• 대한소아치과학회지
• /
• 제25권4호
• /
• pp.849-857
• /
• 1998

The purpose of this study was to investigate whether fluoride-releasing pit and fissure sealant was more effective in preventing caries than conventional non-fluoride-releasing sealant. Specimens 8mm in diameter were made from sound bovine enamel. Fluoride-releasing pit and fissure sealant(Helioseal F, Vivadent, Schaan, Liechtenstein) and non-fluoride-releasing sealant(Helioseal, Vivadent, Schaan, Liechtenstein) were applied to the specimens and artificial caries was induced. Microhardness and the depth of the carious lesion was measured. The following results were obtained: 1. In group 2, sealed with fluoride-releasing sealant, there was a 58.4% decrease in microhardness. This was significantly less than the 84.4% decrease observed in group 1, sealed with non-fluoride-releasing sealant(p<0.01). 2. The average depth of the artificial carious lesion in group 2 was $30.1{\pm}9.8{\mu}m$. In group 1, sealed with non-fluoride-releasing sealant, the lesion was significantly deeper with an average depth of $58.5{\pm}4.9{\mu}m$(p<0.01). 3. Fluoride-releasing pit and fissure sealant was more anticariogenic compared to non-fluoride-releasing sealant.

• 한국환경보건학회지
• /
• 제31권6호
• /
• pp.475-482
• /
• 2005

This study aimed to determine the fluoride intakes in 120 preschool children aged 3 to 6 residing in Jumunjin (community water fluoridation area) and Gangneung (non-fluoridation area). The parents were asked to collect 24-hour urine samples and to duplicate the samples of all the diets that their children ingested in the day of urine collection. The acid-diffusible fluoride in the food and non-carbonate beverages were isolated by the acid-diffusion technique and then measured with a fluoride electrode. The fluoride in carbonate beverages, drinking waters and urine samples were measured directly with a fluoride electrode. The geometric mean (geometric standard deviation) of daily fluoride intakes from all kinds of diet was 5.99 (2.27) $\mu$g/kg/day in the children in Gangneung and that of the children in Jumunjin was 18.36 (2.69). The amount of fluoride intake by food and drinking water in fluoridation area were significantly larger than that in non-fluoridation area but the statistical difference of fluoride intake by beverages between two areas was not observed. The GMs (GSDs) of daily fluoride excretion by urine of children in non-fluoridation area and in fluoridation area were 8.39 (1.73) and 18.62 (1.77) $\mu$g/kg/day, respectively. The correlation between fluoride intake from diet excluding beverage and urinary excretion was statistically significant. It is concluded that the amount of fluoride intake of children living in fluoridation area did not exceed the upper intake level to avoid the risk of dental fluorosis (2.2 mg/day in 4- to 8-year-olds) and urinary excretion of fluoride was good indicator of fluoride intake from diets.

• 한국치위생학회지
• /
• 제12권1호
• /
• pp.113-122
• /
• 2012

Objectives : This study was carried out to investigate the caries resistant effect of fluoride by dental polishing prior to fluoride application in vitro. Methods : Artificial caries lesion was made on the surface of specimen enamel taken from cow's permanent cuspid on the part of labial surface after resin embedding and polishing. Artificial dental plaque was formed on the 72 dental specimen 25~45 VHN(Vickers Hardness Number) which were divided into three groups(fluoride varnish, APF gel, control) with dental polishing and without polishing respectively. Fluoride varnish and APF gel group with 20 second polishing or without polishing were immersed in the artificial saliva respectively. Control group with or without polishing were immersed in the artificial saliva. Results : 1. Significant difference was not found by fluoride varnish between polishing group and non polishing group (p>0.01). 1) polishing group. The changes of Vickers Hardness Number(VHN) were $14.49{\pm}13.73$. 2) non-polishing group. The changes of VHN were $11.67{\pm}5.39$. 2. Significant difference was not found by APF gel between polishing group and non polishing group (p>0.01). 1) polishing group. The changes of VHN were $8.48{\pm}8.37$. 2) non-polishing group. The changes of VHN were $5.32{\pm}2.59$. Conclusions : Showed no significant difference between polishing group and non-polishing group regardless of fluoride materials (fluoride varnish, APF gel).

