enamel. This in vitro study aimed to evaluate the effect of two fluoride varnishes and one fluoride gel on the dissolution of bovine enamel by acids. Enamel samples (72) were divided (n = 8): artificial saliva (control-G1), Pepsi Twist® (G2), orange juice (G3), Duraphat® + Pepsi Twist® (G4), Duraphat® + orange juice (G5), Duofluorid® + Pepsi Twist® (G6), Duofluorid® + orange juice (G7), fluoride gel + Pepsi Twist® (G8), and fluoride gel + orange juice (G9). Fluoride gel was applied for 4 min and the varnishes were applied and removed after 6 h. The samples were submitted to six cycles (demineralization: Pepsi Twist® or orange juice, 10 min; remineralization: saliva, 1 h). Samples were analyzed by energy-dispersive X-ray fluorescence (144 line-scanning). The amount of Ca and P decreased significantly in the samples of G2 and G3, and the Ca/P ratio decreased in G3. Mineral gain (Ca) was greater in G9 samples than in G4 > G3 > G5 > G1, and (P) greater in G7 samples than in G9 > G4-6 > G2-3. The protective effect of Duofluorid® was significantly lower than fluoride gel against orange juice. The fluoride varnishes can interfere positively with the dissolution of dental enamel in the presence of acidic beverages. Fluoride gel showed the best protection level to extrinsic erosion with low costs. Copyright © 2010 Wiley-Liss, Inc.

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.

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.

Ion mobility and transport properties of bismuth fluoride-containing solid solutions with tysonite-type structure

NASA Astrophysics Data System (ADS)

Kavun, V. Ya.; Uvarov, N. F.; Slobodyuk, A. B.; Merkulov, E. B.; Polyantsev, M. M.

2018-07-01

The ion mobility and conductivity of solid solutions with tysonite-type structure obtained by doping bismuth trifluoride with lead (II) fluoride, and zirconium and bismuth oxides have been studied using 19F NMR, X-ray diffraction analysis, and impedance spectroscopy. The types of ionic motions in the fluoride sublattice of the synthesized solid solutions in the temperature range 150-450 K have been determined and the energy of their activation has been estimated. Due to high ionic conductivity, above 10-2 S/cm at 570 K, these solid solutions can be considered as superionic conductors.

The effect of pregnancy and lactation on bone mineral density in fluoride-exposed rats.

PubMed

Yildiz, Mustafa; Oral, Baha

2006-06-01

Fluoride increases metabolic turnover of the bone in favour of bone formation. Excessive intake of fluoride may lead to pathological changes in teeth and bones: dental and skeletal fluorosis. In this study, we investigated the effect of pregnancy and lactation on bone mineral density (BMD) in fluoride-exposed rats. Female Wistar rats were given commercially available spring water with 100 ppm fluoride (N = 8), or without addition (N = 8) for 18 weeks. At 16 weeks of age, four female rats and one male rat were kept in a cage for 5 days; all females were successfully impregnated. BMD was measured at 16 weeks of age, on the first day postpartum, and at the end of lactation. Spinal BMD was significantly higher in fluoride-exposed rats than control (P < 0.05), but there were no differences in femoral BMD (P = 0.670). During pregnancy, spinal BMD and femoral BMD were not significantly changed in fluoride-exposed rats, whereas BMD of the spine was significantly decreased in the control rats (P = 0.013), but not in the femur. During lactation, BMD was significantly decreased at the two regions compared to initial values (P < 0.05) in both groups. This study shows that pregnancy has no effect on bone, but lactation has a decreasing effect on BMD in fluoride-exposed rats.

Solid electrolytes for fluoride ion batteries: ionic conductivity in polycrystalline tysonite-type fluorides.

PubMed

Rongeat, Carine; Reddy, M Anji; Witter, Raiker; Fichtner, Maximilian

2014-02-12

Batteries based on a fluoride shuttle (fluoride ion battery, FIB) can theoretically provide high energy densities and can thus be considered as an interesting alternative to Li-ion batteries. Large improvements are still needed regarding their actual performance, in particular for the ionic conductivity of the solid electrolyte. At the current state of the art, two types of fluoride families can be considered for electrolyte applications: alkaline-earth fluorides having a fluorite-type structure and rare-earth fluorides having a tysonite-type structure. As regard to the latter, high ionic conductivities have been reported for doped LaF3 single crystals. However, polycrystalline materials would be easier to implement in a FIB due to practical reasons in the cell manufacturing. Hence, we have analyzed in detail the ionic conductivity of La(1-y)Ba(y)F(3-y) (0 ≤ y ≤ 0.15) solid solutions prepared by ball milling. The combination of DC and AC conductivity analyses provides a better understanding of the conduction mechanism in tysonite-type fluorides with a blocking effect of the grain boundaries. Heat treatment of the electrolyte material was performed and leads to an improvement of the ionic conductivity. This confirms the detrimental effect of grain boundaries and opens new route for the development of solid electrolytes for FIB with high ionic conductivities.

Fluoride-associated ultrastructural changes and apoptosis in human renal tubule: a pilot study.

PubMed

Quadri, J A; Sarwar, S; Sinha, A; Kalaivani, M; Dinda, A K; Bagga, A; Roy, T S; Das, T K; Shariff, A

2018-01-01

The susceptibility of the kidneys to fluoride toxicity can largely be attributed to its anatomy and function. As the filtrate moves along the complex tubular structure of each nephron, it is concentrated in the proximal and distal tubules and collecting duct. It has been frequently observed that the children suffering from renal impairments also have some symptoms of dental and skeletal fluorosis. The findings suggest that fluoride somehow interferes with renal anatomy and physiology, which may lead to renal pathogenesis. The aim of this study was to evaluate the fluoride-associated nephrotoxicity. A total of 156 patients with childhood nephrotic syndrome were screened and it was observed that 32 of them had significantly high levels ( p ≤ 0.05) of fluoride in urine (4.01 ± 1.83 ppm) and serum (0.1 ± 0.013 ppm). On the basis of urinary fluoride concentration, patients were divided into two groups, namely group 1 (G-1) ( n = 32) containing normal urine fluoride (0.61 ± 0.17 ppm) and group 2 (G-2) ( n = 32) having high urine fluoride concentration (4.01 ± 1.83 ppm). Age-matched healthy subjects ( n = 33) having normal levels of urinary fluoride (0.56 ± 0.15 ppm) were included in the study as control (group 0 (G-0)). Kidney biopsies were taken from G-1 and G-2 only, who were subjected to ultrastructural (transmission electron microscopy) and apoptotic (terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling) analysis. Various subcellular ultrastructural changes including nuclear disintegration, chromosome condensation, cytoplasmic ground substance lysis, and endoplasmic reticulum blebbing were observed. Increased levels of apoptosis were observed in high fluoride group (G-2) compared to normal fluoride group (G-1). Various degrees of fluoride-associated damages to the architecture of tubular epithelia, such as cell swelling and lysis, cytoplasmic vacuolation, nuclear condensation, apoptosis, and necrosis, were observed.

Influence of methionine and vitamin E on fluoride concentration in bones and teeth of rats exposed to sodium fluoride in drinking water.

PubMed

Błaszczyk, Iwona; Birkner, Ewa; Gutowska, Izabela; Romuk, Ewa; Chlubek, Dariusz

2012-06-01

Increased exposure to fluorine-containing compounds leads to accumulation of fluorides in hard tissues of bones and teeth, which may result in numerous skeletal and dental disorders. This study evaluates the influence of methionine and vitamin E on fluoride concentration in bones and teeth of rats subjected to long-term exposure to sodium fluoride in drinking water. The study was conducted in 30 3-month-old female Wistar FL rats. The animals were divided into five groups, six rats per group. The control group consisted of rats receiving only distilled water as drinking water. All other groups received NaF in the amount of 10 mg/kg of body mass/day in their drinking water. In addition, respective animal groups received: NaF + Met group--10 mg of methionine/kg of body mass/day, NaF + Met + E group--10 mg of methionine/kg of body mass/day and 3 mg of vitamin E (tocopheroli acetas)/rat/day and NaF + E group--3 mg of vitamin E/rat/day. Femoral bones and incisor teeth were collected for the study, and the fluoride concentration was determined using a fluoride ion-selective electrode. Fluoride concentration in both bones and teeth was found to be higher in the NaF and NaF + Met groups compared to the control group. In groups NaF + Met + E and NaF + E, the study material contained much lower fluoride concentration compared to the NaF group, while the effect was more prominent in the NaF + E group. The results of the studies indicate that methionine and vitamin E have opposite effects on accumulation of fluorides in hard tissue in rats. By stimulating fluoride accumulation, methionine reduces the adverse effect of fluorides on soft tissue, while vitamin E, which prevents excessive accumulation of fluorides in bones and teeth, protects these tissues from fluorosis. Therefore, it seems that combined application of both compounds would be optimal for the prevention of the adverse effects of chronic fluoride intoxication.

High fluoride and low pH level have been detected in popular flavoured beverages in Malaysia.

PubMed

Ha Rahim, Zubaidah; M Bakri, Marina; Hm, Zakir; Ia, Ahmed; Na, Zulkifli

2014-03-01

In children, excessive ingestion of fluoride from different sources including bottled drinking water and flavoured beverages or soft drinks can lead to the development of dental fluorosis. In addition, the pH level of beverages is important. Low pH can cause dental erosion. In this study we explore the fluoride content and pH level of certain popular beverages available in Malaysian supermarkets and hawkers' stalls. Bottled drinking water and selected popular flavoured packet drinks were purchased from a supermarket and the corresponding flavoured hawkers' drinks, from a hawker's stall in Kuala Lumpur. Fluoride and pH of the beverages were determined using digital fluoride meter and digital pH meter respectively. It was found that fluoride content and pH level vary among the beverages. The mean fluoride content in both packet and hawkers' drinks (7.64±1.88 mg/L, 7.51±1.60 mg/L, respectively) was approximately 7 times higher than the bottled drinking water (1.05±0.35 mg/L). Among the beverages, the tea packet drink was found to contain the highest amount of fluoride (13.02±0.23 mg/L). The mean pH of bottled-drinking water was near neutral (6.96±0.17), but acidic for both supermarket (4.78.00±0.49) and hawkers' drinks (5.73±0.24). The lychee packet drink had the lowest pH level (2.97±0.03). Due to the wide variation of the fluoride content and pH level of the drinks tested in this study, it is recommended that steps should be taken to control the fluoride concentration and pH level in beverages if dental fluorosis and erosion are to be prevented.

Geochemical characterization of fluoride in water, table salt, active sediment, rock and soil samples, and its possible relationship with the prevalence of enamel fluorosis in children in four municipalities of the department of Huila (Colombia).

PubMed

Martignon, Stefania; Opazo-Gutiérrez, Mario Omar; Velásquez-Riaño, Möritz; Orjuela-Osorio, Iván Rodrigo; Avila, Viviana; Martinez-Mier, Esperanza Angeles; González-Carrera, María Clara; Ruiz-Carrizosa, Jaime Alberto; Silva-Hermida, Blanca Cecilia

2017-06-01

Fluoride is an element that affects teeth and bone formation in animals and humans. Though the use of systemic fluoride is an evidence-based caries preventive measure, excessive ingestion can impair tooth development, mainly the mineralization of tooth enamel, leading to a condition known as enamel fluorosis. In this study, we investigated the geochemical characterization of fluoride in water, table salt, active sediment, rock and soil samples in four endemic enamel fluorosis sentinel municipalities of the department of Huila, Colombia (Pitalito, Altamira, El Agrado and Rivera), and its possible relationship with the prevalence of enamel fluorosis in children. The concentration of fluoride in drinking water, table salt, active sediment, rock, and soil was evaluated by means of an ion selective electrode and the geochemical analyses were performed using X-ray fluorescence. Geochemical analysis revealed fluoride concentrations under 15 mg/kg in active sediment, rock and soil samples, not indicative of a significant delivery to the watersheds studied. The concentration of fluoride in table salt was found to be under the inferior limit (less than 180 μg/g) established by the Colombian regulations. Likewise, exposure doses for fluoride water intake did not exceed the recommended total dose for all ages from 6 months. Although the evidence does not point out at rocks, soils, fluoride-bearing minerals, fluoridated salt and water, the hypothesis of these elements as responsible of the current prevalence of enamel fluorosis cannot be discarded since, aqueducts might have undergone significant changes overtime.

Health impact of supplying safe drinking water on patients having various clinical manifestations of fluorosis in an endemic village of west bengal.

PubMed

Majumdar, Kunal K; Sundarraj, Shunmuga N

2013-01-01

Excessive fluoride in drinking water causes dental, skeletal and non-skeletal fluorosis which is encountered in endemic proportions in several parts of the world. The World Health Organization (WHO) guideline value and the permissible limit of fluoride as per the Bureau of Indian Standards (BIS) is 1.5 mg/L. Studies showed that withdrawal of sources identified for fluoride, often leads to reduction of fluoride in the body fluids (re-testing urine and serum after a week or ten days) and results in the disappearance of non-skeletal fluorosis within a short duration of 10-15 days. To determine the prevalence of signs and symptoms of suspected dental, skeletal and non-skeletal fluorosis along with food habits, addictions and use of fluoride-containing toothpaste among participants taking water with fluoride concentration above permissible limit and to assess the changes in clinical manifestations of the above participants after consumption of safe drinking water with fluoride concentration below permissible limit. A longitudinal intervention study was conducted from October 2010 to December 2011 in a village selected randomly in Purulia District of West Bengal which is endemic for fluorosis. Thirty-six families with 104 family members in the above village having history of taking unsafe water containing high level of fluoride were selected for the study. The occurrence of various dental, skeletal and non-skeletal manifestations of fluorosis along with food habits, addictions and use of fluoride-containing toothpaste among the study population was assessed; the impact of taking safe water with fluoride concentration below permissible limit from a supplied community filter on these clinical manifestations was studied by follow-up examination of the above participants for six months. The data obtained is compared with the collected data from the baseline survey. The prevalence of signs and symptoms of dental, skeletal and non-skeletal fluorosis was (18.26%), (18.26-43.26%) and (12.49-38.46%) among the study population. Withdrawal of source(s) identified for fluoride by providing community filters supplying safe water along with nutritional interventions lead to 1.92% decrease of manifestation of dental fluorosis, 2.88-18.26% decrease of manifestations of skeletal fluorosis and 3.8-5.77% decrease in manifestations of non-skeletal fluorosis within six months. Following repeated motivation of participants during visit there was also 2.88% decrease in the usage of fluoride-containing toothpaste, 4.81% decrease in consumption of black lemon tea, supari and tobacco which are known sources of fluoride ingestion in our body. Increased prevalence of dental, skeletal and non-skeletal fluorosis was found among the study population. Withdrawal of sources(s) identified for fluoride by supplying community filter, dietary restriction and other nutritional interventions led to decrease of manifestations of the three types of fluorosis within six months. The government should play a vital role in ensuring drinking water safety at the household and community level by supplying domestic filters at affordable costs and community filter along with nutritional intervention to the fluorosis-affected villages on a priority basis to mitigate the problem.

Mechanisms of inhibition by fluoride of urease activities of cell suspensions and biofilms of Staphylococcus epidermidis, Streptococcus salivarius, Actinomyces naeslundii and of dental plaque.

PubMed

Barboza-Silva, E; Castro, A C D; Marquis, R E

2005-12-01

Fluoride is known to be a potent inhibitor of bacterial ureases and can also act in the form of hydrofluoric acid as a transmembrane proton conductor to acidify the cytoplasm of intact cells with possible indirect, acid inhibition of urease. Our research objectives were to assess the inhibitory potencies of fluoride for three urease-positive bacteria commonly found in the mouth and to determine the relative importance of direct and indirect inhibition of ureases for overall inhibition of intact cells or biofilms. The experimental design involved intact bacteria in suspensions, mono-organism biofilms, cell extracts, and dental plaque. Standard enzymatic assays for ammonia production from urea were used. We found that ureolysis by cells in suspensions or mono-organism biofilms of Staphylococcus epidermidis, Streptococcus salivarius or Actinomyces naeslundii was inhibited by fluoride at plaque levels of 0.1-0.5 mm in a pH-dependent manner. The results of experiments with the organic weak acids indomethacin and capric acid, which do not directly inhibit urease enzyme, indicated that weak-acid effects leading to cytoplasmic acidification are also involved in fluoride inhibition. However, direct fluoride inhibition of urease appeared to be the major mechanism for reduction in ureolytic activity in acid environments. Results of experiments with freshly harvested supragingival dental plaque indicated responses to fluoride similar to those of S. salivarius with pH-dependent fluoride inhibition and both direct and indirect inhibition of urease. Fluoride can act to diminish alkali production from urea by oral bacteria through direct and indirect mechanisms.

Synthesis of Novel Thiazole Based Carbaldehyde as Potential Sensor for Fluoride Anion and their Spectroscopic Properties.

PubMed

Tayade, Rajratna P; Sekar, Nagaiyan

2017-05-01

A novel thiazole based carbaldehyde bearing benzimidazole fluorophore as the receptor unit for F - anion was prepared by multi steps synthesis. Density functional theory was used to understand the structural and electronic properties the receptor. The anion sensing activities of receptor 4 were studied for various anions in acetonitrile solvent. The receptor showed fluorescence enhancement in the presence of fluoride anion due to intramolecular charge transfer (ICT) mechanism. No significant changes were observed upon addition of less basic anions such as OAc - , Cl - , Br - , I - , HSO 4 - . After the interaction of fluoride anion with the receptor 4 leads to an 88 nm red shift in emission maxima. [TBA]OH and 1 H NMR titration experiments indicated that deprotonation of N-H in the benzimidazole due to interaction with fluoride anions.

PREDICTING LEAD DISSOLUTION IN DRINKING WATER DISTRIBUTION SYSTEMS: EFFECT OF FLUORIDE ADDITIVES ON LEAD SOLUBILITY AND CORROSION

EPA Science Inventory

Many water systems have encountered difficulties in meeting the action levels established by the Lead and Copper Rule. Several chemical parameters contribute to the corrosion of lead plumbing and may influence the nature of the passivating films formed on distribution materials....

Design and development of novel sensors for the determination of fluoride in water.

PubMed

Pillai, Aji Balan; Varghese, Benjamin; Madhusoodanan, Kottarathil Naduvil

2012-01-03

The presence of high fluoride content in drinking water is a serious health hazard as it may lead to fluorosis, a serious bone disease. Taking into account of the importance of fluoride an attempt has been made to design and develop simple, low cost, and easy to use sensors for the in situ determination of fluoride in water. Two novel absorption sensors have been fabricated and their characterization done. The first one is a light emitting diode based sensor and the other one is an evanescent wave fiber optic sensor. Reagents prepared using standard methods are mixed with water sample containing fluoride ion, and the peak absorption wavelength is found out. Suitable light sources and photo detectors have been selected, and the sensors are designed to give accurate results over a wide range. A microcontroller based setup has been fabricated for recording the concentration of the measured sample in parts per billion. Both sensors have been used to analyze water samples collected from various sources and regions. The results obtained have been compared with those obtained by using a spectrophotometer used for fluoride measurement and found to have one to one correspondence.

Low-Cost, Robust, and Field Portable Smartphone Platform Photometric Sensor for Fluoride Level Detection in Drinking Water.

PubMed

Hussain, Iftak; Ahamad, Kamal Uddin; Nath, Pabitra

2017-01-03

Groundwater is the major source of drinking water for people living in rural areas of India. Pollutants such as fluoride in groundwater may be present in much higher concentration than the permissible limit. Fluoride does not give any visible coloration to water, and hence, no effort is made to remove or reduce the concentration of this chemical present in drinking water. This may lead to a serious health hazard for those people taking groundwater as their primary source of drinking water. Sophisticated laboratory grade tools such as ion selective electrodes (ISE) and portable spectrophotometers are commercially available for in-field detection of fluoride level in drinking water. However, such tools are generally expensive and require expertise to handle. In this paper, we demonstrate the working of a low cost, robust, and field portable smartphone platform fluoride sensor that can detect and analyze fluoride concentration level in drinking water. For development of the proposed sensor, we utilize the ambient light sensor (ALS) of the smartphone as light intensity detector and its LED flash light as an optical source. An android application "FSense" has been developed which can detect and analyze the fluoride concentration level in water samples. The custom developed application can be used for sharing of in-field sensing data from any remote location to the central water quality monitoring station. We envision that the proposed sensing technique could be useful for initiating a fluoride removal program undertaken by governmental and nongovernmental organizations here in India.

