• 대한소아치과학회지
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• 제26권2호
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• pp.377-398
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• 1999

불소도포시 주로 형성되는 calcium fluoride는 구강내 환경에서 pH에 의해 조절되는 불소의 저장고 역할을 하여 치아우식 예방에 있어서 중요한 역할을 하는 것으로 알려져 있다. 따라서 불소도포의 우식예방 효과는 calcium fluoride를 얼마나 많이 형성시켜 오래 지속시키는 가에 달려 있다. 이에 치아 내산성 증가에 효과 있다고 알려진 Nd:YAG 레이저 조사가 calcium fluoride형성 및 치아 내산성에 미치는 영향에 대해 알아보기 위해서 실험을 시행하였다. 소의 영구전치에서 276개의 시편을 제작하여 아무런 처치를 하지 않은 군을 대조군으로 하고 1.23% acidulated phosphate fluoride (APF) 5분, 30분 도포 및 Nd:YAG 레이저 조사에너지 밀도 $20J/cm^2,\;40J/cm^2$의 조건에 따라 불소 도포군, 레이저 조사군, 불소 도포후 레이저 조사군, 레이저 조사후 불소 도포군으로 분류하였다. 불소도포를 시행한 경우 이를 다시 KOH 처리 여부에 따라 나누어 23개의 실험조건을 만들었다. 각 실험조건에 12개의 시편을 배정하고 이중 10개의 시편은 불소 및 무기인 측정에, 나머지 2개의 시편은 표면 관찰에 사용하였다. KOH 비처치군에서 0.1 N HClO4로 enamel biopsy를 시행하여 탈회 법랑질의 불소농도 및 탈회깊이를 측정하였으며 KOH 처치군에서는 1 M KOH로 24시간 처리하여 calcium fluoride를 정량 후 enamel biopsy를 시행하였다. 실험결과 얻어진 자료 및 주사 전자현미경 관찰 소견을 비교하여 다음의 결과를 얻었다. 1. KOH 비처치군에서 탈회된 법랑질의 불소농도는 레이저조사 후 불소도포시 레이저 에너지 밀도 증가에 따라 증가되는 경향을 보였다. 2. KOH 비처치군에서 법랑질 탈회깊이는 불소를 5분 도포후 레이저 $20J/cm^2$를 조사한 경우를 제외하고는 레이저와 불소를 병행하여 처치시 각각을 단독으로 처치시보다 탈회깊이가 작았다 (p<0.05). 3. Calcium fluoride의 양은 레이저의 조사에 의해 유의 있게 증가하지 않았다 (p>0.05). 4. Calcium fluoride 입자는 불소만 도포한 경우에 비해 레이저 조사후 불소도포시 입자크기가 증가되었으며, 불소도포후 레이저 조사시 입자크기의 증가와 함께 일부 융합된 양상을 보였다. 5. KOH 처치군에서 법랑질의 불소농도는 불소를 30분 도포후 레이저를 조사한 경우를 제외하고는 대조군의 불소농도와 유의한 차이가 없었다(p>0.05). 6. KOH 처치군에서 불소와 레이저를 병행한 경우, 불소만 도포한 경우보다 탈회된 법랑질의 깊이가 작았다 (p<0.05). 7. KOH 비처치군에서 탈회된 법랑질의 불소농도와 탈회깊이의 상관관계(Spearman correlation coefficient: -0.6281)는 KOH 처치군(Spearman correlation coefficient: -0.3792)에 비해 높은 음의 상관 관계를 보였고, 동일한 조건으로 불소도포 및 레이저 조사를 시행한 경우에 있어서 KOH 처리 여부에 따른 탈회법랑질 깊이의 유의차가 있는 경우 calcium fluoride의 형성량이 많았다. 이상의 실험결과로 미루어 보아 레이저 조사가 calcium fluoride의 형성량에 영향을 미치지 않았으나 레이저 조사의 영향으로 calcium fluoride의 용해가 감소하는 것으로 판단된다. 또한 불소도포 및 레이저 조사의 병행은 각각을 단독으로 처치한 경우에 비하여 치아 내산성 증가면에서 유리하므로 임상에서 불소도포주기 연장과 같은 유용한 결과를 얻을 수 있을 것으로 생각된다.

