Fluoride Action Network

First Page of Study

Since the investigation of Black an,d McKay in 1916 into the problem of mottled enamel, and the definite association of this anomaly with the fluorine content of drinking waters by Churchill (1931, 1932), the matter of fluorine intoxication has been studied in detail by different workers in various parts of the World. It has been shown that this mottling of the enamel occurs only if the fluorine content of the water is above 2 to 3 mg. per litre (Smith and Smith, 1932) or, at any rate, above 1 part per million (Smith et al., 1935).

It has been found by various workers that although the most obvious effect of chronic fluorine intoxication is the characteristic tooth mottling, yet this is only a part of the picture, and the rest of the skeletal tissue and certain other systems also get affected. It is however only rarely and under certain special conditions that clinical affections of the bones and other systems manifest themselves.

Roholm described in 1937 cases of acute and chronic fluorine poisoning contracted by cryolite workers through dust inhalation. The commonest symptoms exhibited by these workers were nausea, vomiting, and various bone, joint and muscle symptoms  – the chief of which was stiffness, especially of the spine. Characteristic bone changes were described. Fluorine intoxication of plants and animals also has been observed in close proximity to metal, glass or super-phosphate factories where raw material containing fluorine is used.

The condition of chronic fluorine intoxication, which in most cases has been first recognized through the typical and vivid clinical picture of enamel mottling, is really widely spread throughout the world. It has been reported in 325 dis- tricts in 25 states of the United States (Dean, 1937), in Mexico, Argentine, Barbados, and the “Bahama Islands. In Europe, it has been recognized in England, Spain, Italy and the Netherlands. In fact, in some parts of England the incidence of mottled enamel seems to be quite high. Spira (1942), examining 5,019 service men and women, found mottled teeth in 1>099 or nearly 22 per cent. The proportion was highest in those who had lived in Hertfordshire and Northamptonshire. The condition has also been reported from Morocco, Tunisia, Algeria, South Africa, the Azores, Cape Verde’ Islands, North China and Japan.

In India, so far as bone symptoms are con- cerned, the first report of the cases was by Shortt, Pandit and Raghavachari (1937), and Shortt et al. (1937) who discovered marked skeletal changes with mottled enamel in patients coming from the Nellore District of the Madras Presidency, and, complaining of certain skeletal symptoms notably stiffness of the spine. The diagnosis of fluorine intoxication was made, and later detailed investigations confirmed the diagnosis and proved it to be due to the high content of fluorine in water.

Certain investigations tend to show that sensitivity to fluorine is influenced to some extent by the calcium, phosphorus and vitamin D content of the diet. Phillips (1933) demonstrated a relationship between vitamin C and chronic fluorine intoxication, and certain investigations in Madras (Pandit et al., 1940) also tended to prove that the skeletal changes were more likely to occur if, along with a high fluorine content of water, there was deficiency of vitamin C in the diet.

The main pathological lesion in the teeth generally occurs in those people who have spent the first fourteen years of life in an area with a high fluorine content of water. The teeth lose their glossy translucent appearance and appear chalky white or opaque on the areas which had been affected during calcification, the lesion being due to the absence, to a greater or less degree, of the cementing substance between the enamel. A common manifestation is the appearance of white, yellow, or brown areas in the form of bands extending horizontally across the tooth surface. Sometimes the affected areas are very irregular in outline, and closely resemble ‘ flow-pattern ‘ porcelain.

Skeletal changes are very rare in comparison with the incidence of mottled enamel. Apart from workers in factories of cryolite, etc., they have been found in certain villages with a very high content of fluorine in water (6 parts per million). There is some evidence to suggest that although dental fluorosis and fluorosis of bones are both primarily due to fluorine poisoning, the mode of action of the causative element in the production of the two conditions may not be identical. Pillai, Rajasopalan and De (1944) have shown in experimental animals that the addition of milk powder or bone powder to their diet affords remarkable protection against fluorine poisoning especially against the bone symptoms. The main changes in the skeletal tissues when they are affected as described by Roholm (1937) are :

The pelvis and the spine are the earliest to be affected. Ultimately the changes affect the

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