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PubMed2003

Adsorption kinetics of fluoride on low cost materials.

Adsorption is one important technique in fluoride removal from aqueous solutions. The viability of adsorption techniques is greatly dependent on the development of adsorptive materials. A large number of materials have been tested at a fluoride concentration greater than 2 mg/l, and the lowest limit for fluoride reduction by them is about 2 mg/l. Decreasing the fluoride concentration to less than 2 mg/l, most of the tested materials displayed a very low capacity of fluoride removal. This paper has concentrated on investigating the adsorption kinetics and adsorption capacity of low cost materials at a low initial fluoride concentration. The experiments were carried out at a natural pH, and radioisotope 18F rather than 19F was used since 18F can be rapidly measured by measuring the radioactivity with a resolution of 1 x 10(-13)mg or 0.01 microCi. The tested materials are hydroxyapatite, fluorspar, calcite, quartz and quartz activated by ferric ions. Their adsorption capacities follow the order: Hydroxyapatite>Fluorspar>Quartz activated using ferric ions>Calcite>Quartz. The uptake of fluoride on hydroxyapatite is an ion-exchange procedure and follows the pseudo-first- and second-order equations, while the uptake of fluoride on the others is a surface adsorption and follows the pseudo-second-order equation. Calcite has been seen as a good adsorbent in fluoride removal and has been patented. However, our data suggested that its adsorption capacity is only better than quartz. The external mass transfer is a very slow and rate-determining step during fluoride removal from the aqueous solution. Under static conditions, there was no relative movement between adsorbents and solutions, the fluoride uptake was at a very slow rate and the adsorbent properties did not significantly affect the fluoride uptake. Under shaken conditions, the adsorption of fluoride was controlled by the adsorbent structure and chemical properties.

Adsorption↗
PubMed1998

Fluoride release and uptake by glass-ionomers and related materials and its clinical effect.

The anticariogenic effect of silicate cement is well known and considered a result of fluoride release. In several studies a similar fluoride release from conventional glass-ionomer cement (GIC) has been established. Therefore, an anticariogenic effect may be predicted from the GICs too. In my studies the fluoride release was studied by exposing the test specimens to a continuous flow of running tap water. At certain time periods the specimens were transferred for 1 week in a small amount of deionized water (5 ml). The determination of the fluoride content of the solution showed the fluoride release of the material at that time. There was an initial 'burst' effect of fluoride release and then the release gradually decreased, settling at a constant level. The long-term release from conventional GICs was shown to remain on the same level for at least 8 years. The amount of the constant release did not differ much between different brands. Resin-modified GICs released fluoride to the same extent and in the similar way as conventional GICs whereas polyacid-modified composites ('compomers') did not show an initial fluoride 'burst' effect. To study the fluoride binding ability of GICs, specimens which had been exposed to running water for different periods of time were treated with a 50 ppm fluoride solution. After this 'recharging' GIC and resin-modified GIC specimens released more than twice the amount of fluoride released before the treatment. The fluoride treatment had no effect on polyacid-modified composites or on fluoride-containing composites or on the amalgams. To get an impression of the clinical effect of GICs a questionnaire was handed out to practitioners attending courses in the Nordic countries and in Australia during the period 1991-1992 which resulted in 954 answers. Among other questions, the dentists were asked if they had observed caries and gingival inflammation in association with GIC and composite fillings. According to the opinion of most dentists caries and gingival inflammation had never or only seldom been observed in association with GIC fillings whereas most dentists had observed these complications often in connection with composite restorations.

Biocompatible Materials↗
PubMed1999

Fluoride release/uptake of polyacid-modified resin composites (compomers) in neutral and acidic buffer solutions.

