Fluoride
Fluoride is a naturally occurring element found in rock, soil, air and vegetation. It is nature’s answer to tooth decay and makes the structure of teeth more resistant to decay. It is toxic to bacteria and stops it from producing acids that cause tooth decay.
It also encourages remineralization in the surface of the teeth which help in repairing early decay or damage before causing cavity. Apart from the above, it helps in developing enamel on a child’s tooth before they start growing and reduces enamel solubility.
Fluoridated water protects against cavities, root caries and helps to remineralize small decay. It is the most effect public health measure to prevent tooth decay and improve oral health for a lifetime. Fluoridation inexpensively and safely benefits both children and adults by preventing tooth decay, regardless of their socio economic status or access to care. It has played an important role in reduction of decay (40 percent to 70 percent in children) and loss of teeth in adults (40 percent to 60 percent). Fluoridation of water has brought about an improvement in the oral health of children in rural areas.
Though fluoridation of water has a lot of advantages, higher concentration of fluoride in water can be dangerous too. Fluoride taken in doses of 10-20 parts per million may cause bone weakness. However, fluorosis (white spots in teeth) can happen only if certain infant formulas are mixed with fluoridated water, yet it does not impair the integrity of the child’s teeth and the benefits of fluoridation are much higher.
There is no evidence that fluoride accumulates in the body to a toxic level. Rather, the risk of not fluoridating drinking water is much greater. Fluoride levels in drinking water do not pose a risk for health problems such as cancer, kidney failure or bone diseases.
Fluorine is an univalent poisonous gaseous halogen, it is pale yellow-green and it is the most chemically reactive and electronegative of all the elements. Fluorine readily forms compounds with most other elements, even with the noble gases krypton, xenon and radon. It is so reactive that glass, metals, and even water, as well as other substances, burn with a bright flame in a jet of fluorine gas.
In aqueous solution, fluorine commonly occurs as the fluoride ion F-. Fluorides are compounds that combine fluoride with some positively charged counterpart.
[edit] Applications
- Atomic fluorine and molecular fluorine are used for plasma etching in semiconductor manufacturing, flat panel display production and MEMs fabrication.
- Fluorine is indirectly used in the production of low friction plastics such as teflon and in halons such as freon, in the production of Uranium. Fluorochlorohydrocarbons are used extensively in air conditioning and in refrigeration.
- Fluorides are often added to toothpaste and, somewhat controversially, to municipal water supplies to prevent dental cavities. Fore more information visit our page on mineral water.
[edit] Fluorine in the environment
Annual world production of the mineral fluorite in around 4 million tonnes, and there are around 120 million tonnes of mineral reserves. The main mining areas for fluorite are China, Mexico and Western Europe. Fluorine occurs naturally in the earth's crust where it can be found in rocks, coal and clay. Fluorides are released into the air in wind-blown soil. Fluorine is the 13th most aboundant element in the Earth's crust: 950 ppm are contanined in it. Soils contain approximatively 330 ppm of fluorine, ranging from 150 to 400 ppm. Some solis can have as much as 1000 ppm and contaminated solis have been found with 3500 ppm. Hydrogen fluorides can be released into air through combustion processes in the industry. Fluorides that are found in air will eventually drop onto land or into water. When fluorine is attached to very small particles it can remain in the air for a long period of time. In the atmosphere 0.6 ppb of fluorine are present as salt spray and organicochloride compounds. Up to 50 ppb has been recorded in city environments.
[edit] Health effects of fluorine
Small amounts of fluorine are naturally present in water, air, plants and animals. As a result humans are exposed to fluorine through food and drinking water and by breathing air. Fluorine can be found in any kind of food in relatively small quantities. Large quantities of fluorine can be found in tea and shellfish.
Fluorine is essential for the maintenance of solidity of our bones. Fluorine can also protect us from dental decay, if it is applied through toothpaste twice a day. If fluorine is absorbed too frequently, it can cause teeth decay, osteoporosis and harm to kidneys, bones, nerves and muscles.
Fluorine gas is released in the industries. This gas is very dangerous, as it can cause death at very high concentrations. At low concentrations it causes eye and nose irritations.
[edit] Environmental effects of fluorine
When fluorine from the air ends up in water it will settle into the sediment. When it ends up in soils, fluorine will become strongly attached to soil particles. In the environment fluorine cannot be destroyed; it can only change form.