• 한국환경보건학회:학술대회논문집
• /
• 한국환경보건학회 2005년도 국제학술대회
• /
• pp.286-288
• /
• 2005

This study was conducted to compare the fluoride concentrations in urine of preschool children aged 3${\sim}$6 years between residing in community water fluoridation area(Kwangju City) and non-fluoridation area(Sungnam City). The acid-diffusible fluoride in the urine and drinking water was isolated by the acid-diffusion technique and measured with a fluoride electrode. The mean daily fluoride excretion to urine of children residing in Kwangju and Sungnam were $1.27{\pm}0.75mgF^-$/g creatinine and $0.87{\pm}47 mgF^-$/g creatinine, respectively. It is concluded from this investigation that the $F^-$concentration in urine sample of kindergarten and drinking water of children living in Kwanju(fluoridated areas) were significantly higher than that of children living in Sungnam(non-fluoridated areas).

• 치위생과학회지
• /
• 제14권4호
• /
• pp.580-588
• /
• 2014

본 연구는 편의추출된 K대학교 학생들을 대상으로 치아우식예방 불화물에 관한 인식과 경험을 알아보고자 실시하였다. 2014년 5월 23일부터 6월 13일까지 대전지역 대학생들을 대상으로 총 450부의 설문지를 배부하여 444부가 회수되었고 응답이 불충분한 20부를 제외한 424부를 본 연구분석에 사용하였으며 치위생학과, 치위생학과를 제외한 보건계열, 비보건계열을 중심으로 비교분석하였다. 1. 치아우식예방을 위한 불소경험은 불소세치제 사용 치위생학과 68.9%, 보건계열 23.6%, 비보건계열 33.3%, 학교 불소용액양치사업 치위생학과 50.0%, 보건계열 46.3%, 비보건계열 44.1%. 시판 불소함유 구강세정제 사용 치위생학과 84.2%, 보건계열 72.4%, 비보건계열 62.2%, 전문가 불소도포 치위생학과 58.9%, 보건계열 30.9%, 비보건계열 30.6%, 수돗물불소농도조정사업 지역거주 치위생학과 13.7%, 보건계열 10.6%, 비보건계열 13.5%로 나타났다. 2. 비치위생학과 학생들은 불화물 사용의 목적 84.6%, 불소함유 구강세정제 63.2%, 불소함유 세치제 61.5%, 전문가 불소도포 56.4%, 수돗물불소농도조정사업 43.6% 순으로 인지하고 있었다. 3. 불화물에 대한 인식경로는 치위생학과 학생은 대학 강의가 가장 높았으나, 비치위생학과 학생은 인터넷과 방송, 보건교사 순이었고 대학강의에 관한 응답은 거의 없었으며 치과의료진에 의한 정보전달은 10%을 약간 상회하였다. 4. 불화물 이용 의향은 자녀를 위한 불소도포, 불소용액양치, 수돗물불소농도조정사업, 자신을 위한 불소도포 순으로 나타났으며, 불소이용시 필요정보는 불화물 부작용, 불화물이용 방법, 불화물이용 비용, 불화물 효과 순으로 나타났다. 5. 불화물을 경험한 군이 그렇지 않은 군에 비해서 불화물이용 의향이 높았으며, 공중구강보건사업보다는 개인이 선택하여 불화물을 경험한 군이 불화물이용에 더 긍정적이었다. 6. 불화물을 인지하는 군이 그렇지 않은 군에 비해서 불화물 이용의향이 높았으나, 불화불에 대한 부작용 인지여부는 이용의향에 영향을 끼치지 않았다. 따라서, 치아우식증 예방을 위한 불화물 인지와 경험은 불화물 이용에 영향을 미치므로 대중매체를 통한 교육 콘텐츠 개발 및 치과병의원을 통한 환자 개별 교육이 필요할 것으로 생각된다.

• 상하수도학회지
• /
• 제10권4호
• /
• pp.73-84
• /
• 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.

• Nuclear Engineering and Technology
• /
• 제53권6호
• /
• pp.1931-1938
• /
• 2021

Uranium ingot is produced by metallothermic reduction of uranium tetrafluoride using magnesium or calcium as reductant. Presence of oxygen containing compounds viz. uranyl fluoride and uranium oxide in the starting uranium fluoride has a significant effect on the firing time, final temperature of the charge, slag-metal separation and hence the metal recovery. As reported in the literature, the maximum tolerable limit for uranyl fluoride in the UF₄ is 2.5 wt% and limit for uranium oxide content is in the range 2-3 wt%. No theoretical or experimental basis is available till date for these limits. Analyses have been carried out in this study to understand the effect of UO₂F₂ concentration in the starting fluoride on the final temperature of the products and thus the reduction characteristics. UF₄ having uranyl fluoride concentration, less than as well as more than 2.5 wt%, have been investigated. Thermodynamic calculations have been carried out to arrive at a general expression for the final temperature attained by the products during calciothermic reduction of UF₄. Finally, an upper limit for the oxygen containing impurities has been estimated using the CaO-CaF₂ phase diagram.