The aim of the present study was to evaluate the fluoride uptake/release of polyacid-modified resin composites (compomers) in neutral and acidic buffer solutions. Two compomers (Dyract and Compoglass) were tested and the conventional glass-ionomer cement (GIC) Vivaglass Base served as a control. Forty specimens were fabricated from each of the respective materials. Twenty of these specimens were placed in artificial saliva and the other 20 specimens in a fluoridated dentifrice slurry for 5 min. Then, 10 fluoridated and 10 non-fluoridated specimens were immersed in a neutral buffer solution (pH 6.8), and the other specimens were immersed in an acidic solution (pH 4.0). After 1, 2, 3, 4, and 5 days the samples were again placed in either a fluoridated dentifrice slurry or saliva for 5 min, after which time they were transferred to fresh buffer solutions. The fluoride content of the solutions was assessed with a fluoride sensitive electrode. Fluoride release from all the materials decreased continuously during the experiment, with a significantly higher release in the acidic solution compared to the neutral buffer solution. Fluoridation did not result in an increased fluoride release for the compomers. However, the conventional GIC revealed a significantly higher fluoride release after fluoridation. It is concluded that Dyract and Compoglass can not be replenished with fluoride, irrespective of the pH value of the environment.

Analysis of Variance↗
PubMed2002

Fluoride release and uptake characteristics of aesthetic restorative materials.

The aims of this study were firstly to investigate the fluoride-releasing characteristics of two composite resins (Tetric and Valux Plus), two polyacid-modified resin composites (Compoglass and Dyract), and conventional glass-ionomer cement (Ceramfil beta). The second aim was to assess the fluoride uptake and subsequent release from the same range of materials. Fifteen discs (6 mm diameter and 1.5 mm height) were prepared for each material. Each disc was immersed in 4 ML of deionized water within a plastic vial. The release of fluoride was measured daily at 1, 2, 3, 4, 5, 15, 30 and 60 days. After daily fluoride release was measured for 60 days, samples were refluoridated in 1000-ppm sodium fluoride (NaF) solutions (pH 6.6) for 10 min and fluoride release was measured daily for a total of 5 days. The release of fluoride from aesthetic restorative materials was measured by using specific fluoride electrode and an ionanalyser. Results were statistically analysed by two-way repeated measure ANOVA and Duncan's multiple range test. The results revealed that all fluoride-containing materials (Ceramfil beta, Compoglass, Dyract, Tetric) released fluoride initially and the release was greatest at the first day. At any time during the test period Ceramfil beta released the most and Valux Plus did not release any detectable fluoride (P < 0.01). Sample exposures to 1000 ppm NaF solution increased the 24-h fluoride release from all fluoride-containing materials. This difference lasted only 24-48 h after exposure. Ceramfil beta had a tendency to recharge not seen with the other materials (P < 0.05).

Analysis of Variance↗
PubMed2006

Fluoride exposure and bone status in patients with chronic intestinal failure who are receiving home parenteral nutrition.

BACKGROUND AND OBJECTIVE: Metabolic bone disease is frequent in chronic intestinal failure. Because fluoride has a major effect on bones, the status of both fluoride and bone was studied in long-term home parenteral nutrition (HPN) patients. DESIGN: We studied 31 adults aged (x +/- SD) 56.3 +/- 15.1 y, mainly patients with short-bowel syndrome, who had been receiving HPN for >1 y. Bone mineral density (BMD) was measured by absorptiometry, and serum fluoride was measured by using a fluoride-sensitive electrode. All patients ate and drank ad libitum. HPN (3.4 +/- 1.2 times/wk) complemented oral nutrition. Potential explicative factors were estimated by using a linear regression model (mixed-effects model). RESULTS: Of 120 fluoride dosages (2-6/patient), 102 were above the upper normal limit (1.58 micromol/L) at the laboratory. Mean (+/- SD) daily fluoride supply was 8.03 +/- 7.71 mg (US adequate intake: 3.1 mg/d for women and 3.8 for men; tolerable upper normal limit: 10 mg/d); intravenous fluoride varied from 0.06 to 1.45 mg, and oral fluoride varied from 0.09 to 27.8 mg. Serum fluoride concentrations were correlated with creatinine clearance and fluoride supply. BMD was significantly lower in the femoral neck than in the spinal area. After adjustment for sex and the duration of HPN, only the effect of serum fluoride on spinal BMD was significant. Two patients had symptoms of fluorosis, eg, calcaneum fissures, interosseous calcifications, or femoral neck osteoporosis. CONCLUSIONS: In chronic intestinal failure, high intakes of fluoride are frequent because of the beverages ingested to compensate for stool losses. Hyperfluoremia has an effect on bone metabolism and may increase skeletal fragility. The consumption of fluoride-rich beverages for extended periods is therefore not advisable.