40 CFR 471.65 - Pretreatment standards for new sources (PSNS).

Code of Federal Regulations, 2010 CFR

2010-07-01

... Zinc 0.713 0.298 Ammonia 65.1 28.6 Fluoride 29.1 12.9 (c) Drawing spent neat oils—Subpart F—PSNS. There... Ammonia 9.59 4.22 Fluoride 4.28 1.90 (f) Extrusion press hydraulic fluid leakage. Subpart F—PSNS Pollutant... off-pounds) of titanium extruded Cyanide 0.052 0.022 Lead 0.075 0.036 Zinc 0.260 0.109 Ammonia 23.7 10...

40 CFR 471.65 - Pretreatment standards for new sources (PSNS).

Code of Federal Regulations, 2011 CFR

2011-07-01

... Zinc 0.713 0.298 Ammonia 65.1 28.6 Fluoride 29.1 12.9 (c) Drawing spent neat oils—subpart F—PSNS. There... Ammonia 9.59 4.22 Fluoride 4.28 1.90 (f) Extrusion press hydraulic fluid leakage. Subpart F—PSNS Pollutant... off-pounds) of titanium extruded Cyanide 0.052 0.022 Lead 0.075 0.036 Zinc 0.260 0.109 Ammonia 23.7 10...

A PEGylated fluorescent turn-on sensor for detecting fluoride ions in totally aqueous media and its imaging in live cells.

PubMed

Zheng, Fangyuan; Zeng, Fang; Yu, Changmin; Hou, Xianfeng; Wu, Shuizhu

2013-01-14

Owing to the considerable significance of fluoride anions for health and environmental issues, it is of great importance to develop methods that can rapidly, sensitively and selectively detect the fluoride anion in aqueous media and biological samples. Herein, we demonstrate a robust fluorescent turn-on sensor for detecting the fluoride ion in a totally aqueous solution. In this study, a biocompatible hydrophilic polymer poly(ethylene glycol) (PEG) is incorporated into the sensing system to ensure water solubility and to enhance biocompatibility. tert-Butyldiphenylsilyl (TBDPS) groups were then covalently introduced onto the fluorescein moiety, which effectively quenched the fluorescence of the sensor. Upon addition of fluoride ion, the selective fluoride-mediated cleavage of the Si-O bond leads to the recovery of the fluorescein moiety, resulting in a dramatic increase in fluorescence intensity under visible light excitation. The sensor is responsive and highly selective for the fluoride anion over other common anions; it also exhibits a very low detection limit of 19 ppb. In addition, this sensor is operative in some real samples such as running water, urine, and serum and can accurately detect fluoride ions in these samples. The cytotoxicity of the sensor was determined to be Grade I toxicity according to United States Pharmacopoeia and ISO 10993-5, suggesting the very low cytotoxicity of the sensor. Moreover, it was found that the senor could be readily internalized by both HeLa and L929 cells and the sensor could be utilized to track fluoride level changes inside the cells. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A new perspective on metals and other contaminants in fluoridation chemicals*

PubMed Central

Mullenix, Phyllis J

2014-01-01

Background: Fluoride additives contain metal contaminants that must be diluted to meet drinking water regulations. However, each raw additive batch supplied to water facilities does not come labeled with concentrations per contaminant. This omission distorts exposure profiles and the risks associated with accidents and routine use. Objectives: This study provides an independent determination of the metal content of raw fluoride products. Methods: Metal concentrations were analyzed in three hydrofluorosilicic acid (HFS) and four sodium fluoride (NaF) samples using inductively coupled plasma-atomic emission spectrometry. Arsenic levels were confirmed using graphite furnace atomic absorption analysis. Results: Results show that metal content varies with batch, and all HFS samples contained arsenic (4.9–56.0 ppm) or arsenic in addition to lead (10.3 ppm). Two NaF samples contained barium (13.3–18.0 ppm) instead. All HFS (212–415 ppm) and NaF (3312–3630 ppm) additives contained a surprising amount of aluminum. Conclusions: Such contaminant content creates a regulatory blind spot that jeopardizes any safe use of fluoride additives. PMID:24999851

Fluoride-containing podophyllum derivatives exhibit antitumor activities through enhancing mitochondrial apoptosis pathway by increasing the expression of caspase-9 in HeLa cells

PubMed Central

Zhao, Wei; Yang, Yong; Zhang, Ya-Xuan; Zhou, Chen; Li, Hong-Mei; Tang, Ya-Ling; Liang, Xin-Hua; Chen, Tao; Tang, Ya-Jie

2015-01-01

This work aims to provide sampling of halogen-containing aniline podophyllum derivatives and their mode of action with an in-depth comparison among fluorine, chloride and bromide for clarifying the important role and impact of fluorine substitution on enhancing antitumor activity, with an emphasis on the development of drug rational design for antitumor drug. The tumor cytotoxicity of fluoride-containing aniline podophyllum derivatives were in general improved by 10–100 times than those of the chloride and bromide-containing aniline podophyllum derivatives since fluoride could not only strongly solvated in protic solvents but also forms tight ion pairs in most aprotic solvents. When compared with chloride and bromide, the higher electronegativity fluoride substituted derivatives significantly enhanced mitochondrial apoptosis pathway by remarkably increasing the expression of caspase-9 in HeLa cells. The current findings would stimulate an enormous amount of research directed toward exploiting novel leading compounds based on podophyllum derivatives, especially for the fluoride-substituted structures with promising antitumor activity. PMID:26608216

Cytotoxicity of dental glass ionomers evaluated using dimethylthiazol diphenyltetrazolium and neutral red tests.

PubMed

Lönnroth, E C; Dahl, J E

2001-02-01

The purpose of this study was to assess the cytotoxicity of some commonly used glass ionomers. Three chemically cured glass ionomers (Fuji II, Lining cement, and Ketac Silver) and one light-cured (Fuji II LC) were tested. Extracts of mixed non-polymerized materials and polymerized specimens were prepared in accordance with ISO standard 10993-12. The polymerized specimens were cured and placed either directly in the medium (freshly cured), left for 24 h (aged), or aged plus ground before being placed in the medium. The cytotoxicity of extracts was evaluated on mouse fibroblasts (L, 929), using dimethylthiazol diphenyltetrazolium (MTT) and neutral red (NR) assays. Further, the concentrations of aluminum, arsenic and lead were analyzed in aqueous extracts from freshly cured and aged samples, and the fluoride levels analyzed in aqueous extracts from freshly cured samples. All extracts except that of non-polymerized Ketac Silver were rated as severely cytotoxic in both assays. Extracts of polymerized material were significantly more cytotoxic than extracts of non-polymerized material. All freshly cured glass ionomers released aluminum and fluoride concentrations far above what is considered cytotoxic (aluminum >0.2 ppm and fluoride >20 ppm). Extracts from freshly cured Lining Cement contained the highest concentrations of aluminum and fluoride (215 ppm and 112 ppm). Extracts from freshly cured Ketac Silver had the lowest concentrations of aluminum and fluoride but the highest of lead (100 ppm). It can be concluded that all extracts from non-cured, freshly cured, and aged glass ionomers contained cytotoxic levels of substances. Curing did not reduce the toxicity significantly.

Red Mn4+-Doped Fluoride Phosphors: Why Purity Matters.

PubMed

Verstraete, Reinert; Sijbom, Heleen F; Joos, Jonas J; Korthout, Katleen; Poelman, Dirk; Detavernier, Christophe; Smet, Philippe F

2018-06-06

Traditional light sources, e.g., incandescent and fluorescent lamps, are currently being replaced by white light-emitting diodes (wLEDs) because of their improved efficiency, prolonged lifetime, and environmental friendliness. Much effort has recently been spent to the development of Mn 4+ -doped fluoride phosphors that can enhance the color gamut in displays and improve the color rendering index, luminous efficacy of the radiation, and correlated color temperature of wLEDs used for lighting. Purity, stability, and degradation of fluoride phosphors are, however, rarely discussed. Nevertheless, the typical wet chemical synthesis routes (involving hydrogen fluoride (HF)) and the large variety of possible Mn valence states often lead to impurities that drastically influence the performance and stability of these phosphors. In this article, the origins and consequences of impurities formed during synthesis and aging of K 2 SiF 6 :Mn 4+ are revealed. Both crystalline impurities such as KHF 2 and ionic impurities such as Mn 3+ are found to affect the phosphor performance. While Mn 3+ mainly influences the optical absorption behavior, KHF 2 can affect both the optical performance and chemical stability of the phosphor. Moisture leads to decomposition of KHF 2 , forming HF and amorphous hydrated potassium fluoride. As a consequence of hydrate formation, significant amounts of water can be absorbed in impure phosphor powders containing KHF 2 , facilitating the hydrolysis of [MnF 6 ] 2- complexes and affecting the optical absorption of the phosphors. Strategies are discussed to identify impurities and to achieve pure and stable phosphors with internal quantum efficiencies of more than 90%.

Is fluoride a risk factor for bone cancer? Small area analysis of osteosarcoma and Ewing sarcoma diagnosed among 0-49-year-olds in Great Britain, 1980-2005.

PubMed

Blakey, Karen; Feltbower, Richard G; Parslow, Roger C; James, Peter W; Gómez Pozo, Basilio; Stiller, Charles; Vincent, Tim J; Norman, Paul; McKinney, Patricia A; Murphy, Michael F; Craft, Alan W; McNally, Richard J Q

2014-02-01

Artificial fluoridation of drinking water to improve dental health has long been a topic of controversy. Opponents of this public health measure have cited the possibility of bone cancer induction. The study objective was to examine whether increased risk of primary bone cancer was associated with living in areas with higher concentrations of fluoride in drinking water. Case data on osteosarcoma and Ewing sarcoma, diagnosed at ages 0-49 years in Great Britain (GB) (defined here as England, Scotland and Wales) during the period 1980-2005, were obtained from population-based cancer registries. Data on fluoride levels in drinking water in England and Wales were accessed through regional water companies and the Drinking Water Inspectorate. Scottish Water provided data for Scotland. Negative binomial regression was used to examine the relationship between incidence rates and level of fluoride in drinking water at small area level. The study analysed 2566 osteosarcoma and 1650 Ewing sarcoma cases. There was no evidence of an association between osteosarcoma risk and fluoride in drinking water [relative risk (RR) per one part per million increase in the level of fluoride = 1·001; 90% confidence interval (CI) 0·871, 1·151] and similarly there was no association for Ewing sarcoma (RR = 0·929; 90% CI 0·773, 1·115). The findings from this study provide no evidence that higher levels of fluoride (whether natural or artificial) in drinking water in GB lead to greater risk of either osteosarcoma or Ewing sarcoma.

A model to determine the economic viability of water fluoridation.

PubMed

Kroon, Jeroen; van Wyk, Philippus Johannes

2012-01-01

In view of concerns expressed by South African local authorities the aim of this study was to develop a model to determine whether water fluoridation is economically viable to reduce dental caries in South Africa. Microsoft Excel software was used to develop a model to determine economic viability of water fluoridation for 17 water providers from all nine South African provinces. Input variables for this model relate to chemical cost, labor cost, maintenance cost of infrastructure, opportunity cost, and capital depreciation. The following output variables were calculated to evaluate the cost of water fluoridation: per capita cost per year, cost-effectiveness and cost-benefit. In this model it is assumed that the introduction of community water fluoridation can reduce caries prevalence by an additional 15 percent and that the savings in cost of treatment will be equal to the average fee for a two surface restoration. Water providers included in the study serve 53.5 percent of the total population of South Africa. For all providers combined chemical cost contributes 64.5 percent to the total cost, per capita cost per year was $0.36, cost-effectiveness was calculated as $11.41 and cost-benefit of the implementation of water fluoridation was 0.34. This model confirmed that water fluoridation is an economically viable option to prevent dental caries in South African communities, as well as conclusions over the last 10 years that water fluoridation leads to significant cost savings and remains a cost-effective measure for reducing dental caries, even when the caries-preventive effectiveness is modest. © 2012 American Association of Public Health Dentistry.

THE EFFECT OF FLUORIDE ON LEAD SOLUBILITY

EPA Science Inventory

Difficulties in predicting and controlling lead corrosion are encountered by hundreds of water systems across the country. Inorganic carbonate, sulfate, silicate, orthophosphate, pH, total organic carbon, temperature and the type/amount of chlorine residual are all known factors ...

High fluoride and low pH level have been detected in popular flavoured beverages in Malaysia

PubMed Central

HA Rahim, Zubaidah; M Bakri, Marina; HM, Zakir; IA, Ahmed; NA, Zulkifli

2014-01-01

Objective: In children, excessive ingestion of fluoride from different sources including bottled drinking water and flavoured beverages or soft drinks can lead to the development of dental fluorosis. In addition, the pH level of beverages is important. Low pH can cause dental erosion. In this study we explore the fluoride content and pH level of certain popular beverages available in Malaysian supermarkets and hawkers’ stalls. Methods: Bottled drinking water and selected popular flavoured packet drinks were purchased from a supermarket and the corresponding flavoured hawkers’ drinks, from a hawker’s stall in Kuala Lumpur. Fluoride and pH of the beverages were determined using digital fluoride meter and digital pH meter respectively. Results: It was found that fluoride content and pH level vary among the beverages. The mean fluoride content in both packet and hawkers’ drinks (7.64±1.88 mg/L, 7.51±1.60 mg/L, respectively) was approximately 7 times higher than the bottled drinking water (1.05±0.35 mg/L). Among the beverages, the tea packet drink was found to contain the highest amount of fluoride (13.02±0.23 mg/L). The mean pH of bottled-drinking water was near neutral (6.96±0.17), but acidic for both supermarket (4.78.00±0.49) and hawkers’ drinks (5.73±0.24). The lychee packet drink had the lowest pH level (2.97±0.03). Conclusions: Due to the wide variation of the fluoride content and pH level of the drinks tested in this study, it is recommended that steps should be taken to control the fluoride concentration and pH level in beverages if dental fluorosis and erosion are to be prevented. PMID:24772152

Fluorosis increases the risk of postmenopausal osteoporosis by stimulating interferon γ.

PubMed

Lv, Yun-Gang; Kang, Li; Wu, Guangyao

2016-10-14

Estrogen deficiency in postmenopausal women frequently activates osteoclasts (OC), accelerates bone resorption, and leads to osteoporosis (OP). Previous studies have demonstrated that interferon γ (IFNγ) could increase bone resorption and may be involved in postmenopausal OP. Fluorosis also increased the risk of fractures and dental fluorosis, and fluoride may enhance osteoclast formation and induce osteoclastic bone destruction in postmenopausal women, but the underlying mechanisms are as yet unknown. Here, we show that serum fluoride and IFNγ levels are negatively correlated with bone mineral density (BMD) in postmenopausal women residing in a fluorotic area. Estrogen suppresses IFNγ, which is elevated by fluoride, playing a pivotal role in triggering bone loss in estrogen-deficient conditions. In vitro, IFNγ is inhibited by estrogen treatment and increased by fluoride in Raw264.7 cell, an osteoclast progenitor cell line. In ovariectomized (Ovx) mice, estrogen loss and IFNγ promote OC activation and subsequent bone loss in vivo. However, IFNγ deficiency prevents bone loss in Ovx mice even in fluoride conditions. Interestingly, fluoride fails to increase IFNγ expression in estrogen receptor α (ERα)-deficient conditions, but not in ERβ-deficient conditions. These findings demonstrate that fluorosis increases the bone loss in postmenopausal OP through an IFNγ-dependent mechanism. IFNγ signaling activates OC and aggravates estrogen deficiency inducing OP. Thus, stimulation of IFNγ production is a pivotal ''upstream'' mechanism by which fluoride promotes bone loss. Suppression of IFNγ levels may constitute a therapeutic approach for preventing bone loss. Copyright © 2016 Elsevier Inc. All rights reserved.

Characterisation of a new adsorbent (beta cyclodextrin modified hybrid hydrous iron-zirconium oxide) to remove fluoride from aqueous solution

NASA Astrophysics Data System (ADS)

Saha, Indranil

2017-04-01

Prolonged use of fluoride contaminated water (>1.5mg L-1) causes serious problems to public health and ultimately leads to skeletal fluorosis. There is an urgent need to develop more efficient fluoride scavenging materials for designing water filters. A simple and efficient adsorbent (CHIZO, beta-Cyclodextrin (b-CD) amended hydrous iron-zirconium hybrid oxide), has been developed, characterised and tested. The results indicate the efficacy of CHIZO on fluoride removal from an aqueous solution. The agglomerated micro structured composite material has several new features such as very poor crystallinity confirmed from TEM images. BET experiment reveals a surface area of 0.2070 m2 g-1 and pore volume of 0.0476 cm3 g-1. The findings also indicate the highly pH dependent fluoride adsorption by CHIZO which decreases with an increase in pH, and pseudo-second order kinetics control the reaction.Isotherm study indicates Langmuir isotherm was the best fit model to describe the adsorption equilibrium. Significantly higher monolayer adsorption capacity of fluoride (31.35 mg g-1) than the host hydrous Fe-Zr oxide (8.21 mg g-1) at pH 7.0 and 303 K was observed. Thermodynamic parameter indicates spontaneous nature of CHIZO which is due to the exothermic nature of the reaction. Apart from this phosphate and sulphate have some impact (interference) on fluoride adsorption. b-CD forms inclusion complexes by taking up fluoride ions from water into its central cavity. Several factors are involved regarding high efficacy of the system such as the release of enthalpy-rich water molecules from its cavity, electrostatic interactions, hydrogen bonding and release of conformational strain. However, the regeneration is difficult because of probable entrapping of fluoride inside the cavity of b-CD with hydrogen bonding. It has been found that only 0.9 g of CHIZO is able to reduce the fluoride level to below 1.0 mg L-1 in one-litre of fluoride spiked (5.0 mg L-1) natural water sample. The study highlights the potentiality of the developed adsorbent. Examples are high adsorption capacity and economical viability.

Fluoride toothpaste efficacy and safety in children younger than 6 years: a systematic review.

PubMed

Wright, J Timothy; Hanson, Nicholas; Ristic, Helen; Whall, Clifford W; Estrich, Cameron G; Zentz, Ronald R

2014-02-01

The authors conducted a systematic review to assess the efficacy and safety of fluoride toothpaste use in children younger than 6 years. The authors defined research questions to formulate a search strategy. They screened studies, extracted data and assessed risk of bias systematically. They conducted meta-analyses to determine the effects of brushing with fluoride toothpaste. Use of fluoride toothpaste brushing had a statistically significant effect on mean decayed, missing and filled primary tooth surfaces and decayed, missing and filled primary teeth for populations at high risk of developing caries (standard mean difference [95 percent confidence interval {CI}], -0.25 [-0.36 to -0.14] and -0.19 [-0.32 to -0.06], respectively). The effects of using different fluoride concentration toothpastes on caries varied. Study findings showed either a decrease in the odds of having fluorosis (odds ratio [OR] [95 percent CI] = 0.66 [0.48-0.90]) when the use of fluoride toothpaste was initiated after 24 months or no statistically significant difference (OR [95 percent CI] = 0.92 [0.71-1.18]). Beginning use after 12 or 14 months of age decreased the risk of fluorosis (OR = 0.70 [0.57-0.88]). Limited scientific evidence demonstrates that for children younger than 6 years, fluoride toothpaste use is effective in caries control. Ingesting pea-sized amounts or more can lead to mild fluorosis. Practical Implications. To minimize the risk of fluorosis in children while maximizing the caries-prevention benefit for all age groups, the appropriate amount of fluoride toothpaste should be used by all children regardless of age. Dentists should counsel caregivers by using oral description, visual aids and actual demonstration to help ensure that the appropriate amount of toothpaste is used.

