Availability Of Fluoride Research Articles

In vitro assessment of a toothpaste range specifically designed for children

A number of factors should be taken into account when designing toothpaste formulations for use by children at the different stages of their development. While adult toothpaste formulations may provide caries prevention benefits for children at risk of caries, these formulations may also contain higher levels of abrasive in order to address the staining needs of the adult population owing to smoking and the consumption of dietary chromogens such as coffee and tea, which are not normally found in the diet of children. While toothpastes formulated for adults are also likely to contain higher concentrations of surfactant and flavour, many children prefer toothpastes with mild flavours and modest foaming characteristics. An ideal children's toothpaste formulation should therefore aim to maximise fluoride availability, with appropriate abrasivity, while still delivering effective cleaning, as well as levels and types of flavour and surfactant to provide an acceptable brushing experience. Selection of toothpaste flavour types for children of different ages should ideally be based directly upon preference data from children. Flavours perceived as pleasant during brushing studies have been linked to increased brushing time, which, in turn, can increase the delivery and efficacy of fluoride from toothpastes. Therefore, manufacturers select tested, child-friendly flavours to maximise compliance, providing a more pleasurable brushing experience and oral health benefits.

The cariostatic mechanisms of fluoride

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.

Caries risk profile of Korean dental patients with severe intellectual disabilities.

This study evaluated the caries risk profile of patients with severe intellectual disabilities (IDs) who received dental treatment under general anesthesia. One hundred and two patients with ID [ID group, mean age (SD); 23.8(9.3)] and 100 healthy patients without ID [NID group, mean age (SD); 23.19(3.3)] were included. Medication, disability type, oral hygiene maintenance, and cooperation of the patients were investigated. Dietary habits, plaque index, mutans streptococci counts, fluoride availability, and salivary buffering were scored and analyzed using the Cariogram. The mean chance of avoiding caries (SD) was 28.1(20.4) in the ID group and 54.7(18.4) in the NID group. The ID group had significantly higher numbers of decayed and missing teeth, but fewer filled teeth than the NID group (p < .05). Significant disparities existed in the distributions of all caries-related factors except for mutans streptococci counts between the two groups (p < .05). The low chance to avoid future caries in ID patients was closely associated with insufficient oral hygiene maintenance (p < .05). Fluoride availability was strongly associated with the chance of avoiding caries in the ID group. Dental patients with severe ID exhibited a higher risk of developing caries than normal patients. Among several caries-related factors, insufficient oral hygiene maintenance and low fluoride availability most contributed to the high risk.

Contemporary perspective on the use of fluoride products in caries prevention

Dental caries has declined in the 40 years since fluoridated toothpastes were introduced. Much has been learned about why fluoride is so effective and how this knowledge can be used to optimise programmes for caries prevention. Fluoride works through enhancing the remineralisation of early stages of caries and by inhibiting demineralisation, which would lead to dental caries. Remineralisation involves the deposition of calcium phosphates from saliva to rebuild partly dissolved enamel crystallites. When fluoride is incorporated the dissolution of these reinforced crystallites will be reduced during a subsequent sugar-induced and bacteria-mediated acid attack. Fluoride works primarily when it is present in the oral cavity. Based on our understanding of the fluoride mode of action the following advice can be given from clinicians to their patients: The fluoride concentration in oral products is related to efficacy but the concentration does not necessarily need to be high to be efficacious. Fluoride availability throughout the day is important; this can be achieved when fluoride products are used as part of the daily hygiene routine (F-brushing or rinsing). Alternatively, when fluoride is provided in the drinking water or through professionally applied F-varnishes or gels, the patient will benefit without requiring daily compliance to its use. The latter methods are particularly effective as additional treatments in high caries individuals.

