What is the optimal waterborne fluoride concentration for Australia ?

The optimal fluoride concentration in drinking water is that which maximizes caries reduction and minimizes enamel fluorosis. Since fluid intake is dependent on ambient temperature and since fluorosis is dose related, children living in warmer climates drink more water and are more at risk of fluorosis than children living in cooler climates who drink water of the same fluoride concentration. Galagan and Vermillion (1957) developed a formula for determining the optimal fluoride concentration for a given climatic region based on fluoride intake and the mean maximum daily temperature. The Centers for Disease Control (CDC), USA, continues to recommend the use of this formula for setting the optimal fluoride concentration in community drinking water. Further, the CDC recommends that due to risk of fluorosis, the fluoride concentration in drinking water should not exceed 2 ppm. Objectives: The purpose of this study was to review the target fluoride concentrations for drinking water in Australian fluoridated communities. Material and Method: Published target fluoride concentrations for fluoridated communities were obtained and meteorological data in relation to the same communities was obtained from the Australian Bureau of Statistics. Optimal fluoride concentrations were calculated and compared with target values. Results: Published target fluoride concentrations ranged from 0.6 – 1.1 ppm. One calculated optimal value was 8.5% lower than the target value but the others were up to more than 20% higher. Discussion: Compared with when the formula for determining optimal fluoride concentrations was developed, children today are exposed during their tooth formation years not only to fluoride from drinking water but from toothpaste, infant formula, and manufactured foods and drinks. Conclusion: In view of the probably higher than optimal fluoride concentration set as the target concentration in many communities, there is an urgent need to review fluoridation policy in Australia.