• Journal of Korean Society of Water and Wastewater
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• v.14 no.2
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• pp.164-173
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• 2000

Fluoridation of drinking water to a level of about 0.8mg/l (below 1.5mg/l) for reducing the incidence of tooth decay is recommended. However, concerns about potential problems of unknown effects and overdosing hinders the fluoridation. This study describes the work performed to obtain information on the behavior of fluoride under various conditions in the process of water fluoridation. Effects of water treatment chemicals, water treatment unit, and water distribution on water fluoridation were investigated at both lab and an actual water treatment plant. Residual fluoride concentration was not affected by lime and chlorine dosage up to 20mg/l. Flocculation with PAC slightly decreased the residual fluoride concentration as PAC dosage increased. Average fluoride concentration of 0.87mg/l at an intake basin was decreased to 0.83mg/l by sedimentation, 0.81mg/l by dual media(sand+anthracite) filtration, and 0.79mg/l by granular activated carbon filtration in the water treatment plant.

• Journal of the Korean Ceramic Society
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• v.37 no.1
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• pp.33-43
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• 2000

Up-conversion of rare-earth element added glass is promising area for short wavelength laser source by utilizing high power semiconductor infra-red laser if the efficiency can be increased by proper method. In this study, relatively low phonon energy fluoride glasses were prepared by co-doping rare-earth elements to realize the high efficiency up-convertor. The physical, chemical, andoptical properties of co-doped fluoride glasses were measured. 10 combinations of 5 different rare-earth fluoride elements doped samples were prepared and their transition temperatures, chemical durability, density, hardness, refractive index, absorption, fluorescence, and fluorescence lifetime were measured. 480nm wavelengths blue up-conversion was found in the Yb3+/Tm3+ co-doped glass sample with 800nm laser source and the optimum composition for the most efficient blue up-conversion was found from the glass sample with 0.3 mol% TmF3 and 1 mol% YbF3.

• Textile Coloration and Finishing
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• v.25 no.3
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• pp.153-158
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• 2013

In this study, pyrene based chemosensor was synthesized by two step reaction. The chemosensor showed that high selectivity toward fluoride in DMSO. The fluorescence intensity was drastically increased by binding between chemosensor and fluoride ion. Absorption and fluorescence spectra were obtained by UV-Vis spectrometer and fluorescence spectrophotometer. The binding ratio between chemosensor and fluoride ion was also investigated by job's plot method and Benesi-Hildebrand plot. The HOMO/LUMO energy levels and electron distribution were calculated and simulated by Material studio 6.0 Package.

• Proceedings of the Korean Environmental Health Society Conference
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• 2004.06a
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• pp.210-212
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• 2004

This study was conducted to determine the fluoride intakes in 120 preschool children aged $3{\sim}6$ residing in Jumunjin(community water fluoridation area) and Kangnung(non-fluoridation area). The parents duplicated all the diets that their children ingested in a day. The acid-diffusible fluoride in the diet was isolated by the acid-diffusion technique and measured with a fluoride electrode. The mean daily fluoride intakes form all kinds of diet by children residing in Jumunjin and Kangnung were $0.445{\pm}0.354mg/day$ and $0.131{\pm}0.097mg/day$, respectively. It is concluded from this investigtion that the amount of fluoride intake of children living in Jumunjin(fluoridated areas) did not exceed the upper intake level designated by the Institute of medicine of the US National Academy of Science to avoid the risk of dental fluorosis(2.2mg/day in 4- to 8-year-olds).

• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.19-22
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• 1988

For decreasing the level of fluoride content in Antarctic krill, the changes of the content in solubel protein from the krill muscle depended on pH, ion species and ionic strength of the extracting solutions were investigated. The content of total fluoride of boiled muscle was higher than that of raw material, and the portions of fluoride with ionic form to the total content were 70% and 49%, respectively. In the effect of pH, fluoride contents of soluble protein from raw and boiled muscle showed the lowest values near 10. The effective ionic strength for decrease of fluoride content was 0.05M as NaCl at pH 11, and the content in the protein from raw material in this conditions was about 8 ppm.

