Today, the chief fluoride sources are water and topical agents such as toothpaste. The World Health Organization also recognizes that fluoridated salt or milk may also act as fluoride sources when generalised fluoridation of water is not appropriate. [WHO, 2004]
The benefits of fluoridated water were studied extensively in the 1940s and 1950s [WHO, 2004] and currently, large-scale water fluoridation programs are available globally. Recognising the beneficial effects of fluoride on dental decay, the World Health Organization has set an optimal concentration of fluoride in drinking water of 0.5–1.0 mg/litre. Excessive fluoride ingestion (well above the WHO limits) should be avoided due to the risk of fluorosis, a condition which in mild form can lead to discolouration of the teeth and in more serious form can lead to interference with bone formation.
Following a demonstration of effectiveness in preventing cavities, fluoride toothpastes were introduced around the world in the mid 1950s. Since then, the benefits of fluoride toothpastes, mouthwashes, gels and varnishes have been demonstrated in numerous clinical trials. [Marinho et al., 2003] Overall, more than 500 million people worldwide use fluoridated toothpaste. [WHO, 2004] Since the introduction of fluoride-containing dentifrices, the incidence of caries has reduced by 9.7%–24.9%. [Twetman, 2003]
Different forms of fluoride
Although amine fluoride and stannous fluoride are occasionally used in dentifrices, the main fluoride sources used in daily applications of toothpastes are sodium fluoride (NaF) or sodium monofluorophosphate (MFP) – used either alone or in combination. The European Commission's Cosmetics Directive stipulates that when classified as a cosmetic, toothpastes should not contain fluoride at a concentration higher than 1500 parts per million (ppm). In the USA, the levels allowed range between 850 and 1150 ppm theoretical total. Around the rest of the world, the maximum licensed fluoride concentration in toothpastes varies between 900 and 1500 ppm.