An efficient incentive of Nitrate and Fluoride on Organic highland cropping systems

Exerting necessitated concentrations of Nitrate and fluoride to the organic highland cropping systems is a vital management technique. All the chemical elements of the earth's crust occur in widely differing omnipresent concentrations, due to their different nuclear chemical formation and geochemical history. The use of biological nitrogen and fluoride inputs complicates its balancing act due to dandier uncertainty in inorganic Nitrogen and Fluoride availability. The growers to strike maintain Nitrogen provisioning to support crop growth and retention of limit pollution followed by fluoride associated soils. Due to various activities of the man in domestic field, agriculture area and industrial establishment the environment around us consisting soil, water and air gets polluted. Fluoride inexhaustible concentrations forbid the growth of crop even though nitrates reposit in the cultivated soils. The purpose of this project was to establish kinetics when nitro fluorides associated in the highland soils to different crop systems towards environmental pollutions. Cordia Africana and alfalfa are the plants which make soil to get enrichment of Nitrates and deescalate of concentrations of fluorides from cultivated soils through its decomposition. This entire study went on its conventionally tilled crops followed by Cordia Africana and alfalfa stems and leaf particles. Surface soil nitrate concentrations were measured weekly, biweekly by volumetric analysis and nitrate leaching was estimated from tension Lysimeters which were buried at the soil bedrock interface. Subsequently by using Orion 720A fluoride ion meter, de- escalated concentrations of fluorides have been measured. The demonstrated concentrations of Soil in NO3 variables, coefficients of variations from the mean concentrations across all samplings have been recorded sporadically. The total area of the soil bed was maintained the same P H values until project was completed by weigh Lysimeters. The timing of elevated Nitrate concentrations (10-15PPM) and the concentrations of fluoride in deeper soil water corresponds with fallow periods. These dynamics will assist growers in adapting the timing management operations and reduces nitrate departures.

The occurrence and hydrochemistry of fluoride and boron in carbonate aquifer system, central and western Estonia

Silurian-Ordovician (S-O) aquifer system is an important drinking water source of central and western Estonia. The fluoride and boron contents of groundwater in aquifer system vary considerably. The fluoride concentration in 60 collected groundwater samples ranged from 0.1 to 6.1 mg/l with a mean of 1.95 mg/l in the study area. Boron content in groundwater varied from 0.05 mg/l to 2.1 mg/l with a mean value of 0.66 mg/l. Considering the requirements of EU Directive 98/83/EC and the Estonian requirements for drinking water quality, the limit value for fluoride (1.5 mg/l) and for boron (1.0 mg/l) is exceeded in 47 and 28 % of wells, respectively. Groundwater with high fluoride and boron concentrations is found mainly in western Estonia and deeper portion of aquifer system, where groundwater chemical type is HCO3-Cl-Na-Mg-Ca, water is alkaline, and its Ca(2+) content is low. Groundwater of the study area is undersaturated with respect to fluorite and near to equilibrium phase with respect to calcite. The comparison of TDS versus Na/(Na + Ca) and Cl/(Cl + HCO3) points to the dominance of rock weathering as the main process, which promotes the availability of fluoride and boron in the groundwater. The geological sources of B in S-O aquifer system have not been studied so far, but the dissolution of fluorides from carbonate rocks (F = 100-400 mg/kg) and K-bentonites (F = 2,800-4,500 mg/kg) contributes to the formation of F-rich groundwater.

Influences of charcoal and bamboo charcoal amendment on soil-fluoride fractions and bioaccumulation of fluoride in tea plants

High levels of fluoride in tea plants pose a potential health risk to humans who drink tea. It has been demonstrated that tea plant fluoride is closely related to the available fluoride in soil. But approaches that could be used to regulate the availability of fluoride in soil have been rarely seen. This study aims to investigate how the addition of charcoal and bamboo charcoal affected soil fluoride availability and bioaccumulation of fluoride in tea plants. In a microcosm experiment, tea plants were grown in the tea garden soil mixed with different amounts of charcoal and bamboo charcoal [that is, 0.5, 1.0, 2.5, and 5.0% (w/w)]. Soil-fluoride fractions and fluoride accumulated in tea plants were determined using the sequential extraction and ion selective electrode method. Obtained results showed that both charcoal and bamboo charcoal additions significantly enhanced the concentrations of Fe/Mn oxide-bound fluoride, but significantly reduced the concentrations of water-soluble and exchangeable fluoride (p<0.05) in soil. Charcoal and bamboo charcoal additions also significantly decreased the amounts of fluoride in tea roots and tea leaves (p<0.05). However, the additions of charcoal and bamboo charcoal had no impacts on the tea quality, as indexed by the concentrations of polysaccharides, polyphenols, amino acids, and caffeine in tea leaves. These results suggested that application of charcoal and bamboo charcoal may provide a useful method to reduce the availability of fluoride in soil and the subsequent fluoride uptake by tea plants.