• 상하수도학회지
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• 제14권2호
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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.

• 한국수산과학회지
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• 제46권6호
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• pp.682-688
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• 2013

In this study, we investigated about cell toxicity and oxidative stress of HepG2 cell by treatment of sodium fluoride (NaF) and fluoride extracts from krill Euphausia superba meat, shell, whole body and krill meal. The cell toxicity showed significant at 300 and $500{\mu}g/mL$ NaF treatment group. But krill (Euphausia superba) fluoride extract (KFE) treatment in all groups were not toxic. The superoxide radical production increased significantly in NaF treated group, but there was no significant change in KFE treated group. The superoxide dismutase activity was a significant increase 21.5% at $100{\mu}g/mL$ and 24.7% at $300{\mu}g/mL$ treatment group of fluoride extracts from krill meat, and 8.7% at $300{\mu}g/mL$ in krill meals, compared to the control group. However, hydroxy radical flux and catalase and glutathione peroxidase activity of fluoride extracts from krill meat did not change. As a result, for a short period of time, NaF treatment in HepG2 cells affect the cell toxicity and oxidative stress, but in the case of KFE, these were not recognized. Thus, depending on the type of food ingested with fluoride, cell toxicity and oxidative stress was found to be different.

• 상하수도학회지
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• 제19권2호
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• pp.125-134
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• 2005

Waste concrete powder was used to remove fluoride ions in highly concentrated fluoride wastewater. 92.6% of fluoride in 100 mg F/L wastewater was removed by 1% dose of the cement paste powder that represents characteristics of waste concrete powder, whereas the removal efficiencies of raw cement and lime were 47.3% and 96.4%, respectively. The cement paste powder was competitive to lime, common fluoride removal agent. Various Ca-bearing hydrates such as portlandite, calcium silicate hydrate, and ettringite in cement paste slurry can remove fluoride by precipitating $CaF_2$ and absorbing $F^-$ ions. In the experiments using both cement paste and lime, 50~67% of lime can be substituted by cement paste to satisfy fluoride effluent limitation of 15 mg/L. Since cement paste has higher acid neutralization capacity than lime, it can be recycled to neutralize more acid and to remove more fluoride. Therefore waste concrete powder can be more economical and viable alternative for lime in fluoride wastewater treatment.

• 한국치위생학회지
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• 제10권3호
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• pp.473-481
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• 2010

Objectives : To evaluate the effect of fluoride application on the color and microhardness of bleached enamel and compare it to that of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) application. Methods : Twenty freshly extracted human adult molar were each sectioned into halves, the specimens divided and treated according to five experimental groups: Group 1, treatment with 10% carbamide peroxide (CP) bleaching agent; Group 2, treatment with 10% CP followed by a 1.23% fluoride gel application; Group 3, treatment with 10% CP followed by a 2.23% sodium fluoride varnish application; Group 4, treatment with 10% CP followed by a 0.11% sodium fluoride gel application; Group 5, treatment with 10% CP followed by a CPP-ACP gel application. All groups were treated 6 h per day for 14 days then immersed in distilled water for 2 weeks. Changes in enamel color were evaluated on Baseline and Day 14. Microhardness were evaluated on Baseline, Days 7 and 14. Statistical analysis was performed using one-way ANOVA and post-hoc Tukey tests. Results : All the bleached enamel specimens revealed increased whiteness and overall color value. Group 1 showed the lowest microhardness values than that of Groups 2, 3, 4 and 5. In all groups, the hardness of tooth after bleaching showed a significant decrease in the microhardness as compared with the one prior to tooth bleaching. The specimens treated with remineralizing agents showed relatively less reduction in enamel microhardness than control group. Conclusions : The addition of fluoride and CPP-ACP did not impede the whitening effect. The use of remineralizing agents during bleaching treatment can significantly enhance the microhardness of bleached enamel.

