Commentary on and recommendations for the proper uses of fluoride

Determining the optimal concentration of fluoride in drinking water in Pakistan

OBJECTIVES

This study was designed to determine the optimal concentrations of fluoride for drinking water in Pakistan. Clinical dental examination of 1020 school children aged 12 years was carried out in 19 cities of Pakistan. Correlation between concentrations of water fluoride, caries and fluorosis was investigated by analyzing the data on fluoride concentrations in drinking water in the sampled population for which the caries and the fluorosis levels were also measured.

METHODS

The optimal level of fluoride in drinking water is universally calculated by applying the equation of Galagan and Vermillion, which permits the calculation of water intake as a function of temperature. The annual mean maximum temperatures (AMMT) recorded during the last 5 years were collected from the meteorological centres of the 28 divisional headquarter stations. The average AMMT of Pakistan is 29 degrees C at which the optimal fluoride in drinking water of Pakistan was calculated to be 0.7 ppm. As drinking habits differ in various parts of the world, determination of optimal concentration of fluoride for drinking water in Pakistan was performed using a modified Galagan and Vermillion equation, which applies a correction factor of 0.56 to the equation. The optimal fluoride in drinking water in Pakistan using this modified equation was determined to be 0.39 ppm.

RESULTS

Observation of the correlation showed that a fluoride concentration of 0.35 ppm in drinking water was associated with maximum reduction in dental caries and a 10% prevalence of fluorosis.

CONCLUSIONS

Determining the most appropriate concentrations of fluoride in drinking water is crucial for communities. It is imperative that each country calculates its own optimal level of fluoride in drinking water based on the dose-response relationship of fluoride in drinking water with the levels of caries and fluorosis. Climatic conditions, dietary habits of the population and other possible fluoride exposures need to be considered in formulating these recommendations.

[Dental fluorosis in Brazil: a critical review]

This paper discusses dental fluorosis as a relevant public health problem, using a review of epidemiological studies published in the last 10 years on the disease's prevalence, severity, and risk factors. The results suggest that there are already more cases than expected, although few studies refer to major severity. Thus, measures are needed for the prevention and surveillance of dental fluorosis.

The effectiveness of community water fluoridation in the United States

Grand Rapids, the first city in the world to implement controlled water fluoridation, has served as a model for thousands of other communities. Fluoridation is one of the greatest public health and disease-preventive measures of all time. Its advantages include effectiveness for all, ease of delivery, safety, equity, and low cost. Today, nearly 56 percent of the US population lives in fluoridated communities (62% of those on central water supplies). Previously observed caries reductions of one-half to two-thirds are no longer attainable in the United States because other fluoride methods and products have reduced the caries prevalence in all areas, thus diluting the measurement of effectiveness, and because benefits of fluoridation are dispersed in many ways to persons in nonfluoridated areas. Water fluoridation itself, however, remains as effective as it ever was among groups at high risk to dental caries. Contrary to early beliefs that stressed the importance of preeruptive fluoride exposure, fluoridation also provides an important source of topical fluoride and facilitates remineralization. Although data on effectiveness and safety are compelling, future progress of water fluoridation will be affected by economic, political, and public perception factors.

Infants' fluoride ingestion from water, supplements and dentifrice

Concerns about dental fluorosis and the paucity of detailed fluoride intake data prompted this longitudinal study of fluoride intake in infants from birth to 9 months of age. On average, water fluoride intake greatly exceeded that from dietary fluoride supplements or fluoride dentifrice. However, fluoride supplements and dentifrice contributed substantial proportions of fluoride intake among children using them. Some children had estimated fluoride intake from water, supplements and dentifrice that exceeded the recommended "optimal" intake (a level that has yet to be determined scientifically). Practitioners should estimate fluoride ingestion from all these sources if considering systemic fluoride supplementation.