Fluorine that is located in soils may accumulate in plants. The amount of uptake by plants depends upon the type of plant and the type of soil and the amount and type of fluorine found in the soil. With plants that are sensitive for fluorine exposure even low concentrations of fluorine can cause leave damage and a decline in growth. Too much fluoride, wheater taken in form the soil by roots, or asdorbed from the atmosphere by the leaves, retards the growth of plants and reduces crop yields. Those more affected are corns and apricots.
Animals that eat fluorine-containing plants may accumulate large amounts of fluorine in their bodies. Fluorine primarily accumulates in bones. Consequently, animals that are exposed to high concentrations of fluorine suffer from dental decay and bone degradation. Too much fluorine can also cause the uptake of food from the paunch to decline and it can disturb the development of claws. Finally, it can cause low birth-weights.
[edit] Ecological Effects
The critical question for biologists is whether chronic exposure to these fluoride concentrations, which may be from two to ten or more times higher than the background level, poses any significant physiological or ecological hazard to aquatic life. It seems reasonable to conclude that fluoride at these levels poses no major risk to marine organisms. (32) Both the dilution factor, and the fact that most oceanic forms evolved in an environment that contains from 0.6 to 0.7 ppm fluoride ion, suggest that potential effects on marine life should be minimal if fluoride in rivers rarely exceeds 2 ppm However, freshwater organisms evolved in an environment that was almost fluoride-free, and thus might be expected to be less well-equipped to tolerate fluoride concentrations encountered in polluted streams.
Relatively little is known about the potential impact of fluoride on either freshwater or marine organisms. A number of investigators have measured the short-term toxicity of various fluoride compounds for a good number of species, but systematic inquiries on the more general effects of long-term, low-level pollution, analagous to the Montana air pollution studies discussed above, have rarely been published. Thus, we may know the lethal concentrations for many organisms, but we have very little knowledge of the sublethal effects of fluoride on behavior or reproductive processes, or of potential accumulation of the pollutant in aquatic food chains. Yet such effects, should they occur, would probably be more important ecologically than the mortality which might result from very high, but short-lived, pollution episodes. (36)
Several investigators have exposed a variety of bacteria and microscopic animal species that live in freshwater to a range of fluoride concentrations extending well above those likely to be encountered in streams, without any demonstrable toxic effects. (37) Not many species have yet been tested, however, and the criteria for evaluating toxicity were not sophisticated. The finding that bacterial digestion of sewage removes much of the fluoride content of the effluent (26) suggests that some bacteria may accumulate fluoride from water. The importance of bacteria as a basic element in food chains makes it important to learn more about the capacity of microorganisms to bioconcentrate this contaminant.
The single-celled green alga Chlorella showed a 37 percent reduction in growth over 48 hours when exposed to a 2 ppm fluoride solution; (38) 43 ppm was reported lethal to another alga, Scenedesmus. (39) Few other data on toxicity of fluoride to aquatic plants are available, but several studies suggest that water plants can accumulate the element. Five-day exposures to 100 ppm led to a 50-told concentration of fluoride by aquatic plants, and fourteen days at 20 ppm produced a 38 fold increase. (27) Water hyacinths absorb fluoride efficiently at concentrations above 10 ppm, and to a much lesser extent at lower Ievels. (40) Several species of marine algae (exposed to 0.5 to 0.7 ppm) contained 2 to 22 ppm fluoride. Eel grass and the alga Cladophora, however, showed no significant fluoride buildup after seventy-two days in sea water with 52 ppm fluoride. (42) One Russian study found an average fluoride content of 40.5 ppm in samples of several freshwater plants, (43) and other studies strongly suggest that aquatic vegetation accumulates fluoride. (44) However, the evidence as a whole is still too fragmentary to provide a clear or systematic picture of the capacity for fluoride buildup in aquatic plants.