Adult↗
PubMed1994

Fluoride supplements: current effectiveness, side effects, and recommendations.

A critical review of the literature was conducted to determine the current effectiveness of fluoride supplements in caries prevention and their role as risk factors for dental fluorosis. Use of fluoride supplements by young children is idiosyncratic and all of the studies which investigated the effectiveness of this regimen suffered from a significant drop in the number of participants receiving daily supplements. The scientific evidence supports the efficacy of fluoride supplements in caries prevention but there is weaker support for their effectiveness. Fluoride supplements are a risk factor for dental fluorosis, though their contribution to the increase in fluorosis prevalence is less than that of water fluoridation and fluoridated dentifrices because of their more limited and shorter use. There is also evidence that fluoride supplements are used inappropriately in fluoridated areas. The availability of optimal levels of fluorides in beverages in non-fluoridated communities raises the question of whether fluoride supplements are needed in the 1990s, and whether it is time to consider the total fluoride intake not only from water but also from foods, beverages, and dentifrices, when recommending supplements. A re-evaluation of the need for and dosage schedules of fluoride supplements is warranted.

Adolescent↗
PubMed2006

Availability of fluoride from meals given to kindergarten children in Brazil.

OBJECTIVES: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Animals↗
PubMed1988

The pre- and posteruptive effects of fluoride in the caries decline.

The widespread availability of fluoride from many sources is accepted as a major reason for the caries decline among children in developed countries. There is still controversy, however, about its principal mode of action. This article reviews the evidence on fluoride's preeruptive and posteruptive effects, and suggests reasons for its continuing role in the caries decline. Early fluoridation studies accepted that fluoride acted preruptively through incorporation into developing enamel; but further research could not explain why fluoride levels were not clearly higher in enamel exposed to fluoride, nor why there were no clear correlations between caries experience and enamel fluoride concentration. Instead, considerable evidence suggests that fluoride acts mainly, though not entirely, through posteruptive remineralization of demineralized enamel. Caries experience has declined in nonfluoridated as well as in fluoridated areas, though DMF scores are still consistently lower in fluoridated areas. Posteruptive remineralization effects are seen from fluoridated drinking water as well as with fluoride from other sources. The continuing caries decline, beyond the level suggested by early fluoridation field trials, can be attributed either to more efficient remineralization or to long-term, intraoral ecological change, or to both.

Child↗
PubMed2006

Fluoride content of still bottled water in Australia.

BACKGROUND: Recently there has been a considerable increase in the consumption of bottled water in Australia. Overseas studies have found the fluoride levels in many bottled waters are well below levels considered optimal for preventing dental caries. This raises the concern that if bottled water is regularly consumed an effective means of preventing dental caries is unavailable. The aim of this study was to determine the fluoride concentration in 10 popular brands of still bottled water currently sold in Australia. METHODS: The fluoride content of water samples were determined using an ion analyser and compared to a fluoride standard. RESULTS: The fluoride concentration of all bottled waters was less than 0.08 ppm. Only three of the 10 brands indicated the fluoride content on their labels. Melbourne reticulated water was found to be fluoridated at 1.02 ppm. CONCLUSIONS: All bottled waters tested contained negligible fluoride which justifies the concern that regular consumption of bottled water may reduce the benefits gained from water fluoridation. It is recommended that all bottled water companies should consider stating their fluoride content on their labels. This will inform consumers and dental care providers of the levels of fluoride in bottled water and allow an informed decision regarding consumption of fluoridated versus non-fluoridated drinking water.

Australia↗
PubMed1995

Antimicrobial actions of fluoride for oral bacteria.