Is fluoride a risk factor for bone cancer? Small area analysis of osteosarcoma and Ewing sarcoma diagnosed among 0–49-year-olds in Great Britain, 1980–2005

PubMed Central

Blakey, Karen; Feltbower, Richard G; Parslow, Roger C; James, Peter W; Gómez Pozo, Basilio; Stiller, Charles; Vincent, Tim J; Norman, Paul; McKinney, Patricia A; Murphy, Michael F; Craft, Alan W; McNally, Richard JQ

2014-01-01

Background: Artificial fluoridation of drinking water to improve dental health has long been a topic of controversy. Opponents of this public health measure have cited the possibility of bone cancer induction. The study objective was to examine whether increased risk of primary bone cancer was associated with living in areas with higher concentrations of fluoride in drinking water. Methods: Case data on osteosarcoma and Ewing sarcoma, diagnosed at ages 0–49 years in Great Britain (GB) (defined here as England, Scotland and Wales) during the period 1980–2005, were obtained from population-based cancer registries. Data on fluoride levels in drinking water in England and Wales were accessed through regional water companies and the Drinking Water Inspectorate. Scottish Water provided data for Scotland. Negative binomial regression was used to examine the relationship between incidence rates and level of fluoride in drinking water at small area level. Results: The study analysed 2566 osteosarcoma and 1650 Ewing sarcoma cases. There was no evidence of an association between osteosarcoma risk and fluoride in drinking water [relative risk (RR) per one part per million increase in the level of fluoride = 1·001; 90% confidence interval (CI) 0·871, 1·151] and similarly there was no association for Ewing sarcoma (RR = 0·929; 90% CI 0·773, 1·115). Conclusions: The findings from this study provide no evidence that higher levels of fluoride (whether natural or artificial) in drinking water in GB lead to greater risk of either osteosarcoma or Ewing sarcoma. PMID:24425828

Metabolomic effects of xylitol and fluoride on plaque biofilm in vivo.

PubMed

Takahashi, N; Washio, J

2011-12-01

Dental caries is initiated by demineralization of the tooth surface through acid production from sugar by plaque biofilm. Fluoride and xylitol have been used worldwide as caries-preventive reagents, based on in vitro-proven inhibitory mechanisms on bacterial acid production. We attempted to confirm the inhibitory mechanisms of fluoride and xylitol in vivo by performing metabolome analysis on the central carbon metabolism in supragingival plaque using the combination of capillary electrophoresis and a time-of-flight mass spectrometer. Fluoride (225 and 900 ppm F(-)) inhibited lactate production from 10% glucose by 34% and 46%, respectively, along with the increase in 3-phosphoglycerate and the decrease in phosphoenolpyruvate in the EMP pathway in supragingival plaque. These results confirmed that fluoride inhibited bacterial enolase in the EMP pathway and subsequently repressed acid production in vivo. In contrast, 10% xylitol had no effect on acid production and the metabolome profile in supragingival plaque, although xylitol 5-phosphate was produced. These results suggest that xylitol is not an inhibitor of plaque acid production but rather a non-fermentative sugar alcohol. Metabolome analyses of plaque biofilm can be applied for monitoring the efficacy of dietary components and medicines for plaque biofilm, leading to the development of effective plaque control.

Sodium fluoride and sulfur dioxide affected male reproduction by disturbing blood-testis barrier in mice.

PubMed

Zhang, Jianhai; Li, Zhihui; Qie, Mingli; Zheng, Ruibo; Shetty, Jagathpala; Wang, Jundong

2016-08-01

Fluoride and sulfur dioxide (SO2), two well-known environmental toxicants, have been implicated to have adverse effects on male reproductive health in humans and animals. The objective of this study to investigate if the BTB is one of the pathways that lead to reproductive toxicity of sodium fluoride and sulfur dioxide alone or in combination, in view of the key role of blood testis barrier (BTB) in testis. The results showed that a marked decrease in sperm quality, and altered morphology and ultrastructure of BTB in testis of mice exposure to fluoride (100 mg NaF/L in drinking water) or/and sulfur dioxide (28 mg SO2/m(3), 3 h/day). Meanwhile, the mRNA expression levels of some vital BTB-associated proteins, including occluding, claudin-11, ZO-1, Ncadherin, α-catenin, and connexin-43 were all strikingly reduced after NaF exposure, although only the reduction of DSG-2 was statistically significant in all treatment groups. Moreover, the proteins expressions also decreased significantly in claudin-11, N-cadherin, α-catenin, connexin-43 and desmoglein-2 in mice treated with fluoride and/or SO2. These changes in BTB structure and constitutive proteins may therefore be connected with the low sperm quality in these mice. The role of fluoride should deserves more attention in this process. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of topical fluoride prophylactic agents on the mechanical properties of orthodontic nickel-titanium closed coil springs and stainless steel closed coil springs

NASA Astrophysics Data System (ADS)

Carpenter, Brittany Gelene

The purpose of this study was to investigate the effects of topical fluoride prophylactic agents on the mechanical unloading properties of nickel-titanium (NiTi) and stainless steel (SS) closed coil springs. Spring were stored at 37°C under static load in phosphate buffered saline (PBS) and treated with either neutral sodium fluoride (NaF) or acidulated phosphate fluoride (APF) five days per week for two minutes. Mechanical testing was done in a dH2O bath at 37°C at 0-, 1-, 4-, 8-, and 12 weeks. Unloading forces for NiTi and SS springs were measured at 9-, 6-, and 3 mm and 2-, 1.5-, and 1 mm, respectively. Scanning electron microscopy was used to evaluate surface topography of selected springs after 12 weeks. Based on a 1-Factor ANOVA and Dunnett's post hoc, 3M NiTi springs showed a significant decrease (p <0.01) in the unloading force at each extension following exposure to both fluoride treatments, but only after 12 weeks. The AO NiTi springs showed a significant decrease in unloading force at each extension after 12 weeks following exposure to NaF. However, with SS springs, there was no significant effect of either fluoride treatment on the SS springs at any extension or time point. SS also springs showed no significant surface topography changes, irrespective of storage conditions, which correlates with the lack of fluoride effects on SS mechanical property effects. In contrast, while there were NiTi surface topography changes (pitting and mottling) following PBS+APF exposure, those changes could not be directly linked to the observed changes in mechanical properties. Results suggest topical fluoride used with NiTi springs could potentially lead to prolonged treatment time due to decreased unloading properties. However, topical fluoride used with SS springs should not affect treatment duration.

Nanocomposite scintillator, detector, and method

DOEpatents

Cooke, D Wayne [Santa Fe, NM; McKigney, Edward A [Los Alamos, NM; Muenchausen, Ross E [Los Alamos, NM; Bennett, Bryan L [Los Alamos, NM

2009-04-28

A compact includes a mixture of a solid binder and at least one nanopowder phosphor chosen from yttrium oxide, yttrium tantalate, barium fluoride, cesium fluoride, bismuth germanate, zinc gallate, calcium magnesium pyrosilicate, calcium molybdate, calcium chlorovanadate, barium titanium pyrophosphate, a metal tungstate, a cerium doped nanophosphor, a bismuth doped nanophosphor, a lead doped nanophosphor, a thallium doped sodium iodide, a doped cesium iodide, a rare earth doped pyrosilicate, or a lanthanide halide. The compact can be used in a radiation detector for detecting ionizing radiation.

Fluoride-selective optical sensor based on the dipyrrolyl-tetrathiafulvalene chromophore.

PubMed

Rivadehi, Shadi; Reid, Ellen F; Hogan, Conor F; Bhosale, Sheshanath V; Langford, Steven J

2012-01-28

A chemosensor bearing dipyrrolyl motifs as recognition sites and a tetrathiafulvalene redox tag has been evaluated as an optical and redox sensor for a series of anions (F(-), Cl(-), Br(-), HSO(4)(-), CH(3)COO(-), and H(2)PO(4)(-)) in DCM solution. The receptor shows specific optical signaling for fluoride but little electrochemical effect in solution. The solid-state performance of the sensor leads to measurable changes in water. Design implications towards better systems based on these results and other examples are discussed.

Casting of Halide and Fluoride Alloys for Laser Windows

DTIC Science & Technology

1974-07-15

mechanism leads to an inverse square root dependence of fracture strength on grain size. Since CaF2, SrFp and BaFp all exhibit at least microplastic ...flaws or microplasticity is the strength limiting factor is not known. 4.2.2 Solid-solution strengthening 4.2.2. 1 General If fracture in these...Temperature Microplasticity in SrF2 Single Crystals, " J. Appl. Phys. 41_(4) 1871 (1970). 12. T.S. Liu and C.H. Li, " Plasticity of Barium Fluoride

Sodium fluoride mouthrinse used twice daily increased incipient caries lesion remineralization in an in situ model.

PubMed

Songsiripradubboon, Siriporn; Hamba, Hidenori; Trairatvorakul, Chutima; Tagami, Junji

2014-03-01

To investigate the remineralizing effects of fluoride mouthrinses used at different times and frequency in addition to fluoride toothpaste. A randomized crossover single blinded study comprised 4 experimental phases of 21 days each. Twelve orthodontic volunteers were fixed with an orthodontic bracket containing an artificial carious enamel slab, which was from the same tooth in all 4 phases, and were randomly assigned to the following groups: (1) brushing with F toothpaste 2× per day (F- brush), (2) F- brush+rinsing with 0.05% NaF (F- rinse) after lunch, (3) F- brush+F-rinse before bedtime, and (4) F- brush+F- rinse 2× per day. Mean mineral gain after each phase was determined from mineral density profiles obtained using Micro-CT. The mean mineral gain in all treatments with F- brush and F-rinse were significantly greater than those in F- brush (p<0.05). Moreover F- rinse 2× per day increased lesion remineralization more than F- rinse once a day. The twice-daily use of 0.05% NaF mouthrinse combined with twice-daily regular use of fluoride toothpaste resulted in the greatest remineralization of incipient caries. These data indicate that rinsing frequency is a factor affecting the effectiveness of fluoride mouthrinse. The rinsing frequency of NaF mouthrinse, when used with fluoride toothpaste, also affects the remineralization. This finding, if confirmed by a clinical study, would lead to a new recommendation for fluoride mouthrinse used in high caries risk patients who could benefit from using it twice a day. Copyright © 2014 Elsevier Ltd. All rights reserved.

Thermal, optical, and dielectric properties of fluoride Rb2TaF7

NASA Astrophysics Data System (ADS)

Pogorel'tsev, E. I.; Mel'nikova, S. V.; Kartashev, A. V.; Gorev, M. V.; Flerov, I. N.; Laptash, N. M.

2017-05-01

The thermal, optical, and dielectric properties of fluoride Rb2TaF7 were investigated. It was observed that the variation in chemical pressure in fluorides A 2 +TaF7 caused by the cation substitution of rubidium for ammonium does not affect the ferroelastic nature of structural distortions, but leads to stabilization of the high- and low-temperature phases and enhancement of birefringence. The entropy of the phase transition P4/nmm ↔ Cmma is typical of the shift transformations, which is consistent with a model of the initial and distorted phase structures. The anisotropy of chemical pressure causes the change of signs of the anomalous strain and baric coefficient dT/ dp of Rb2TaF7 as compared with the values for its ammonium analog.

[The effect of alternating administration of aluminum chloride and sodium fluoride in drinking water on the concentration of fluoride in serum and its content in bones of rats].

PubMed

Lubkowska, Anna; Chlubek, Dariusz; Machoy-Mokrzyniska, Anna

2006-01-01

Fluorine and aluminum remain a very interesting research topic due to equivocal and relatively unknown toxic action, role in the etiology of various diseases, and interactions of both elements. Fluorine and aluminum compounds are absorbed by organisms through the gastric and respiratory systems, although the latter route operates only at very high concentrations in air. Chronic exposure to fluorine and aluminum leads to accumulation of both elements, especially in bones and teeth, but also in lung, brain, kidney, and liver. Organisms excrete these elements with urine, faeces, and to a minor extent with sweat and bile. In the light of reports suggesting that aluminum has protective properties against fluorine toxicity during exposure to both elements, we decided to examine the effect of alternating doses of aluminum fluoride and sodium fluoride in drinking water on rats. Four female groups received: I--100 ppm fluorine ions during one month; II--100 ppm fluorine ions alternating every two days with 300 ppm aluminum ions during one month; III--100 ppm fluoride ions during four months; IV--100 ppm fluorine ions alternating every two days with 300 ppm aluminum ions during four months. The respective male groups called IA, IIA, IIIA, and IVA were treated identically. Subsequently, the animals were anesthetized and sacrificed. Blood was sampled from the heart and the right femur was removed for fluorine determination. Fluorine content in the femur and serum was determined with an ion-selective electrode (Orion). The results were analyzed statistically (Statistica 6). We observed higher fluoride concentrations in serum as compared with control values in all groups of female and male rats exposed to sodium fluoride only. Longer exposure time (4 months) did not result in further increase in serum fluoride concentration. However, longer exposure increased fluoride accumulation in the femur (p < 0.001). All groups exposed to NaF had significantly higher fluoride concentration in the femur as compared with control animals. Groups receiving NaF and AlCl3 showed lower fluoride concentration in serum and femur compared with those exposed to NaF only and higher in comparison with controls. Fluorine content in the femur of rats exposed to NaF and AlCI3 for four months was similar to the results obtained after one month of exposure.

Effect of lead fluoride incorporation on the structure and luminescence properties of tungsten sodium phosphate glasses

NASA Astrophysics Data System (ADS)

Nardi, Rachel Prado Russo Delorenzo; Braz, Celso Eduardo; de Camargo, Andrea S. S.; Ribeiro, Sidney J. L.; Rocha, Lucas A.; Cassanjes, Fábia Castro; Poirier, Gael

2015-11-01

Tungsten phosphate glasses are known to be promising materials for several applications in optics such as non linear optical properties, lower phonon energy or photochromic effects related with tungsten oxide incorporation inside the phosphate network. In this study, lead fluoride has been incorporated in a 60NaPO3-40WO3 glass composition according to the ternary molar compositions (100 - x)[0.6NaPO3-0.4WO3]-xPbF2 with x varying from 0 to 60 mol%. The structural changes as a function of composition were investigated by thermal analysis, UV-visible absorption, Raman spectroscopy, X-ray diffraction of the crystallized samples, and Eu3+ emission in the visible. While DSC analyzes points out a strong decrease in the glass network connectivity and higher crystallization tendency with increasing PbF2 contents, Raman spectra clearly identify a progressive incorporation of PbF2 in the phosphate network with the formation of terminal Psbnd F and Wsbnd F bonds. These results are also in agreement with the crystallization of β-PbF2 observed for the most lead fluoride concentrated samples. Investigation of Eu3+ emission data in the visible showed longer 5D0 excited state lifetime values and higher quantum efficiencies. These results are discussed in terms of the assumption of higher local symmetry around Eu3+ with increasing PbF2 contents.

Electrochemical OFF-ON ratiometric chemodosimeters for the selective and rapid detection of fluoride.

PubMed

Mani, Veerappan; Li, Wen-Yung; Gu, Jiun-An; Lin, Chun-Mao; Huang, Sheng-Tung

2015-01-01

We have described two "OFF-ON electrochemical latent ratiometric redox chemodosimeters", 1,4-Bis(tert-butyldimethylsiloxy)benzene (H2Q') and 1,4-Bis (tert-butyldimet hylsiloxy)-2-methoxybenzene (MH2Q') for the selective detection of inorganic fluoride. The electrochemical signals of hydroquinone (H2Q) and o-methoxy hydroquinone (MH2Q) within this latent redox probes (H2Q' and MH2Q') were completely masked by protecting their hydroxyl group as silylether (OFF state). The externally added fluoride ions triggered the deprotection of H2Q' and MH2Q' and unmasked the electrochemical properties of H2Q and MH2Q respectively. The electrochemical reporters (H2Q and MH2Q) presented a pair of redox peaks at the electrode surface (ON state) and the peak currents are linearly dependent with the concentration of fluoride which leading to the ratiometric detection of fluoride. The limit of detection (signal-to-noise ratio=3) observed for the probes are 23.8 µM and 2.38 µM for H2Q' and MH2Q' respectively. The deprotection is highly selective for fluoride over other anions investigated. The probes are highly stable and the proposed approach offers rapid response time and promising practical applicability. The proposed strategy holds great promise for the commencement of new H2Q based electrochemical probes by tuning the electrochemical behavior of H2Q. Copyright © 2014 Elsevier B.V. All rights reserved.

Metabolomic Effects of Xylitol and Fluoride on Plaque Biofilm in Vivo

PubMed Central

Takahashi, N.; Washio, J.

2011-01-01

Dental caries is initiated by demineralization of the tooth surface through acid production from sugar by plaque biofilm. Fluoride and xylitol have been used worldwide as caries-preventive reagents, based on in vitro-proven inhibitory mechanisms on bacterial acid production. We attempted to confirm the inhibitory mechanisms of fluoride and xylitol in vivo by performing metabolome analysis on the central carbon metabolism in supragingival plaque using the combination of capillary electrophoresis and a time-of-flight mass spectrometer. Fluoride (225 and 900 ppm F−) inhibited lactate production from 10% glucose by 34% and 46%, respectively, along with the increase in 3-phosphoglycerate and the decrease in phosphoenolpyruvate in the EMP pathway in supragingival plaque. These results confirmed that fluoride inhibited bacterial enolase in the EMP pathway and subsequently repressed acid production in vivo. In contrast, 10% xylitol had no effect on acid production and the metabolome profile in supragingival plaque, although xylitol 5-phosphate was produced. These results suggest that xylitol is not an inhibitor of plaque acid production but rather a non-fermentative sugar alcohol. Metabolome analyses of plaque biofilm can be applied for monitoring the efficacy of dietary components and medicines for plaque biofilm, leading to the development of effective plaque control. PMID:21940519

Open circuit voltage durability study and model of catalyst coated membranes at different humidification levels

NASA Astrophysics Data System (ADS)

Kundu, Sumit; Fowler, Michael W.; Simon, Leonardo C.; Abouatallah, Rami; Beydokhti, Natasha

Fuel cell material durability is an area of extensive research today. Chemical degradation of the ionomer membrane is one important degradation mechanism leading to overall failure of fuel cells. This study examined the effects of relative humidity on the chemical degradation of the membrane during open circuit voltage testing. Five Gore™ PRIMEA ® series 5510 catalyst coated membranes were degraded at 100%, 75%, 50%, and 20% RH. Open circuit potential and cumulative fluoride release were monitored over time. Additionally scanning electron microscopy images were taken at end of the test. The results showed that with decreasing RH fluoride release rate increased as did performance degradation. This was attributed to an increase in gas crossover with a decrease in RH. Further, it is also shown that interruptions in testing may heavily influence cumulative fluoride release measurements where frequent stoppages in testing will cause fluoride release to be underestimated. SEM analysis shows that degradation occurred in the ionomer layer close to the cathode catalyst. A chemical degradation model of the ionomer membrane was used to model the results. The model was able to predict fluoride release trends, including the effects of interruptions, showing that changes in gas crossover with RH could explain the experimental results.

Effective use of fluorides in the People's Republic of China--a model for WHO Mega Country initiatives.

PubMed

Petersen, P E; Kwan, S; Zhu, L; Zhang, B X; Bian, J Y

2008-12-01

Poor dental health has been reported in the Chinese National Surveys of Oral Health. With the changing lifestyle and growing consumption of sugars, the incidence of dental caries may well continue to rise, compounded by limited access to professional care. The increasing oral disease burden could become a major public health problem in China, leading to considerable personal and health service costs. There is a desperate need for systematic implementation of preventive programmes. Currently, China is strengthening the prevention of chronic diseases, which provides an excellent opportunity to integrate oral disease prevention into the overall non-communicable disease (NCD) prevention programmes. In order to address this growing public health problem, the World Health Organization (WHO) Global Oral Health Programme advocates the effective use of fluoride as an essential approach to prevent dental caries in the 21st century--part of the WHO Global Oral Health Strategy. Population-wide automatic fluoridation measures are considered the most effective, complemented by appropriate use of toothpastes containing fluoride. There are wide variations of fluoride levels in drinking water in China and, in many areas, the levels of fluoride in drinking water are lower than the recommended levels. The use of toothpaste containing fluoride is still too low in some areas and decreases with age. Those who live in rural areas have limited access to affordable toothpastes containing fluoride. In March 2006, as part of the WHO Mega Country Health Promotion Network initiatives, the WHO Global Oral Health Programme organised a three-day symposium in Beijing, People's Republic of China. The aim of the symposium was to bring together international experience and Chinese expertise to facilitate policy development for effective use of fluoride in China, highlighting the benefits of, and barriers to, the implementation of different fluoridation programmes at the strategic levels as well as for operational planning. This article reports the proceedings of the meeting. In summary, China is a Mega country with much diversity and disparity. The situation in China is unique with endemic fluorosis due to other non-water sources of fluoride in some areas and a considerable dental caries burden in others. It is important to regulate the appropriate exposure to fluoride to obtain the benefits and avoid adverse effects of fluorides, controlling enamel fluorosis without jeopardising the prevention of dental caries. Various complementary fluoridation programmes can be considered for different population groups with varying needs, strategies that bring about additive effects. A multi-tier policy making approach at national, regional and provincial levels can be employed, based on sound evidence. The roles of WHO, Ministry of Health and the National Committee for Oral Health (NCOH) were emphasised. Lessons learned from the Chinese experience will prove invaluable to other countries with similar socio demographic characteristics that are in the same process of developing and implementing fluoridation policies and programmes.

