Title: Water fluoridation
Content:  dental bacteria, its effect on bacterial growth does not seem to be relevant to cavity prevention. Fluoride's effects depend on the total daily intake of fluoride from all sources. About 70–90% of ingested fluoride is absorbed into the blood, where it distributes throughout the body. In infants 80–90% of absorbed fluoride is retained, with the rest excreted, mostly via urine; in adults about 60% is retained. About 99% of retained fluoride is stored in bone, teeth, and other calcium-rich areas, where excess quantities can cause fluorosis. Drinking water is typically the largest source of fluoride. In many industrialized countries 
Title: Fluoride therapy
Content:  is available as profluoride compounds which can precipitate in the mouth during toothbrushing and release ionic fluoride. Lastly, fluoride in toothpaste can exist as unavailable fluoride compounds which do not release fluoride ions. This is due to the fluoride ions being swallowed or expelled when spitting. High-fluoride content toothpaste generally contains 1.1% (5,000 ppm) sodium fluoride toothpaste. This type of toothpaste is used in the same manner as regular toothpaste. The application of high-fluoride content toothpaste in adults twice daily improves the surface hardness of untreated root decay when compared to toothpaste with regular fluoride content. Fluoridated toothpaste is also available in the form of 0.454% stannous fluoride (SnF2 with fluoride concentration 1,100 ppm). When combined 
Title: Fluoride
Content:  of local fluoride-containing minerals. For example, natural levels of under 0.05 mg/L have been detected in parts of Canada but up to 8 mg/L in parts of China; in general levels rarely exceed 10 mg/litre Fluoride can be present in rain, with its concentration increasing significantly upon exposure to volcanic activity or atmospheric pollution derived from burning fossil fuels or other sorts of industry, particularly aluminium smelters. All vegetation contains some fluoride, which is absorbed from soil and water. Some plants concentrate fluoride from their environment more than others. All tea leaves contain fluoride; however, mature leaves contain as much as 10 to 20 times the fluoride levels of young leaves from the same plant.
Title: Fluoride
Content:  At physiological pHs, hydrogen fluoride is usually fully ionised to fluoride. In biochemistry, fluoride and hydrogen fluoride are equivalent. Fluorine, in the form of fluoride, is considered to be a micronutrient for human health, necessary to prevent dental cavities, and to promote healthy bone growth. The tea plant (Camellia sinensis L.) is a known accumulator of fluorine compounds, released upon forming infusions such as the common beverage. The fluorine compounds decompose into products including fluoride ions. Fluoride is the most bioavailable form of fluorine, and as such, tea is potentially a vehicle for fluoride dosing. Approximately, 50% of absorbed fluoride is excreted renally with a twenty-four-hour period. The remainder can be retained in the oral cavity, and lower digestive tract. Fasting dramatically increases the rate 
Title: Water fluoridation
Content:  Fluoride naturally occurring in water can be above, at, or below recommended levels. Rivers and lakes generally contain fluoride levels less than 0.5 mg/L, but groundwater, particularly in volcanic or mountainous areas, can contain as much as 50 mg/L. Higher concentrations of fluorine are found in alkaline volcanic, hydrothermal, sedimentary, and other rocks derived from highly evolved magmas and hydrothermal solutions, and this fluorine dissolves into nearby water as fluoride. In most drinking waters, over 95% of total fluoride is the F− ion, with the magnesium–fluoride complex (MgF+) being the next most common. Because fluoride levels in water are usually controlled by the solubility of fluorite (CaF2), high natural fluoride levels are associated with calcium-deficient, alkaline, and soft waters. Defluoridation is needed when the naturally 
Title: Fluoride
Content:  fluoride absorption to near 100%, from a 60% to 80% when taken with food. Per a 2013 study, it was found that consumption of one litre of tea a day, can potentially supply the daily recommended intake of 4 mg per day. Some lower quality brands can supply up to a 120% of this amount. Fasting can increase this to 150%. The study indicates that tea drinking communities are at an increased risk of dental and skeletal fluorosis, in the case where water fluoridation is in effect. Fluoride ion in low doses in the mouth reduces tooth decay. For this reason, it is used in toothpaste and water fluoridation. At much higher doses and frequent exposure, fluoride causes health complications and can be toxic.
Title: Water fluoridation
Content:  (milligrams per liter, equivalent to parts per million), depending on the average maximum daily air temperature; the optimal level is lower in warmer climates, where people drink more water, and is higher in cooler climates. These standards are not appropriate for all parts of the world, where fluoride levels might be excessive and fluoride should be removed from water, and is based on assumptions that have become obsolete with the rise of air conditioning and increased use of soft drinks, processed food, fluoridated toothpaste, and other sources of fluorides. In 2011, the World Health Organization stated that 1.5 mg/L should be an absolute upper bound and that 0.5 mg/L may be an appropriate lower limit. A 2007 Australian systematic review recommended a range from 0.6 to 1.1 mg/L. 
Title: Fluoride therapy
Content:  Most toothpastes contains between 0.22% (1,000 ppm) and 0.312% (1,450 ppm) fluoride, usually in the form of sodium fluoride, stannous fluoride, or sodium monofluorophosphate (MFP). Frequent use of toothpaste with 1,100 ppm fluoride content enhances the remineralization of enamel and inhibits the demineralization of enamel and root surfaces. Most toothpastes with fluoride contain mild abrasives in order to remove heavier debris and light surface staining. These abrasives include calcium carbonate, silica gels, magnesium carbonates and phosphate salts. Fluoride is available in three forms during toothbrushing. First, it is available as a free ionic fluoride which can react with the tooth structure, interfere with the metabolism of bacteria in plaque, or absorb to the oral mucosa. Second, 
Title: Food fortification
Content:  Although fluoride is not considered an essential mineral, it is useful in prevention of tooth decay and maintaining adequate dental health. In the mid-1900s it was discovered that towns with a high level of fluoride in their water supply was causing the residents' teeth to have both brown spotting and a strange resistance to dental caries. This led to the fortification of water supplies with fluoride in safe amounts (or reduction of naturally occurring levels) to retain the properties of resistance to dental caries but avoid the staining cause by fluorosis (a condition caused by excessive fluoride intake). The tolerable upper intake level (UL) set for fluoride ranges from 0.7 mg/day for infants aged 0–6 months and 10 mg/day for adults over the age of 19.
Title: Fluorapatite
Content:  phosphate mineral. It occurs widely as an accessory mineral in igneous rocks and in calcium rich metamorphic rocks. It commonly occurs as a detrital or diagenic mineral in sedimentary rocks and is an essential component of phosphorite ore deposits. It occurs as a residual mineral in lateritic soils. Fluorapatite is found in the teeth of sharks and other fishes in varying concentrations. It is also present in human teeth that have been exposed to fluoride ions, for example, through water fluoridation or by using fluoride-containing toothpaste. The presence of fluorapatite helps prevent tooth decay or dental caries. Fluoroapatite has a critical pH of 4.5, thus it makes tooth structure more resistant to additional caries attack. It has a mild bacteriostatic property as well, which helps decrease the proliferation of Streptococcus mutans, the predominant bacterium related to dental caries.

Question: where is the highest level of fluoride stored in the teeth?
Answer: surface of the enamel.