Fluoridation for dental public health

This article reviews the means by which fluoride is supplied to populations. Many public health authorities provide fluoridated drinking water, with typical concentrations of fluoride of between 0.5 and 1.0 ppm. This has been found to be safe and effective, though differences in caries incidence between fluoridated and non-fluoridated regions are less than they were 50 years ago, because of the wider availability of fluoridated products to the whole population. Concerns about the effect of fluoride on bone density and associated conditions are reviewed and the general conclusion from considering the literature on fluoride is that there is almost no cause for concern. Alternatives to water as a means of delivering fluoride to the general public that are being used in a number of countries are salt and milk. These alternatives are also reviewed and have been shown to give satisfactory levels of protection against caries, though milk is shown to be less satisfactory than water as a vehicle for fluoride delivery. Milk is also less effective in providing fluoride to individuals in the population, and is less likely to be consumed by people in lower socio-economic groups, precisely those who suffer most from dental caries. This study concludes that mass water fluoridation remains an important contribution to good oral health throughout the community.

Review paper: role of aluminum in glass-ionomer dental cements and its biological effects

The role of aluminum in glass-ionomers and resin-modified glass-ionomers for dentistry is reviewed. Aluminum is included in the glass component of these materials in the form of Al(2)O(3) to confer basicity on the glass and enable the glass to take part in the acid-base setting reactions. Results of studies of these reactions by FTIR and magic-angle spinning (MAS)-NMR spectroscopy are reported and the role of aluminum is discussed in detail. Aluminum has been shown to be present in the glasses in predominantly 4-coordination, as well as 5- and 6-coordination, and during setting a proportion of this is converted to 6-coordinate species within the matrix of the cement. Despite this, mature cements may contain detectable amounts of both 4- and 5-coordinate aluminum. Aluminum has been found to be leached from glass-ionomer cements, with greater amounts being released under acidic conditions. It may be associated with fluoride, with which it is known to complex strongly. Aluminum that enters the body via the gastro-intestinal tract is mainly excreted, and only about 1% ingested aluminum crosses the gut wall. Calculation shows that, if a glass-ionomer filling dissolved completely over 5 years, it would add only an extra 0.5% of the recommended maximum intake of aluminum to an adult patient. This leads to the conclusion that the release of aluminum from either type of glass-ionomer cement in the mouth poses a negligible health hazard.