In , fluoride was documented as a neurotoxin that could be hazardous to child development, along with 10 other industrial chemicals, including lead, arsenic, toluene, and methylmercury. According to the International Association of Oral Medicine and Toxicology IAOMT , an organization that campaigns against the use of added fluoride, it may also contribute to the following health problems:. This will not result from drinking tap water.
It is only likely to happen in cases of accidental contamination of drinking water, due, for example to an industrial fire or explosion. It is worth remembering that many substances are harmful in large quantities but helpful in small amounts.
Fluoride is added to many dental products. Some geographical areas have drinking water that is naturally high in fluoride , for example, southern Asia, the eastern Mediterranean, and Africa. Flouride has been linked to a reduction in tooth decay. Fluoride is present in natural water. Adding fluoride, says the ADA, is like fortifying milk with vitamin D , orange juice with calcium, or cereals with B vitamins and folic acid.
A Cochrane review published in found that when fluoride was introduced to water:. Fluoride prevents tooth decay by:. Protection from demineralization : When bacteria in the mouth combine with sugars, they produce acid. This acid can erode tooth enamel and damage our teeth. Fluoride can protect teeth from demineralization that is caused by the acid. Remineralization : If acid has already caused some damage to the teeth, fluoride accumulates in the demineralized areas and begins strengthening the enamel.
This is remineralization. Everyone can benefit from added dental protection, but those who can benefit particularly are people who:. Most public health authorities and medical associations worldwide recommend that children and adults receive some fluoride, to protect their teeth from decay. These methods are especially important in regions where other preventive programs are not available In certain countries, preventive methods also include fluoridated milk and salt 7.
Fluoridated salt has been widely used in Germany, France and Switzerland since Salt usually contains ppm of fluoride 11 , whereas milk contains 2. However, this method is becoming less suitable, because of modern guidelines for low salt diets 7.
According to different evidence based research, there is insufficient evidence that fluoridated milk has caries-protective effects Products used for oral hygiene are also an important means of systemic fluoride intake.
A certain amount of toothpaste is consumed during brushing. It is therefore recommended that children use toothpaste with a lower fluoride concentration in small amounts Table 2 Recommended use of fluoride toothpaste for children.
After absorption, fluoride is transported into the bloodstream and is distributed through the organism 4. The mean time of the peak concentration is minutes after consumption In the plasma, fluoride ions are bound to plasma protein Concentration rarely exceeds 0. It is usually about 0. The remaining part of the absorbed fluoride is excreted through the kidneys into the urine; excretion through saliva and sweat is negligible 4. The kidneys are therefore the only human organ that helps maintain the fluoride concentration in our bodies.
There are different factors that can influence fluoride metabolism. The most important are: acid base disorders, hematocrit, altitude, physical activity, circadian rhythm, hormones, kidney function, genetic predispositions and diet When the concentration is low, fluoride is transmitted into the placenta If the fluoride concentration increases over 0.
The idea of using fluoride as a beneficial agent in caries prevention is not new. The pioneers in the field were Black and McKay. They started observing and describing the effects of fluoride in the late 19 th and beginning of the 20 th century McKay was studying brown stains on enamel observed in the population from different parts of the USA.
A condition which he termed mottled enamel. After the discovery, Dean systematically conducted a series of epidemiological investigations He listed enamel spots based on size and color and measured the degree of tooth impairment. He compared enamel changes to fluoride concentration in drinking water and made the connection between fluoride content and the quantity of enamel spots, which he termed dental fluorosis He documented dental fluorosis prevalence in the USA until and then compared it to caries prevalence in children.
He noticed a strong inverse relationship After concluding his city study 25 , 26 , he found that drinking water with 1 ppm of fluoride can prevent dental caries, increase tooth strength and does not have a negative impact on enamel.
The first studies about positive effects were conducted in with systemic fluoridation of drinking water in four American cities Grand Rapids, Evanston, Brantford and Newberg , where 1 mg of fluoride per liter was added to drinking water.
The results were convincing. They came to the conclusion that fluoride in suitable concentrations significantly affects dental caries prevalence 27 - These observations and discoveries triggered massive drinking water fluoridation, the use of fluoridated salt and milk and an increase in diet supplement production pills, drops, chewing gum, lozenges. Consequently, caries prevalence was successfully decreased. In , Bibby et al 31 conducted a study comparing the efficacy of fluoride-coated pills intended to be swallowed, with fluoride lozenges intended to be dissolved slowly in the mouth.