Fluoride is widely used as a highly effective anticaries agent. Although it is felt that its anticaries action is related mainly to effects on mineral phases of teeth and on the process of remineralization, fluoride also has important effects on the bacteria of dental plaque, which are responsible for the acidification of plaque that results in demineralization. The results of recent studies have shown that fluoride can affect bacterial metabolism through a set of actions with fundamentally different mechanisms. It can act directly as an enzyme inhibitor, for example for the glycolytic enzyme enolase, which is inhibited in a quasi-irreversible manner. Direct action seems also to occur in inhibition of heme-based peroxidases with binding of fluoride to heme. The flavin-based peroxidases of many oral bacteria are insensitive to fluoride. Another mode of action involves formation of metal-fluoride complexes, most commonly AlF4-. These complexes are responsible for fluoride inhibition of proton-translocating F-ATPases and are thought to act by mimicking phosphate to form complexes with ADP at reaction centers of the enzymes. However, the actions of fluoride that are most pertinent to reducing the cariogenicity of dental plaque are those related to its weak-acid character. Fluoride acts to enhance membrane permeabilities to protons and compromises the functioning of F-ATPases in exporting protons, thereby inducing cytoplasmic acidification and acid inhibition of glycolytic enzymes. Basically, fluoride acts to reduce the acid tolerance of the bacteria. It is most effective at acid pH values. In the acidic conditions of cariogenic plaque, fluoride at levels as low as 0.1 mM can cause complete arrest of glycolysis by intact cells of Streptococcus mutans. Overall, the anticaries actions of fluoride appear to be complex, involving effects both on bacteria and on mineral phases. The antibacterial actions of fluoride appear themselves to be complex but to be dominated by weak-acid effects.

Anti-Infective Agents, Local↗
PubMedDate not supplied

How to improve the effectiveness of caries-preventive programs based on fluoride.

During recent years, an increasing number of reports have been published in which the observed caries-preventive effect of fluoride has been lower than could have been expected on the basis of the earlier literature. The current low levels of caries occurrence and the widespread use of fluoridated toothpastes as well as other fluoride products and methods have been suggested as reasons for the reduced relative effect of fluoride from any single source. Theoretically, one can improve the effectiveness of fluoride in caries-preventive programs by using measures that are more effective than the previous ones and still safe and feasible in everyday conditions. Another possibility is to direct fluoride-based prevention to high caries risk susceptible individuals who are most likely to benefit from it. Thirdly, one can enhance the intensity of existing fluoride prevention by increasing the frequency of applications, but this is of course worthwhile only if the recipients are lacking sufficient exposure to fluoride. In theory, people themselves could easily take care of their adequate fluoride supply by using fluoride toothpastes and/or other home use products frequently enough to maintain a sufficient salivary fluoride concentration at all times. Many people are unwilling to adopt healthy lifestyles, however, and therefore caries-preventive programs will remain necessary for the foreseeable future. Fluoride is the backbone of all such programs. Since conditions strongly determine the usefulness of caries prevention including different fluoride regimes, more research is still needed to monitor the effectiveness of caries-preventive programs and their components in variable conditions of today and tomorrow.

Cariostatic Agents↗
PubMed1990

Physical and chemical considerations of the role of firmly and loosely bound fluoride in caries prevention.

Historically, there has been considerable debate concerning the roles of loosely bound (calcium fluoride) and firmly bound (fluorapatite) fluoride for caries prevention. Research now shows that fluorapatite (FAP) is a finite reaction product of enamel/apatite fluoridation with or without CaF2 formation, suggesting that CaF2 always be considered as a supplement to, rather than a substitute for, FAP formation. In the presence of low levels of fluoride in the solution phase, the crystallization of hydroxyapatite is enhanced, while the corresponding dissolution is retarded. Fluoride in the bulk FAP or CaF2 solid phase, in contrast, has limited impact on crystal growth or dissolution kinetics. Both FAP and CaF2 can provide F to the solution phase to enhance remineralization and retard demineralization of enamel HAP crystallites. The FAP provides most of this F under low pH conditions, while CaF2 provides F at neutral or lower pH. The reactivity of fluoride on sound and carious enamel differs significantly. Carious enamel acquires more fluoride, acquires it more quickly, and itself acts as a source of retained fluoride in comparison with the more limited reactivity of sound enamel. Overall, the most important question concerning fluoride reactivity relates to its efficiency in enhancing remineralization or retarding demineralization processes. This is influenced not only by the reaction products, e.g., loosely or firmly bound fluoride, but also by the nature of the enamel substrate and frequency of application of the topical fluoridating agent. Inasmuch as the reactivity of bulk HAP is dominated by surface layers of FAP material, the debate over usefulness of various fluoride reaction products solely on a chemical level is no longer critical. Instead, all factors influencing the efficiency of a fluoridating regimen must be considered in the development of improved systems for caries prevention.