• 한국환경보건학회:학술대회논문집
• /
• 한국환경보건학회 2004년도 International Conference Global Environmental Problems and their Health Consequences
• /
• pp.213-216
• /
• 2004

This work was based on the hypotheses that fingernail clippings can be used as a biomarker for the subchronic exposure to fluoride. This study was conducted to prove the hypotheses and fingernail clippings were collected form 120 preschool children aged $3{\sim}6$ residing in Jumunjin(community water fluoridation area) and Kangnung(non-fluoridation area). The acid-diffusible fluoride in the fingernail clipping was isolated by the acid-diffusion technique and measured with a fluoride electrode. The mean fingernail fluoride as the children's living area were 4.49ug/g(SD 2.43) to Jumunjin and 2.68ug/g(SD 1.13) to Kangnung. As would be expected, the fluoride concentration in fingernail clippings were significantly different between the two geographical groups(p<0.001) determined by t-test.

• 한국지구과학회지
• /
• 제42권5호
• /
• pp.556-570
• /
• 2021

This study presents the data analysis results of groundwater chemistry and the occurrence of fluoride in groundwater obtained from the groundwater quality monitoring network of Korea. The groundwater data were collected from the National Groundwater Information Center and censored for erratic values and charge balance (±10%). From the geochemical graphs and various ionic ratios, it was observed that the Ca-HCO₃ type was predominant in Korean groundwater. In addition, water-rock interaction was identified as a key chemical process controlling groundwater chemistry, while precipitation and evaporation were found to be less important. According to a non-parametric trend test, at p=0.05, the concentration of fluoride in groundwater did not increase significantly and only 4.3% of the total groundwater exceeded the Korean drinking water standard of 1.5 mg/L. However, student t-tests revealed that the fluoride concentrations were closely associated with the lithologies of tuff, granite porphyry, and metamorphic rocks showing distinctively high levels. This study enhances our understanding of groundwater chemical composition and major controlling factors of fluoride occurrence and distribution in Korean groundwater.

• 구강회복응용과학지
• /
• 제22권4호
• /
• pp.349-365
• /
• 2006

State of problem : A number of investigation about increase of surface area via various surface treatments and modification of surface constituent have been carried out. Purpose : The surface characteristics and stability of implants treated with anodic oxidation, fluoride ion incorporation, and groups treated with both methods were evaluated. Material and method : Specimens were divided into six groups, group 1 was the control group with machined surface implants, groups 2 and 3 were anodic oxidized implants (group 2 was treated with 1M $H_2SO_4$ and 185V, group 3 was treated with 0.25M $H_2SO_4$ and $H_3PO_4$ and 300V). Groups 4, 5 and 6 were treated with fluoride. Group 4 was machined implants treated with 0.1% HF, and groups 5 and 6 were groups 2 and 3 treated with 10% NaF respectively. Using variable methods, implant surface characteristics were observed, and the implant stability was evaluated on rabbit tibia at 0, 4, 8 and 12 weeks. Result : 1. In comparison of the surface characteristics of anodic oxidized groups, group 2 displayed delicate and uniform oxidation layer with small pore size containing Ti, C, O and showed mainly rutile, but group 3 displayed large pore size and irregular oxidation layer with many crators. 2. In comparison of the surface characteristics of fluoride treated groups 4, 5, 6 and non-fluoride treated groups 1, 2, 3, the configurations were similar but the fluoride treated groups displayed rougher surfaces and composition analysis revealed fluoride in groups 4, 5, 6. 3. The fluoride incorporated anodic oxidized groups showed the highest resonance frequency values and removal torque values, and the values decreased in the order of anodic oxidized groups, fluoride treated group, control group. 4. According to implant stability tests, group 2 and 3 showed significantly higher values than the control group (P<.05). The fluoride treated groups showed relatively higher values than the non fluoride treated groups and there were significant difference between group 4 and group 1 (P<.05). Conclusion : From the results above, it can be considered that the anodic oxidation method is an effective method to increase initial bone stability and osseointegration and fluoride containing implant surfaces enhance new bone formation. Implants containing both of these methods should increase osseointegration, and reduce the healing period.