Research showed a lower number of new caries lesions in the research group which consumed lozenges. This research triggered different studies comparing pre- and post-eruptive effects, which consequently led to a rethinking of the theory of systemic use of fluoride and its incorporation into enamel during teeth development odontogenesis.
In the last 30 years, studies have shown that the maximum anti-caries benefits of fluoride are primarily through topical use and direct contact on the tooth surface. Daily use of topical supplements with suitable fluoride concentration is beneficial 2. The primary and most important action of fluoride is topical, when the fluoride ion is present in the saliva 33 in the appropriate concentration. Hydroxyapatite is the main mineral responsible for building the permanent tooth enamel after the development of the teeth is finished During tooth growth, the enamel is constantly exposed to numerous demineralization processes, but also important remineralization processes, if the appropriate ions are present in the saliva.
These processes can either weaken or strengthen the enamel. The presence of fluoride in an acidic environment reduces the dissolution of calcium hydroxyapatite. The main action is inhibition of demineralization of enamel, which is carried out through different mechanisms.
There are different cariogenic bacteria in the plaque fluid the most important being S. When bacteria metabolize sugars, they produce lactic acid 33 which decreases the pH in saliva. When the pH falls below the critical level of hydroxyapatite pH 5.
At the beginning, the process is reversible and it is possible to reduce the formation of new lesions with appropriate preventive measures. If fluoride is present in plaque fluid, it will reduce the demineralization, as it will adsorb into the crystal surface and protect crystals from dissolution.
Because the fluoride ion coating is only partial, the uncoated parts of the crystal will undergo dissolution on certain parts of the tooth, if the pH falls below level 5. When the pH rises above the critical level of 5.
Many countries have decided to stop adding fluoride to public drinking water due to safety and efficacy concerns, but it is available through other means — like fluoridated milk and salt, or fluoride supplements 8.
Many people are also skeptical about the effectiveness of fluoridated water. Some feel that dental health should be dealt with at the individual level, rather than through a community-wide intervention. Additionally, fluoride appears to be more effective for cavities when applied directly in the mouth, rather than merely passing through it, as is the case with water 8 , 9. However, a review notes that most of the studies justifying the use of fluoridated water were conducted in the s or earlier, highlighting a need for more recent research to support this widespread public health initiative Water fluoridation is a public health intervention that continues to be a subject of debate.
While many health organizations support it, recent evidence suggests that targeted interventions may be more effective. Dental caries, also known as cavities or tooth decay, are an oral disease. These bacteria break down carbs and produce organic acids that can damage tooth enamel, the mineral-rich outer layer of a tooth. This acid can lead to loss of minerals from the enamel, a process called demineralization Fluoride may help prevent cavities by decreasing demineralization, enhancing remineralization, and inhibiting bacterial growth and bacterial acid production in the mouth.
However, more research is needed on this subject 1. Fluoride may fight cavities by improving the balance between mineral gain and loss from the tooth enamel. It may also inhibit the activity of harmful oral bacteria. Fluorosis occurs after prolonged exposure to excessive amounts of fluoride. There are two types: dental affecting the teeth and skeletal affecting the bones. Mild dental fluorosis, characterized by white spots on the teeth, is fairly common and presents only a cosmetic issue.
More severe cases are less common, but are associated with brown stains and weakened teeth 10 , Although fluoride is the cause of skeletal fluorosis in these cases, many other factors, including nutritional factors, can play a significant role in the severity of the health condition. Evidence for an association between the consumption of fluoridated water and hip fractures is mixed; some studies support the association, others do not, some even report protective effects of fluoride on bones.
Two comparative studies carried out on groups of people drinking water with different levels of fluoride showed greater risks of fracture at higher fluoride levels. Studies on human populations did not show any association between the consumption of fluoridated drinking water by mothers and increased risk of spontaneous abortion or congenital malformation.
Studies on workers exposed to airborne fluorides have provided no reasonable evidence of effects upon lungs, blood system, liver or kidneys attributable to fluoride exposure alone.
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