Natural Fluoride Concentration Research Articles

A comparative analysis of water quality guidelines for fluoride in Canada and Spain

Although anthropogenic fluoride (F−) pollution is a serious worldwide environmental problem, only a few countries have currently established national water quality criteria for the protection of freshwater biota. Since Canada is a global leader in biodiversity conservation that exhibits restrictive water quality benchmarks, I carry out a comparative analysis of water quality guidelines for fluoride in Canada and Spain. The Canadian water quality benchmark of 0.12 mg F−/l (maximum allowable concentration) prevents Canada’s fresh waters from significant adverse events of fluoride pollution, thereby protecting sensitive native aquatic invertebrates and adult-migrating Pacific salmon. By contrast, the Spanish water quality benchmark of 1.7 mg F−/l (annual mean concentration) allows not only continuous levels of fluoride pollution more than six times higher than natural fluoride concentrations in the fresh waters of mainland Spain, but also much higher discontinuous levels of fluoride pollution (> 15 mg F−/l). This unacceptable scenario is contrary to the current environmental goal of “zero pollution” in the European Union. In view of the existing toxicological data, a Spanish water quality guideline of 0.15−0.3 mg F−/l (maximum allowable concentration) seems much more reasonable. The recommended water quality guideline for fluoride would much better protect sensitive native fish and invertebrate species, and prevent significant bioaccumulation of fluoride in tolerant freshwater organisms.

Tap water natural fluoride and parent-reported experience of child dental caries in Japan: Evidence from a nationwide birth cohort survey.

Water fluoridation is an effective measure to prevent dental caries. In Japan, artificial water fluoridation is not implemented, and tap water natural fluoride concentration geographically differs because of various soil natures. This study aimed to examine the association between tap water natural fluoride and parent-reported experience of dental caries in children. Data from the Longitudinal Survey of Newborns in the twenty-first century, a national birth cohort study following all infants born between January 10-17 and July 10-17, 2001, were analysed. Caregivers answered the child's caries treatment history, a proxy for dental caries, yearly from 5.5 to 12 years of age (N=202 517 observations from 34 998 children). The annual data on tap water natural fluoride concentration in the municipality of residence were obtained from the national statistics. Cross-classified multilevel Poisson regression models were fitted, adjusting for child, household and municipality characteristics, including average income and dental clinic density. The average tap water natural fluoride concentration across municipalities was 0.0887ppm (SD=0.0422). The proportion of parent-reported experience of child dental caries treatment ranged from 24.9% (at 12 years) to 40.3% (at 7 years) and was lower among children living in municipalities with high natural fluoride concentrations, which were 35.0%, 35.4%, 33.4% and 32.3% for <0.10, 0.10-0.19, 0.20-0.29 and ≥0.30ppm respectively. A 0.1 ppm increment in tap water natural fluoride after controlling for all covariates was significantly associated with a lower prevalence of parent-reported child dental caries treatment by 3.3% (prevalence ratio=0.967, 95% credible interval: 0.939, 0.996). Natural fluoride in tap water showed a protective effect for the parent-reported experience of child dental caries in Japan.

Surprisingly high fluorine content in some exotic superfoods

Recent years have seen soaring interest in exotic superfoods, which are believed to have extraordinary health benefits. The purpose of the study was to broaden the current knowledge on exotic superfoods and to analyse them for fluorine (F)11In this paper, “fluorine” is used to denote the element in any of its forms and “fluoride” is used to denote the inorganic compound and the fluoride ion F−. since excessive intake during prolonged periods of time can cause adverse effects. The F content was determined in 18 plant-based exotic superfoods available on Slovenian market by fluoride ion selective electrode after prior total decomposition by alkaline carbonate fusion. In 8 of the analysed samples, the F content was surprisingly high in comparison to F content in commonly consumed foods (<3 μg/g). The highest F content was found in matcha (373 μg/g), followed by gotu kola (111 μg/g) and gingko biloba (91.0 μg/g). The F content in tulsi, neem, brahmi, gynostemma and moringa was lower and ranged between 16.4–68.8 μg/g. Despite high F content, these superfoods do not pose a risk to human health in non-fluoridated water areas, because they are usually consumed in low quantities. However, in fluoridated water areas (e.g. some parts of Ireland, United Kingdom, United States, Canada) or in areas with high natural fluoride concentration in drinking water, superfoods should be consumed with caution, since the intake of F can with simultaneous consumption of superfoods and tea on a normal diet easily exceed the adequate intake or even reach the upper limit of fluorine. The F content in these 8 superfoods was also surprisingly high in comparison to the usual F content in most plant species (<10 μg/g). The high F content in matcha is understandable since it is made of Camellia sinensis L. leaves, but the high F content in other superfoods is worrisome because the reason for such high F content is unknown and it is possible that these superfoods are contaminated with fluoride due to industrial or agricultural activities.