Relationship Between Dental Fluorosis and Intelligence Quotient of School Going Children In and Around Lucknow District: A Cross-Sectional Study.

PubMed

Khan, Suleman Abbas; Singh, Rahul Kumar; Navit, Saumya; Chadha, Dheera; Johri, Nikita; Navit, Pragati; Sharma, Anshul; Bahuguna, Rachana

2015-11-01

Fluoridation of drinking water, despite being regarded as one of the top ten public health achievements of the twentieth century, has remained a much debated concept. Various studies on animals and aborted human fetuses have confirmed that excessive fluoride intake during infancy and early childhood, causes a number of irreversible structural and functional changes in the CNS leading to memory, learning and intellectual deficits. To compare the IQ levels of school children of two different locations, having different fluoride levels in water, and to establish a relationship between fluoride levels, prevalence of fluorosis and its effect on IQ levels. A cross-sectional study was conducted among 429 children aged 6 - 12 years, selected by stratified random sampling from two different areas with different levels of fluoride in drinking water in and around Lucknow district. Dental fluorosis was measured using Dean's Fluorosis Index. Intelligence Quotient was measured using Raven's Coloured Progressive Matrices (1998 edition). Majority of the fluorosis free children (76.3%) had an IQ grade 2 (definitely above the average). Majority of the children suffering from very mild and mild dental fluorosis were found to have IQ grade 3 (Intellectually average). Children with moderate cases of dental fluorosis were found to have IQ grade 4 (Definitely below average). Only 5 children with severe fluorosis were included in the study and they all were found to have an IQ grade 5. Hence, a trend of increase in the IQ grade (decrease in intellectual capacity) was observed indicating a strong correlation between fluorosis grade and IQ grade. Findings of this study suggest that the overall IQ of the children exposed to high fluoride levels in drinking water and hence suffering from dental fluorosis were significantly lower than those of the low fluoride area.

Temperature dependence of the ratio of intensities of up-conversion fluorescence bands of YVO4 and YGdVO4 crystals and lead fluoride nano glass ceramics activated with erbium ions

NASA Astrophysics Data System (ADS)

Varaksa, Yu. A.; Sinitsyn, G. V.; Khodasevich, M. A.; Aseev, V. A.; Kolobkova, E. V.; Yasyukevich, A. S.

2015-01-01

Up-conversion fluorescence spectra of YVO4 and YGdVO4 crystals and lead fluoride nano glass ceramics coactivated with erbium and ytterbium ions have been studied in the wavelength range of 520-560 nm under 967-nm pumping. The ratio of intensities of fluorescence bands in the ranges of 520-530 and 540-550 nm has been measured in the temperature range of from room temperature to 150°C. It is shown that the considered materials can be used for preparing a sensing element of optical fluorescent temperature sensors; the sensitivity of measuring the temperature of nano glass-ceramics can be close to that of crystal samples.

Azocalix[4]arene strapped calix[4]pyrrole: a confirmable fluoride sensor.

PubMed

Thiampanya, Preecha; Muangsin, Nongnuj; Pulpoka, Buncha

2012-08-17

A new chromogenic fluoride sensor based on 1,3-di-p-nitrophenylazocalix[4]arene-calix[4]pyrrole (1) was designed and synthesized. The color of the solution of probe 1 changed upon the addition of any F(-), CH(3)CO(2)(-), PhCO(2)(-), and H(2)PO(4)(-) ions. However, from these ions the highly specific sensing of F(-) is achieved by the addition of Ca(2+) which leads to a color change from light sky blue (of 1·F(-)) back to the original light orange color of 1.

Chronic Fluoride Toxicity: Dental Fluorosis

PubMed Central

DenBesten, Pamela; Li, Wu

2012-01-01

Dental fluorosis occurs as a result of excess fluoride ingestion during tooth formation. Enamel fluorosis and primary dentin fluorosis can only occur when teeth are forming, and therefore fluoride exposure (as it relates to dental fluorosis) occurs during childhood. In the permanent dentition, this would begin with the lower incisors, which complete mineralization at approximately 2–3 years of age, and end after mineralization of the third molars. The white opaque appearance of fluorosed enamel is caused by a hypomineralized enamel subsurface; with more severe dental fluorosis, pitting and a loss of the enamel surface occurs, leading to secondary staining (appearing as a brown color). Many of the changes caused by fluoride are related to cell/matrix/mineral interactions as the teeth are forming. At the early maturation stage, the relative quantity of amelogenin protein is increased in fluorosed enamel in a dose-related manner. This appears to result from a delay in the removal of amelogenins as the enamel matures. In vitro, when fluoride is incorporated into the mineral, more protein binds to the forming mineral, and protein removal by proteinases is delayed. This suggests that altered protein/mineral interactions are in part responsible for retention of amelogenins and the resultant hypomineralization that occurs in fluorosed enamel. Fluoride also appears to enhance mineral precipitation in forming teeth, resulting in hypermineralized bands of enamel, which are then followed by hypomineralized bands. Enhanced mineral precipitation with local increases in matrix acidity may affect maturation stage ameloblast modulation, potentially explaining the doserelated decrease in cycles of ameloblast modulation from ruffleended to smooth-ended cells that occur with fluoride exposure in rodents. Specific cellular effects of fluoride have been implicated, but more research is needed to determine which of these changes are relevant to the formation of fluorosed teeth. As further studies are done, we will better understand the mechanisms responsible for dental fluorosis. PMID:21701193

Chronic fluoride toxicity: dental fluorosis.

PubMed

Denbesten, Pamela; Li, Wu

2011-01-01

Dental fluorosis occurs as a result of excess fluoride ingestion during tooth formation. Enamel fluorosis and primary dentin fluorosis can only occur when teeth are forming, and therefore fluoride exposure (as it relates to dental fluorosis) occurs during childhood. In the permanent dentition, this would begin with the lower incisors, which complete mineralization at approximately 2-3 years of age, and end after mineralization of the third molars. The white opaque appearance of fluorosed enamel is caused by a hypomineralized enamel subsurface. With more severe dental fluorosis, pitting and a loss of the enamel surface occurs, leading to secondary staining (appearing as a brown color). Many of the changes caused by fluoride are related to cell/matrix interactions as the teeth are forming. At the early maturation stage, the relative quantity of amelogenin protein is increased in fluorosed enamel in a dose-related manner. This appears to result from a delay in the removal of amelogenins as the enamel matures. In vitro, when fluoride is incorporated into the mineral, more protein binds to the forming mineral, and protein removal by proteinases is delayed. This suggests that altered protein/mineral interactions are in part responsible for retention of amelogenins and the resultant hypomineralization that occurs in fluorosed enamel. Fluoride also appears to enhance mineral precipitation in forming teeth, resulting in hypermineralized bands of enamel, which are then followed by hypomineralized bands. Enhanced mineral precipitation with local increases in matrix acidity may affect maturation stage ameloblast modulation, potentially explaining the dose-related decrease in cycles of ameloblast modulation from ruffle-ended to smooth-ended cells that occur with fluoride exposure in rodents. Specific cellular effects of fluoride have been implicated, but more research is needed to determine which of these changes are relevant to the formation of fluorosed teeth. As further studies are done, we will better understand the mechanisms responsible for dental fluorosis. Copyright © 2011 S. Karger AG, Basel.

Effect of Pre-Irradiation Annealing and Laser Modification on the Formation of Radiation-Induced Surface Color Centers in Lithium Fluoride

NASA Astrophysics Data System (ADS)

Voitovich, A. P.; Kalinov, V. S.; Novikov, A. N.; Radkevich, A. V.; Runets, L. P.; Stupak, A. P.; Tarasenko, N. V.

2017-01-01

It is shown that surface color centers of the same type are formed in the surface layer and in regions with damaged crystal structure inside crystalline lithium fluoride after γ-irradiation. Results are presented from a study of the effect of pre-irradiation annealing on the efficiency with which surface centers are formed in lithium fluoride nanocrystals. Raising the temperature for pre-irradiation annealing from room temperature to 250°C leads to a substantial reduction in the efficiency with which these centers are created. Surface color centers are not detected after γ-irradiation for pre-irradiation annealing temperatures of 300°C and above. Adsorption of atmospheric gases on the crystal surface cannot be regarded as a necessary condition for the formation of radiation-induced surface centers.

Surface Hardness of Dental Composite Resin Restorations in Response to Preventive Agents.

PubMed

Al-Samadani, Khalid H

2016-12-01

To assess the impact of using preventive mouthwash agents on the surface hardness of various resins composites. Hundred specimens were prepared from five types of composite resin material in a Teflon mold. Five specimens from each type of restorative materials (Herculite XRV Ultra, Estelite Σ Quick, Z Hermack, Versa Comp Sultan, and Empress Direct IPS) were evaluated posttreatment with immersion in four types of preventive mouthwashes gels and rinses - group 1: Flocare gel (0.4% stannous fluoride), group 2: Pascal gel (topical APF fluoride), group 3: Pro-relief mouthwash (Na fluoride), and group 4: Plax Soin mouthwash (Na fluoride) - at 37°C in a dark glass container at 24, 48, and 72 hours. Surface hardness measurement was made for each tested material. Statistically, we analyzed the mean values with one-way analysis of variance (ANOVA) and Tukey's test, with significance level of p < 0.05. All composite resin materials showed decrease in their surface hardness with the time elapsed (24, 48, and 72 hours) postimmersion in the preventive mouthwashes and gels except the Herculite XRV Ultra and Versa Comp Sultan materials. Flocare gel group showed increase in the surface hardness after 48 hours of immersion than the other periods and in Estelite Σ Quick after 72 hours. There was significant differences in all materials tested with the immersion in the preventive mouthwashes and gels, such as Flocare gel (0.4% stannous fluoride), Pro-relief mouthwash (Na fluoride), and Plax Soin mouthwash (Na fluoride) except Pascal gel (topical APF fluoride) (p > 0.05), at time intervals mentioned earlier (p < 0.05). The effect of preventive mouthwashes and gels on resin composite materials was decreased surface hardness with the time elapse of immersion for all materials except the Flocare gel group, which contains 0.4% stannous fluoride as a preventive ingredient increases the surface hardness after 48 h for Herculite XRV Ultra and Versa Comp Sultan and Estelite Σ Quick after 72 hours. The preventive agents in the form of mouthwash and gel are used to prevent oral diseases that affect the surface hardness of composite resin, and this leads to occlusion, color stability, and surface roughness.

Human Health Impact of Fluoride in Groundwater in the Chiang Mai Basin

NASA Astrophysics Data System (ADS)

Matsui, Y.; Takizawa, S.; Wattanachira, S.; Wongrueng, A.; Ibaraki, M.

2005-12-01

Chiang Mai Basin, in Northern Thailand, is known as a fluorotic area. Groundwater of the Chiang Mai Basin has been gradually replaced by contaminated surface water since the 1980's. People have been exposed to fluoride contaminated groundwater since that time. As a result, harmful health effects on dental and skeletal growth were observed in the 90's. These include dental and skeletal fluorosis. Dental fluorosis is characterized by yellow or white spots on teeth and pitting or mottled enamel, consequently causing the teeth to look unsightly. Skeletal fluorosis leads to changes in bone structure, making them extremely weak and brittle. The most severe form of this is known as ``crippling skeletal fluorosis,'' a condition that can cause immobility, muscle wasting, and neurological problems related to spinal cord compression. This study focuses on the problematic issue of the Chiang Mai Basin's groundwater from the viewpoint of fluoride occurrence and current health impacts. Chiang Mai and Lamphun Provinces comprise the Chiang Mai Basin. Fluoride rich granites or fluorite deposits are scattered across the mountainside of the Lamphun Province. Tropical savanna climate conditions with seasonal monsoons bring more than 1,000 mm of annual precipitation, which can prompt weathering of minerals containing fluoride. The Ping River dominates the Basin, and the main eastern tributary of the Ping River runs through the Lamphun Province. The Basin has geological units composed of lower semi-consolidated Tertiary fluvial and upper unconsolidated Quaternary alluvium deposits. The main aquifers are in the upper unconsolidated unit. High fluoride concentrations tend to be observed in the aquifer located in lower part of this unconsolidated unit. We have been investigating two areas in the Basin. These two locations are similar with respect to geological and hydrological settings. However, one area in which groundwater is Ca-bicarbonate dominant has a low fluoride occurrence. Groundwater of the other area contains a high fluoride concentration and is Na-bicarbonate dominant. We will present how naturally-occurring fluoride found in this groundwater has impacted the health of a large portion of residents in the Chiang Mai Basin, and we will explain the mechanism that differentiates Ca concentration, which controls fluoride concentration in groundwater, between different areas in the Basin.

Vitamin E and Lycopene Reduce Coal Burning Fluorosis-induced Spermatogenic Cell Apoptosis via Oxidative Stress-mediated JNK and ERK Signaling Pathways.

PubMed

Tian, Yuan; Xiao, Yuehai; Wang, Bolin; Sun, Chao; Tang, Kaifa; Sun, Fa

2017-12-22

Although fluoride has been widely used in toothpaste, mouthwash, and drinking water to prevent dental caries, the excessive intake of fluoride can cause fluorosis which is associated with dental, skeletal, and soft tissue fluorosis. Recent evidences have drawn the attention to its adverse effects on male reproductive system that include spermatogenesis defect, sperm count loss, and sperm maturation impairment. Fluoride induces oxidative stress through the activation of mitogen activated protein kinase (MAPK) cascade which can lead to cell apoptosis. Vitamin E (VE) and lycopene are two common anti-oxidants, being protective to reactive oxygen species (ROS)-induced toxic effects. However, whether and how these two anti-oxidants prevent fluoride-induced spermatogenic cell apoptosis are largely unknown. In the present study, a male rat model for coal burning fluorosis was established and the histological lesions and spermatogenic cell apoptosis in rat testes were observed. The decreased expression of clusterin, a heterodimeric glycoprotein reported to regulate spermatogenic cell apoptosis, is detected in fluoride-treated rat testes. Interestingly, the co-administration with VE or lycopene reduced fluorosis-mediated testicular toxicity and rescued clusterin expression. Further, fluoride caused the enhanced Jun N-terminal kinase (JNK) and extracellular signal-regulated protein kinase (ERK) phosphorylation, which was reduced by VE or lycopene. Thus, VE and lycopene prevent coal burning fluorosis-induced spermatogenic cell apoptosis through the suppression of oxidative stress-mediated JNK and ERK signaling pathway, which could be an alternative therapeutic strategy for the treatment of fluorosis. ©2017 The Author(s).

Comparative proteomic analysis of fluoride treated rat bone provides new insights into the molecular mechanisms of fluoride toxicity.

PubMed

Wei, Yan; Zeng, Beibei; Zhang, Hua; Chen, Cheng; Wu, Yanli; Wang, Nanlan; Wu, Yanqiu; Zhao, Danqing; Zhao, Yuxi; Iqbal, Javed; Shen, Liming

2018-07-01

Long-term excessive intake of fluoride (F) could lead to chronic fluorosis. To explore the underlying molecular mechanisms, present study is designed to elucidate the effect of fluoride on proteome expression of bone in sodium fluoride (NaF)-treated SD rats. Hematoxylin and eosin (H&E) staining was used to determine the severity of osteofluorosis, and bone samples were submitted for iTRAQ analysis. The results showed that the cortical thickness and trabecular area of femur bone in medium- and high-dose groups were higher than in control group. Contrary to this, trabecular area was reduced in the low-dose group, indicating that the bone mass was increased in medium- and high-dose groups, and decreased in the low-dose group. Thirteen (13), 35, and 34 differentially expressed proteins were identified in low-, medium-, and high-dose group, respectively. The medium- and high-dose groups shared a more similar protein expression pattern. These proteins were mainly associated with collagen metabolism, proteoglycans (PGs), matrix metalloproteinases (MMPs), etc. The results suggested that the effect of NaF on SD rats is in a dose-dependent manner. Some key proteins found here may be involved in affecting the bone tissues and bone marrow or muscle, and account for the complex pathology and clinical symptoms of fluorosis. Copyright © 2018 Elsevier B.V. All rights reserved.

[The effect of overdose fluoride on the expression of TGF-beta1 in rat's dental pulps].

PubMed

Wu, Yu; He, Ke-xing; Yang, Yi-ping; Cao, Yang; Liang, Zhi-feng

2006-04-01

To observe the effect of overdose fluoride on the expression of TGF-beta1 in rat's dental pulps. 20 wister rats were divided into two groups. In the control group, equal dose distilled water were given to the rats. In the experimental group, 20 mg.kg(-1).d(-1) NaF were given. After 8 weeks of treatment, immunohistochemical staining was adopted for detection of the expression of TGF-beta1 in dental pulps of the rats. SPSS10.0 software package was used for Student's t test. Image analysis results showed that the expression of TGF-beta1 in the dental pulp and inner dentin were inhibited in the experimental group as compared with the control group (P<0.01). The overdose fluoride will inhibit the secretion of TGF-beta1, which leads to abnormal development of the teeth.

Fluoride anion sensing mechanism of 2-ureido-4[1H]-pyrimidinone quadruple hydrogen-bonded supramolecular assembly: photoinduced electron transfer and partial configuration change.

PubMed

Chen, Jun-Sheng; Zhou, Pan-Wang; Li, Guang-Yue; Chu, Tian-Shu; He, Guo-Zhong

2013-05-02

The fluoride anion sensing mechanism of 6-methyl-5-(9-methylene-anthracene)-(2-butylureido-4[1H]-pyrimidinone) (AnUP) has been investigated using the DFT/TDDFT method. The theoretical results indicate that the proton of the N3-H3 group in pyrimidine moiety is captured by the added fluoride anion and then deprotonated. The calculated vertical excitation energies of AnUP-dimer and its deprotonated form agree well with the experimental results. The molecular orbital analysis demonstrates that the first excited state (S1) of AnUP-dimer is a local excited state with a π-π* transition, whereas for the deprotonated form, S1 is a completely charge-separation state and is responsible for the photoinduced electron transfer (PET) process. The PET process from anthracene to the pyrimidine moiety leads to the fluorescence quenching.

Health impact of supplying safe drinking water containing fluoride below permissible level on flourosis patients in a fluoride-endemic rural area of West Bengal.

PubMed

Majumdar, Kunal Kanti

2011-01-01

The problem of high fluoride concentration in groundwater resources has become one of the most important toxicological and geo-environmental issues in India. Excessive fluoride in drinking water causes dental and skeletal fluorosis, which is encountered in endemic proportions in several parts of the world. World Health Organization (WHO) guideline value and the permissible limit of fluoride as per Bureau of Indian Standard (BIS) is 1.5 mg/L. About 20 states of India, including 43 blocks of seven districts of West Bengal, were identified as endemic for fluorosis and about 66 million people in these regions are at risk of fluoride contamination. Studies showed that withdrawal of sources identified for fluoride often leads reduction of fluoride in the body fluids (re-testing urine and serum after a week or 10 days) and results in the disappearance of non-skeletal fluorosis within a short duration of 10-15 days. To determine the prevalence of signs and symptoms of suspected dental, skeletal, and non-skeletal fluorosis, along with food habits, addictions, and use of fluoride containing toothpaste among participants taking water with fluoride concentration above the permissible limit, and to assess the changes in clinical manifestations of the above participants after they started consuming safe drinking water. A longitudinal intervention study was conducted in three villages in Rampurhat Block I of Birbhum district of West Bengal to assess the occurrence of various dental, skeletal, and non-skeletal manifestations of fluorosis, along with food habits, addictions, and use of fluoride containing toothpaste among the study population and the impact of taking safe water from the supplied domestic and community filters on these clinical manifestations. The impact was studied by follow-up examination of the participants for 5 months to determine the changes in clinical manifestations of the above participants after they started consuming safe drinking water from supplied domestic filters and community filter with fluoride concentration below the permissible limit. The data obtained were compared with the collected data from the baseline survey. The prevalence of signs of dental, skeletal, and non-skeletal fluorosis was 66.7%, 4.8-23.8%, and 9.5-38.1%, respectively, among the study population. Withdrawal of source(s) identified for fluoride by providing domestic and community filters supplying safe water led to 9.6% decrease in manifestation of dental fluorosis, 2.4-14.3% decrease in various manifestations of skeletal fluorosis, and 7.1-21.5% decrease in various non-skeletal manifestations within 5 months. Following repeated motivation of participants during visit, there was also 9.7-38.1% decrease in the usage of fluoride containing toothpaste, and 9.8-45.3% and 7.3-11.9% decrease in the consumption of black lemon tea and tobacco, respectively, which are known sources of fluoride ingestion in our body and have an effect on the occurrence of various manifestations of fluorosis following drinking of safe water from domestic and community filters. Increased prevalence of dental, skeletal, and non-skeletal fluorosis was found among the study population. Withdrawal of source(s) identified for fluoride by supplying domestic and community filters, dietary restriction, and other nutritional interventions led to decrease in manifestation of the three types of fluorosis within 5 months.