• 한국치위생학회지
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• 제9권4호
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• pp.740-752
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• 2009

Objectives : This study was carried out to examine the effect of varnish fluoride and APF gel on the acid resistance and the remineralization of the enamel. Methods : At first, the microhardness changes of enamel surface were measured after demineralizing the fluoride treated tooth surface. Next, the changes were measured after fluoride application to the demineralized enamel surface. Results : 1. Acid resistance was higher in varnish fluoride groups than APF gel groups and the difference was significant(p<0.001). 1) Varnish fluoride groups Microhardness of enamel surface showed $297.76{\pm}9.89$ after fluoride treatment and $260.90{\pm}28.67$ after drmineralization. The changes of Vickers hardness number(VHN) were $-36.86{\pm}27.30$. 2) APF gel groups Microhardness of enamel surface showed $298.79{\pm}17.28$ after fluoride treatment and $43.75{\pm}18.58$ after demineralization The changes of VHN were $-255.04{\pm}21.31$. 2. No significant changes were surveyed in both varnish fluoride groups and APF gel groups as for remineralization of enamel(p>0.05). 1) Varnish fluoride groups Microhardness of enamel surface showed $46.58{\pm}15.42$ after demineralization and $46.61{\pm}15.70$ after fluoride treatment. The changes of VHN were $0.02{\pm}3.75$. 2) APF gel groups Microhardness of enamel surface showed $47.13{\pm}19.31$ after demineralization and $42.59{\pm}16.12$ after fluoride treatment. The changes of VHN were $-4.54{\pm}5.06$. Conclusions : Varnish fluoride showed higher acid resistance than APF gel, however both of them were observed to have no effect on the remineralization of the enamel.

• 상하수도학회지
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• 제25권5호
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• pp.767-775
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• 2011

In this study we verified if the electro-coagulation process can treat properly the nitrate and fluoride that are not removed well in the conventional small water treatment plants which usually employ chlorination and filtration only. As we gave a change of electrode material and gap-distance between electrodes, removal efficiency of the nitrate and fluoride was determined by electro-coagulation process which were equipped with aluminum and stainless steel (SUS304) electrodes. In addition, electrode durability was investigated by determination of electrodes mass change during the repetitive experiments. Removal efficiency was great when aluminum was used as an anode material. Nitrate removals increased as electric density and number of electrodes increased, but fluoride removal was less sensitive to both parameters than nitrate. After 10 minutes of contact time with the current density from $1{\times}10^{-3}$ to $3{\times}10^{-3}A/cm^{2}$, nitrate and fluoride concentration ranged from 9.2 to 1.2mg/L and from 0.02 to 0.01mg/L, which satisfied the regulation limits. Regardless of the repeating number of experiments, removal efficiency of both ions were almost similar and the change of electrode mass ranged within ${\pm}$0.5%, indicating that the loss of the electrode mass is not so much great under the limited circumstances.

• Environmental Analysis Health and Toxicology
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• 제14권3호
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• pp.113-120
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• 1999

Fluorination of drinking water has been used world widely to reduce the incidence of caries. Recently, contradictory results on the cytotoxicity of fluoride compounds are reported. In addition, there are attempts to use fluorosilicate for fluorination of drinking water in Korea, therefore, we tried to analyze the cytotoxicity of fluoride compounds on oral epidermoid carcinoma (KB and A253) and osteosarcoma (HOS and MG-63) cells in this study. We treated cells with 0, 10, 50 and 250 ppm of fluorosilicic acid (domestic or from Fluka, F$\_$6/H$_2$Si), sodium fluorosilicate (F$\_$6/Na$_2$Si), sodium fluoroacetate (FCH$_2$CO$_2$Na), sodium fluoride (NaF) or potassium fluoride(KF) and measured the relative cell survival by MTT assay. At the concentration of < 10ppm, no significant cytotoxicity was observed. At 50 ppm, each cells revealed different response to fluoride treatment. Among cells used in this study, MG-63 was the most resistant to fluoride treatment. Comparable toxicity data from domestic and imported fluorosilicic acids were obtained. When we compared the relative cytotoxicity of fluoride compounds against their fluoride contents, the differences in relative cell survival were smaller. Most of cells showed < 20% of survival at 250 ppm. In order to analyze the pH dependence of the cytotoxicity of fluorosilicates, the pH of cell culture media containing fluorosilicate was adjusted to 7.4 or 6.5 and the relative cytotoxicity was measured. At lower pH, about 10% higher cytotoxicity was obtained. Thus, our data suggested that the toxicity of domestic fluorosilicic acid was similar to that of fluorosilicic acid from Fluka, and the cytotoxicity of fluoride compounds was dependent on the relative content of fluoride and pH.