Dental caries in Mexican schoolchildren: A comparison of 1988-1989 and 1998-2001 surveys

Objectives: To compare two surveys across seven states for the prevalence of dental caries among Mexican schoolchildren. Study Design: Analysis of two cross-sectional surveys: Schoolchildren from 6 to 10 years of age were examined in the 1988–1989 survey and 6- to 10-year-old and 12-year-old students were included in the 1998–2001 survey. The baseline data of seven states were available for analysis. Representative probability samples were conducted statewide in both surveys. The World Health Organization (WHO) method was used to obtain the dental caries index (dmft, DMFT). At present, additional and more recent epidemiological data representative statewide in Mexico are unavailable. Results: The participants were 9798 schoolchildren in the 1988–1989 survey and 16882 schoolchildren in the 1998–2001 survey. The prevalence of caries in children ages 6 to 10 years was 86,6% in the first survey and 65,5% in the second survey, showing a 24,4% reduction. The primary teeth index in the first survey was dmft = 3,86 (IC95% 3,68 4,04) and in permanent teeth, it was DMFT = 1,03 (IC95% 0,95 1,11). In the second survey, the comparable values were dmft = 2,36 (IC95% 2,20 2,52) and DMFT = 0,35 (IC95% 0,29 0,40), corresponding to a reduction of 38,89% and 66,02% in the primary and permanent dentition, respectively. Treatment needs remain high: In the second survey, as 92,75% of the index DMFT was conformed as decayed teeth. Conclusion: Overall, we detected a downward trend in the dental caries indices, particularly in the permanent dentition. The increase in the availability of fluoride likely contributed to the observed decline in dental caries. Key words:Schoolchildren, dental caries, treatment needs, salt fluoridation, Mexico.

Contemporary fluid intake and dental caries in Australian children

In Australia, caries experience of 6-year-old and 12-year-old children has increased since the mid to late 1990s. Previously, caries rates had declined, attributable to community water fluoridation. The recent caries increase has been attributed speculatively to changes in fluid intake, including increased consumption of sweet drinks and bottled waters. Increasing urbanization and globalization have altered children's diets worldwide, promoting availability and access to processed foods and sweet drinks. Studies in Australia and internationally have demonstrated significant associations between sweet drink intake and caries experience. Despite widespread fluoride availability in contemporary Australian society, the relationship between sugar consumption and caries development continues and restricting sugar intake remains key to caries prevention. Caries risk assessment should be included in treatment planning for all children; parents should be advised of their child's risk level and given information on oral health promotion. Readily-implemented caries risk assessment tools applicable to parents and clinicians are now available. Public health information should increase awareness that consuming sweet drinks can have deleterious effects on the dentition as well as the potential for promoting systemic disease. Restricting sales of sweet drinks and sweet foods and providing healthy food and drinks for purchase in schools is paramount.

Influence of Individual Saliva Secretion on Fluoride Bioavailability

The aim of this preliminary investigation was to compare the individual saliva secretion rate with the fluoride bioavailability in saliva after using sodium fluoride and amine fluoride.Methods:To assess oral fluoride kinetics 10 highly trained volunteers brushed their teeth with one of the formulations and saliva was collected. The amount of saliva was measured, and the fluoride content was determined. Data underwent statistical analysis using the Mann-Whitney-U test and Pearson correlation. The ex vivo experiment I included individual saliva collection of the same volunteers. Then the oral hygiene products were solved in equal amounts of whole saliva (ex-vivo experiment II), and the fluoride content was measured. Finally, both products were dispersed in distilled water (ex-vivo experiment III) to calculate the dissociation of both products in water.Results:In vivo results of fluoride content after 3 min. tooth brushing demonstrated a negative correlation with saliva secretion: for NaF r = -0.695 (p<0.01) and for amine fluoride r = -0.446 (p<0.01). The in-vitro experiment I resulted for NaF in 251.7±22.4 µg/g fluoride and for amine fluoride in 171.7±14.4 µg/g.Conclusions:Fluoride bioavailability of saliva after exposure to NaF was higher compared to amine fluoride. The individual secretion rate changes the fluoride content and normal secretors keep the fluoride availability longer.

