the highest level of fluoride is stored in the teeth in the saliva.
the highest level of fluoride is stored in the teeth in the saliva.
where is the highest level of fluoride stored in the teeth?
saliva
the presence of fluoride in saliva and plaque fluid interacts with remineralisation process in many ways and thus exerts a topical or surface effect. a person living in an area with fluoridated water may experience rises of fluoride concentration in saliva to about 0.04 mg/l several times during a day. technically, this fluoride does not prevent cavities but rather controls the rate at which they develop making them take a lot longer and making them easier to prevent via normal brushing as it will take a higher amount of acid, usually built up over a number of days, to destroy the created fluorapatite. when fluoride ions are present in plaque fluid along with dissolved hydroxyapatite, and the ph is higher than 4.5, a fluorapatite-like remineralised veneer is formed over the remaining surface of the enamel; this veneer is much more acid-resistant than the original hydroxyapatite, and is formed more quickly than ordinary remineralised enamel would be. the cavity-prevention effect of fluoride is partly due to these surface effects, which occur during and after tooth eruption. fluoride interferes with the process of tooth decay as fluoride intake during the period of enamel development for up to 7 years of age; the fluoride alters the structure of the developing enamel making it more resistant to acid attack. in children and adults when teeth are subjected to the alternating stages of demineralisation and remineralisation, the presence of fluoride intake encourages remineralisation and ensures that the enamel crystals that are laid down are of improved quality. fluoride is commonly found in toothpastes. fluoride can be delivered to many parts of the oral cavity during brushing, including the tooth surface, saliva, soft tissues and remaining plaque biofilm.
remineralisation of teeth
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 swallowed toothpaste is the main source of fluoride exposure in unfluoridated communities. other sources include dental products other than toothpaste; air pollution from fluoride-containing coal or from phosphate fertilizers; trona, used to tenderize meat in tanzania; and tea leaves, particularly the tea bricks favored in parts of china. high fluoride levels have been found in other foods, including barley, cassava, corn, rice, taro, yams, and fish protein concentrate. the u.s. institute of medicine has established dietary reference intakes for fluoride: adequate intake values range from 0.01 mg/day for infants aged 6 months or less, to 4 mg/day for men aged 19 years and up; and the tolerable upper intake level is 0.10 mg/kg/day for infants and children through age 8 years, and 10 mg/day thereafter. a rough estimate is that an adult in a temperate climate consumes 0.6 mg/day of fluoride without fluoridation, and 2 mg/day with fluoridation. however, these values differ greatly among the world's regions: for example, in sichuan, china the average daily fluoride intake is only 0.1 mg/day in drinking water but 8.9 mg/day in food and 0.7 mg/day directly from the air due to the use of high-fluoride soft coal for cooking and drying foodstuffs indoors.
water fluoridation