• 대한소아치과학회지
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• 제31권2호
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• pp.212-222
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• 2004

치아 우식의 예방에 있어서 불소 도포는 효과적인 방법으로 재광화를 촉진하고 탈회를 억제한다. APF gel은 전문가 불소도포용으로 가장 일반적인 방법이었으나 최근 fluoride varnish가 소개되면서 그 사용이 증가되고 있다. 이번 연구의 목적은 fluoride varnish와 acidulated phosphate fluoride(APF) gel이 인공우식 병소에 미치는 영향을 시편의 화학적 고정이나 절단 없이 미세전산화 단층 촬영과 3차원 영상을 이용하여 재광화 효과를 비교해 보고자 함이다. 48개의 우식이 없는 건전한 영구 소구치에 인공우식을 유발하고 각 군당 16개씩, 세 군으로 나누었다. 1군은 대조군으로 어떠한 처치도 시행하지 않았다. 2군은 APF gel을 도포하고 1분 후에 gel을 거즈로 제거하여 수세하고 3군은 fluoride varnish를 도포한 후 45분 후에 얇은 varnish 막을 외과용 칼로 조심스럽게 제거하였다. 그 후 각 시편을 50ml의 인공타액에 3개월 동안 담그어 둔 후 그 사이 기간동안 매달 미세전산화 단층 촬영을 이용하여 3차원 영상을 얻었다. 3차원 영상분석 프로그램으로 재광화 부위의 밀도를 측정하고 다음과 같은 결과를 얻었다. 1. 모든 군에서 시간이 지남에 따라 인공우식 부위의 밀도는 증가하였다. 2. APF gel군과 fluoride varnish군에서 한 달, 두 달, 세 달 후 밀도가 대조군보다 통계학적으로 유의성 있게 높았다(P<0.05). 3. APF gel군과 fluoride varnish군에서 처치전과 처치 한 달 후의 밀도 차이가 대조군보다 통계학적으로 유의성 있게 높았으며 fluoride varnish군에서 처치 한 달 후와 처치 두달 후의 밀도 차이가 대조군과 APF gel군보다 유의성 있게 높았다(P<0.05). 4. Fluoride varnish가 APF gel보다 불소 처치 후 두 달, 세 달 후 재광화 효과가 더 우수하였고 오래 지속되었다.

• Advances in environmental research
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• 제12권2호
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• pp.77-93
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• 2023

The water can be contaminated by natural sources or by industrial effluents. One such contaminant is fluoride. Fluoride contamination in the water environment due to natural and artificial activities has been recognized as one of the major problems worldwide. Among the commonly used treatment technologies applied for fluoride removal, the adsorption technique has been explored widely and offers a highly efficient simple and low-cost process for fluoride removal from water. This review paper the recent developments in fluoride removal from surface water by adsorption methods. Studies on fluoride removal from aqueous solutions using various carbon materials are reviewed. Various adsorbents with high fluoride removal capacity have been developed, however, there is still an urgent need to transfer the removal process to an industrial scale. Regeneration studies need to be performed to more extent to recover the adsorbent in field conditions, enhancing the economic feasibility of the process. Based on the review, technical strategies of the adsorption method including the Nano-surface effect, structural memory effect, anti-competitive adsorption and ionic sieve effect can be proposed. The design of adsorbents through these strategies can greatly improve the removal efficiency of fluoride in water and guide the development of new efficient methods for fluoride removal in the future. This paper describes brief discussions on various low-cost adsorbents used for the effective removal of fluoride from water.