Influence of Fluoride Availability of Dentifrices on Eroded Enamel Remineralization in situ

Remineralization of eroded enamel by dentifrices containing similar sources/concentrations of fluoride was investigated in situ. Fifty-three subjects completed a double-blind crossover study with 3 randomly assigned dentifrice treatments: placebo (0 ppm F, PD); reference (1,450 ppm NaF, RD) and test (1,450 ppm NaF + 5% KNO₃, TD). Fluoride availability for each dentifrice was analyzed in vitro by standard tests (1-min fluoride release rate and enamel fluoride uptake). The subjects wore palatal appliances holding bovine enamel specimens previously eroded in vitro. Surface microhardness was determined before and after the in vitro erosive challenge, after in situ remineralization and after a second in vitro erosive challenge. ANOVA and pairwise comparisons were performed (α = 0.05). TD was superior to RD in the fluoride release tests, but similar to RD in the enamel fluoride uptake test. The mean percent surface microhardness recovery was 21.9 (standard deviation 8.0) for PD, 28.6 (8.0) for RD and 36.0 (8.0) for TD. The mean percent relative erosion resistance change was –58.8 (12.7) for PD, –31.3 (12.7) for RD and –27.3 (12.6) for TD. Both fluoride-containing dentifrices provided superior remineralization (p < 0.001) and erosion resistance (p < 0.001) compared to PD. The percent surface microhardness recovery demonstrated by the TD was significantly greater than for the RD (p < 0.001). There was no significant difference (p = 0.073) between TD and RD in relative resistance to further erosive challenge. The results suggest that fluoride availability may be different in dentifrices with similar sources/concentrations of fluoride, providing different levels of remineralization of eroded enamel.

Fluoride availability from natural resources in The Gambia - implications for oral health care

Changing food patterns in combination with ineffective oral hygiene measures and insufficient bioavailability of fluoride from drinking water and other sources seem to impair the dental health status in developing countries, especially in the younger population. Therefore, preventive programmes in controlling dental caries progression should be based on local conditions. For mapping the drinking water fluoride content throughout The Gambia, samples of water from rural community wells, public water taps, commercial mineral water, and from the Gambia-River were measured. Additionally, fluoride concentrations of locally extracted table salt and green tea were determined. Showed the need for supplementary fluoride intake, because natural dietary fluoride availability is very low. Age-related recommendations for oral health care and for additional fluoride bioavailability are given, taking into account local socio-economic conditions in the Republic of The Gambia and similar developing countries.

Low-fluoride dentifrice and the effect of post-brushing rinsing on fluoride availability in saliva

Post-brushing water rinsing may reduce the risk of fluoride (F) ingestion from dentifrice, however the decreased salivary F bioavailability may compromise any consequent anticaries benefits. As the use of low-F concentration dentifrices is still a matter of debate, a comparison was made between the salivary F bioavailability after brushing with a conventional F dentifrice followed by a water rinse and after brushing with a low-F dentifrice without post-brushing rinse. In a crossover, blind study, F concentration in saliva of 5 adult volunteers was determined after brushing with a low-F dentifrice (500 microg F/g) or with a conventional F concentration dentifrice (1100 microg F/g), followed or not by a 15-mL water rinse. Salivary F bioavailability was reduced by 2.5 times when a water rinse was used (p<0.05), irrespective of dentifrice concentration, and it was 2 times lower for the low-F dentifrice (p<0.05). The salivary F bioavailability was similar when the low-F dentifrice was used without post-brushing rinse and the conventional F dentifrice was followed by a rinse (p>0.05). Habits of post-brushing rinse should be taken into account on the recommendation of dentifrice use by young children, considering the risks and benefits balance of F use.