40 CFR 426.132 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2012 CFR

2012-07-01

... waste water, shall meet the following limitations. Effluent characteristic Effluent limitations Lead No limitation. Fluoride Do. TSS Do. pH Do. (b) Any plant which melts raw materials, produces non-leaded hand pressed or blown glassware, discharges greater than 50 gallons per day of process waste water, and employs...

40 CFR 426.132 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2014 CFR

2014-07-01

... waste water, shall meet the following limitations. Effluent characteristic Effluent limitations Lead No limitation. Fluoride Do. TSS Do. pH Do. (b) Any plant which melts raw materials, produces non-leaded hand pressed or blown glassware, discharges greater than 50 gallons per day of process waste water, and employs...

40 CFR 426.132 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2013 CFR

2013-07-01

... waste water, shall meet the following limitations. Effluent characteristic Effluent limitations Lead No limitation. Fluoride Do. TSS Do. pH Do. (b) Any plant which melts raw materials, produces non-leaded hand pressed or blown glassware, discharges greater than 50 gallons per day of process waste water, and employs...

40 CFR 426.115 - Standards of performance for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (the fluoride and lead limitations are applicable to the abrasive polishing and acid polishing waste water streams while the TSS, oil, and pH limitations are applicable to the entire process waste water...

Inhibition of the Quorum Sensing System (ComDE Pathway) by Aromatic 1,3-di-m-tolylurea (DMTU): Cariostatic Effect with Fluoride in Wistar Rats

PubMed Central

Kaur, Gurmeet; Balamurugan, P.; Princy, S. Adline

2017-01-01

Dental caries occurs as a result of dysbiosis among commensal and pathogenic bacteria leading to demineralization of enamel within a dental biofilm (plaque) as a consequence of lower pH in the oral cavity. In our previous study, we have reported 1,3-disubstituted ureas particularly, 1,3-di-m-tolylurea (DMTU) could inhibit the biofilm formation along with lower concentrations of fluoride (31.25 ppm) without affecting bacterial growth. In the present study, RT-qPCR analysis showed the target specific molecular mechanism of DMTU. In vivo treatment with DMTU, alone or in combination with fluoride, resulted in inhibition of caries (biofilm development of Streptococcus mutans) using a Wistar rat model for dental caries. The histopathological analysis reported the development of lesions on dentine in infected subjects whereas the dentines of treated rodents were found to be intact and healthy. Reduction in inflammatory markers in rodents' blood and liver samples was observed when treated with DMTU. Collectively, data speculate that DMTU is an effective anti-biofilm and anti-inflammatory agent, which may improve the cariostatic properties of fluoride. PMID:28748175

Inhibition of the Quorum Sensing System (ComDE Pathway) by Aromatic 1,3-di-m-tolylurea (DMTU): Cariostatic Effect with Fluoride in Wistar Rats.

PubMed

Kaur, Gurmeet; Balamurugan, P; Princy, S Adline

2017-01-01

Dental caries occurs as a result of dysbiosis among commensal and pathogenic bacteria leading to demineralization of enamel within a dental biofilm (plaque) as a consequence of lower pH in the oral cavity. In our previous study, we have reported 1,3-disubstituted ureas particularly, 1,3-di-m-tolylurea (DMTU) could inhibit the biofilm formation along with lower concentrations of fluoride (31.25 ppm) without affecting bacterial growth. In the present study, RT-qPCR analysis showed the target specific molecular mechanism of DMTU. In vivo treatment with DMTU, alone or in combination with fluoride, resulted in inhibition of caries (biofilm development of Streptococcus mutans ) using a Wistar rat model for dental caries. The histopathological analysis reported the development of lesions on dentine in infected subjects whereas the dentines of treated rodents were found to be intact and healthy. Reduction in inflammatory markers in rodents' blood and liver samples was observed when treated with DMTU. Collectively, data speculate that DMTU is an effective anti-biofilm and anti-inflammatory agent, which may improve the cariostatic properties of fluoride.

Impact of urbanization coupled with drought situations on groundwater quality in shallow (basalt) and deeper (granite) aquifers with special reference to fluoride in Nanded-Waghala Municipal Corporation, Nanded District, Maharashtra (India).

PubMed

Pandith, Madhnure; Kaplay, R D; Potdar, S S; Sangnor, H; Rao, A D

2017-09-01

Rapid expansion in urbanization and industrialization coupled with recent drought conditions has triggered unplanned groundwater development leading to severe stress on groundwater resources in many urban cities of India, particularly cities like Nanded, Maharashtra. In the quest of tapping drinking water requirement, due to recent drought conditions, people from the city are piercing through entire thickness of shallow basalt aquifers to reach productive deeper granite aquifers. Earlier reports from Nanded and surrounding districts suggest that deeper granite aquifer is contaminated with fluoride (geogenic). The study aimed to find out variations in fluoride concentration in shallow basalt (10-167 m) and deeper granite aquifers (below 167 m) and to find out the relationship between fluoride and other ions. Study suggests that concentration of fluoride in shallow basalt aquifer is within maximum permissible limits of Bureau of Indian Standards and deeper granite aquifer contains as high as 4.9 mg/l of fluoride and all samples from granite aquifers are unfit for human consumption. The groundwater from basalt aquifer is mainly Ca-HCO 3- Cl type, and from granite aquifer, it is Ca-Na-Cl type. The correlation plot between F - vs. pH, Na + and HCO 3 - shows a positive correlation and an inverse relationship with Ca 2+ in both aquifers. As recommendations, it is suggested that granite aquifers should not be tapped for drinking purposes; however, in drought situations, water from this aquifer should be blended with treated surface water before supplying for drinking purposes. Efforts may be made to utilize 1.35 MCM of rainwater from available rooftop, which is sufficient to cater for the needs of ~40,800 people annually. Most effective defluoridation techniques like electrolytic de-fluoridation (EDF), ion exchange and reverse osmosis may be adopted along with integrated fluorosis mitigation measures.

Ammonium boranes for the selective complexation of cyanide or fluoride ions in water.

PubMed

Hudnall, Todd W; Gabbaï, François P

2007-10-03

With the recognition of aqueous fluoride and cyanide ions as an objective, we have investigated the anion binding properties of two isomeric ammonium boranes, namely [p-(Mes2B)C6H4(NMe3)]+ ([1]+) and [o-(Mes2B)C6H4(NMe3)]+ ([2]+). These cationic boranes, which could be obtained by reaction of the known 4- and 2-dimesitylboryl-N,N-dimethylaniline with MeOTf, have been investigated both experimentally and computationally. They both react with fluoride and cyanide ions in organic solvents to afford the corresponding fluoroborate/ or cyanoborate/ammonium zwitterions 1F, 1CN, 2F, and 2CN. In aqueous solution, however, these cationic boranes behave as remarkably selective receptors. Indeed, [1]+ only complexes cyanide ions while [2]+ only complexes fluoride ions. In H2O/DMSO 60:40 vol (HEPES 6 mM, pH 7), the cyanide binding constant of [1]+ and the fluoride binding constant of [2]+ are respectively equal to 3.9 (+/-0.1) x 108 and 910 (+/-50) M-1. Structural and computational studies indicate that both steric and electronic effects contribute to the unusual selectivity displayed by these cationic boranes. Owing to favorable Coulombic effects, the para-derivative [1]+ has a very high affinity for cyanide; yet these effects are not sufficiently intense to allow complexation of the more efficiently hydrated and less basic fluoride anion. In the case of the ortho-derivative [2]+, the proximity of the ammonium moiety leads to an increase in the Lewis acidity of the boron center thus making fluoride binding possible. However, steric effects prevent cyanide coordination to the boron center of [2]+. Finally, cation [1]+ and [2]+ bind their dedicated anions reversibly and show a negligible response in the presence of other common anions including Cl-, Br-, I-, NO3-, OAc-, H2PO4-, and HSO4-.

Cow bones char as a green sorbent for fluorides removal from aqueous solutions: batch and fixed-bed studies.

PubMed

Nigri, Elbert M; Cechinel, Maria Alice P; Mayer, Diego A; Mazur, Luciana P; Loureiro, José M; Rocha, Sônia D F; Vilar, Vítor J P

2017-01-01

Cow bone char was investigated as sorbent for the defluoridation of aqueous solutions. The cow bone char was characterized in terms of its morphology, chemical composition, and functional groups present on the bone char surface using different analytical techniques: SEM, EDS, N 2 -BET method, and FTIR. Batch equilibrium studies were performed for the bone chars prepared using different procedures. The highest sorption capacities for fluoride were obtained for the acid washed (q = 6.2 ± 0.5 mg/g) and Al-doped (q = 6.4 ± 0.3 mg/g) bone chars. Langmuir and Freundlich models fitted well the equilibrium sorption data. Fluoride removal rate in batch system is fast in the first 5 h, decreasing after this time until achieving equilibrium due to pore diffusion. The presence of carbonate and bicarbonate ions in the aqueous solution contributes to a decrease of the fluoride sorption capacity of the bone char by 79 and 31 %, respectively. Regeneration of the F-loaded bone char using 0.5 M NaOH solution leads to a sorption capacity for fluoride of 3.1 mg/g in the second loading cycle. Fluoride breakthrough curve obtained in a fixed-bed column presents an asymmetrical S-shaped form, with a slow approach of C/C 0  → 1.0 due to pore diffusion phenomena. Considering the guideline value for drinking water of 1.5 mg F - /L, as recommended by World Health Organization, the service cycle for fluoride removal was of 71.0 h ([F - ] feed  ∼ 9 mg/L; flow rate = 1 mL/min; m sorbent  = 12.6 g). A mass transfer model considering the pore diffusion was able to satisfactorily describe the experimental data obtained in batch and continuous systems.

Toxicology of hydrogen fluoride in relation to major accident hazards.

PubMed

Meldrum, M

1999-10-01

A major industrial accident involving the release of hydrogen fluoride has the potential to cause serious injury and possibly death in the surrounding human population. Given the potential for such serious and large-scale effects, there is a need for scientifically based risk assessments for determining appropriate on-site risk control measures, as well as for informing off-site emergency plans and land-use development decisions. Within Great Britain, the Health and Safety Executive (HSE) has the statutory responsibility for providing land-use planning advice in the vicinity of major accident hazard sites. The advice is based on quantified assessment of the individual risk of exposure to a specified amount of the toxic substance. Among other things this requires a consistent, reliable, and transparent understanding of the major hazard toxicology of the substance concerned. An assessment of the toxicology of hydrogen fluoride in relation to major accident hazards, based on conventional inhalation toxicity studies, was published by HSE in 1993. Recently, studies have been reported in which rats inhaled hydrogen fluoride via a mouthpiece attached to an endotracheal cannula. HSE has explored the use of this "mouth-breathing" rat model as a possible basis for human health risk assessment for hydrogen fluoride in the context of major accident hazards. A number of uncertainties in the use of this animal model have been identified that warrant caution in the use of this model for regulatory purposes. Overall, the results from the "mouth-breathing" rat model did not lead to a change in the HSE assessment of hydrogen fluoride, which remains based on experimental data obtained following "mainstream" toxicological practices. Copyright 1999 Academic Press.

Dentifrice fluoride and abrasivity interplay on artificial caries lesions.

PubMed

Nassar, Hani M; Lippert, Frank; Eckert, George J; Hara, Anderson T

2014-01-01

Incipient caries lesions on smooth surfaces may be subjected to toothbrushing, potentially leading to remineralization and/or abrasive wear. The interplay of dentifrice abrasivity and fluoride on this process is largely unknown and was investigated on three artificially created lesions with different mineral content/distribution. 120 bovine enamel specimens were randomly allocated to 12 groups (n = 10), resulting from the association of (1) lesion type [methylcellulose acid gel (MeC); carboxymethylcellulose solution (CMC); hydroxyethylcellulose gel (HEC)], (2) slurry abrasive level [low (REA 4/ RDA 69); high (REA 7/RDA 208)], and (3) fluoride concentration [0/275 ppm (14.5 mM) F as NaF]. After lesion creation, specimens were brushed in an automated brushing machine with the test slurries (50 strokes 2×/day). Specimens were kept in artificial saliva in between brushings and overnight. Enamel surface loss (SL) was determined by optical profilometry after lesion creation, 1, 3 and 5 days. Two enamel sections (from baseline and post-brushing areas) were obtained and analyzed microradiographically. Data were analyzed by analysis of variance and Tukey's tests (α = 5%). Brushing with high-abrasive slurry caused more SL than brushing with low-abrasive slurry. For MeC and CMC lesions, fluoride had a protective effect on SL from day 3 on. Furthermore, for MeC and CMC, there was a significant mineral gain in the remaining lesions except when brushed with high-abrasive slurries and 0 ppm F. For HEC, a significant mineral gain took place when low-abrasive slurry was used with fluoride. The tested lesions responded differently to the toothbrushing procedures. Both slurry fluoride content and abrasivity directly impacted SL and mineral gain of enamel caries lesions.

Rare-Earth-compound nanowires, nanotubes, and fullerene-like nanoparticles: synthesis, characterization, and properties.

PubMed

Wang, Xun; Li, Yadong

2003-11-21

Various low-dimensional nanostructures, such as nanowires, nanotubes, nanosheets, and fullerene-like nanoparticles have been selectively synthesized from rare-earth compounds (hydroxides, fluorides) based on a facile hydrothermal method. The subsequent dehydration, sulfidation, and fluoridation processes lead to the formation of rare-earth oxide, oxysulfide, and oxyhalide nanostructures, which can be functionalized further by doping with other rare-earth ions or by coating with metal nanoparticles. Owing to the interesting combination of novel nanostructures and functional compounds, these nanostructures can be expected to bring new opportunities in the vast research areas of and application in biology, catalysts, and optoelectronic devices.

Immobilization of Alkali Metal Fluorides via Recrystallization in a Cationic Lamellar Material, [Th(MoO4)(H2O)4Cl]Cl·H2O.

PubMed

Lin, Jian; Bao, Hongliang; Qie, Meiying; Silver, Mark A; Yue, Zenghui; Li, Xiaoyun; Zhu, Lin; Wang, Xiaomei; Zhang, Linjuan; Wang, Jian-Qiang

2018-06-05

Searching for cationic extended materials with a capacity for anion exchange resulted in a unique thorium molybdate chloride (TMC) with the formula of [Th(MoO 4 )(H 2 O) 4 Cl]Cl·H 2 O. The structure of TMC is composed of zigzagging cationic layers [Th(MoO 4 )(H 2 O) 4 Cl] + with Cl - as interlamellar charge-balancing anions. Instead of performing ion exchange, alkali thorium fluorides were formed after soaking TMC in AF (A = Na, K, and Cs) solutions. The mechanism of AF immobilization is elucidated by the combination of SEM-EDS, PXRD, FTIR, and EXAFS spectroscopy. It was observed that four water molecules coordinating with the Th 4+ center in TMC are vulnerable to competition with F - , due to the formation of more favorable Th-F bonds compared to Th-OH 2 . This leads to a single crystal-to-polycrystalline transformation via a pathway of recrystallization to form alkali thorium fluorides.

Effects of air pollutants on lemons and naval oranges

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

Thompson, C.R.

1968-01-01

The effects of photochemical oxidant and fluoride air pollutants on lemon and orange trees were evaluated in a series of greenhouse experiments. Trees exposed to the pollutants show increased lead drop and decreased fruit yield in comparison to controls.

The Effect of Fluoroethylene Carbonate as an Additive on the Solid Electrolyte Interphase on Silicon Lithium-Ion Electrodes

DOE PAGES

Schroder, Kjell; Li, Juchuan; Dudney, Nancy J.; ...

2015-08-03

Fluoroethylene carbonate (FEC) has become a standard electrolyte additive for use with silicon negative electrodes, but how FEC affects solid electrolyte interphase (SEI) formation on the silicon anode’s surface is still not well understood. Herein, SEI formed from LiPF6-based carbonate electrolytes, with and without FEC, were investigated on 50 nm thick amorphous silicon thin film electrodes to understand the role of FEC on silicon electrode surface reactions. In contrast to previous work, anhydrous and anoxic techniques were used to prevent air and moisture contamination of prepared SEI films. This allowed for accurate characterization of the SEI structure and composition bymore » X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry depth profiling. These results show that FEC reduction leads to fluoride ion and LiF formation, consistent with previous computational and experimental results. Surprisingly, we also find that these species decrease lithium-ion solubility and increase the reactivity of the silicon surface. We conclude that the effectiveness of FEC at improving the Coulombic efficiency and capacity retention is due to fluoride ion formation from reduction of the electrolyte, which leads to the chemical attack of any silicon-oxide surface passivation layers and the formation of a kinetically stable SEI comprising predominately lithium fluoride and lithium oxide.« less

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.

Human kidney methoxyflurane and sevoflurane metabolism. Intrarenal fluoride production as a possible mechanism of methoxyflurane nephrotoxicity.

PubMed

Kharasch, E D; Hankins, D C; Thummel, K E

1995-03-01

Methoxyflurane nephrotoxicity is mediated by cytochrome P450-catalyzed metabolism to toxic metabolites. It is historically accepted that one of the metabolites, fluoride, is the nephrotoxin, and that methoxyflurane nephrotoxicity is caused by plasma fluoride concentrations in excess of 50 microM. Sevoflurane also is metabolized to fluoride ion, and plasma concentrations may exceed 50 microM, yet sevoflurane nephrotoxicity has not been observed. It is possible that in situ renal metabolism of methoxyflurane, rather than hepatic metabolism, is a critical event leading to nephrotoxicity. We tested whether there was a metabolic basis for this hypothesis by examining the relative rates of methoxyflurane and sevoflurane defluorination by human kidney microsomes. Microsomes and cytosol were prepared from kidneys of organ donors. Methoxyflurane and sevoflurane metabolism were measured with a fluoride-selective electrode. Human cytochrome P450 isoforms contributing to renal anesthetic metabolism were identified by using isoform-selective inhibitors and by Western blot analysis of renal P450s in conjunction with metabolism by individual P450s expressed from a human hepatic complementary deoxyribonucleic acid library. Sevoflurane and methoxyflurane did undergo defluorination by human kidney microsomes. Fluoride production was dependent on time, reduced nicotinamide adenine dinucleotide phosphate, protein concentration, and anesthetic concentration. In seven human kidneys studied, enzymatic sevoflurane defluorination was minima, whereas methoxyflurane defluorination rates were substantially greater and exhibited large interindividual variability. Kidney cytosol did not catalyze anesthetic defluorination. Chemical inhibitors of the P450 isoforms 2E1, 2A6, and 3A diminished methoxyflurane and sevoflurane defluorination. Complementary deoxyribonucleic acid-expressed P450s 2E1, 2A6, and 3A4 catalyzed methoxyflurane and sevoflurane metabolism, in diminishing order of activity. These three P450s catalyzed the defluorination of methoxyflurane three to ten times faster than they did that of sevoflurane. Expressed P450 2B6 also catalyzed methoxyflurane defluorination, but 2B6 appeared not to contribute to renal microsomal methoxyflurane defluorination because the P450 2B6-selective inhibitor had no effect. Human kidney microsomes metabolize methoxyflurane, and to a much lesser extent sevoflurane, to fluoride ion. P450s 2E1 and/or 2A6 and P450 3A are implicated in the defluorination. If intrarenally generated fluoride or other metabolites are nephrotoxic, then renal metabolism may contribute to methoxyflurane nephrotoxicity. The relative paucity of renal sevoflurane defluorination may explain the absence of clinical sevoflurane nephrotoxicity to date, despite plasma fluoride concentrations that may exceed 50 microM.

