• The Journal of the Korean dental association
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• v.12 no.5
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• pp.327-332
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• 1974

The effects of enamel solubility by the varying concentration of fluoride and phosphate as well as pH of the acid fluoride-phosphate solutions were tested and compared with th 7% stannous fluoride solution. The smooth surface of the sound permanent 1st premolars were demineralized by the Buttner's method. And the phosphorus extracted from the 1st premolars were analyzed by the Fiske and Subbarow's method. Enamel smooth surfaces treated with the acid fluoride-phosphate solution and the 8% stannous fluoride solution were obserbed electron-microscopically by the Filmy Replica method. The results of this study were summarized as follows: !. The least enamel dissolution rate was observed at the acid fluoride-phosphate solution contained 1.25% fluorine, 0.5% phosphate, and pH 4. 2. The anti-cariogenic effects comparison between the acid fluoride-phosphate solution and 8% stannous fluoride, the former was higher.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.4
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• pp.73-84
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• 1996

Fluoride was first introduced into the drinking water of residents of Grand Rapids, Michigan in 1945 for the prevention of dental caries. Ever since, growing numbers of communities favor fluoridation. Now, over 7000 communities in the United States are adding F(0.7~1.2ppm) to their drinking water. The most effective to prevent tooth decay is putting lower concentrated fluoride(F, 0.7~1.2ppm) into drinking water. However, exact fluoride injection amount have not been decided, because the research of the fluoride injection effect was insufficient. Therefore, after separating fluoridation and non-fluoridation into public water supplies, we investigated concentration of fluoride, alkalinity, Al, Ca, Mg, evaporation residuals in APT, domestic, commercial area. Then, we decided allowable concentration of fluoride, injection point of fluoride in water supply system, cost effectiveness.

• Journal of Korean society of Dental Hygiene
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• v.18 no.3
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• pp.323-334
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• 2018

Objectives: The purpose of this study was to provide the basic data necessary for the development of educational programs and materials that enable the public to have accurate knowledge and awareness of fluoride. Methods: A survey was conducted from December 2016 on 354 members of the public, aged 20 or older in South Korea to find out the effects of using toothbrush. The results can be summarized as follows. Statistical analysis of the collected data was performed using the SPSS WIN 21.0 statistical program. Results: As a result of examining the factors affecting the perception of fluoride, when fluoride education was experienced (p<0.01), fluoride was recognized (p<0.01), fluoride was experienced (p<0.05), When fluoride was considered to be good (p<0.01), the perception of fluoride was high. Conclusions: The perception of fluoride was relatively low, and the need for more active promotion of fluoride was identified. Therefore, dental medical personnel and the personnel who carry out the oral health education should make the people actively carry out education about fluoride.

• Restorative Dentistry and Endodontics
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• v.29 no.1
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• pp.36-43
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• 2004

The purpose of this study was to compare the microhardness and the fluoride content of enamel and dentin around fluoride- or non fluoride-containing restorations. Forty extracted human teeth were used and prepared cervical cavities on proximal surface. Experimental teeth were divided into five groups . Group 1 : Prime & Bond NT and Z100, Group 2 Prime & Bond NT and F2000, Group 3 : Scotchbond Multi-purpose and Z100, Group 4 : Scothcbond Multi-purpose and F2000, Group 5 : Fuji II LC. The cavities were filled with dentin adhesives and restorative materials. After each tooth was bisected, one half was tested microharaness and the other half was analyzed the fluoride at the enamel and dentin by an EPMA-WDX device. The results were as follows; 1. There was no statistical difference among the microhardness of enamel surface in all group. 2. The microhardness at dentin of $100{\;}\mu\textrm{m}$ point in Group 2 and $20{\;}\mu\textrm{m}$ point in Grocup 4 was lower than that of normal dentin (p>0.05). 3. There was no statistical difference among the fluoride content of enamel surface in all group. 4. The fluoride content at the dentin of $30{\;}\mu\textrm{m}$ point in Group 2 and 5 were higher than those at $100{\;}\mu\textrm{m}{\;}and{\;}200{\;}\mu\textrm{m}$ point in Group 2 and normal dentin (p<0.05). 5. At the dentin of $30{\;}\mu\textrm{m}$ point, Group 2 showed higher fluoride content than Group 1 and 3, and Group 5 showed higher fluoride content than other groups.