Dental health status and its indicators in adult Brazilian Indians without exposition to drinking water fluoridation: a cross-sectional study.

Water fluoridation is considered a cost-effective and practical method for controlling and preventing dental caries in the general population. The objective of this study was to evaluate the dental health status and risk indicators for dental caries in adult Brazilian Indians without exposition to dental caries-preventive effects of water fluoridation. Decayed (DT), missing (MT), and filled (FT) permanent teeth (DMFT), as well as plaque index, unstimulated salivary flow rate, salivary buffering capacity, and fasting blood glucose were examined in 225 adult Indians. Smoking habits and sociodemographic data were evaluated using a structured questionnaire. Drinking water samples from 10 Indian villages were analyzed for the natural fluoride concentration. The mean DMFT was 10.33 ± 6.91 (DT, 4.19 ± 3.99; MT, 4.99 ± 5.64; FT, 1.14 ± 1.75). DMFT index ≥ 9 was associated with age ≥ 35 years (p = 0.000), lower education (p = 0.03), and plaque index > 40% (p = 0.003). DT was associated only with plaque index (p = 0.03). MT was associated with age (p < 0.001) and plaque index (p = 0.01). FT was negatively associated with age (p = 0.02) and income (p = 0.02). Fluoride concentration varied from 0.01 to 0.07 mg/L and was not associated with dental health status (p ≥ 0.29). In conclusion, poorer dental health status was associated with older age, higher plaque index, and lower education and income levels. The fluoride level in the drinking water of Kiriri villages was lower than the level recommended for preventing dental caries. Water fluoridation may be recommended for this population.

Anuran tadpoles inhabiting a fluoride-rich stream: diets and morphological indicators

We in situ assessed the influence of natural fluoride concentrations in lotic freshwater ecosystems on diet and morphology of Boana cordobae tadpoles. Two streams were sampled in Argentina: Los Vallecitos stream (LF-LV) and Los Cerros Negros stream (HF-CN) with low and high fluoride levels, respectively. We captured tadpoles of B. cordobae in each stream using nets. Body weight (BW), total length (TL) and body condition (BC) of tadpoles was registered. Food items were identified to genus level and assigned to functional traits. Tadpoles showed significant differences in TL between streams, with smaller individuals in HF-CN, while did not show differences in BW and BC. The diet of tadpoles consisted mostly of microalgae. In tadpoles from HF-CN stream the proportion of cyanobacteria was lower than tadpoles from LF-LV. In relation to functional traits, small algae, high profile and colonial algae were more abundant in HF-CN. Algae attached by pads showed a higher proportion in HF-CN diets and stalked algae were more abundant in LF-LV. The differences in TL and diet of tadpoles can be attributed to differences in algal community composition, with genera that are affected by high concentrations of natural fluoride; for example cyanobacteria. The low algal richness registered in HF-CN stream does not affect the physiological state of the tadpoles, possibly because of a higher algal density in HF-CN diets. However, in further studies it would be important to evaluate the population status of B. cordobae from the HF-CN, because a small body length of tadpoles could have consequences at the population level.

Community water fluoridation predicts increase in age-adjusted incidence and prevalence of diabetes in 22 states from 2005 and 2010.

Community water fluoridation is considered a significant public health achievement of the 20th century. In this paper, the hypothesis that added water fluoridation has contributed to diabetes incidence and prevalence in the United States was investigated. Panel data from publicly available sources were used with population-averaged models to test the associations of added and natural fluoride on the outcomes at the county level in 22 states for the years 2005 and 2010. The findings suggest that a 1 mg increase in the county mean added fluoride significantly positively predicts a 0.23 per 1,000 person increase in age-adjusted diabetes incidence (P < 0.001), and a 0.17% increase in age-adjusted diabetes prevalence percent (P < 0.001), while natural fluoride concentration is significantly protective. For counties using fluorosilicic acid as the chemical additive, both outcomes were lower: by 0.45 per 1,000 persons (P < 0.001) and 0.33% (P < 0.001), respectively. These findings are adjusted for county-level and time-varying changes in per capita tap water consumption, poverty, year, population density, age-adjusted obesity and physical inactivity, and mean number of years since water fluoridation started. Sensitivity analyses revealed robust effects for both types of fluoride. Community water fluoridation is associated with epidemiological outcomes for diabetes.

