Fluoride chronic effects

Human Toxicity Prolonged absorption may cause mottling of teeth, skeletal changes see Sodium Fluoride (chronic effects). 

Health and Safety Factors. Boron trifluoride is primarily a pulmonary irritant. The toxicity of the gas to humans has not been reported (58), but laboratory tests on animals gave results ranging from an increased pneumonitis to death. The TLV is 1 ppm (59,60). Inhalation toxicity studies in rats have shown that exposure to BF at 17 mg/m resulted in renal toxicity, whereas exposure at 6 mg/m did not result in a toxic response (61). Prolonged inhalation produced dental fluorosis (62). High concentrations bum the skin similarly to acids such as HBF and, if the skin is subject to prolonged exposure, the treatment should be the same as for fluoride exposure and hypocalcemia. No chronic effects have been observed in workers exposed to small quantities of the gas at frequent intervals over a period of years. 

Already in 1937 Roholm [40], originator of modern fluoride research, distinguished between chronic and acute toxicity of inorganic fluorides. Chronic toxicity is the result of continuous or repeated exposure of an organism to a toxic substance. Acute toxicity involves harmful effects in an organism through a single or short-term exposure to a toxic substance. 

The synergistic action of aluminum ions with fluoride may be the underlying mechanism of the observed neurotoxic effects of fluoride. Chronic exposure of humans to A1FX begins in the fetus. Elevated fluoride content was found in embryonic brain tissues obtained from required abortions in areas where fluorosis was prevalent [78, 124]. These studies showed poor differentiation of brain nerve cells and delayed brain development. High fluoride exposure appears to weaken mental function among children, as well as adults [125, 126]. 

Caution Highly irritating to the respiratory tract. For chronic effects see Sodium Fluoride... 

Because of the corrosive effects and discomfort associated with inhalation of fluorine, chronic toxicity does not occur. Although the metaboHc fate of fluorine is not clear, it does not seem that much is converted to fluoride ion in the body (107). Therefore comparisons to effects of fluoride ion poisoning, known as fluorosis, are probably incorrect. 

The toxicity of these fluoroaluminates is mainly as inorganic fluorides. The ACGIH adopted (1992—1993) values for fluorides as F is TLV 2.5 mg/m. The oral toxicity in laboratory animal tests is reported to be LD q rat 2.15 mg/kg (41). Because of the fine nature of the products they can also be sources of chronic toxicity effects as dusts. 

Controlled and sustained drug delivery has recently begun to make an impression in the area of treatment of dental diseases. Many researchers have demonstrated that controlled delivery of antimicrobial agents, such as chlorhexidine [128-130], ofloxacin [131-133], and metronidazole [134], can effectively treat and prevent periodontitis. The incidence of dental caries and formation of plaque can also be reduced by controlled delivery of fluoride [135,136]. Delivery systems used are film-forming solutions [129,130], polymeric inserts [132], implants, and patches. Since dental disease is usually chronic, sustained release of therapeutic agents in the oral cavity would obviously be desirable. 

Chromous chloride hexahydrate, 6 531 Chromous sulfate heptahydrate, 6 531 Chromyl chloride, molecular formula, properties, and uses, 6 561t Chromyl compounds, 6 526, 536 Chromyl fluoride, 6 535 Chromyl perchlorate, anhydrous, 18 279 Chronic asthmatic bronchitis, effect on heart, 5 107... 

Whereas much attention has been paid to the effects of dietary fluoride on the skeleton of domestic and experimental animals and man (T8), knowledge about the accumulation of fluoride in soft tissues such as heart, liver or kidney is scarce. The results in Table X indicate that the fluoride content of the kidneys of mice increased with age when the dietary Ca was low and fluoride feeding resulted in much higher levels at 653 days of age irrespective of the dietary Ca content. It is likely that such high fluoride levels had an adverse effect on kidney function. In cases of chronic fluoride intoxication, kidney function was reported to be impaired in the majority of cases (18). It should be noted that fluoride accumulated in the kidneys of mice even though the capacity of bone to store fluoride (5000 yg/g dry weight) without skeletal damage was not reached. 

Fluoride is a cumulative toxin, which accumulates in mineralized tissues, notably in the lattice of bone and tooth crystals [8,39]. The biological effects in humans due to chronic fluoride ingestion depend not only on the total dosage and duration of exposure, but also on associated factors such as nutritional status, functional status of the renal tissue and interaction with other trace elements [41]. The effect of... 

The primary adverse effects associated with chronic, excess fluoride intake are skeletal, and dental or enamel, fluorosis. Other effects, including hypersensitivity reactions, renal insufficiency, immunological effects, possible association with repetitive strain injury, birth defects and cancer have been observed and discussed [17,41-45]. 

Small amounts of fluoride have been proven to be effective in preventing dental caries, but excessive, chronic intake by young children can result in the development of dental fluorosis the critical period of exposure for all permanent teeth... 

A number of studies have examined the potential for airborne aluminum to induce respiratory effects in chronically exposed workers. Exposure to aluminum fumes and dust occurs in potrooms where hot aluminum metal is recovered from ore, in welding operations, and the production and use of finely powdered aluminum. Wheezing, dyspnea, and impaired lung function have been observed in potroom workers (Bast-Peetersen et al. 1994 Chan-Yeung et al. 1983 Simonsson et al. 1985). Because these workers were also exposed to a number of other toxic chemicals including sulfur dioxide, polycyclic aromatic hydrocarbons (PAHs), carbon monoxide, and hydrogen fluoride, it is difficult to ascribe the respiratory effects to aluminum. 

Another kind of environmental interaction may result when in a homeostatic adjustment to the pollutant, the plant sacrifices part of its capacity to respond to environmental fluctuations. For example, the metabolic adjustment to fluorides may increase the susceptibility to nutrient stress. This hypothesis could explain why some symptoms of chronic fluoride toxicity resemble those produced by Mn, Fe, or Zn deficiencies. If air pollution is one environmental factor that alters the susceptibility of the plant to other environmental stress, it would also be logical to expect an interaction between pollutants if the receptor is exposed to two or more of them. Such interactive effects have been found. Sub-threshold concentrations of SOL> and 03 or S02 and N02 produce foliar lesions when plants are exposed to both pollutants (34). Additionally, plants exposed to S02 differ from non-fumigated plants in their resistance to subsequent fumigations (35). Thus the plants susceptibility or capacity to adapt to a pollutant is altered by concurrent exposures to another or consecutive exposures to the same one. 

In chronic-duration feeding studies, no adverse effects on the respiratory system were reported in 1-year studies of dogs given oral doses of 31 mg U/kg/day as uranium tetrachloride, 3,790 mg U/kg/day as uranium hexachloride, 8 mg U/kg/day as uranyl fluoride, or 4,407 mg U/kg/day as uranium dioxide (Maynard and Hodge 1949 Maynard et al. 1953). In 2-year studies, the respiratory system was unaffected in dogs and rats given 2 mg U/kg/day as uranyl nitrate hexahydrate and in rats given 12,141 mg U/kg/day as uranium dioxide, 664 mg U/kg/day as uranyl nitrate hexahydrate,... 

Chronic ingestion of fluorides causes exaggerated buildup on teeth, bones, and ligaments. Exposure to skin, eyes, and mucous membranes has a corrosive effect. 

Chronic fluoride intoxication is more common and, since fluoride is concentrated in the hard tissues, the bones and teeth show the most obvious effects of fluorosis. Intake of excessive amounts of fluoride during tooth development results in mottled enamel which is characterized by the presence of scattered irregular white flecks. The permanent teeth are particularly susceptible. Towards the end of the last century this condition was found to be of common... 

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