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.

Novel fragmentation pathways of anionic adducts of steroids formed by electrospray anion attachment involving regioselective attachment, regiospecific decompositions, charge-induced pathways, and ion-dipole complex intermediates.

PubMed

Rannulu, Nalaka S; Cole, Richard B

2012-09-01

The analysis of several bifunctional neutral steroids, 5-α-pregnane diol (5-α-pregnane-3α-20βdiol), estradiol (3,17α-dihydroxy-1,3,5(10)-estratriene), progesterone (4-pregnene-3,20-dione), lupeol (3β-hydroxy-20(29)-lupene), pregnenolone (5-pregnen-3β-ol-20-one), and pregnenolone acetate (5-pregnen-3β-ol-20-one acetate) was accomplished by negative ion electrospray mass spectrometry (ESI-MS) employing adduct formation with various anions: fluoride, bicarbonate, acetate, and chloride. Fluoride yielded higher abundances of anionic adducts and more substantial abundances of deprotonated molecules compared with other investigated anions. Collision-induced dissociation (CID) of precursor [M + anion](-) adducts of these steroids revealed that fluoride adduct [M + F](-) precursors first lose HF to produce [M - H](-) and then undergo consecutive decompositions to yield higher abundances of structurally-informative product ions than the other tested anions. In addition to charge-remote fragmentations, the majority of CID pathways of estradiol are deduced to occur via charge-induced fragmentation. Most interestingly, certain anions exhibit preferential attachment to a specific site on these bifunctional steroid molecules, which we are calling "regioselective anion attachment." Regioselective anion attachment is evidenced by subsequent regiospecific decomposition. Regioselective attachment of fluoride (and acetate) anions to low (and moderate) acidity functional groups of pregnenolone, respectively, is demonstrated using deuterated compounds. Moreover, the formation of unique intermediate ion-dipole complexes leading to novel fragmentation pathways of fluoride adducts of pregnenolone acetate, and bicarbonate adducts of d(4)-pregnenolone, are also discussed.

Novel Fragmentation Pathways of Anionic Adducts of Steroids Formed by Electrospray Anion Attachment Involving Regioselective Attachment, Regiospecific Decompositions, Charge-Induced Pathways, and Ion-Dipole Complex Intermediates

NASA Astrophysics Data System (ADS)

Rannulu, Nalaka S.; Cole, Richard B.

2012-09-01

The analysis of several bifunctional neutral steroids, 5-α-pregnane diol (5-α-pregnane-3α-20βdiol), estradiol (3,17α-dihydroxy-1,3,5(10)-estratriene), progesterone (4-pregnene-3,20-dione), lupeol (3β-hydroxy-20(29)-lupene), pregnenolone (5-pregnen-3β-ol-20-one), and pregnenolone acetate (5-pregnen-3β-ol-20-one acetate) was accomplished by negative ion electrospray mass spectrometry (ESI-MS) employing adduct formation with various anions: fluoride, bicarbonate, acetate, and chloride. Fluoride yielded higher abundances of anionic adducts and more substantial abundances of deprotonated molecules compared with other investigated anions. Collision-induced dissociation (CID) of precursor [M + anion]- adducts of these steroids revealed that fluoride adduct [M + F]- precursors first lose HF to produce [M - H]- and then undergo consecutive decompositions to yield higher abundances of structurally-informative product ions than the other tested anions. In addition to charge-remote fragmentations, the majority of CID pathways of estradiol are deduced to occur via charge-induced fragmentation. Most interestingly, certain anions exhibit preferential attachment to a specific site on these bifunctional steroid molecules, which we are calling "regioselective anion attachment." Regioselective anion attachment is evidenced by subsequent regiospecific decomposition. Regioselective attachment of fluoride (and acetate) anions to low (and moderate) acidity functional groups of pregnenolone, respectively, is demonstrated using deuterated compounds. Moreover, the formation of unique intermediate ion-dipole complexes leading to novel fragmentation pathways of fluoride adducts of pregnenolone acetate, and bicarbonate adducts of d4-pregnenolone, are also discussed.

The toxic effect of sodium fluoride on Spodoptera frugiperda 9 cells and differential protein analysis following NaF treatment of cells.

PubMed

Zuo, Huan; Chen, Liang; Kong, Ming; Yang, Yanhua; Lü, Peng; Qiu, Lipeng; Wang, Qiang; Ma, Shangshang; Chen, Keping

2018-05-01

Accumulation of excess fluoride has a destructive effect on the environment, endangering human health, affecting organism growth and development, and leading to damage to the biological chain, thereby affecting ecological environment balance. In recent years, numerous studies focused on the molecular mechanisms associated with fluoride toxicity; however, fluoride-toxicity mechanisms in insect cells remain unclear. This study explored the toxic impact of sodium fluoride (NaF) on Spodoptera frugiperda 9 (Sf9) insect cells. High concentrations of NaF (10 -4  M, 10 -3  M and 10 -2  M) resulted in cell enlargement, cell membrane blurring and breakage, and release of cellular contents. Dose-response curves indicated that NaF-specific inhibition rates on Sf9-cell activity increased along with increases in NaF concentration, with a half-inhibitory concentration (IC 50 ) for NaF of 5.919 × 10 -3  M at 72 h. Compared with controls, the percentages of early and late apoptotic and necrotic cells clearly increased based on observed increases in NaF concentrations. Two-dimensional gel electrophoresis combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to detect differentially expressed proteins in Sf9 cells treated with IC 50 NaF, identifying 17 proteins, seven of which were upregulated and 10 downregulated. These results demonstrated that Sf9 cells showed signs of NaF-mediated toxicity through alterations in cell morphology, apoptosis rates, and protein expression. Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

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.

Hydrogeochemical processes controlling changes in fluoride ion concentration within alluvial and hard rock aquifers in a part of a semi-arid region of Northern India

NASA Astrophysics Data System (ADS)

Singh, Priyadarshini; Ashthana, Harshita; Rena, Vikas; Kumar, Pardeep; Mukherjee, Saumitra

2017-04-01

Geochemical signatures from alluvial and hard rock aquifers in a part of Northern India elucidate the chemical processes controlling fluctuations in fluoride ion concentration linked to changes in major ion groundwater chemistry. Majority of samples from the hard rock and the alluvial aquifers for pre-monsoon show both carbonate and silicate weathering, ion exchange, evaporation and rock water interaction as the processes controlling major ion chemistry whereas for post monsoon samples, contribution of silicate weathering and ion exchange process were observed. Evaporative processes causing the increase in Na+ ion concentration in premonsoon enhance the reverse ion exchange processes causing increase in Ca2+ ions which impedes fluorite mineral dissolution in the premonsoon groundwater samples within the study area. Alternately, it is observed that the removal of Ca2+ ion from solution plays a key role in increase in fluorite mineral dissolution despite its saturation in groundwater in the postmonsoon samples. Also, ion exchange process on clay surfaces is more pronounced in the postmonsoon samples leading to the uptake of Ca2+ ion upon release of Na+ and K+ ion in solution. Ca2+ ion concentration is inversely correlated with F- ion concentration in both the aquifers in the postmonsoon season validating the role of calcite precipitation as a major reason for the fluoride ion increase. Moreover, increase in silicate weathering in the postmonsoon samples leads to increase in clay particles acting as suitable sites for ion exchange enhancing Ca2+ removal from groundwater. Cationic dominance of Na+ ion in the post monsoon samples also validates the occurrence of this process. Collectively, these processes set the ideal conditions for increase in the fluoride ion concentration particularly in the alluvium aquifer waters in the postmonsoon season Keywords: geochemistry, ion-exchange, rock-water interaction, mineral dissolution, weathering.

Methyl fluoride-13C in nematic liquid crystals: Anisotropy of the indirect 13C-19F spin-spin coupling and of the 1H, 13C, and 19F chemical shieldings

NASA Astrophysics Data System (ADS)

Jokisaari, J.; Hiltunen, Y.; Lounila, J.

1986-09-01

The anisotropy of the indirect 13C-19F spin-spin coupling tensor of methyl fluoride-13C in the liquid crystals ZLI 1167, EBBA, their mixtures, phase IV, and phase 1221 was studied by applying 1H and 19F NMR spectroscopy. The relative anisotropy ΔJCF/JCF gets values between -4.3 (in ZLI 1167) and +30.7 (in EBBA) when determined in the conventional way from the experimental dipolar coupling constants taking into account only harmonic vibrational corrections. The inclusion of the deformational corrections in both the direct and indirect C-F coupling tensors leads to a constant, solvent independent relative anisotropy of -2.5±0.2. This result is also obtained when a mixture of the liquid crystals ZLI 1167 and EBBA is used which mixture gives an undistorted geometry for methyl fluoride. The chemical shielding anisotropies ΔσH, ΔσC, and ΔσF for methyl fluoride were determined by applying the method of mixing two thermotropic nematogens (ZLI 1167 and EBBA) with opposite anisotropies of diamagnetic susceptibility. The results ΔσH =+5.2±0.2 ppm, ΔσC =+87±4 ppm, and ΔσF =-90±4 ppm are in fair agreement with theoretical calculations.

Infrared/submillimeter optical properties data base

NASA Technical Reports Server (NTRS)

Alley, Phillip W.

1989-01-01

The general goal was to build a data base containing optical properties, such as reflectance, transmittance, refractive index, in the far infrared to submillimeter wavelength region. This data base would be limited to selected crystalline materials and temperature between 300 and 2 K. The selected materials were: lithium, lead, and strontium; the bromides of potassium and thallium; the carbides of silicone and tungsten; and the materials of KRS5, KRS6, diamond, and sapphire. Last summer, barium fluoride was selected as prototype material for building the data base. This summer the literature search, preparation of the data for barium fluoride was completed. In addition the literature search for data related to the compounds mentioned was completed. The current status is that barium fluoride is in a form suitable for a NASA internal publication. The papers containing the data on the other materials were xeroxed and they are ready to be reduced. On the reverse side, the top figure is a sample combination of data for the index of refraction at 300 K. The lower figure shows the transmittance vs wavelength at 300 and 80 K. These figures are a sample of many which were developed. Since barium fluoride was studied more than most of the materials listed above, it is clear that additional measurements should be made to fill in the gaps present on both temperature and wavelength data.

Role of inhibition of osteogenesis function by Sema4D/Plexin-B1 signaling pathway in skeletal fluorosis in vitro.

PubMed

Liu, Xiao-li; Song, Jing; Liu, Ke-jian; Wang, Wen-peng; Xu, Chang; Zhang, Yu-zeng; Liu, Yun

2015-10-01

Skeletal fluorosis is a chronically metabolic bone disease with extensive hyperostosis osteosclerosis caused by long time exposure to fluoride. Skeletal fluorosis brings about a series of abnormal changes of the extremity, such as joint pain, joint stiffness, bone deformity, etc. Differentiation and maturation of osteoblasts were regulated by osteoclasts via Sema4D/Plexin-B1 signaling pathway. Furthermore, the differentiation and maturation of osteoclasts are conducted by osteoblasts via RANKL/RANK/OPG pathway. Both of these processes form a feedback circuit which is a key link in skeletal fluorosis. In this study, an osteoblast-osteoclast co-culture model in vitro was developed to illustrate the mechanism of skeletal fluorosis. With the increase of fluoride concentration, the expression level of Sema4D was decreased and TGF-β1 was increased continuously. OPG/RANKL mRNA level, however, increased gradually. On the basis of that, the inhibition of Sema4D/Plexin-B1/RhoA/ROCK signaling pathway caused by fluoride promoted the level of TGF-β1 and activated the proliferation of osteoblasts. In addition, osteroprotegerin (OPG) secreted by osteoblasts was up-regulated by fluoride. The competitive combination of OPG and RANKL was strengthened and the combination of RANKL and RANK was hindered. And then the differentiation and maturation of osteoclasts were inhibited, and bone absorption was weakened, leading to skeletal fluorosis.

NMR parameters in column 13 metal fluoride compounds (AlF₃, GaF₃, InF₃ and TlF) from first principle calculations.

PubMed

Sadoc, Aymeric; Biswal, Mamata; Body, Monique; Legein, Christophe; Boucher, Florent; Massiot, Dominique; Fayon, Franck

2014-01-01

The relationship between the experimental (19)F isotropic chemical shift and the (19)F isotropic shielding calculated using the gauge including projector augmented-wave (GIPAW) method with PBE functional is investigated in the case of GaF3, InF3, TlF and several AlF3 polymorphs. It is shown that the linear correlation between experimental and DFT-PBE calculated values previously established on alkali, alkaline earth and rare earth of column 3 basic fluorides (Sadoc et al., Phys. Chem. Chem. Phys. 13 (2011) 18539-18550) remains valid in the case of column 13 metal fluorides, indicating that it allows predicting (19)F solid state NMR spectra of a broad range of crystalline fluorides with a relatively good accuracy. For the isostructural α-AlF3, GaF3 and InF3 phases, PBE-DFT geometry optimization leads to noticeably overbended M-F-M bond angles and underestimated (27)Al, (71)Ga and (115)In calculated quadrupolar coupling constants. For the studied compounds, whose structures are built of corner shared MF6 octahedra, it is shown that the electric field gradient (EFG) tensor at the cationic sites is not related to distortions of the octahedral units, in contrast to what previously observed for isolated AlF6 octahedra in fluoroaluminates. Copyright © 2014 Elsevier Inc. All rights reserved.

Caries Epidemiology and Community Dentistry: Chances for Future Improvements in Caries Risk Groups. Outcomes of the ORCA Saturday Afternoon Symposium, Greifswald, 2014. Part 1.

PubMed

Splieth, Christian H; Christiansen, Jette; Foster Page, Lyndie A

2016-01-01

This paper reviews the first part of the outcomes of the ORCA Saturday Afternoon Symposium 2014 dealing with 'caries epidemiology and community dentistry: chances for future improvements in caries risk groups'. After the caries decline in many countries, there are remaining pockets of higher caries levels, mostly in the primary dentition and/or linked to a low socio-economic status (SES). The review into the evidence of caries-preventive measures clearly points to the use of fluorides, especially toothbrushing with fluoridated toothpaste and collective measures such as water fluoridation. In contrast to several unsuccessful high-risk approaches, community and public health programmes seem to be able to ensure a population-wide access and compliance in risk groups. Their simple and evidence-based measures mostly combine regular plaque removal and fluoride applications via toothbrushing, at least for children and adolescents. For the future, the common risk factor approach which addresses associations between oral health, social deprivation, diet, hygiene, smoking, alcohol use and stress should lead to combined efforts with other community health and education specialists. Further engagement with public policy, community leaders and administration is needed in order to strengthen healthy choices and behaviour, e.g. in 'healthy' schools and kindergartens. It seems advisable that these population programmes also aim at improving upstream factors. © 2016 S. Karger AG, Basel.

Models and role models.

PubMed

ten Cate, Jacob M

2015-01-01

Developing experimental models to understand dental caries has been the theme in our research group. Our first, the pH-cycling model, was developed to investigate the chemical reactions in enamel or dentine, which lead to dental caries. It aimed to leverage our understanding of the fluoride mode of action and was also utilized for the formulation of oral care products. In addition, we made use of intra-oral (in situ) models to study other features of the oral environment that drive the de/remineralization balance in individual patients. This model addressed basic questions, such as how enamel and dentine are affected by challenges in the oral cavity, as well as practical issues related to fluoride toothpaste efficacy. The observation that perhaps fluoride is not sufficiently potent to reduce dental caries in the present-day society triggered us to expand our knowledge in the bacterial aetiology of dental caries. For this we developed the Amsterdam Active Attachment biofilm model. Different from studies on planktonic ('single') bacteria, this biofilm model captures bacteria in a habitat similar to dental plaque. With data from the combination of these models, it should be possible to study separate processes which together may lead to dental caries. Also products and novel agents could be evaluated that interfere with either of the processes. Having these separate models in place, a suggestion is made to design computer models to encompass the available information. Models but also role models are of the utmost importance in bringing and guiding research and researchers. 2015 S. Karger AG, Basel

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.

The decreased expression of mitofusin-1 and increased fission-1 together with alterations in mitochondrial morphology in the kidney of rats with chronic fluorosis may involve elevated oxidative stress.

PubMed

Qin, Shuang-Li; Deng, Jie; Lou, Di-Dong; Yu, Wen-Feng; Pei, Jinjing; Guan, Zhi-Zhong

2015-01-01

This study was designed to characterize changes in the expression of mitofusin-1 (Mfn1) and fission-1 (Fis1), as well as in mitochondrial morphology in the kidney of rats subjected to chronic fluorosis and to elucidate whether any mitochondrial injury observed is associated with increased oxidative stress. Sixty Sprague-Dawley (SD) rats were divided randomly into 3 groups of 20 each, i.e., the untreated control group (natural drinking water containing <0.5mg fluoride/L), the low-fluoride group (drinking water supplemented with 10mg fluoride/L, prepared with NaF) and the high-fluoride group (50mg fluoride/L), and treated for 6 months. Thereafter, renal expression of Mfn1 and Fis1 at both the protein and mRNA levels was determined by immunohistochemistry and real-time PCR, respectively. In addition, the malondiadehyde (MDA) was quantitated by the thiobarbituric acid procedure and the total antioxidative capability (T-AOC) by a colorimetric method. The morphology of renal mitochondria was observed under the transmission electron microscope. In the renal tissues of rats with chronic fluorosis, expression of both Mfn1 protein and mRNA was clearly reduced, whereas that of Fis1 was elevated. The level of MDA was increased and the T-AOC lowered. Swollen or fragmented mitochondria in renal cells were observed under the electronic microscope. These findings indicate that chronic fluorosis can lead to the abnormal mitochondrial dynamics and changed morphology in the rat kidney, which in mechanism might be induced by a high level of oxidative stress in the disease. Copyright © 2014 Elsevier GmbH. All rights reserved.

Fluoride glass fibers: applications and prospects

NASA Astrophysics Data System (ADS)

Poulain, Marcel

1998-09-01

Fluoride glass fibers have been intensively developed for the last 20 years. A major effort was devoted to the fabrication of low loss fibers for repeaterless long haul telecommunications. This step which ended in the late eighties provided the basic technology for the manufacturing of multimode and single mode fibers with minimum losses below 10 dB/km. Such fibers area now used for various passive applications requiring the handling of IR signal. In this respect, fluoride fibers are complementary to silica fibers when wavelength exceeds 2 micrometers . Some practical set ups are operating for IR imaging, remote spectroscopy and thermometry. Special fibers such as polarization maintaining fibers have been developed for interferometric astronomy, which could also apply to sensors. UV transmission has still to be developed. Laser power delivery is another field of application for these fibers. YAG:Er laser at 2.9 micrometers attracts a growing interest for medical applications, ophthalmology and dentistry, while prospects for CO laser are positive. Active fibers are based on rare earth doped single mode fibers. They lead to the definition of numerous new laser lines and emphasized the potential of up conversion for the generation of visible light using IR pumping laser diodes. High power output has been achieved in the blue and the red light, which open prospects for compact and all solid state fiber lasers for a wide range of applications, from displays to medical uses. Optical amplification makes another field of R and D centered on telecommunication needs. Pr3+ doped fluoride fibers have been used for the 1.3 micrometers band, and Er based fluoride fiber amplifiers exhibit wider and flatter gain than those made from silica. Optical amplification may be implemented at other wavelengths for more general purposes.

The impact of aluminum, fluoride, and aluminum-fluoride complexes in drinking water on chronic kidney disease.

PubMed

Wasana, Hewa M S; Perera, Gamage D R K; De Gunawardena, Panduka S; Bandara, Jayasundera

2015-07-01

It is suspected that drinking water containing fluoride and aluminum results in negative health effects especially on brain, liver, and kidney. In this investigation, the effect of F, Al, and AlFx complex on chronic kidney disease (CKD) was investigated. Mice were treated either with WHO recommended or slightly higher F and Al levels in drinking water. Treatment solutions contained 0.05-10.0 mg/L of F, 0.08-10.0 mg/L of Al, or 0.07-15 mg/L of AlFx, and the treatment period was 42 weeks. Blood urea level and creatinine levels were investigated as a measure of malfunction of kidneys. Histopathological evaluations of kidney tissues were carried out to assess the extent of damage that F, Al, and AlFx complex could cause. It was demonstrated that the treated drinking water containing F and Al with par with WHO or moderately above the WHO levels or AlFx in low level (0.07-15 mg/L) does not lead to CKD in mice.

