Decision-making for national programs of community fluoride use.

Every community, region or country with a high or rising prevalence of dental caries should implement a caries-preventive program that automatically brings the benefits of systemic and topically applied fluoride to the entire population. The fluoridation of community water supplies or salt fulfills the requirements of providing safe, effective protection from dental caries at reasonable cost. The use of dietary fluoride supplements or fluoridated milk does not meet the requirements of a comprehensive national or community program because compliance is poor or only selected age groups are targeted. Water fluoridation is ideal for countries, regions or communities with many central water supplies or where salt production or distribution is not centralized or easy to control. Water fluoridation also has advantages where many areas exist with natural water fluoride concentrations at optimal or greater than optimal concentrations. Salt fluoridation is ideal for countries or regions with few, potable central water supplies in which salt production and distribution are centralized and easily controlled. Concentrations of fluoride for water fluoridation range from 0.5 to 1.2 parts per million (ppm) parts of water depending on climate and dietary practices. The concentration for fluoridation of salt is approximately 200 to 250 mg fluoride per kg of salt, also depending on dietary practices. Properly fluoridated salt should produce levels of urinary fluoride excretion similar to those found in communities with fluoridated water. Benefits of the two methods are similar. Salt fluoridation may be done more cheaply.

The role of dietary fluoride supplements in caries prevention.

Nearly all dental researchers and public health authorities agree that fluoride supplements are highly effective in reducing dental caries in primary and permanent teeth, that benefits to all teeth are greater when administration begins at 2 years of age or younger, that both preeruptive and posteruptive exposure is important in imparting cariostatic benefits, that effectiveness is neither enhanced nor reduced by their being combined with vitamins, and that benefits to the offspring of pregnant women who take supplements are uncertain. Several studies show that fluoride supplements delivered in school-based programs effectively reduce dental caries, and benefits are greater to teeth that receive preeruptive exposure in addition to posteruptive exposure. Many parents who, for a variety of reasons, did not administer fluoride supplements at home will enroll their children in school-based fluoride tablet programs. Effectiveness of fluoride supplements today is undoubtedly smaller than observed previously because of dilution and diffusion effects from other fluoride sources; nevertheless, they still have the same potential efficacy. It is apparent that the current ADA dosage schedule is too high and requires modification; however, the availability of this known-to-be-effective regimen should not be eliminated or restricted.

Research issues in early childhood caries.

Research is needed to establish what nomenclature and case definition for early childhood caries (ECC) are most relevant to health care professionals and to the public. Profiles or indexes for predicting the prevalence of ECC in communities should be developed on the basis of the socioeconomic factors, immigrant status and ethnic/racial backgrounds of populations. Future research should target risk factors of ECC, particularly prenatal and perinatal histories, nutritional status and microbiologic factors. Determining the relation of malnutrition of infants and young children, low birthweight, complicated pregnancies and traumatic births with the development of enamel linear hypoplasia deserves research attention. Factors that affect how and when infants and young children are colonized by mutans streptococci also need further study. The evaluation of chemotherapeutic preventive agents will likely yield more fruitful interventions for prevention than trying to change behaviors. Research in young children to prevent ECC, however, has particular ethical considerations. Withholding treatments or administering placebos to vulnerable subjects is not acceptable. Consequently, future clinical research likely will determine the relative rather than the absolute effectiveness of preventive regimens; the former requires large sample sizes and may necessitate multi-center studies. Human studies may be hampered by problems of recruitment, compliance and transiency of subjects. Because federal support for research on dental caries has declined in recent years, a special initiative that focuses specifically on ECC may be necessary to obtain adequate funding for research on the disease.

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.

Commentary on and recommendations for the proper uses of fluoride.

Fluorosis has been associated with the fluoride concentration of drinking water, use of dietary fluoride supplements, early use of dentifrices, and prolonged use of infant formula. The literature, however, does not show associations between fluorosis and use of fluoride mouthrinses, professionally applied fluorides, bottled waters, carbonated beverages, and juices. It is unwise to issue laundry lists of items that may be implicated as problem-causing when, in fact, they may not be. Although usually classified without fluorosis, children in Dean's "questionable" category would be classified with the condition if the TFI or TSIF were used. Accordingly, Dean, in 1942, really reported only 52.8 percent of children without fluorosis in Kewanee, a community with 0.9 ppm fluoride in drinking water. Because the morbidity and sequelae of dental caries have declined, undue emphasis has been placed recently on the risks of using fluoride rather than on its profound beneficial effects. Although of paramount importance, conclusions cannot be drawn on whether fluoride protects against, contributes to, or has no effect on bone fractures or is valuable in treating osteoporosis. Careful thought is required before making recommendations that may reduce health benefits because of unfounded concerns about perceived risks. There should be greater regulation of extraneous fluoride sources, rather than reliance on educational efforts or recommendations to eliminate use of highly effective preventive regimens.