[edit] Effects on Aquatic Animals
Short-term fluoride toxicity data are available for a number of invertebrate species, the majority of them marine varieties. Water fleas are killed or immobilized by concentrations of various fluoride compounds ranging from 5 to 500 ppm (45) Lobsters are not harmed by 5 ppm fluoride. (46) Mussels may be killed by 1.4 to 7.2 ppm, (42) and concentrations of 20 ppm or higher for extended periods have been shown to be toxic or lethal to oysters, two species of crabs, and a sand shrimp, but not to two types of prawns. (47) More significant than the lethal effects of high concentrations, however, is the marked ability demonstrated by almost all species studied in these investigations to accumulate substantial bodily burdens of fluoride. Even animals kept in sea water containing only 1 ppm fluoride had bodily concentrations of from 100 to 300 ppm (48) The entry of fluoride into food chains through bioconcentration in aquatic invertebrates is a subject in need of much more careful research.
Studies of the effects of fluoride on fish are far more numerous than for any other form of aquatic life . (49)
Short-term lethal effects may occur at concentrations as low as 3 ppm in sensitive species (for example, rainbow trout), while other fish are not damaged until fluoride levels reach 100 ppm Water temperature, hardness, chlorinity, and other environmental factors, as well as the age and physiological state of the fish, can influence the toxicity of a given concentration of fluoride. (50)
Sublethal concentrations may have adverse effects on fish behavior or reproduction, which could be ecologically significant. Research findings are few and not confirmed, but trout eggs seem to be delayed in development and hatching by 1.5 ppm fluoride. (51)
Fish are important food-chain organisms, and the ability of many fish, like many other vertebrates, to accumulate elevated fluoride levels in their skeletons (52) can introduce the contaminant into the diet of fish-eating predators. Levels of 550 to 6,800 ppm have been reported in bones of ocean fish, and 400 to 1,600 ppm in trout from a naturally high-fluoride stream in Yellowstone National Park. Such accumulation might pose a hazard to animals that eat whole fish.
Data on other aquatic vertebrates which may be exposed to fluoride are sparse. Frogs were killed in one week by 900 ppm fluoride, (53) and decreased red and white blood cell counts were observed in frogs kept in fluoride concentrations of 5 to 300 ppm (54) There have also been indications that sublethal fluoride concentrations may adversely affect amphibian reproductive cycles. (55) Frog eggs were retarded in development but hatched prematurely in 1 ppm fluoride in well water, higher concentrations (13 to 450 ppm) had the same effects on toad eggs, and metamorphosis in tadpoles was significantly delayed by fluoride at 0 5 and 4.5ppm. (56)
Most research on the effects of fluoride on aquatic organisms dates back to the early 1960s or before, and more definitive studies are required on the potential hazards suggested here. There is also a pressing need to examine the potential impact of chronic, low-level bioaccumulation of fluoride on predatory animals higher in aquatic-based food chains. As is the case with fluoride air pollution, the logic of ecosystem energy and nutrient flow patterns suggests that species at the highest levels of a food chain are likely to bear the greatest risk of harm, but virtually no effort has been made to look for such damage. If fluoride has had such adverse effects on aquatic wildlife, they have thus far been too subtle to attract attention. In the absence of any substantive research data, it would be unwise to assume that no risks exist.
[edit] Soil Pollution Sources
Because fluoride is a common constituent of several relatively abundant minerals, most soils contain this element. The range for most normal soils is 100 to 300 ppm, but levels of up to 8,300 ppm have been found in heavy clay soil. (2) Additional sources of fluoride input to the soil may be present in many localities. Air pollution can lead to a substantial increase in soil fluoride content, both through fallout of particulate fluorides and through the absorption of gaseous fluorides in rain and snow. (57) Phosphate fertilizers may contain 0.5 to 4.0 percent fluoride by weight as an impurity. One investigator calculated that fertilizer applications in Germany were adding from 7.0 to 17.6 pounds of fluoride each year per acre of land fertilized. (58) This compared to 1.8 pounds per acre of fluoride added to the soils in his study area by air pollution, and to values of 6.1 to 19.2 pounds for each acre input from air pollution in similar studies. In the US, 5 million tons of phosphate fertilizers were applied to soils in 1973. (59) If it is assumed that the average fluoride content of that fertilizer was 2 percent by weight, this represents an input of 100,000 tons of fluoride to US soils.
Additional fluoride input to soils may occur when fluoride-containing waters are used in irrigation. No quantitative estimates are available for the magnitude of such contributions to fluoride contamination of the soil, however.