Water fluoridation in 40 Brazilian cities: 7 year analysis

Objectives:Fluoride levels in the public water supplies of 40 Brazilian cities were analyzed and classified on the basis of risk/benefit balance.Material and Methods:Samples were collected monthly over a seven-year period from three sites for each water supply source. The samples were analyzed in duplicate in the laboratory of the Center for Research in Public Health - UNESP using an ion analyzer coupled to a fluoride-specific electrode.Results:A total of 19,533 samples were analyzed, of which 18,847 were artificially fluoridated and 686 were not artificially fluoridated. In samples from cities performing water fluoridation, 51.57% (n=9,720) had fluoride levels in the range of 0.55 to 0.84 mg F/L; 30.53% (n=5,754) were below 0.55 mg F/L and 17.90% (n=3,373) were above 0.84 mg F/L (maximum concentration=6.96 mg F/L). Most of the cities performing fluoridation that had a majority of samples with fluoride levels above the recommended parameter had deep wells and more than one source of water supply. There was some variability in the fluoride levels of samples from the same site and between collection sites in the same city.Conclusions:The majority of samples from cities performing fluoridation had fluoride levels within the range that provides the best combination of risks and benefits, minimizing the risk of dental fluorosis while preventing dental caries. The conduction of studies about water distribution systems is suggested in cities with high natural fluoride concentrations in order to optimize the use of natural fluoride for fluoridation costs and avoid the risk of dental fluorosis.

Auswirkung des Trinkwasserfluoridgehalts auf die Zahngesundheit von Erstklässlern in einem Gebiet mit natürlich erhöhter Fluoridkonzentration zu Beginn des 21. Jahrhunderts

Since the end of the first half of the 20 (th) century it is well-known that fluoride concentrations in drinking water of about 1 ppm reduce the prevalence of dental caries by about 40-60%. This knowledge led to the fluoridation of drinking water during the second half of the 20 (th) century in many countries, including East Germany. Although the natural F (-) content in drinking water in Germany is usually very low, the eastern Eifel is one of the few larger areas in Germany with (nearly) optimal (0.7-1.0 ppm) or moderately enhanced (0.3-0.7 ppm) natural fluoride concentrations in drinking water. 30 years ago, in 1977, the caries prevalence of children of various age groups in the fluoride-rich areas of the eastern Eifel was established by Einwag to be about 40% lower than in adjacent fluoride-poor regions (0.1 ppm). Meanwhile fluoride has become available from many different sources for children of any age: e. g., toothpaste (with 500 ppm fluoride even for very young children who just got the first tooth), fluoridated salt, professional fluoride applications (paid by health insurances), the rising consumption of mineral waters (many of which have a fluoride content >0.3 ppm). This poses the question of the current influence of enhanced natural drinking water fluoride concentrations on caries prevalence in children. The results of the dental examinations of 9 555 pupils (6 or 7 years old) of the first classes of all 63 primary schools in the Landkreis Mayen-Koblenz from 5 years (2004/2005-2008/2009) are compared to the fluoride content of the drinking water. The data show no obvious correlation between dental health and fluoride concentration for any of the dental health parameters investigated. However, in spite of the low geographic resolution of social parameters, there was a notable connection between dental health status and sociodemographic indicators for the respective region. 30 years after the study by Einwag in the same region, the natural fluoride content of drinking water either had no influence on dental health at all, or this influence is so diminutive that it is exceeded by far by sociodemographic factors. Obviously there is much more fluoride available from other sources nowadays compared to 30 years ago. The results may also have implications for the administration of fluoride tablets and support the recommendations of the DGZMK (Deutsche Gesellschaft für Zahn-, Mund- und Kieferheilkunde) from the year 2000, restricting the administration of fluoride tablets to special situations following an individual anamnesis of fluoride uptake.

Natural fluoride levels from public water supplies in Piauí State, Brazil

The aim of this work was to determine the natural fluoride concentrations in public water supplies in Piauí State, Brazil, in order to identify cities in risk for high prevalence of dental fluorosis. For each city, two samples of drinking water were collected in the urban area: one from the main public water supply and another from a public or residential tap from the same source. Fluoride analyses were carried out in duplicate using a specific ion electrode and TISAB II. From a total of 222 cities in Piauí, 164 (73.8%) samples were analyzed. Urban population in these towns corresponds to 92.5% of the whole state with an estimated population of 1,654,563 inhabitants from the total urban population (1,788,590 inhabitants). A total of 151 cities showed low fluoride levels (<0.30 mg/L) and 13 were just below optimum fluoride concentration in the drinking water (0.31-0.59 mg/L). High natural fluoride concentration above 0.81 mg/L was not observed in any of the surveyed cities. As a conclusion, most of the cities in Piauí have low fluoride concentration in the drinking water. The risk for a high prevalence of dental fluorosis in these urban areas due to natural fluoride in the water supplies is very unlikely. Thus, surveys about the dental fluorosis prevalence in Piauí should be related with data about the consumption of fluoridated dentifrices and other fluoride sources.