Availability of fluoride from meals given to kindergarten children in Brazil

The aim of this study was to evaluate the amount of fluoride supplied daily in the meals given in 44 public kindergarten schools in Bauru, Brazil. In addition, the fluoride concentration of water supplies and its impact on the amount of fluoride found in the meal samples were also investigated. Meal samples and water were collected during 2 weeks (10 working days) in public kindergarten schools. Samples of meals were homogenized with known volumes of deionized water. Fluoride present in meal samples was analyzed with the ion-specific electrode (Orion 9609), after hexamethyldisilazane-facilitated diffusion. Fluoride in water samples was analyzed with the same electrode, after buffering with TISAB II. All the analyses were made in duplicate. Fluoride analyzed (mean+/-SD) was 0.50+/-0.20 microg/ml, ranging from nondetectable to 1.42 microg/ml for water samples (n=424) and 0.067+/-0.059 mg, ranging from 0.007 to 0.580 mg for meal samples (n=431). A weak but significant correlation was observed between the amount of fluoride in meals and fluoride concentration in water supplies (r=0.139, P=0.0042). Despite the seemingly small role played by school meals in the total daily fluoride intake, they can contribute to the total fluoride intake of children on a chronic basis, when in association with other fluoride products. Additionally, the impact of fluoridated public water supply on the final fluoride concentration of the school meals analyzed may be regarded as low.

Alkali-soluble fluoride deposition on enamel after professional application of topical fluoride in vitro

Since the efficacy of topical fluoride products is related to the fluoride (F) availability and its reactivity with enamel, this study was conducted. The F concentration of the following materials was verified: I- acidulated phosphate fluoride (APF) gel (1.23% F), II- APF foam (1.23% F) and III- Varnish (2.26% F). Forty blocks of bovine enamel were divided into 4 groups and treated according to the materials described, being one of them used as control. Loosely bound fluoride (''CaF2'') was determined on enamel after extraction with 1.0M KOH and analyzed by ion-selective electrode. Total F concentration found in gel was 12,642, in foam 12,755 and in varnish 23,183 mg F/g. All products formed statistically higher amounts of ''CaF2'' on enamel compared to the control group (p < 0.05), but the difference between them was not significant (p > 0.05). Thus, ''CaF2'' formation was not proportional to the total F content in the products, suggesting that the pH and the vehicle used are more important.

Evaluation of fluoride release from commercially available fluoride varnishes

The authors conducted a study to evaluate the fluoride released from two fluoride varnishes: Duraphat (Colgate-Palmolive Co., New York) and Duraflor (Pharmascience Inc., Montreal). Fluoride-release information for these commercially available dental products has not been available to clinicians treating children at risk of developing dental caries. The authors painted enamel slabs from primary molar teeth with 30 milligrams of two varnishes: nine samples received Duraphat, nine received Duraflor and five samples served as controls. The samples were immersed in buffered calcium phosphate solution (pH, 6.0) to simulate the oral environment, and the amount of fluoride released was measured weekly for six months. From week 4 to the end of the study, Duraphat released significantly more fluoride than Duraflor. Duraflor continued releasing fluoride until week 19, while Duraphat released fluoride until week 28. The authors found greater variability in the release of fluoride from the Duraflor samples than from the Duraphat samples. Two-thirds of the fluoride was released from both products by the end of the study. Both varnishes released fluoride for five to six months. However, the two products exhibited differences in their release kinetics. These findings show that either of the fluoride varnishes may maintain a high level of fluoride in plaque fluid around primary teeth over a long period, but that the availability of fluoride may vary among tubes of the same product and between the two products themselves.

Direct tensile strength of visible light‐cured restorative materials containing fluoride

The purpose of this study was to compare the fluoride release and direct tensile strength at 24 h, 1 month, and 3 months of two conventional glass–ionomers, two visible light‐cured resin‐modified glass–ionomers, a polyacid resin composite and two resin composites. The results were statistically analysed using ANOVA and Fisher’s PLSD at α=0·05. The data on fluoride release indicated that the immersion period (24 h, 1 month, and 3 months) significantly influenced the cumulative amount of fluoride released (P &lt; 0·001). The direct tensile strengths after 1 month of storage were significantly higher than those after 24 h or 3 months of storage (P &lt; 0·001). Thus, the cements and resins were not weakened by the loss of fluoride. Conventional glass–ionomer cement showed the lowest direct tensile strength. Resin‐modified glass–ionomer behaved in between the resin composites and conventional glass–ionomers in terms of all three testing times, however, the polyacid resin composites most closely resembled the resin composites. The polyacid resin composites had greatly enhanced direct tensile strength, however, this material also reduced the fluoride availability.

Patterns of fluoride intake from birth to 36 months.