[edit] Fate of Fluoride in Soils
More than 90 percent of the natural fluoride content of soils is insoluble, or tightly bound to soil particles. (27) Most soil samples show lower fluoride content near the surface than at depths of a few feet, indicating that the soluble fraction of fluoride may be removed from the surface by water seeping into the ground. It appears, therefore, that under normal conditions very little fluoride is available for uptake by plants, even in soils that may be relatively rich in fluoride.
Research findings differ on the degree to which fluoride added by pollution or fertilization is available for uptake in the plant roots. When soluble fluoride compounds (for example, sodium fluoride) were added to soils in concentrations of 150 ppm or more during one experiment, significant uptake by plants occurred. (60) Other experiments showed that a substantial amount of fluoride was removed from polluted soils by water. (61) On the other hand, it has been found that as much as 90 percent of fluoride from fertilizers and air pollution may remain in the soil; (58) another report showed that some soils, especially those with relatively high calcium content, were very effective in fixing fluoride, with the result that little was available for plants to incorporate. (62)
It seems very likely that a number of soil characteristics, as well as other environmental factors, can have a marked influence on the availability of fluoride to plants. For example, fluoride is more readily available in sand or acid soils than in high-clay soils. (63) Also, a relationship exists between the type of nitrogen fertilizer applied and the toxicity of fluoride to crops. (64) The use of certain boron-containing fertilizers leads to a dramatic increase in the accumulation of fluoride in the leaves of fruit trees. (65)
[edit] Biological Effects
The only research on the biological impacts of soils contaminated by fluoride has dealt with uptake of the chemical by plants. Data from one study showed that grasses grown in soils containing 1,350 ppm fluoride could contain as much as 1,330 ppm (14) In many similar reports, it has been observed that when fluoride is present as both an air pollutant and a soil pollutant, plant uptake from air (through the tiny openings in leaves where gases are exchanged) is far more significant than from soil. Several investigators have shown, however. that substantial uptake can occur from soil alone under some conditions. (66)
A number of investigators have shown that the uptake of fluoride pollution from soil can have toxic effects on some plants. For example, 1,000 to 1,500 ppm fluoride added to soil in one experiment reduced the yield of winter wheat by 40 to 65 percent and 400 ppm reduced growth of Tradescantia, a flowering plant by 28 to 34 percent; (60) a strong correlation has been demonstrated between inhibition of pea seedling growth and increased fluoride content of the soil, (67) and fluoride concentrations of 1.9 to 190 ppm in soil reduced the growth of loblolly pine and red maple trees. (68)
The most obvious ecological concerns arising from fluoride pollution of the soil center around uptake of the contaminant by plants, not only because of potential toxic effects to the plants themselves, but also because the process may introduce additional fluoride into the diets of animals.
But uptake by plants is just a small part of the possible impact soil fluoride might have on living things. The soil is anything but a sterile medium; it is, in fact, a very rich, and highly diverse, ecosystem which includes thousands of species of microbes, fungus, worms, and insects. (69) Many of these soil organisms are essential to the fertility of the land - for example, they convert nitrogen to a form useful to plants, help break down organic matter and by turning the soil, help aerate it. Disruptions by soil ecology by toxic pollutants could potentially reduce the land's ability to support plant life, and thus, all life.
Whether the fluoride now being added to soils in fertilizers and as fallout from air pollution poses any real threat to the ecological balance of the soil community cannot be determined yet. There are virtually no published data on the toxicity of fluoride to soil organisms, or the potential for accumulation of fluoride in soil food chains. Until research has been conducted on this subject, we will have no way of knowing, but the possibility must be considered that fluoride may be potentially as dangerous to some soil organisms as it is known to be to some terrestrial and aquatic varieties.