Critique of Kingman's methods of projecting long-term relative efficacy of products exhibiting small short-term efficacy.

This paper critically reviews Kingman's "methods of projecting long-term relative efficacy of products exhibiting small short-term efficacy," a report he prepared for a scientific workshop on the relative anticaries efficacy of fluoride dentifrices, which reveals serious deficiencies. Of the three specific models that Kingman suggests, the compound growth model (CGM), which leads to the largest projected future percentage reductions, is based on a false premise of an increasing universe of caries-free surfaces available for caries-attack with the passage of time. The second suggested model, the demineralization square root model (DSR), is supported only by a personal communication, unavailable for scrutiny. The third suggested model, a stabilization model (STA) is plausible, but unsupported. Other plausible models for extrapolating short-term observed effects are ignored by Kingman. Most of Kingman's choices of data illustrations to fit his suggested models are ill-chosen because the studies were repeated cross-sectional surveys or involved the delivery of systemically and topically delivered fluorides, which contraindicate their use. The most serious breach is Kingman's selective use of subsets of data from two long-term studies of fluoride dentifrices that support his premise, when other, more comprehensive data from the same studies do not. He also ignores findings from other studies that fail to support his suggested models. Kingman's report fails to prove that studies which show small short-term effectiveness after 1, 2 or 3 years will lead to greater relative effectiveness after long periods of use.

The need for toothpastes with lower than conventional fluoride concentrations for preschool-aged children.

Since 1945, when community water fluoridation was first implemented in the United States, not only has the procedure grown to cover more than half of the US population, but the development and use of other fluoride methods have expanded greatly. A concomitant, dramatic decrease has occurred in the caries prevalence of US school-aged children. Recent studies indicate, however, that the prevalence and, to a lesser extent, the intensity of dental fluorosis have increased in schoolchildren in both fluoridated and fluoride-deficient areas. Several studies show that young children inadvertently ingest sizable proportions of toothpaste during toothbrushing. Although ingestion of fluoride toothpastes by preschool-aged children may not be the major contributor to the increase in fluorosis, the findings of at least four studies suggest that the use of fluoride toothpastes by young children is a risk factor. The direct dose-response relation between effectiveness and fluoride concentration of toothpastes is far from clear-cut and, at best, is weak. Thus, considering today's reduced risk of caries, it is timely to market fluoride toothpastes in the US with 400-500 ppm fluoride for preschool-aged children, who are still at risk for developing fluorosis, as has been done in several other countries. Dental public health authorities must work with toothpaste manufacturers, professional organizations, and regulatory agencies to facilitate the approval and marketing of such pediatric fluoride toothpastes.

A researcher's view.

The Food and Drug Administration (FDA), by ensuring that the health care products used by Americans are both safe and effective, provides an essential regulatory function. With respect to the regulation of dental drug products, this researcher perceives that the FDA has not changed or modified its position on a number of issues to reflect new scientific information. Reasons for this inflexibility include the size and ponderousness of the agency, inadequate staff with dental expertise, and a failure to keep current with new dental research findings. The FDA must solve these problems if it wishes to regulate intelligently. The acceptance and certification programs of the American Dental Association ensure that products offered to the profession and the public that bear its seal of acceptance are safe and effective. The ADA's Council on Dental Therapeutics has a long history of staying current on issues in dental research and public health and regularly seeks consultation from eminently qualified experts. Overall, it has done an excellent job over the years in conducting an important voluntary regulatory program. Both the FDA and the ADA benefit and help protect the oral health of the public.

The future of water fluoridation and other systemic fluorides.

School and community water fluoridation, salt fluoridation, and use of dietary fluoride supplements have abundant scientific support as effective caries-preventive methods. Because caries has declined greatly in many developed countries from use of topical fluorides, the absolute caries reduction will be considerably smaller when systemic fluoride methods are implemented now than it was 20 to 40 years ago. For countries with most of the population living in cities with communal water supplies, community fluoridation is the most logical approach from the standpoints of cost-effectiveness and total caries-preventive impact. In countries with a mostly rural population without central water supplies, salt fluoridation is more practical. Dietary fluoride supplements can be recommended only for regions where neither water fluoridation nor salt fluoridation is possible, or as a temporary measure. Although divergent views exist concerning the relative caries-preventive effects of pre-eruptive and post-eruptive fluoride administration, the effectiveness of systemic fluoride methods for preventing dental caries remains unchallenged. Persuasive scientific and public health arguments exist to justify implementing and sustaining their use. The future of these methods will be influenced by the findings of new clinical and epidemiological research. Social, political, economic, and educational factors will be of equal, if not greater, importance. Perceptions of the current severity of dental caries as a health problem and of risks associated with preventing the problem may affect the future uses of systemic fluorides more than will recommendations of scientists.