• Journal of Environmental Science International
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• v.23 no.5
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• pp.887-893
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• 2014

In order to remove fluoride ions from aqueous solution, PVC-$Al(OH)_3$ beads were prepared by immobilizing $Al(OH)_3$ with polyvinyl chloride (PVC). The prepared PVC-$Al(OH)_3$ bead was characterized by using SEM, EDS and Zeta potential. Dependences of pH, contact time and initial fluoride concentration on the adsorption of fluoride ions were studied. The optimal pH was in the range of 4~10. The adsorption was rapid during the initial 12 hr, and equilibrium was attained within 72 hr. The adsorption rate of fluoride ions by PVC-$Al(OH)_3$ beads obeyed the pseudo-second-order kinetic model. The maximum adsorption capacity obtained from Langmuir isotherm model was found to be 62.68 mg/g.

• Journal of Korean society of Dental Hygiene
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• v.13 no.6
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• pp.1057-1062
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• 2013

Objectives : The purpose of this study was to investigate the possible differences in elementary schools jointed to fluoride mouth rinse plans in health centers. Methods : Students from the third to sixth grades filled out the questionnaires. Data were analyzed by the statistical package SPSS 12.0. Results : The rate of a personal toothbrush holding and toothbrushing after lunch were higher in those who rinsed their mouths with fluoride than those who did not.(p<0.05). Toothbrushing by the rolling method was more prevailing in the students who rinsed their mouths with fluoride(57.0%) and having regular dental checkup(p<0.05) than in those who did not(39.8%). Conclusions : The students who had rinsed their mouths with fluoride showed the good oral health behavior. Continuing good quality of oral health care education must be provided to the students by professional dental hygienists.

• Advances in environmental research
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• v.2 no.1
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• pp.35-49
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• 2013

Research work on removal of fluoride from water, referred to as water defluoridation, has resulted into the development of a number of technologies over the years but they suffer from either cost or efficiency drawbacks. In this work, enhancement effects of phosphate and silicate on defluoridation of water by low-cost Plaster of Paris (calcined gypsum) were studied. To our knowledge, the influence of silicate on defluoridation was not reported. It was claimed, that the presence of some ions in the treated water samples, was decreasing the fluoride removal since these ions compete the fluoride ions on occupying the available adsorption sites, however, phosphate and silicate ions, from its sodium slats, have enhanced the fluoride % removal, hence, precipitation of calcium-fluoro compounds of these ions can be suggested. Percentage removal of $F^-$ by neat Plaster is 48%, the electrical conductance (EC) curve shows the typical curve of Plaster setting which begins at 20 min and finished at 30 min. The addition of phosphate and silicate ions enhances the removal of fluoride to high extent > 90%. Thermodynamics parameters showed spontaneous fluoride removal by neat Plaster and Plaster-silicate system. The percentage removal with time showed second-order reaction kinetics.

• The korean journal of orthodontics
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• v.2 no.1
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• pp.23-28
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• 1971

In this study, sections of twenty eight teeth were used to investigate the effect of topical application of $8\%$ stannous fluoride on the decalcification rate of enamel surfaces stripped in a manner suggested for orthodontic purpose. The enamel treated with a single application of a fluoride had a significantly lower tile rate of decalcification for the first 96 hours to lactate buffer solution. After double application of fluoride, decalcification rate decreased signicantly. This study suggested that the continuing protection of stripped surfaces should be sought by regularly scheduled treatment of the enamel with the topical application of fluoride and regular use of a fluoride containing dentifrice.

• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.575-595
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• 1997

Replacement resorption is followed by the delayed replantation of an avulsed tooth. Currently no effective treatment is substantiated for replacement resorption. The purpose of this study was to investigate the effect of stannous fluoride, bisphosphonate (etidronate disodium) and gallium nitrate, which have been shown to reduce dentin resorption, on human dentin. Osteoclasts were collected from tibeas of chick embryo. The cells were well agitated to prevent adhesion and seeded onto the sliced human dentin wafers which had been soaked in either culture media (control), or several different concentrations of stannous fluoride, etidronate disodium (l-hydroxyethylidene -1,1-bisphosphonate disodium), and gallium nitrate. Resorption was measured by counting the number of resorptive pit produced by the cells. Results are as follows. Stannous fluoride and etidronate disodium showed statistically significant reduction of dentin resorption(p<0.05) but the effect of stannous fluoride seemed to be its high cytotoxicity. Etidronate disodium did not show cytotoxicities in all experimented concentrations. Gallium nitrate did not show differences in resorption either between different concentrations or from the control group.