Fluoride in drinking water in Cuba and its association with geological and geographical variables

To determine the association between different concentrations of the fluoride ion in drinking water and some geological and geographical variables in Cuba, by using a geographic information system. From November 1998 to October 1999 we studied the fluoride concentration in the sources of drinking water for 753 Cuban localities that had at least 1 000 inhabitants. For the information analysis we utilized the MapInfo Professional version 5.5 geographic information system, using the overlaying method. The study variables were the concentration of the fluoride ion in the water sources, the geological characteristics of the area, the alignments (geological characteristics that were found together), the types of water sources, and whether an area was a plain or mountainous. The results were grouped by locality and municipality. In 83.1% of the localities, the water samples were collected from wells and springs, and the remaining 16.9% came from dams and rivers. Of the 753 localities studied, 675 of them (89.6%) had low or medium fluoride concentrations (under 0.7 mg/L). The eastern region of the country was the one most affected by high fluoride concentrations in the waters, followed by the central region of the country. The majority of the localities with high natural fluoride concentrations were in areas located on Cretaceous volcanic arc rocks. The presence of fluoride in the drinking waters was related to the alignments with the earth's crust, in rock complexes of volcanic-sedimentary origin and of intrusive origin and also in carbonate rocks. However, the highest fluoride concentrations generally coincided with rock complexes of volcanic-sedimentary origin and of intrusive origin. All the localities with high fluoride concentrations in the water were associated with wells. The fluoride concentration is low or medium in the drinking water sources for 89.6% of the Cuban localities with at least 1 000 inhabitants. Geological and geographical characteristics can help identify areas with optimal or high concentrations of the fluoride ion in the drinking water.

High-fluoride drinking water, fluorosis, and dental caries in adults

This study measures the prevalence and distribution of dental fluorosis and coronal caries in lifelong adult residents of two New Mexico communities. One community has a natural fluoride concentration of approximately 0.7 mg/L in its drinking water, optimum for the climate, and the water of the other community is naturally fluoridated at approximately 3.5 mg/L, five times optimum. The differences between the communities in amounts of dental fluorosis and any reduced susceptibility to dental caries associated with higher levels of fluorosis, particularly in molars, the teeth most susceptible to decay, are discussed.

Root caries in an optimally fluoridated and a high-fluoride community.

The purpose of this study was to measure the prevalence and distribution of root caries in two New Mexico communities. One community, Deming, had a natural fluoride concentration of 0.7 mg/L in its drinking water, optimum for its climate. The other, Lordsburg, was naturally fluoridated at 3.5 mg/L, five times the optimum. Dental examinations were carried out on 151 adults in Deming (mean age, 39.8 years) and 164 in Lordsburg (mean age, 43.2 years); only persons born in the communities were included. Prevalence of root caries was 23.8% in Deming and 7.3% in Lordsburg; mean number of lesions was 0.69 in Deming and 0.08 in Lordsburg (p less than 0.0001). Although there was more gingival recession in Lordsburg, Root Caries Index scores were five times greater in Deming. Root caries was more prevalent in older age groups, and was correlated with coronal caries experience in both communities. Root caries was correlated with plaque and calculus scores in Deming only. Logistic regression showed that city of residence was the major predictor of root caries, with other significant predictors being age, education, gingival recession, and loss of periodontal attachment. When combined with previous research, these results confirm that root caries experience is directly related to the fluoride concentration in the drinking water.

Fluoridation a clinical survey in Corby and Scunthorpe

Following the fluoridation of water supplies in 1968, a 7-year survey was undertaken to study the prevalence of caries in children living in Scunthorpe, using Corby, Northamptonshire, as a control area. During this period the average level of fluoride in the Scunthorpe drinking water was maintained between 0·85 parts/10 6 and 0·90 parts/10 6 . The natural fluoride concentration in the water supplied to Corby was 0·35 parts/10 6 . Between 1969 and 1975, children aged 5 years, 8 years and 12 years were examined annually in both towns. In Scunthorpe, the percentage of children caries-free in the 5-year-old age group rose from 20% in 1969 to 45% in 1975, and the average number of decayed, missing and filled teeth (d.m.f.)/child dropped from 4·29 to 1·80, a reduction of 58%. By comparison, the mean d.m.f. for the same age group of children in Corby dropped from 4·28 to 3·5, a reduction of 18%, and the percentage of children caries-free rose from 20% to 30%. The dental health of Scunthorpe children in the other two age groups also improved, in comparison both with the baseline figures for 1969 and with the control area, Corby.