• Environmental Engineering Research
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• v.11 no.2
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• pp.77-83
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• 2006

The hot spring water of the north Jeonla province such as Wanggung, Jookrim, Seokjung, and Hwasim, has fluoride concentration of 3.9 mg/L, 12.7 mg/L, 1.9 mg/L, and 6.3 mg/L, respectively. These figures fairly exceed the Korean and WHO standard for potable water, which is 1.5 mg/L. Therefore, in this study, research on elimination of fluoride in a hot spring water of Jookrim region, which has the highest level of fluoride concentration level in the north Jeonla province, was carried out. In analysis of Jookrim hot spring water according to the water quality standard for potable water, pH was very high at 9.25 and the concentration of fluoride was 10 times higher than the standard at 18.2 mg/L. Other measurements were within the standard or not detected. After injecting 10g of activated carbon for elimination of fluoride, the fluoride concentration was measured at 13.5 mg/L, and when 70mL or more of alum 10 g/L solution was injected, the concentration was measured at 2.8 mg/L, and injecting 3g of lime was measured at 9 mg/L. Alum showed the best elimination performance among all individual injections. Injection of 25 mL of activated carbon and 100 mL of alum solution together reduced the fluoride concentration down to 1.3 mg/L, which is under the potable standard. Injection of lime 1g and 75 mL of alum 10 g/L solution together reduced fluoride concentration to 4.1 mg/L. From the modifying HRT, by using ion exchange resin column, the pH was stabilized when HRT was Imin and showed range of $6.7{\sim}7.8$. The fluoride concentration reduced gradually as the HRT increased, and satisfied the potable standard when HRT passed 6 min, and after 30 min HRT, the concentration of fluoride was 0.05 mg/L: almost eliminated.

• Restorative Dentistry and Endodontics
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• v.41 no.2
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• pp.121-129
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• 2016

Objectives: The purpose of this study was to assess the effect of single and combined applications of fluoride on the amount of fluoride release, and the remineralization and physical properties of enamel. Materials and Methods: Each of four fluoride varnish and gel products (Fluor Protector, FP, Ivoclar Vivadent; Tooth Mousse Plus, TM, GC; 60 Second Gel, A, Germiphene; CavityShield, CS, 3M ESPE) and two fluoride solutions (2% sodium fluoride, N; 8% tin(ii) fluoride, S) were applied on bovine teeth using single and combined methods (10 per group), and then the amount of fluoride release was measured for 4 wk. The electron probe microanalysis and the Vickers microhardness measurements were conducted to assess the effect of fluoride application on the surface properties of bovine teeth. Results: The amount of fluoride release was higher in combined applications than in single application (p < 0.05). Microhardness values were higher after combined applications of N with FP, TM, and CS than single application of them, and these values were also higher after combined applications of S than single application of A (p < 0.05). Ca and P values were higher in combined applications of N with TM and CS than single application of them (p < 0.05). They were also increased after combined applications of the S with A than after single application (p < 0.05). Conclusions: Combined applications of fluoride could be used as a basis to design more effective methods of fluoride application to provide enhanced remineralization.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.115-115
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• 2015

Many efforts have been devoted on chemical modification of graphene layer to modulate its electrical properties. In the previous report, laser irradiation on the CYTOP (Amorphous Fluoropolymer) covered graphene layer induces chemical modification wherein carbon fluoride is formed on the graphene surface. This results in the insulating I-V characteristics, which have been attracting much research interests on it. However, the direct analytical evidence of the fluoride formation on graphene surface is not yet studied. In this work we investigated what happened on the CYTOP/graphene interface during photon irradiation using spatially resolved photoemission spectroscopy method. It is found that the soft x-ray (614 eV) induces desorption of fluoride atoms from the CYTOP and change di-fluoride form to mono-fluoride. As the photo-induced fluorine desorption is continue strong dipole field generated by initial di-fluoride forms is gradually decreased, resulting in the overall binding energy shift of the C 1s core levels. Both photo-modified CYTOP and CYTOP starts to desorb above $286^{\circ}C$ (~ 0.047 eV), which means that no strong chemical interaction between CYTOP and graphene is established.