[edit] Biosynthesis of Organofluorides
Many environmental contaminants may be altered chemically by the action of living things, and in this way be transformed into substances more toxic than the pollutants in their original form. The methylation of mercury by bacteria is one example of such biotransformation. (See "Mercury in the Environment," and "Mercury in Man," Environment, May 1971.) Another is the synthesis of highly toxic azo compounds from aniline-based herbicides which has been reported to occur in soil microorganisms. (See "The Soil Transforms," Environment, May 1971.) There is convincing evidence now that some plants can synthesize organic fluoride compounds, primarily fluoroacetate and fluorocitrate, from inorganic fluorides. Although inorganic fluorides are themselves quite toxic, fluorocitrate and fluoroacetate are much more toxic. According to one expert in the field, "Fluoroacetates and their related compounds...are among the most poisonous substances known." (70)
The biosynthesis of organofluorides was initially demonstrated in certain tropical plants noted for their extreme toxicity to livestock. It has been observed that these plants may contain several hundred ppm of fluoro-organic compounds in their leaves, but the plants usually grow in soils which are low in fluoride (11 and 216 ppm). (71) Fluoroacetate levels of up to 1,100 ppm have been measured in the leaves of one tropical plant growing in an area where soils contained 1 to 6 ppm fluoride, and the water only 0.05 ppm No other plants in the vicinity contained more than 2 ppm fluoride. Some of the plants that synthesize fluoro-organic compounds, therefore, appear to have an exceptional ability to extract fluoride from an environment in which the element is present only in extremely small traces. (72)
More than two dozen toxic plants are known to be able to synthesize fluoroacetate, (73) but much interest has been generated by recent findings, which could be of great ecological importance, that suggest that the ability to make organic fluoride toxins may be much more widespread than was previously suspected. Fluoro-organic residues have been detected in several salad and forage crops.(74) Measurements have shown 179 ppm fluoroacetate and 896 ppm fluorocitrate in forage crops grown in fields near a phosphate plant. (75) Soybean plants exposed to hydrogen fluoride in the laboratory had concentrations of 40 and 140 ppm of the same two compounds. (76) Other workers have reported that single-cell cultures of soybeans possess the ability to synthesize fluoro-organic compounds; (77) lettuce can convert fluoroacetate to fluorocitrate. (78) At least one attempt to detect organic fluoride compounds in crop plants exposed to fluoride was not successful (79) although others have repeatedly confirmed these findings. (73)
Compared to the amounts of fluoro-organic toxins found in some of the poisonous tropical plants mentioned above, the quantities detected in most of the more common plants tested are quite small and may not be a toxic threat. However, organofluorides have also been reported in tea and in oatmeal (80) and may be very widespread in both the human and natural food chains. Recent reports that fluoro-organic residues are present in the bones of cattle and horses (81) are suggestive of food-chain transfer. Sodium fluoroacetate, sold commercially under the name "Compound 1080" is a widely employed rodenticide, (92) and unintended transfer of the poison through the food chain has had adverse effects on some predators which feed on rodents. If increasing fluoride pollution of the environment should lead to a general buildup of fluoro-organic compounds in natural food webs, it is possible that the ecological damage which might occur could be severe.
A great deal of research is needed to determine whether biosynthesis of organic fluorides does in fact add a serious new dimension to the potential ecological consequences of fluoride pollution. We need to know which organisms possess the ability to synthesize these toxins, and in particular whether such abilities exist in members of aquatic and soil communities. There is evidence that some soil microorganisms may synthesize fluoroacetate; (83) the existence of this capacity in microbes, as well as higher plants, needs to be explored. Some plants have also been shown to break down organic fluoride compounds.(84) Some bacteria may also be able to defluorinate these substances. (71) A great deal of work is still needed to track the environmental fate of fluoro-organic toxins in natural biological systems, and to determine the magnitude of any threat arising from the biosynthesis of such compounds that may occur in a fluoride-contaminated environment.
[edit] Fluoride helps prevent cavities in these ways:
- Fluoride will make the entire tooth structure more resistant to decay. Fluoride will combine into the tooth structure to make enamel more resistant to acid attack.
- Fluoride is toxic to Bacteria stops the bacterial from producing acids that cause tooth decay
- Fluoride use can also encourage remineralization or replace minerals in the tooth surfaces that have been demineralized or broken down by bacterially produced acids which can help in repairing early decay or damage before it causes a cavity.
- Fluoride aids development of enamel on "baby" teeth before they erupt.
- Fluoride reduces enamel solubility.
Thus, "Fluoride offers additional help when present at the tooth surface by providing its own ions, which inhibit demineralization (enamel breakdown) and promotes remineralization (reinforces structure of the outside surface of the tooth), as opposed to rebuilding the tooth structure itself"*.
This process of incorporating minerals such as Calcium into the teeth can also help decrease tooth sensitivity.