[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.

Physiological Effects of Trace Elements and Chemicals in Water

ERIC Educational Resources Information Center

Varma, M. M.; And Others

1976-01-01

The physiological effects on humans and animals of trace amounts of organic and unorganic pollutants in natural and waste waters are examined. The sensitivity of particular organs and species is emphasized. Substances reviewed include mercury, arsenic, cadmium, lead, chromium, fluorides, nitrates and organics, including polychlounated biphenyls.…

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.

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

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

NA

2004-05-18

Titanium Grade 7 (UNS R52400) is a titanium-based alloy with 0.12-0.25% Pd. The addition of the small amount of palladium is to ennoble the corrosion potential of Ti, thus improving the corrosion resistance of titanium in reducing environments. In most aqueous environments, Ti and Ti alloys demonstrate excellent corrosion resistance due to the protective oxide film that forms spontaneously and remains stable on the surface. However, Ti and Ti alloys are susceptible to corrosion in fluoride-containing environments due to the formation of complexes such as TiF{sub 6}{sup 2-} and TiF{sub 6}{sup 3-}, which are stable and soluble in electrolyte solutions.more » Without the presence of fluoride, only slight effects from [Cl{sup -}], pH and temperature have been reported [1]. It has been reported that the kinetics of passive corrosion of titanium in neutral solutions and controlled by the migration of the defects in the oxide across the surface film [2]. Thus, the increase in thickness and improvement in film properties, by thermal oxidation, would lead to a significant decrease in the susceptibility to film breakdown and in the passive corrosion rate. This report summarizes recent experiment results in studies of the environmental influence on the corrosion behavior of Titanium Grade 7 (Ti-7) in NaCl brines containing fluoride. The environmental factors to be studied include temperature, pH, chloride and fluoride concentration. This report also includes the effects of oxide film, formed during an anneal treatment, on the corrosion behavior of Ti-7. Polarization measurement techniques including potentiodynamic and potentiostatic scans were use3d to characterize corrosion kinetics and susceptibility. Due to the unique alloying in Titanium Grade 7, the long-term corrosion behavior is heavily influenced by the surface enrichment of Pd. Use of electrochemical impedance spectroscopy in conjunction with a potentiostatic scan will reveal the transformation in the corrosion behavior as a function of Pd enrichment on the metal surface. Surface characterization was done using various analytical techniques including X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and scanning electron microscopy (SEM). The effect of fluoride ion on the corrosion behavior of Ti-7 is strongly dependent on the solution pH. In neutral (pH 8) and alkaline (pH 11) solutions, fluoride did not affect the corrosion rate significantly even though it altered the anodic polarization curve drastically. With pH decreased to 4, the corrosion rate of Ti-7 was increased significantly by the presence of fluoride.« less

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

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)

Sierra Army Depot, Phase 1, Remedial Investigation/Feasibility Study, Lassen County, California. Final Remedial Investigation

DTIC Science & Technology

1991-10-01

8.3.1.2 Cadmium ............................ 8-8 8.3.1.3 Lead .... ............................ 8-8 8.3.1.4 Zinc .... ............................ 8-8...Beryllium, Cadmium , Chromium, Cobalt, Copper, Fluoride Salts, Lead, Mercury, Molydenum, Nickel, Selenium, Silver, Thallium, Vanadium, Zinc . I ~ 2 ,4... cadmium (4.070 ;&g/L), copper (20.100 ug/L), and zinc (28.700 ug/L). Round 2 background 3 groundwater results include arsenic (7.700 g/L), barium

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.

The leaded apron revisited: does it reduce gonadal radiation dose in dental radiology?

PubMed

Wood, R E; Harris, A M; van der Merwe, E J; Nortjé, C J

1991-05-01

A tissue-equivalent anthropomorphic human phantom was used with a lithium fluoride thermoluminescent dosimetry system to evaluate the radiation absorbed dose to the ovarian and testicular region during dental radiologic procedures. Measurements were made with and without personal lead shielding devices consisting of thyroid collar and apron of 0.25 mm lead thickness equivalence. The radiation absorbed dose with or without lead shielding did not differ significantly from control dosimeters in vertex occlusal and periapical views (p greater than 0.05). Personal lead shielding devices did reduce gonadal dose in the case of accidental exposure (p less than 0.05). A leaded apron of 0.25 mm lead thickness equivalent was permeable to radiation in direct exposure testing.

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

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.

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 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.

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.

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.

40 CFR 426.112 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2014 CFR

2014-07-01

... technology currently available (BPT). (The fluoride and lead limitations are applicable to the abrasive polishing and acid polishing waste water streams while the TSS, oil, and pH limitations are applicable to the entire process waste water stream): Effluent characteristic Effluent limitations Maximum for any 1...

40 CFR 426.135 - Standards of performance for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... greater than 50 gallons per day of process waste water, and employs hydrofluoric acid finishing techniques... any 1 day Average of daily values for 30 consecutive days shall not exceed— Lead 0.2 0.1 Fluoride 26.0... waste water, and employs hydrofluoric acid finishing techniques shall meet the following limitations...

40 CFR 426.112 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2012 CFR

2012-07-01

... technology currently available (BPT). (The fluoride and lead limitations are applicable to the abrasive polishing and acid polishing waste water streams while the TSS, oil, and pH limitations are applicable to the entire process waste water stream): Effluent characteristic Effluent limitations Maximum for any 1...

40 CFR 426.135 - Standards of performance for new sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... greater than 50 gallons per day of process waste water, and employs hydrofluoric acid finishing techniques... any 1 day Average of daily values for 30 consecutive days shall not exceed— Lead 0.2 0.1 Fluoride 26.0... waste water, and employs hydrofluoric acid finishing techniques shall meet the following limitations...

40 CFR 426.112 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2013 CFR

2013-07-01

... technology currently available (BPT). (The fluoride and lead limitations are applicable to the abrasive polishing and acid polishing waste water streams while the TSS, oil, and pH limitations are applicable to the entire process waste water stream): Effluent characteristic Effluent limitations Maximum for any 1...

40 CFR 426.135 - Standards of performance for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... greater than 50 gallons per day of process waste water, and employs hydrofluoric acid finishing techniques... any 1 day Average of daily values for 30 consecutive days shall not exceed— Lead 0.2 0.1 Fluoride 26.0... waste water, and employs hydrofluoric acid finishing techniques shall meet the following limitations...

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.

Removal of ammonium and heavy metals by cost-effective zeolite synthesized from waste quartz sand and calcium fluoride sludge.

PubMed

Zhang, Qian; Lin, Bing; Hong, Junming; Chang, Chang-Tang

2017-02-01

This study focuses on the effectiveness of zeolite (10% CF-Z [0.5]) hydrothermally synthesized from waste quartz sand and calcium fluoride (CF) for ammonium ion and heavy metal removal. Zeolite was characterized through powder X-ray diffraction, Fourier-transform infrared spectroscopy, micromeritics N 2 adsorption/desorption analysis, and field emission scanning electron microscopy. The effects of CF addition, Si/Al ratio, initial ammonium concentration, solution pH, and temperature on the adsorption of ammonium on 10% CF-Z (0.5) were further examined. Results showed that 10% CF-Z (0.5) was a single-phase zeolite A with cubic-shaped crystals and 10% CF-Z (0.5) efficiently adsorbs ammonium and heavy metals. For instance, 91% ammonium (10 mg L -1 ) and 93% lead (10 mg L -1 ) are removed. The adsorption isotherm, kinetics, and thermodynamics of ammonium adsorption on 10% CF-Z (0.5) were also theoretically analyzed. The adsorption isotherm of ammonium and lead on 10% CF-Z (0.5) in single systems indicated that Freundlich model provides the best fit for the equilibrium data, whereas pseudo-second-order model best describes the adsorption kinetics. The adsorption degree of ions on 10% CF-Z (0.5) in mixed systems exhibits the following pattern: lead > ammonium > cadmium > chromium.

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

Can we achieve a radionuclide radiation dose equal to or less than that of 99mTc-hydroxymethane diphosphonate bone scintigraphy with a low-dose 18F-sodium fluoride time-of-flight PET of diagnostic quality?

PubMed

Ohnona, Jessica; Michaud, Laure; Balogova, Sona; Paycha, Frédéric; Nataf, Valérie; Chauchat, Paul; Talbot, Jean-Noël; Kerrou, Khaldoun

2013-05-01

18F-Sodium fluoride is a bone tracer with a high signal-to-noise ratio, but its dosimetry is higher than that of 99mTc-labeled phosphonates at the recommended activities. The study's purpose was to determine whether the reduction by half of F-sodium fluoride-injected activity, mimicked by a short-timed reconstruction image, simulating a total dose less than or equal to that of 99mTc-hydroxymethane diphosphonate scintigraphy, had an impact on the accuracy of PET semiquantitative measurements and image quality. Whole-body time-of-flight 18F-sodium fluoride PET/computed tomography (CT) images were acquired prospectively from 40 adult patients for detection of bone metastases. 18F-Sodium fluoride was administered according to the European Association of Nuclear Medicine (EANM) and Society of Nuclear Medicine (SNM) practice guidelines. From the acquired 1 min/bed position list-mode data, 30-s reconstructions were extracted. Measurements of maximum standard uptake value were recorded with a region of interest applied to the same location on the 1-min and 30-s images, which were displayed side by side, and were analyzed using Bland-Altman plots. A masked reading was performed by two senior nuclear medicine physicians who counted the foci of visually increased uptake. Bland-Altman plots showed an excellent agreement between the maximum standard uptake value measurements of the 60- and 30-s images. The paired Wilcoxon test results between the corresponding 60- and 30-s images read by masked readers A and B were not significant (P=0.15 and 0.19, respectively). Reducing acquisition duration by half or injecting half of the activity recommended by the EANM and SNM practice guidelines can lead to 18F-sodium fluoride time-of-flight PET images of diagnostic quality, achieving a radiation dose less than or equal to that of 99mTc-labeled phosphonates.

Characterization of the Kinetics of NF3-Fluorination of NpO2

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

Casella, Andrew M.; Scheele, Randall D.; McNamara, Bruce K.

2015-12-23

The exploitation of selected actinide and fission product fluoride volatilities has long been considered as a potentially attractive compact method for recycling used nuclear fuels to avoid generating the large volumes of radioactive waste arising from aqueous reprocessing [1-7]. The most developed process uses the aggressive and hazardous fluorinating agents hydrogen fluoride (HF) and/or molecular fluorine (F2) at high temperatures to volatilize the greatest fraction of the used nuclear fuel into a single gas stream. The volatilized fluorides are subsequently separated using a series of fractionation and condensation columns to recover the valuable fuel constituents and fission products. In pursuitmore » of a safer and less complicated approach, we investigated an alternative fluoride volatility-based process using the less hazardous fluorinating agent nitrogen trifluoride (NF3) and leveraging its less aggressive nature to selectively evolve fission product and actinide fluorides from the solid phase based on their reaction temperatures into a single recycle stream [8-15]. In this approach, successive isothermal treatments using NF3 will first evolve the more thermally susceptible used nuclear fuel constituents leaving the other constituents in the residual solids until subsequent isothermal temperature treatments cause these others to volatilize. During investigation of this process, individual neat used fuel components were treated with isothermal NF3 in an attempt to characterize the kinetics of each fluorination reaction to provide input into the design of a new volatile fluoride separations approach. In these directed investigations, complex behavior was observed between NF3 and certain solid reactants such as the actinide oxides of uranium, plutonium, and neptunium. Given the similar thermal reaction susceptibilities of neptunium oxide (NpO2) and uranium dioxide (UO2) and the importance of Np and U, we initially focused our efforts on determining the reaction kinetic parameters for NpO2. Characterizing the NF3 fluorination of NpO2 using established models for gas-solid reactions [16] proved unsuccessful so we developed a series of successive fundamental reaction mechanisms to characterize the observed successive fluorination reactions leading to production of the volatile neptunium hexafluoride (NpF6).« less

[Mechanisms of nitroxide-ergic dysregulation in tissues of parodontium in rats under combined excessive sodium nitrate and fluoride intake].

PubMed

Богданов, Алексей В; Гришко, Юлия М; Костенко, Виталий А

2016-01-01

intake of inorganic nitrates is typically accompanied by production of excessive amount of nitric oxide (NO), which level is maintained by the mechanism of autoregulation known as the NO cycle. Hypothetically, this process may be disrupted with fluorides that are able to suppress arginase pathway of L-arginine metabolism, which competes with NO-synthase pathway. to study mechanisms of disregulation of oxidative (NO-synthase) and non-oxidative (arginase) metabolic pathways of L-arginine in the tissues of periodontium under combined excessive sodium nitrate and fluoride intake. these investigations were carried out on 90 white Wistar rats. Homogenates of parodontium soft tissues were used to assess spectrophotometrically the total activities of NO-synthase (NOS), arginase, ornithine decarboxylase as well as the peroxynitrite concentration. typical for the isolated sodium nitrate administration inhibition of total NOS activity varies under combined administration of nitrate and sodium fluoride and is usually manifested by its hyperactivation that is accompanied by an increase in peroxynitrite concentration. At this time arginase and ornithine decarboxylase activity is observed to be substantially reduced. The administration of aminoguanidine, an iNOS inhibitor, (20 mg/kg, twice a week during the experiment) increases arginase and ornithine decarboxylase activities, and the administration of L-arginine (500 mg/kg, twice a week) results in the increase of arginase activity. The administration of L-selenomethionine, a peroxynitrite scavenger (3 mg/kg, twice a week), and JSH-23 (4-methyl-N-(3-phenylpropyl) benzene-1,2-diamine, an inhibitor of NF-κB activation (1 mg/kg, twice a week) for modeling binary nitrate and fluoride intoxication reduces the total concentration of NOS activity and peroxynitrite concentration, and increases ornithine decarboxylase activity. the combined effect of nitrate and sodium fluoride for 30 days leads to disregulatory increased activity of NO-synthase enzymes and reduction of arginase pathway of L-arginine in the soft tissues of parodontium that is promoted by hyperactivation of iNOS and NF-κB, and increased peroxynitrite production.

[Mechanisms of nitroxide-ergic dysregulation in tissues of parodontium in rats under combined excessive sodium nitrate and fluoride intake].

PubMed

Богданов, Алексей В; Гришко, Юлия М; Костенко, Виталий А

intake of inorganic nitrates is typically accompanied by production of excessive amount of nitric oxide (NO), which level is maintained by the mechanism of autoregulation known as the NO cycle. Hypothetically, this process may be disrupted with fluorides that are able to suppress arginase pathway of L-arginine metabolism, which competes with NO-synthase pathway. to study mechanisms of disregulation of oxidative (NO-synthase) and non-oxidative (arginase) metabolic pathways of L-arginine in the tissues of periodontium under combined excessive sodium nitrate and fluoride intake. these investigations were carried out on 90 white Wistar rats. Homogenates of parodontium soft tissues were used to assess spectrophotometrically the total activities of NO-synthase (NOS), arginase, ornithine decarboxylase as well as the peroxynitrite concentration. typical for the isolated sodium nitrate administration inhibition of total NOS activity varies under combined administration of nitrate and sodium fluoride and is usually manifested by its hyperactivation that is accompanied by an increase in peroxynitrite concentration. At this time arginase and ornithine decarboxylase activity is observed to be substantially reduced. The administration of aminoguanidine, an iNOS inhibitor, (20 mg/kg, twice a week during the experiment) increases arginase and ornithine decarboxylase activities, and the administration of L-arginine (500 mg/kg, twice a week) results in the increase of arginase activity. The administration of L-selenomethionine, a peroxynitrite scavenger (3 mg/kg, twice a week), and JSH-23 (4-methyl-N-(3-phenylpropyl) benzene-1,2-diamine, an inhibitor of NF-κB activation (1 mg/kg, twice a week) for modeling binary nitrate and fluoride intoxication reduces the total concentration of NOS activity and peroxynitrite concentration, and increases ornithine decarboxylase activity. the combined effect of nitrate and sodium fluoride for 30 days leads to disregulatory increased activity of NO-synthase enzymes and reduction of arginase pathway of L-arginine in the soft tissues of parodontium that is promoted by hyperactivation of iNOS and NF-κB, and increased peroxynitrite production.

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.

WHO water quality standards Vs Synergic effect(s) of fluoride, heavy metals and hardness in drinking water on kidney tissues.

PubMed

Wasana, Hewa M S; Perera, Gamage D R K; Gunawardena, Panduka De S; Fernando, Palika S; Bandara, Jayasundera

2017-02-14

Despite WHO standards, waterborne diseases among the human being are rising alarmingly. It is known that the prolong exposure to contaminated water has major impact on public health. The effect of chemical contaminations in drinking water on human being is found to be chronic rather than acute and hence can be defined "consumption of contaminated drinking water could be a silent killer". As the WHO recommended water quality standards are only for individual element and synergic effects of trace metals and anions have not been considered, investigation of synergic effects of trace metals and anions and their effect on human being is of prime important research. By an animal trial, we investigated the synergic effect(s) of heavy metals, aluminium, arsenic, fluoride and hardness in drinking water on kidney tissues of mice. Our investigation strongly suggests existing of a synergic effect especially among Cd, F and hardness of water which could lead to severe kidney damage in mice, even at WHO maximum recommended levels. Hence, the synergic effect(s) of trace metals, fluoride and hardness present in drinking water should be investigated meticulously when stipulating the water quality at WHO maximum recommended levels.

WHO water quality standards Vs Synergic effect(s) of fluoride, heavy metals and hardness in drinking water on kidney tissues

NASA Astrophysics Data System (ADS)

Wasana, Hewa M. S.; Perera, Gamage D. R. K.; Gunawardena, Panduka De S.; Fernando, Palika S.; Bandara, Jayasundera

2017-02-01

Despite WHO standards, waterborne diseases among the human being are rising alarmingly. It is known that the prolong exposure to contaminated water has major impact on public health. The effect of chemical contaminations in drinking water on human being is found to be chronic rather than acute and hence can be defined “consumption of contaminated drinking water could be a silent killer”. As the WHO recommended water quality standards are only for individual element and synergic effects of trace metals and anions have not been considered, investigation of synergic effects of trace metals and anions and their effect on human being is of prime important research. By an animal trial, we investigated the synergic effect(s) of heavy metals, aluminium, arsenic, fluoride and hardness in drinking water on kidney tissues of mice. Our investigation strongly suggests existing of a synergic effect especially among Cd, F and hardness of water which could lead to severe kidney damage in mice, even at WHO maximum recommended levels. Hence, the synergic effect(s) of trace metals, fluoride and hardness present in drinking water should be investigated meticulously when stipulating the water quality at WHO maximum recommended levels.

[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

PRODUCTION OF PLUTONIUM FLUORIDE FROM BISMUTH PHOSPHATE PRECIPITATE CONTAINING PLUTONIUM VALUES

DOEpatents

Brown, H.S.; Bohlmann, E.G.

1961-05-01

A process is given for separating plutonium from fission products present on a bismuth phosphate carrier. The dried carrier is first treated with hydrogen fluoride at between 500 and 600 deg C whereby some fission product fluorides volatilize away from plutonium tetrafluoride, and nonvolatile fission product fluorides are formed then with anhydrous fluorine at between 400 and 500 deg C. Bismuth and plutonium distill in the form of volatile fluorides away from the nonvolatile fission product fluorides. The bismuth and plutonium fluorides are condensed at below 290 deg C.

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.

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.

40 CFR 421.94 - Standards of performance for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Plants Subcategory § 421.94 Standards of performance for new sources. Any new source subject to this subpart shall achieve the following new source performance standards: Subpart I—Metallurgical Acid Plant....269 1.558 Lead 0.715 0.332 Zinc 2.605 1.073 Fluoride 1 89.390 50.820 Molybdenum 1 [Reserved] [Reserved...

