Skeletal fluorosis fluoride

Toxicology. Fluoride causes irritation of the eyes and respiratory tract and gastrointestinal effects absorption of excessive amounts of fluoride over a long period of time results in skeletal fluorosis. 

Repeated exposure to excessive concentrations of fluoride over a period of years results in increased radiographic density of bone and eventually may cause skeletal fluorosis. Crip-... 

This paper is written with the aim of providing sufficient background to help understand the mechanism of action of fluoride ion on humans. The main focus is on the effects of fluoride on dental health, in-depth discussion of skeletal fluorosis and use of fluoride for treating osteoporosis being outside the scope of this paper. Current information on the main sources of human exposure to fluoride and current recommendations for adequate intake (Al) of fluoride, as well as methods for assessing exposure, will be reviewed. 

Skeletal fluorosis can be defined as excessive deposition of fluoride in bone. This is a pathological condition that is by far the most important aspect of chronic exposure to elevated levels of fluoride, either by inhalation or by ingestion. The skeletal deformities may be associated with or accentuated by nutritional deficiencies or even malnutrition and hard manual work or, possibly, other conditions found in areas of long-term social and nutritional deprivation [6]. See, for instance Fig. 1 of [54]. The situation is specific also for populations consuming large volumes of water, such as athletes or people with certain medical conditions or... 

Endemic crippling skeletal fluorosis is confined in temperate climates to individuals exposed continuously over many years to very high levels of fluoride these cases are associated with industrial situations, with unusually high levels of fluoride in drinking water (e.g., 10 mg/L) or the use of high fluoride coal for cooking and drying foodstuffs indoors [6,17,55]. 

Most epidemiological research has indicated that an intake of at least 10 mg/day for 10 or more years is needed to produce clinical signs of the milderforms of osteosclerosis [8]. Water fluoride concentrations of 4-8 mg/L in temperate climates have not been found to be associated with any signs or symptoms of skeletal fluorosis [6]. This data should be regarded with scepticism in view of reports from a number of developing countries that endemic skeletal fluorosis occurs in individuals whose drinking water contains more than 6 mg/L of fluoride [6]. 

Reliable analytical techniques are a prerequisite for accurate and precise determination of human exposure to fluoride. The goal is to monitor the intake of fluoride and maintain it at adequate levels so that optimal protection against dental caries is achieved, without excessive intake resulting in the appearance of dental or, in the worst case, skeletal fluorosis. 

Boron elfectively counteracts symptoms of fluoride intoxication in humans (Zhou etal. 1987) and in rabbits poisoned experimentally (Elsair et al. 1980a, 1980b, 1981). Humans suffering from skeletal fluorosis experienced 50 to 80% improvement after drinking solutions containing 300 to IKX) mg of borax per liter daily, 3 weeks a month for 3 months (Zhou et al. 1987). Boron enhances sequestration of fluoride from bone and excretion through kidneys and possibly the intestinal tract (Elsair et al. 1980a, 1981). 

CAUTION Fluorides are eye and respiratory tract irritants and chronic exposure may result in skeletal fluorosis Appropriate safety precautions and procedures should be adopted when handling this substance. 

Federal regulations require that fluoride not exceed a concentration of 4.0 mg L"1 in drinking water. Chronic exposure to levels above 4.0 mg L-1 may result in some cases of crippling skeletal fluorosis, a serious bone disorder. Fluoride in children s drinking water at levels of approximately 1 mg L-1 reduces the number of dental cavities. Federal law also requires that notification take place when monitoring indicates that the fluoride exceeds 2.0 mg L 1. 

What are the characteristic features of skeletal fluorosis in animals intoxicated by fluoride ... 

Occupational exposure to inhaled fluoride dusts in cryolite workers during aluminum refining has resulted in severe bone abnormalities, but safety equipment now limits such exposure. No cases of skeletal fluorosis are attributed to use of controlled fluoridation of water supplies. However, skeletal fluorosis may occur in areas of the world where naturally occurring drinking water has high levels of fluoride, such as China and the Indian subcontinent. It is thought that exposure to fluoride intakes of 10 to 25mg/day for 10 years or more may result in skeletal fluorosis, but other nutritional factors may make these populations more susceptible. ... 

If the fluoride intake is maintained above 10 ppm, the inhibition of enolase (Sects. 16.2.2 and 16.3.1) inhibits both anaerobic and aerobic glycolysis. In addition, skeletal defects may be caused by improper collagen synthesis inhibiting proper bone formation in children. Skeletal fluorosis in children and fluoride poisoning in adults is therefore accompanied by... 

The most important manifestation of hyperfluoric status is dental and skeletal fluorosis. In regions of volcanic activity, and in some arid zones and areas where phosphorites and apatites are mined and processed, agricultural animals and population often suffer from endemic and civilization-related fluorosis that mostly affects the teeth and skeleton. There arises the problem of reproduction and maintenance of dairy cattle (Ermakov etal. 1998, Ermakov 2001). In toxic quantities, fluorides impair the metabolism of calcium and synthesis of bone collagen by stimulating bone accretion, and speed up bone resorption and total calcium turnover in the body (Susheela and Mukher-jee 1981). 

Daijei H (1981) X-ray analysis of 34 cases of food borne skeletal fluorosis. Fluoride 14 51-55. 

At low-level concentrations, fluoride can reduce the risk of dental cavities. Exposure to somewhat higher amounts of fluoride can cause dental fluorosis, which, in its mildest form, can result in the discoloration of teeth. Severe dental fluorosis produces pitting and alteration of tooth enamel. Higher intake of fluoride, taken over a long period of time, can result in changes to bone and in a condition known as skeletal fluorosis. The effects of skeletal fluorosis include joint pain, restriction of mobility, and a possible increase in the risk of some bone fractures. 

Fluoride Dental fluorosis, skeletal effects 4 Geological deposits, drinking water additive, aluminum industries... 

Skeletal fluorosis is endemic in some parts of the world owing to life-long ingestion of high amounts of fluoride in the drinking... 

Excessive intake of fluoride leads to brown discoloration of the teeth (dental fluorosis). A concentration above about 12 ppm in drinking water, as occurs naturally in some parts of the world, is associated with excessive deposition of fluoride in the bones, leading to increased fragility (skeletal fluorosis). 

---