Apatites↗
PubMed1990

The future of water fluoridation.

Recently, questions have been raised about the possible reduced effectiveness and cost-effectiveness of water fluoridation in the prevention of dental caries in developed countries. The increase in environmental fluorides since water fluoridation was first introduced in 1945 (particularly from fluoride toothpastes, mouthrinses, and from foods and drinks) generally provided the basis for these questions. A related phenomenon which might decrease the efficiency of water fluoridation is the reduced caries levels in many developed countries. It has also been suggested that excessive fluoride intake, especially in fluoridated communities where there is widespread use of fluoride toothpastes, is likely to manifest itself in an increased dental fluorosis prevalence. In this paper, recent data from Ireland which are similar to those recorded in many developed countries are used to answer these questions in part. It is concluded that water fluoridation continues to be an effective and cost-effective strategy for caries prevention in areas where the overall caries level has declined and where the cost of water fluoridation implementation has increased. Also, there is no evidence of excessive fluoride intake in fluoridated communities where fluoride toothpastes are widely used.

Adolescent↗
PubMed1992

The changing patterns of systemic fluoride intake.

Fluorosis prevalence has increased in North America since the 1930's-1940's. It may also have increased since 1970, though the evidence for that is less clear. Continued monitoring will help determine whether increased fluorosis prevalence in children in the United States is a cohort effect from the 1970's. This review considers the evidence for an increase in fluoride ingestion from all sources since the 1970's. If an increase has occurred, the most likely sources are fluoride dietary supplements, inadvertent swallowing of fluoride toothpastes, and increased fluoride in food and beverages. For adults, there is no evidence from dietary surveys to show that fluoride intake has increased over the last generation. Dietary surveys for children aged six months to two years are similarly inconclusive, though the great variation in fluoride content of various infant foods might be obscuring real effects. The data on fluoride intake by children from food and beverages, infant foods included, are not strong enough to conclude that an increase in fluoride ingestion has occurred since the 1970's. However, the suggested upper limit of fluoride intake is substantially being reached in many children by ingestion of fluoride from food and drink (0.2-0.3 mg per day) and from fluoride toothpaste (0.2-0.3 mg per day). Two public health issues that arise from this review are: (a) the need for a downward revision in the schedule for fluoride supplementation, and (b) education on the potential for high fluoride concentration of soft drinks and processed fruit juices.

Adult↗
PubMed1989

Effect of prenatal and postnatal fluoride on the human deciduous dentition. A literature review.

Fluoride passes from the mother to fetal teeth. Much of the fluoride is taken up in secretory enamel, probably by the forming mineral apatite crystals. Some is retained with residual proteins. The low concentration of fluoride in the inner enamel is incorporated mainly during the secretory stage, while the enhanced concentration in the surface enamel is produced during the much longer maturation stage. Mature, hard enamel is generally absent during fetal life. The clinical question is whether prenatal fluoride imparts an additional benefit to the universally accepted effect of postnatal fluoride. In general, surface enamel fluoride levels of deciduous teeth increase with increasing pre- and postnatal fluoride administration. A consistent level of caries protection has been reported with pre- and postnatal administration of fluoride unrelated to the acquisition of fluoride in the surface enamel. Many children develop enamel opacities in their deciduous dentition related by various factors to enamel mineralization disturbances in drinking water areas even low in fluoride. Accumulation of fluoride due to an increased fluoride intake is a feature of fluorosed enamel in the deciduous as well as permanent dentition. The resulting mature fluorosed enamel retains a relatively high proportion of immature matrix proteins onto the crystal surface. The degree of fluorosis of the deciduous dentition is less compared with that of the permanent dentition, due probably to a partial protection afforded by the maternal loss of fluoride, formerly known as the "placental barrier".

Dental Enamel↗
PubMed1998

Molecular mechanism of action of fluoride on bone cells.