40 CFR 421.94 - Standards of performance for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Plants Subcategory § 421.94 Standards of performance for new sources. Any new source subject to this subpart shall achieve the following new source performance standards: Subpart I—Metallurgical Acid Plant....269 1.558 Lead 0.715 0.332 Zinc 2.605 1.073 Fluoride 1 89.390 50.820 Molybdenum 1 [Reserved] [Reserved...

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...

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.

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.

Mechanisms Underlying Endothelin-1 Level Elevations Caused by Excessive Fluoride Exposure.

PubMed

Sun, Liyan; Gao, Yanhui; Zhang, Wei; Liu, Xiaona; Li, Bingyun; Cui, Xiaohui; Sun, Dianjun

2016-01-01

To explore the mechanisms underlying endothelin-1 (ET-1) elevations induced by excessive fluoride exposure. We measured serum and bone fluoride ion content and plasma ET-1 levels and compared these parameters among different groups in an animal model. We also observed morphological changes in the aorta and endothelium of rabbits. In cell experiments, human umbilical vein endothelial cells (HUVECs) were treated with varying concentrations of NaF for 24h, with or without 10 µM U0126 pretreatment for 1 h. ET-1 levels in culture fluid and intracellular reactive oxygen species (ROS) levels, as well as ET1 gene, endothelin-converting enzyme-1 (ECE-1), extracellular signal-regulating kinase 1/2 (ERK1/2), pERK1/2 expression levels and RAS activation were measured and compared among the groups. Plasma ET-1 levels of rabbits increased significantly in fluorinated groups compared with those in the control group. The rabbit thoracic aortas became slightly hardened in fluorinated groups compared with those in the control group, and some vacuoles were present in the endothelial cell cytoplasm of the rabbits in fluorinated groups. In our cell experiments, ET1 gene and ECE-1 expression levels in HUVECs and ET-1 expression levels in the cell culture supernatants increased significantly in some experimental groups compared with those in the control group. These trends paralleled the changes in intracellular ROS levels, RAS activation, and the pERK1/2-to-ERK1/2 ratio. After U0126 was added, ECE-1 expression and ET-1 levels decreased significantly. Excessive fluoride exposure leads to characteristic endothelial damage (vacuoles), thoracic aorta hardening, and plasma ET-1 level elevations in rabbits. In addition, the ROS-RAS-MEK1/2-pERK1/2/ERK1/2 pathway plays a crucial-and at least partial-role in ET-1 over-expression, which is promoted by excessive fluoride exposure. © 2016 The Author(s) Published by S. Karger AG, Basel.

Prolonged demand breast-feeding and nursing caries.

PubMed

Weerheijm, K L; Uyttendaele-Speybrouck, B F; Euwe, H C; Groen, H J

1998-01-01

The aim of this study was to study the characteristics and to explore risk factors within a group of Dutch children breast-fed on demand over a prolonged period, whose mothers attended the meetings of La Leche League. Ninety-six children, 55 boys and 41 girls (mean age 28.8 months, SD 8.8), were examined. Most of the parents belong to a higher socio-economic working class. The examination included a questionnaire and dietary sheet, combined with the caries status of the child. On average the children were breast-feed for 21.5 months (SD 9.8). The mean age at which the parents started brushing the children's teeth was 11.7 months (SD 5.1). Fluoridated toothpaste (250 ppm fluoride) was used by 70% of the children. The children were divided into three groups according to their caries pattern: 1 caries-free; 2 caries, and 3 nursing caries. Dentine caries was found in 14 (14.5%) of the children, of which 9 (9.3%) met the criteria of nursing caries. The mean dmfs of all children examined was 1.2 (SD 4.8). Up to 18 months of age the breast was given significantly more frequently during the night and up to 24 months during the day time, to the children of the nursing caries group compared to the children in the other two groups. The children still being breast-fed at the time of investigation more frequently slept in their parents' bed. The children of the nursing-caries group used fluoridated dentifrices less often. The majority of children of the caries and nursing-caries groups did not receive fluoride from other sources. The results of the present study demonstrate that prolonged demand breast-feeding does not lead to a higher caries prevalence although comparison between the groups demonstrates that frequent breast-feeding and low additional fluoride use should be considered as contributing factors in the process of nursing caries.

[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.

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.

The effect of a toothpaste containing 2% zinc citrate and 0.3% Triclosan on bacterial viability and plaque growth in vivo compared to a toothpaste containing 0.3% Triclosan and 2% copolymer.

PubMed

Adams, S E; Theobald, A J; Jones, N M; Brading, M G; Cox, T F; Mendez, A; Chesters, D M; Gillam, D G; Hall, C; Holt, J

2003-12-01

To compare the antimicrobial efficacy and effect on plaque growth of a new silica-based fluoride toothpaste containing 2% zinc citrate/ 0.3% Triclosan with a silica-based fluoride toothpaste containing 0.3% Triclosan/2% copolymer. In Study 1, plaque was collected after one week's use of each toothpaste and assessed for bacterial viability, live/ dead ratio and microbial membrane integrity. In study 2, plaque was measured immediately and 18 hours after a single brushing with the specified toothpastes. The 2% zinc citrate/0.3% Triclosan formulation significantly reduced the total number of viable aerobic and anaerobic bacteria (p = 0.0223 and p = 0.0443 respectively) compared to the 0.3% Triclosan/2% copolymer formulation. Both toothpastes increased the bacterial membrane permeability significantly. However, the proportion of live bacteria for the 2% zinc citrate/0.3% Triclosan product was significantly reduced (p < 0.05). Study 2 showed significantly less plaque growth 18 hours after using the 2% zinc citrate/0.3% Triclosan toothpaste compared to the 0.3% Triclosan/2% copolymer toothpaste (p < 0.01). Regular use of a fluoride toothpaste containing 2% zinc citrate and 0.3% Triclosan, significantly reduced the viability of plaque bacteria compared to a fluoride toothpaste containing 0.3% Triclosan/ 2% copolymer 12 hours after brushing. In addition, a clinical plaque growth study confirmed that this anti-microbial efficacy leads to a significant reduction in plaque growth.

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.

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.

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.

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.

Nanocomposites with increased energy density through high aspect ratio PZT nanowires.

PubMed

Tang, Haixiong; Lin, Yirong; Andrews, Clark; Sodano, Henry A

2011-01-07

High energy storage plays an important role in the modern electric industry. Herein, we investigated the role of filler aspect ratio in nanocomposites for energy storage. Nanocomposites were synthesized using lead zirconate titanate (PZT) with two different aspect ratio (nanowires, nanorods) fillers at various volume fractions dispersed in a polyvinylidene fluoride (PVDF) matrix. The permittivity constants of composites containing nanowires (NWs) were higher than those with nanorods (NRs) at the same inclusion volume fraction. It was also indicated that the high frequency loss tangent of samples with PZT nanowires was smaller than for those with nanorods, demonstrating the high electrical energy storage efficiency of the PZT NW nanocomposite. The high aspect ratio PZT NWs showed a 77.8% increase in energy density over the lower aspect ratio PZT NRs, under an electric field of 15 kV mm(-1) and 50% volume fraction. The breakdown strength was found to decrease with the increasing volume fraction of PZT NWs, but to only change slightly from a volume fraction of around 20%-50%. The maximum calculated energy density of nanocomposites is as high as 1.158 J cm(-3) at 50% PZT NWs in PVDF. Since the breakdown strength is lower compared to a PVDF copolymer such as poly(vinylidene fluoride-tertrifluoroethylene-terchlorotrifluoroethylene) P(VDF-TreEE-CTFE) and poly(vinylidene fluoride-co-hexafluoropropylene) P(VDF-HFP), the energy density of the nanocomposite could be significantly increased through the use of PZT NWs and a polymer with greater breakdown strength. These results indicate that higher aspect ratio fillers show promising potential to improve the energy density of nanocomposites, leading to the development of advanced capacitors with high energy density.

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)

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.

METHOD OF SEPARATING PLUTONIUM

DOEpatents

Brown, H.S.; Hill, O.F.

1958-02-01

Plutonium hexafluoride is a satisfactory fluorinating agent and may be reacted with various materials capable of forming fluorides, such as copper, iron, zinc, etc., with consequent formation of the metal fluoride and reduction of the plutonium to the form of a lower fluoride. In accordance with the present invention, it has been found that the reactivity of plutonium hexafluoride with other fluoridizable materials is so great that the process may be used as a method of separating plutonium from mixures containing plutonium hexafluoride and other vaporized fluorides even though the plutonium is present in but minute quantities. This process may be carried out by treating a mixture of fluoride vapors comprising plutonium hexafluoride and fluoride of uranium to selectively reduce the plutonium hexafluoride and convert it to a less volatile fluoride, and then recovering said less volatile fluoride from the vapor by condensation.

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).

40 CFR 421.92 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2010 CFR

2010-07-01

... CATEGORY Metallurgical Acid Plants Subcategory § 421.92 Effluent limitations guidelines representing the...): Subpart I—Metallurgical Acid Plant Pollutant or pollutant property BPT effluent limitations Maximum for... Cadmium 0.180 0.090 Copper 5.000 2.000 Lead 1.800 0.790 Zinc 3.600 0.900 Fluoride 1 212.800 121.000...

40 CFR 421.92 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2011 CFR

2011-07-01

... CATEGORY Metallurgical Acid Plants Subcategory § 421.92 Effluent limitations guidelines representing the...): Subpart I—Metallurgical Acid Plant Pollutant or pollutant property BPT effluent limitations Maximum for... Cadmium 0.180 0.090 Copper 5.000 2.000 Lead 1.800 0.790 Zinc 3.600 0.900 Fluoride 1 212.800 121.000...

40 CFR 426.133 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2014 CFR

2014-07-01

... than 50 gallons per day of process waste water, and employs hydrofluoric acid finishing techniques... any 1 day Average of daily values for 30 consecutive days shall not exceed— Lead 0.2 0.1 Fluoride 26.0..., discharges greater than 50 gallons per day of process waste water, and employs hydrofluoric acid finishing...

40 CFR 426.133 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2012 CFR

2012-07-01

... than 50 gallons per day of process waste water, and employs hydrofluoric acid finishing techniques... any 1 day Average of daily values for 30 consecutive days shall not exceed— Lead 0.2 0.1 Fluoride 26.0..., discharges greater than 50 gallons per day of process waste water, and employs hydrofluoric acid finishing...

40 CFR 426.133 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2013 CFR

2013-07-01

... than 50 gallons per day of process waste water, and employs hydrofluoric acid finishing techniques... any 1 day Average of daily values for 30 consecutive days shall not exceed— Lead 0.2 0.1 Fluoride 26.0..., discharges greater than 50 gallons per day of process waste water, and employs hydrofluoric acid finishing...

40 CFR 426.116 - Pretreatment standards for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the recognition that animal and vegetable oils can be adequately removed in a publicly owned treatment... (animal and vegetable) (1) (1) Oil (mineral) 260.0 130.0 TSS (1) (1) Fluoride 120.0 60.0 Lead (1) (1) pH (1) (1) English units (lb/1,000 lb of furnace pull) Oil (animal and vegetable) (1) (1) Oil 0.26 0.13...

40 CFR 426.116 - Pretreatment standards for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the recognition that animal and vegetable oils can be adequately removed in a publicly owned treatment... (animal and vegetable) (1) (1) Oil (mineral) 260.0 130.0 TSS (1) (1) Fluoride 120.0 60.0 Lead (1) (1) pH (1) (1) English units (lb/1,000 lb of furnace pull) Oil (animal and vegetable) (1) (1) Oil 0.26 0.13...

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.

Reduction of precursor decay anomaly in single crystal lithium fluoride

NASA Astrophysics Data System (ADS)

Sano, Yukio

2000-08-01

The purpose of this study is to reveal that the precursor decay anomaly in single crystal lithium fluoride is reduced by Sano's decay curve [Y. Sano, J. Appl. Phys. 85, 7616 (1999)], which is much smaller in slope than Asay's decay curve [J. R. Asay, G. R. Fowles, G. E. Duvall, M. H. Miles, and R. F. Tinder, J. Appl. Phys. 43, 2132 (1972)]. To this end, strain, particle, velocity, and stress in a precursor and near the leading edge of the follower changing with time along Sano's decay curve are first analyzed quantitatively. The analysis verified the existence of degenerate contraction waves I and II and a subrarefaction wave R', and the decay process [Y. Sano, J. Appl. Phys. 77, 3746 (1995)] caused in sequence by evolving followers C, I, II, R', Rb. Next, inequalities relating decay rates qualitatively to plastic strain rates at the leading edge of the follower, which are derived using the properties of the followers, are incorporated into the analysis. Calculation results showed that the plastic strain rates were reduced by low decay rates. This indicates that the precursor decay anomaly might be greatly reduced by Sano's decay curve.

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.

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 ...

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.

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.

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.

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.

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)

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.

Determination of the vinyl fluoride line intensities by TDL spectroscopy: the object oriented approach of Visual Line Shape Fitting Program to line profile analysis

NASA Astrophysics Data System (ADS)

Tasinato, Nicola; Pietropolli Charmet, Andrea; Stoppa, Paolo; Giorgianni, Santi

2010-03-01

In this work the self-broadening coefficients and the integrated line intensities for a number of ro-vibrational transitions of vinyl fluoride have been determined for the first time by means of TDL spectroscopy. The spectra recorded in the atmospheric window around 8.7 µm appear very crowded with a density of about 90 lines per cm-1. In order to fit these spectral features a new fitting software has been implemented. The program, which is designed for laser spectroscopy, can fit many lines simultaneously on the basis of different theoretical profiles (Doppler, Lorentz, Voigt, Galatry and Nelkin-Ghatak). Details of the object oriented implementation of the application are given. The reliability of the program is demonstrated by determining the line parameters of some ro-vibrational lines of sulphur dioxide in the ν1 band region around 9 µm. Then the software is used for the line profile analysis of vinyl fluoride. The experimental line shapes show deviations from the Voigt profile, which can be well modelled by using a Dicke narrowed line shape function. This leads to the determination of the self-narrowing coefficient within the framework of the strong collision model.

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.

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.

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.

Fluoride contamination sensor based on optical fiber grating technology

NASA Astrophysics Data System (ADS)

Jadhav, Mangesh S.; Laxmeshwar, Lata S.; Akki, Jyoti F.; Raikar, P. U.; Kumar, Jitendra; Prakash, Om; Raikar, U. S.

2017-11-01

A number of distinct advantages of the optical fiber technology in the field of sensors and communications which leads to enormous applications. Fiber Bragg grating (FBG) developed from the fabrication of photosensitive fiber through phase mask technique is used in the present report. The designed fiber sensor used for the detection and determination of contaminants in drinking water at ppm & ppb level and it is considered as a special type of concentration sensor. The test samples of drinking water have been collected from different regions. In this paper we have calibrated the FBG sensor to detect Flouride concentration in drinking water in the range of 0.05-8 ppm. According to WHO, the normal range of fluoride content in drinking water is about 0.7 ppm to 1.5 ppm. The results for resultant spectral shifts for test samples are closely agree with standard values.

Structural study of VO {sub x} doped aluminium fluoride and aluminium oxide catalysts

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

Scheurell, Kerstin; Scholz, Gudrun; Kemnitz, Erhard

The structural properties of vanadium doped aluminium oxyfluorides and aluminium oxides, prepared by a modified sol-gel synthesis route, were thoroughly investigated. The influence of the preparation technique and the calcination temperature on the coordination of vanadium, aluminium and fluorine was analysed by different spectroscopic methods such as Raman, MAS NMR and ESR spectroscopy. In all samples calcined at low temperatures (350 deg. C), vanadium coexists in two oxidation states V{sup IV} and V{sup V}, with V{sup IV} as dominating species in the vanadium doped aluminium oxyfluorides. In the fluoride containing solids aluminium as well as vanadium are coordinated by fluorinemore » and oxygen. Thermal annealing of 800 deg. C leads to an extensive reorganisation of the original matrices and to the oxidation of V{sup IV} to V{sup V} in both systems. - Graphical abstract: Structure model for VO {sub x} doped aluminium oxide.« less

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

"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.

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.

Leaching of lava and tephra from the Oldoinyo Lengai volcano (Tanzania): Remobilization of fluorine and other potentially toxic elements into surface waters of the Gregory Rift

NASA Astrophysics Data System (ADS)

Bosshard-Stadlin, Sonja A.; Mattsson, Hannes B.; Stewart, Carol; Reusser, Eric

2017-02-01

Volcanic ash leachate studies have been conducted on various volcanoes on Earth, but few have been done on African volcanoes until now. Tephra emissions may affect the environment and the health of people living in this area, and therefore we conducted a first tephra (ash and lapilli sized) leachate study on the Oldoinyo Lengai volcano, situated in northern Tanzania. The recent explosive eruption in 2007-2008 provided us with fresh samples from the first three weeks of the eruption which were used for this study. In addition, we also used a natrocarbonatitic sample from the activity prior to the explosive eruption, as the major activity at Oldoinyo Lengai is natrocarbonatitic. To compare the leaching process affecting the natrocarbonatitic lavas and the tephras from Oldoinyo Lengai, the 2006 natrocarbonatitic lava flow was resampled 5 years after the emplacement and compared to the initial, unaltered composition. Special interest was given to the element fluorine (F), since it is potentially toxic to both humans and animals. A daily intake of fluoride (F-) in drinking water of > 1.5 mg/l can lead to dental fluorosis, and higher concentrations lead to skeletal fluorosis. For this reason, a guideline value for fluoride in drinking water was set by the WHO (2011) to 1.5 mg/l. However, surface waters and groundwaters in the Gregory Rift have elevated fluoride levels of up to 9.12 mg/l, and as a consequence, an interim guideline value for Tanzania has been set at 8 mg/l. The total concentration of fluorine in the samples from the natrocarbonatitic lava flow is high (3.2 wt%), whereas we observed a significant decrease of the fluorine concentration (between 1.7 and 0.5 wt%) in the samples collected three days and three weeks after the onset of the explosive 2007-08 eruption. However, the total amount of water-extractable fluoride is lower in the natrocarbonatitic lavas (319 mg/l) than in the nephelinitic tephra (573-895 mg/l). This is due to the solubility of the different F-bearing minerals. In the natrocarbonatites, fluorine exists predominantly in fluorite (CaF2), and in the early tephra as Na-Mg bearing salts such as neighborite (NaMgF3) and sellaite (MgF2). All these three minerals have very low solubility in water (16-130 mg/l). The later nephelinitic tephras contain surface coating of villiaumite (NaF), which is highly soluble (42,200 mg/l) in water and can thus release the fluoride more readily upon contact with water. Although there is still the need for further data and a more precise study on this topic in Tanzania, we can already draw a first conclusion that the intake of water during or directly following the deposition of the tephra is not advisable and should be avoided, whereas the release of fluoride from the lava flow has less influence on the river waters.

The Potential of Self-assembling Peptides for Enhancement of In Vitro Remineralisation of White Spot Lesions as Measured by Quantitative Laser Fluorescence.

PubMed

Golland, Luca; Schmidlin, Patrick R; Schätzle, Marc

To test the remineralisation potential of a single application of self-assembling peptides or acidic fluoride solution using quantitative light-induced fluorescence (QLF) in vitro. Bovine enamel disks were prepared, and white spot lesions were created on one half of the disk with an acidic buffer solution. After demineralisation, disks were allocated into three groups of 11 specimens each. Group A served as a control group and received no treatment. Group B had a single application of fluoride, and group C was treated once with self-assembling peptides. All disks were embedded in a plastic mold (diameter 15 mm, height 9 mm) with an a-silicone, and remineralisation was initiated using a pH-cycling protocol for five days. Four experimental regions on each disk were measured prior to the start of the study (T0), after demineralisation (T1) and after the remineralisation process (T2) using QLF. After demineralisation, all areas showed a distinct loss of fluorescence, with no statistically significant difference between the groups (ΔF from -69.3 to -10.2). After remineralisation, samples of group B (treated with fluoride) showed a statistically significant fluorescence increase (ΔF from T1 to T2 15.2 ± 7.3) indicating remineralisation, whereas the samples of control group A and group C (treated with self-assembling peptides) showed no significant changes in ΔF of 1.1 ± 1.9 and 2.5 ± 1.9, respectively. Application of self-assembling peptides on demineralised bovine enamel did not lead to increased fluorescence using QLF, indicating either lack of remineralisation or irregular crystals. Increased fluorescence using QLF indicated mineral gain following a single application of a highly concentrated fluoride.

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