Proponent of the fluoridation of drinking water claim that the addition of fluoride compounds to water reduces the incidence of dental caries in children. This is controversial because the scientific evidence for a protective effect in healthy nutritionally replete populations is quite weak. In addition, the mass medication of all humans for the benefit of a small group is unethical and of questionable logic. If fluoride is beneficial to teeth there are better ways to administer it to children than through drinking water. Further, fluoride is already ubiquitous in the diets on most individuals. Most foods and drink contain a small amount of fluoride and it is therefore very doubtful that any human with a balanced healthy diet would develop a fluoride deficiency. Even if fluoride were to be proved to be essential to the health, it would only be needed in minute amounts. Although fluoride is claimed to be essential to human health based on its supposed effects on teeth, fluoride does not satisfy classification to that of an essential minerals in humans.
However, irrespective of the ethical and health implications of this practice, biological mechanisms to explain how the fluoridation of water could affect teeth are available. Proponents of the fluoridation of drinking water state that for fluoride to be beneficial, it must be consumed and absorbed. Fluoride in drinking water increases the fluoride content of tissues and this may then be incorporated into the growing tooth along with other minerals most notably calcium. However, studies have questioned the necessity to actually consume fluoride for it to have beneficial effects. This is because fluoride may be absorbed to teeth through topical application. It is very hard to separate the topical effects of fluoride from the systemic effects, because all systemic fluoride passes through the mouth and comes into contact with teeth. Therefore the systemic effects of fluoride ingestion are confounded by the topical application of fluoride to teeth and studies investigating the two separately have not been forthcoming.
The topical application of fluoride is often used as evidence to support the addition of fluoride in toothpaste. However, controversy also surrounds this practice. The growth in the availability of fluoride free toothpastes would suggest that the public as a whole is becoming suspicious of the medical establishment and their obsession with fluoride. The mineral fluoride and its role in tooth decay receives huge amounts of public campaign money, and yet selenium, a mineral that has been shown to decrease the rate of cancer mortality by 50 % is completely ignored. The use of fluoride in toothpaste is also interesting because fluoride has antimicrobial properties and can significantly reduce the growth of bacteria on tooth enamel, which in turn would prevent dental caries and strengthen the teeth. This fact alone could explain the beneficial effect of fluoride containing toothpaste. However, safer and more effective antimicrobial agents are available to add to toothpaste. The role of refined crystalline sugar in tooth decay is also largely ignored.