Skeletal Fluorosis

Skeletal Fluorosis

Dr. D. Raja Reddy., F.R.C.S., F.R.A.C.S. Apollo Hospital & Dr. Srikanth R.Deme., F.R.C.S.C

Introduction: Fluorine, a gaseous element is a halogen which being most electronegative and reactive of all elements does not occur in free form in nature। This element was isolated in 1886 by Nobel laureate Henri Moissan and it combines directly with most elements and indirectly with few to form fluorides. Fluorides are ubiquitous in nature and are present in rocks, soil, water, plants, foods and even air.

The relationship between fluoride and dental caries was first noted in the early part of the 20th century when it was observed that residents of certain areas of U.S.A. developed brown stains on their teeth. These stained teeth, though unsightly were highly resistant to dental decay and caries (Black and May 1916). In the 1930's it was discovered that the prevalence and severity of this type of mottled enamel was directly related to the amount of fluoride in the water (Smith et al. 1931). Subsequently it was recognized that fluoride consumption in optimal amounts in the water supply imparted protection against the development of dental caries without staining the teeth (Dean 1938). Another benefit of fluorides is that the incidence of osteoporosis seems to occur less frequently in regions with high fluoride content in water than in those in which the inhabitants consumed little fluoride. Although, the importance of this element to normal mineralization of hard tissues and formation of caries resistant enamel has been recognized, there has been as yet no conclusive evidence proving that it is an essential element for human health (McClure 1970). Indeed, fluoride deficiency syndrome is yet to be described. This may be due to the fact that human body requirement of this micronutrient must be small, which is met with naturally through food and water. Excessive ingestion of fluoride through water, food or dust causes acute toxicity or a debilitating disease called 'fluorosis' a term coined and first used by Cristiani and Gautier in 1925. Acute fluoride intoxication is rarely seen and results most frequently from accidental ingestion of large amounts of fluoride compounds. The acute lethal dose of fluoride for the 70 kg man is 2.5-5.0 grams. Chronic fluoride poisoning is more common and can affect animals as well as humans. Excessive intake during pre-eruptive stage of teeth leads to dental fluorosis and further continued ingestion over years and decades causes bony or skeletal fluorosis. Lastly crippling disease produces neurological manifestations. A disease in animals called 'gaddur' believed to have arisen from fluoride intoxication caused by periodic volcanic eruptions that have been taking place since 1000 AD is mentioned in Icelandic literature (Roholm 1937). A disease of the teeth and bones of horses and cattle called 'darmous' was known to have been prevalent in North African coast for centuries and later came to be identified as one caused by fluorides (Velu 1933).

All states of India except northeast reported cases of fluorosis and 25 to 30 million people are exposed to high fluoride intake and half a million suffer from skeletal fluorosis। In China 300 million people are living in endemic areas of fluorosis of whom 40 million have dental fluorosis and 3 million suffer from skeletal changes (Li and Cao 1994).

Total daily fluoride intake: The fluoride contents from all the sources determine the human intake of fluoride. In majority of endemic areas around the world, the main contribution is from water and only in few areas of India and China significant amounts come from foods and rarely the polluted air is the culprit. The estimated range of safe and adequate intake of fluorides for adults is 1.5 to 4.0 mg per day and it is less for children and those with renal disease. The daily intake of fluoride in endemic regions varies from 10 to 35 mg and can be even higher in summer months.

Dental fluorosis: Dental fluorosis mainly involves enamel but severe intoxications may affect dentine as well as pulp. Enamel fluorosis occurs when fluoride concentrations in or in the vicinity of the forming enamel are excessive during its pre-eruptive development. Mottling of teeth is one of the earliest and most easily recognizable features noticed in the first decade of life.
Both sexes are equally affected। It is the permanent teeth that are affected and they lose their normal creamy white translucent color and become rough, opaque and chalky white. Pitting and chipping are other marks of fluorosis. Brown or black pigment gets deposited on the defective enamel and once established tends to remain there permanently. Incidence of dental fluorosis in endemic areas exhibits a linear relationship to the fluoride content of water but it may also vary with other factors (Jolly et al 1968). Dental fluorosis does not obviously occur, when there has been no exposure to fluoride in the first decade of life.
http://images.google.co.in/imgres?imgurl=http://www.medvarsity.com/vmu1.2/dmr/dmrdata/cme/fluorosis/gifs/Map-1.gif&imgrefurl=http://www.medvarsity.com/vmu1.2/dmr/dmrdata/cme/fluorosis/Fluorosis.htm&h=649&w=419&sz=84&hl=en&start=19&um=1&tbnid=uHXpbJgq9TQ9BM:&tbnh=137&tbnw=88&prev=/images%3Fq%3Dfluorosis%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DG