Etude de l'accumulation du fluor dans les lichens d'une vallee alpine polluee

Fluoride accumulation was studied in various corticolous, terricolous and saxicolous lichen species in a polluted alpine valley during three successive years. The fluoride concentration of the lichen thallus depends on the species and variations in the level of atmospheric fluoride pollution in space and time, as it does in the phanerogamic vegetation. The fluoride concentration in corticolous species, which is paralleled in phanerograms, shows seasonal variations in relation to rainfall. In contrast, the fluoride concentration in terricolous lichens seems to be influenced by other factors. A natural fluoride concentration is observed in lichens sampled from non-polluted regions.

Use of geochemical data banks in monitoring the natural environment — a case study from Sri Lanka

A survey carried out on the incidence of dental diseases and the distribution of fluoride in drinking water wells and also copper in such waters in Sri Lanka showed the influence of the natural environmental factors on the prevalence of certain geographical diseases. In the case of the geographical variation of dental fluorosis and dental caries it was found that in Sri Lanka, more than any artificially created causes, the natural environmental factors such as mineral occurrences containing the elements concerned, climate, topography, geology, structure, soil, etc. play a very significant role in the geographic variations of elements and hence incidence of diseases. The same was found to be true in the case of copper in potable waters. Two cities in the dry zone of Sri Lanka namely Anuradhapura and Polonnaruwa had a natural fluoride concentration ranging from 0.34 to 4.55 ppm. In some of these regions dental fluorosis was as high as 77.5%. Kandy, situated in the wet zone on the other hand, had in its well waters a low fluoride concentration of less than 0.2 ppm and hence only 13% dental fluorosis. Similarly copper in the well waters of Sri Lanka showed a range of concentrations depending on many natural environmental factors and in some areas far removed from any effects of industrialization still had high copper concentrations of the order of 1–3 ppm, due to the occurrence of copper bearing mineral deposits. It is the aim of this paper to illustrate the use of establishing natural geochemical data banks in monitoring the environment as they would provide useful background values. Any attempt at erecting national or international acceptable levels for the chemical elements must necessarily consider those which are natural to defined environments.

Fluoride, mineralisation defects of the enamel, and tooth width.

Abstract. Grahnén, H., Lysell, L., Myrberg, N. and Ollinen, P. (Departments of Pedodontics and Orthodontics, University of Umeå, Sweden and Department of Orthodontics, University of Amsterdam, The Netherlands). Fluoride, Mineralisation defects of the enamel, and tooth width. Acta Paediat Scand, 63: 188, 1974.–The purpose of the investigation was to appraise the frequency of enamel mineralisation defects in 151 children, aged 8–11 years, born and raised in a district in Vasterbotten county in northern Sweden, where the fluoride content of the drinking water ranges up to 2 mg/l, and to examine the mesiodistal widths of the teeth for effects of fluoride in these concentrations. The control group consisted of 213 children who had always lived in a town where the fluoride content of the drinking water was ≫0.0 mg/l. The mineralisation defects were recorded clinically and photographically. Owing to the various ages of the children, only mineralisation defects in permanent incisors and six‐year molars were noted. The mesio‐distal widths of the teeth were measured on plaster casts. The frequency of enamel fluorosis was high (34%) in those children whose drinking water had a fluoride content of 1.0–2.0 mg/l and also high (31%) in those children living in areas with a fluoride content of 1.0–1.2 mg/l. No satisfactory explanation can be offered for the relatively high frequency of fluorosis. There are, however, variations in the natural fluoride concentration of the ground water and probably also considerable individual variation in water consumption. This stresses the necessity of further investigation of children's fluoride intake. No significant differences in mesio‐distal widths of individual teeth could be demonstrated.

Effect of natural fluoride concentration of human tooth enamel on fluoride uptake in vitro.

Duplicate enamel blocks were cut from teeth of various age groups from areas differing in water fluoride. One enamel block received a fluoride treatment and the other served as control. Analysis of thin enamel layers revealed that ftuoride uptake was inversely proportional to the natural F- concentration and, in a lesser degree, to the age of the enamel.