• International Journal of Industrial Entomology and Biomaterials
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• v.9 no.1
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• pp.73-78
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• 2004

The impact of low concentration fluoride on toxification was studied by treating $3^rd$ instar silkworm larvae of Qiufeng${\times}$Baiyu (Fluoride resistant strain) and Jinshong${\times}$Haoyue (Fluoride sensitive strain). The $5^th$ instar silkworm larvae of Zhenong-l, Shu-12, Qiufeng ${\times}$ Baiyu, Chunhua ${\times}$ Qhiushi, Jinshong and Haoyue were fed mulberry leaves treated with sodium fluoride at different concentrations to determine its effect on fecundity. Harmful effects of low concentration fluoride at early instars on growth, development and economic characters of Bombyx mori are related to its resistance. Harmful effect on resistant strain Qiufeng${\times}$Baiyu manifested on prolongation of instar duration of 15 and 6% in 70 ppm, where as the sensitive breed Jinshong${\times}$Haoyue manifested with 100% mortality in 50 ppm. The impact of low concentration fluoride on fecundity resulted in considerable increase in formed eggs (9%) and laid eggs (9%) in Zhenong-l and Shu-12 among treated population over control. The present observations emphasis that fluoride apart from exhibiting harmful effects on silkworm growth and development, however, its low concentration do playa vital role in inducing some positive effect on fecundity and cocoon traits.

• The Journal of the Korean dental association
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• v.48 no.6
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• pp.454-458
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• 2010

Dental caries is one of the most common chronic diseases in the world, which are caused by complex actions of oral such factors as the bacteria, food, tooth, saliva and other factors. Although this is one of the typical oral diseases, we can acquire a high prophylactic effect by use of proper prophylactic measures and management. At the beginning of the 1940s, fluorine was first introduced to prevent dental caries which now is widely used. The fluorine application effects are varied from different concentrations and categories of fluorine, and different application method and frequency, etc. There is great debate on the best application method at the present. Dental clinics use iontophoresis as the application method and use it clinically. It uses APF (1.23%, Acidulated phosphate fluoride, APF) and uses 2% NaF so as to encourage more absorption of fluorine. Recently, fluoride varnish, which uses admixture mucus of colophony resin into 5% NaF, and a variety of forms that can be applied in the oral cavity are still being continuously researched. When using fluoride topical application on the enamel surface, it was highly recommended that fluoride varnish be used directly after fluoride iontophoresis rather than fluoride iontophoresis only or fluoride varnish by itself. The new method is more effective and does not need repeated application.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.1
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• pp.1-8
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• 2020

In this study, the physicochemical characteristics and fluoride adsorption capacity of the bone char pyrolyzed at different temperatures; 200℃, 300℃, 350℃, 400℃, 500℃, 600℃, and 700℃ were investigated. Analytical studies of the synthesized bone char including; SEM-EDS, XRD, BET and FT-IR, showed the presence of hydroxyapatite(HAP), which is the main substance that adsorbs fluoride from aqueous solutions containing high fluoride concentrations. Bone char pyrolyzed from 350~700℃ specifically revealed that, the lower the temperature, the higher the fluoride adsorption capacity and vice versa. The loss of the fluoride adsorption function of HAP (OH^- band in the FTIR analysis) was interpreted as the main reason behind this inverse correlation between temperature and fluoride adsorption. Bone char produced at 350℃ hence exhibited a fluoride adsorption capacity of 10.56 mgF/g, resulting in significantly higher adsorption compared to previous studies.