Fluoride is an effective anabolic agent to increase spinal bone density by increasing bone formation, and at therapeutically relevant (i.e., micromolar) concentrations, it stimulates bone cell proliferation and activities in vitro and in vivo. However, the fluoride therapy of osteoporosis has been controversial, in large part because of a lack of consistent antifracture efficacy. However, information regarding the molecular mechanism of action of fluoride may improve its optimum and correct usage and may disclose potential targets for the development of new second generation drugs that might have a better efficacy and safety profile. Accordingly, this review will address the molecular mechanisms of the osteogenic action of fluoride. In this regard, we and other workers have proposed two competing models, both of which involve the mitogen activated protein kinase (MAPK) mitogenic signal transduction pathway. Our model involves a fluoride inhibition of a unique fluoride-sensitive phosphotyrosine phosphatase (PTP) in osteoblasts, which results in a sustained increase in the tyrosine phosphorylation level of the key signaling proteins of the MAPK mitogenic transduction pathway, leading to the potentiation of the bone cell proliferation initiated by growth factors. The competing model proposes that fluoride acts in coordination with aluminum to form fluoroaluminate, which activates a pertussis toxin-sensitive Gi/o protein on bone cell membrane, leading to an activation of cellular protein tyrosine kinases (PTKs), which in turn leads to increases in the tyrosine phosphorylation of signaling proteins of the MAPK mitogenic signal transduction pathway, ultimately leading to a stimulation of cell proliferation. A benefit of our model, but not the other model, is that it accounts for all the unique properties of the osteogenic action of fluoride. These include the low effective fluoride dose, the skeletal tissue specificity, the requirement of PTK-activating growth factors, the sensitivity to changes in medium phosphate concentration, the preference for undifferentiated osteoblasts, and the involvement of the MAPK. Unlike fluoride, the mitogenic action of fluoroaluminate is not specific for skeletal cells. Moreover, the mitogenic action of fluoroaluminate shows several important, different characteristics than that of fluoride. Thus, it is likely that our model of a fluoride-sensitive PTP represents the actual molecular mechanism of the osteogenic action of fluoride.

Animals↗
PubMed1993

Ionic and nonionic fluoride levels in blood of dialyzed and undialyzed patients with renal failure and kidney transplanted patients.

The present study revealed that the total fluoride level in human whole blood is closely related to the renal function. For the undialyzed patients who had not undergone hemodialysis, the total fluoride level in whole blood linearly increased with the increase of creatinine (Cr) value. The increased fluoride was found to be nonionic in the other blood part than serum, while the nonionic fluoride level in serum was almost constant. That is, the hemodialysis treatment finally reduced the nonionic fluoride level in the other blood part than serum. On the other hand, one hemodialysis treatment could excrete ionic fluoride, but not nonionic fluoride. These results suggest that the ionic fluoride is transformed to nonionic fluoride to be accumulated in other blood part than serum and the nonionic fluoride is transformed to the ionic fluoride to be excreted. Thus the accumulation of nonionic fluoride in other blood part than serum plays a role of the buffer in preventing a too high serum fluoride level.

Adolescent↗
PubMed2000

Dietary fluoride intake of children aged 3-7 years in remote areas of Thailand.

The objectives of this study were to measure dietary fluoride intake in children aged 3-7 years, to correlate dietary fluoride and fluoride content in water for use in schools and to estimate fluoride gained from the daily diet. Fifty food samples were collected in 45 schools under the jurisdiction of the Border Patrol Police Department. The schools were sampled by multiple stratified cluster random sampling. The food samples were weighed, then measured for fluoride content by a microdiffusion method. Statistical analysis was conducted using the Kruskal-Wallis test. Dietary fluoride in each age group was compared by Student's t test. Analysis for the relationship between dietary fluoride and fluoride content in water was done using Kendall's tau-b. Our results showed that the mean of dietary fluoride in lunch was 0.08 +/- 0.1 ppm. There were no differences when comparing dietary fluoride between different regions of Thailand (p = 0.07). No correlation was found between dietary fluoride and fluoride content in water used in different schools (r(tau) = 0.017, p = 0.85). The daily dietary fluoride intake in children aged 3-6 years was 0.002-0.004 mgF/kg bw/day, in children aged 7 years was 0.003-0.004 mgF/kg bw/day in boys and 0.002-0.004 mgF/kg bw/day in girls.

Child↗