[edit] Fluoridated water:
- Protects against cavities
- Protect against root caries, a condition often found in adults
- Help remineralize early small decay
Over 140 studies done by 20 different countries proved that:
"Fluoridated water is the single most effective public health measure to prevent tooth decay and improve oral health for a lifetime"
[edit] Recommendations for fluoride use:
Children
- Use less than a pea size amount of toothpaste with children under two and be careful they do not swallow it.
- Don't let them lick the toothpaste tube or "eat" toothpaste. Reserve the toothpaste made for children until they are two or old enough to obey these guidelines
- Weight or dental age is a better determining factor for fluoride dosage than age in years
- Infants past the age of 12 months should not be fed with formula made with fluoridated water.
- Fluoride treatments may begin after the age of three. Topical fluoride gel works on the outer surface of a tooth and is NOT taken in internally so a child can not overdose on fluoride
- Fluoride rinses can be used after the age of six, especially in children who are drinking soft drinks and/or wearing braces. They can cut decay by about 30% if used daily
- For the best result of a fluoridated toothpaste, the toothpaste should be on the teeth for four minutes
- Chewable vitamins with fluoride are recommended for children who: have cavities; live in areas with unfluoridated drinking water and live in families that are prone to tooth decay or periodontal disease. The supplement for these cases is 1 mg/day. Again no supplement should be given until you have consulted with your dentist.
- Chewing these fluoride tablets puts fluoride directly in the grooves of the teeth where most decay is likely to happen
- We use fluoride polishing paste with all our patients when we clean their teeth.
- We apply fluoride gel to all children after they have had their teeth polished
[edit] Fluoride is for Adults:
- For adults with high level of decay or dry mouth, fluoride rinses are recommended twice a day for four minutes. Do not swallow the rinse.
- American adults have an average of 23 decayed and filled tooth surfaces. For rampant decay rinse with fluoride when ever you can, do not swallow the rinse. Try using a professionally high strength fluoride toothpaste and use it in the evening before bed, do not rinse or eat for 30 minutes after its use
- Fluoridated rinses may decrease bleeding problems if used along with good oral hygiene.
- 40-50% of total adult fillings are done to replace existing fillings. Use fluoride to help prevent further decay.
- Root Caries- According to the National Institute of Health and National Institute of Dental Research Studies, 7% of 18 year olds and as high as 21% of 35 year olds have ALREADY suffered from one or more teeth experiencing Root Caries.
- For adults who drink unfluoridated water.
- Adults wearing braces.
- Dietary fluoride supplements will give teeth a low, prolonged exposure to fluoride to help supplement your fluoride intake, especially in areas where fluoride is not added to the water.
- Before bed, rub toothpaste containing fluoride along the gum line and leave it to soak into the gum line while sleeping to ensure teeth get the fluoride they need.
[edit] Fluoride Protection for You
- Sensitivity: This condition affects 25% of most adults. Gum recession and natural wear can cause sensitivity. Fluoride gels can help strengthen these area to insulate them from hot and cold.
- Root surface caries: Fluoride can help protect this area from acid- producing bacteria.
- Cavity control: Fluoride helps to remineralize enamel. Fluoride blocks cavities by forming a more acid-resistant surface layer.
- Implant maintenance: Fluoride blocks plaque formulation an helps protect your valuable implant from premature failure.
- Gum disease: Fluoride can be used to inhibit bleeding and sustain treatment.
- Denture and partials: can irritate gum tissue and fluoride use can help.
- Braces: Fluoride can help control decalcification of teeth that can occur when wearing braces.
- Dry Mouth: Medication can our health condition can cause this condition. Fluoride can help protect against the rapid decay that can occur with this condition.
[edit] Fluoride Toothpaste Significantly Reduces Childhood Cavities
- greater cavity reduction by brushing twice a day or more with fluorided toothpaste than only once a day.
- brushing with toothpaste containing a higher concentration of fluoride is associated with greater reduction in cavities.
- fluorided toothpaste with give greater benefits in those with higher levels of decayed, missing and filled teeth.
- brushing with fluoride toothpaste provides additional reduction of cavities even if children live in areas with fluoridated water
[edit] See Also
Benefits of toothpaste in organic cosmetics