Dental fluorosis prevalence has increased in the United States, Canada, and other nations due to the widespread availability of fluoride in many forms, with fluoride ingestion during the first three years of life appearing most critical in fluorosis etiology. With few contemporary studies of fluoride ingestion in this age group, the purpose of this paper is to describe patterns of estimated fluoride ingestion from birth to 36 months of age from water, dentifrice, and dietary fluoride supplements and combined. Repeated responses to separate series of questions about water intake, use of fluoride dentifrice, and use of fluoride supplements were collected by questionnaire as part of the longitudinal Iowa Fluoride Study and used to estimate fluoride intake. Estimated intake is reported by source and combined at different ages. Effects of subject age and other covariates on fluoride intake were assessed using regression methods appropriate for the analysis of correlated data. For most children, water fluoride intake was the predominant source, especially through age 12 months. Combined daily fluoride intake increased through 9 months, was lower at 12 and 16 months, and increased again thereafter. Mean intake per unit body weight (bw) was about 0.075 mg F/kg bw through 3 months of age, 0.06 mg F/kg bw at 6 and 9 months, 0.035 mg F/kg bw at 12 and 16 months, and 0.043 mg F/kg bw from 20-36 months. Depending on the threshold chosen (e.g., 0.05 or 0.07 mg F/kg bw), variable percentages of the children exceeded the levels, with percentages greatest during the first 9 months. Regression analyses showed fluoride intake (mg F/kg bw) from 1.5-9 months to decrease with increasing child's age, mother's age, and mother's education, with a complex three-way interaction among these factors. From 12-20 months, fluoride intake increased with increasing child age and decreased with increasing mother's age. No statistically significant relationships were found for fluoride intake from 24-36 months. There is considerable variation in fluoride intake across ages and among individuals. Longitudinal studies may be necessary to fully understand the relationships between fluoride ingestion over time and development of fluorosis.

Saliva and Dental Caries

Caries is a unique multifactorial infectious disease. Our understanding of etiological factors, the progress of the disease, and the effectiveness of prophylactic procedures have led us to believe that we understand the disease. However, we still have too few answers to many questions: "Why can we not predict who will get the disease?" "Why do we not become immunized?" "How much saliva is enough?" or "Which salivary components are protective?" and "Which salivary components predispose for caries?" It is generally accepted, however, that saliva secretion and salivary components secreted in saliva are important for dental health. The final result, "caries to be or not to be", is a complex phenomenon involving internal defense factors, such as saliva, tooth surface morphology, general health, and nutritional and hormonal status, and a number of external factors-for example, diet, the microbial flora colonizing the teeth, oral hygiene, and fluoride availability. In this article, our aim is to focus on the effects of saliva and salivary constituents on cariogenic bacteria and the subsequent development of dental caries.

Availability of fluoride to plants grown in contaminated soils

Two pot experiments were carried out to study uptake of fluoride (F) in clover and grasses from soil. Fluoride concentrations in t Trifolium repens (white clover) and t Lolium multiflorium (ryegrass) were highly correlated with the amounts of H2O− and 0.01 t M CaCl2−extractable F in soil when increasing amounts of NaF were added to two uncontaminated soils (r=0.95–0.98, t p<0.001). The amounts of H2O− or 0.01 t M CaCl2−extractable F did not explain the F concentrations to a similar extent in t Agrostis capillaris (common bent) grown in 12 soils (Cambic Arenosols) collected from areas around the Al smelters at A: rdal and Sunndal in Western Norway (r=0.68–0.78). This may be due to variation in soil pH and other soil properties in the 12 soils. Soil extraction with 1 t M HCl did not estimate plant−available F in the soil as well as extraction with H2O or 0.01 t M CaCl2. Fluoride and Al concentrations in the plant material were positively correlated in most cases. Fluoride and Ca concentrations in the plant material were negatively correlated in the first experiment. No consistent effects were found on the K or Mg concentrations in the plant material. The F accumulation in clover was higher than in the grasses. The uptake from soil by grasses was relatively low compared to the possible uptake from air around the Al smelters. The uptake of F in common bent did not exceed the recommended limit for F contents in pasture grass (30 mg kg−1) from soil with 0.5−28 mg F(H2O) kg−1 soil. The concentration in ryegrass was about 50 mg F kg−1 when grown in a highly polluted soil (28 mg F(H2O) kg−1 soil). Concentrations in clover exceeded 30 mg F kg−1 even in moderately polluted soil (1.3–7 mg F(H2O) kg−1 soil). Liming resulted in slightly lower F concentrations in the plant material.