Unfortunately, Dr. John Featherstone, in his eagerness to promote posteruptive topical treatments in "The Science and Practice of Caries Prevention" (July JADA), ignores, misstates and misconstrues the huge body of knowledge published in the past 62 years about the preemptive effect of fluoride. Dr. Featherstone disingenuously cites fluoride enamel levels characteristic of fluoride-deficient teeth as his benchmark and then compares acid dissolutions in his lab—not with teeth, but with artificially produced apatite crystals.
Never mind that 50 years ago, McClure of the then National Institute of Dental Research delineated the fluoride levels needed in the enamel for caries-free permanent teeth, and 32 years ago, Gedalia did the same for primary teeth (
Glenn FB, Glenn WD III, Duncan RC. Prenatal fluoride tablet supplementation and the fluoride content of teeth: part VII. ASDCJ Dent Child 1984;51[5]:344–51
).
Dr. Featherstone totally ignores the effect that nutritional fluoride—supplied in adequate daily amounts from the start of dentogenesis—has on the microstructure of the enamel. LeGeros found especially tight crystalinity in the surface and subsurface enamel of fluoride (F) sufficient primary teeth compared to those produced without F supplements and she, among many others, had no difficulty in measuring the decreased acid dissolution associated with the threefold increase in enamel F content (
LeGeros RZ, Glenn FB, Lee DD, Glenn WD III. Some physico-chemical properties of deciduous enamel of children with and without prenatal fluoride supplementation (PNF). J Dent Res 1985;64[3]:465–9[Abstract/Free Full Text]
).
If Dr. Featherstone were a dentist, he would not have omitted the effect preemptive F has on molar macrostructure, especially occlusal morphology. Even the Karolinska’s Ynge Ericsson wrote that "every keen clinical observer is struck by the low height of cusps and the shallow fissures of permanent molars and premolars in areas of optimum or above optimum fluoride in the water" (
Ericcson SY. Cariostatic mechanisms of fluorides: clinical observations. Caries Res 1977;11[suppl 1]:2–41[Medline]
.
Glenn FB, Glenn WD III, Duncan RC. Prenatal fluoride tablet supplementation and improved molar occlusal morphology: part V. ASDC J Dent Child 1984;51[1]: 19–23[Medline]
).
Contrary to the findings of all the classical water fluoridation studies done in this country, Dr. Featherstone tries to attribute the 50 percent to 60 percent reduction in caries associated with fluoridation to a 1 part per million topical effect. If 1 ppm is so effective, why was the original F toothpaste raised from 500 to 1,000 ppm, and why do rinses and gels have up to 15,000 ppm?
Was the 80 percent reduction in caries achieved by Aasenden and Peebles, using high-dose F supplements from birth, due to the topical effect of the infants’ swishing their vitamin-fluoride drops, or by some of the children possibly chewing, rather than swallowing, a fluoride tablet once a day (
Aasenden R, Peebles TC. Effects of fluoride supplementation from birth on human deciduous and permanent teeth. Arch Oral Biol 1974;19[4]:321–6[Medline]
)? What is the origin of this nonsensical denial of the efficacy of the preemptive F?
Scandinavia’s small countries are admirably advanced in many areas but they are officially antifluoridationist, as are the Netherlands and most of England. Their legislated antifluoridation proved increasingly embarrassing to their dentists, especially at International Association of Dental Research meetings.
Denmark’s Thylstrup, who had shown an excellent understanding of nutritional F, finally snapped in 1980 and declared that all the efficacy of F was essentially posteruptive. Northern Europe could now take pride in their antifluoridation as they had 1,000 to 15,000 ppm topicals while the United States was using a 1 ppm "topical."
Thylstrup justified his epiphany by saying that since assiduous use of posteruptive F can result in caries reduction that approaches the reduction associated with water fluoridation, the mechanism of action must be the same. Students of logic will recognize this as a classic non sequitur. The same delusional thinking would support the contention that as topicals are eventually swallowed, their effect is mostly systemic.
The emotional appeal of Thylstrup’s new belief created a cult in the small countries around him, and a few from England joined. In the United States, the initial converts were persons who, like Dr. Featherstone, had been educated in England, and two ex-Canadians. Thylstrup’s followers supply 37 of the 72 references cited by Dr. Featherstone. Those in the United States are careful to pay lip service to fluoridation as a topical measure, but most are closet antifluoridationists. After all, if fluoridation is merely a homeopathically dilute topical measure, why bother?
In this country, there is no money to be made in fluoridation, and F supplements are not patentable, but there are billions to be made from proprietary posteruptives. The torrent of money from that industry is now driving our academic dental research centers.
With Hersch Horowitz retired, and National Institute of Dental and Craniofacial Research declaring premature victory over caries and turning fluoride policy over to the Centers for Disease Control and Prevention almost a decade ago, there may be no one left who can keep F, officially recognized as an essential nutrient for 32 years, from being turned into just a topical agent.
CDC has hired 12 dental consultants to formulate F policy, but as most of them function as toothpaste salesmen, the report will likely reek of Danish cheese.
A reasonable policy would be to supply a near maximum subfluorosing daily amount of F during the entire time of tooth development for lifetime built-in benefit, and then follow with judicious use of topical F for additional protection. This approach has rendered 93 percent to 97 percent of children caries free, which has resulted in an understandable lack of enthusiasm for this method among those who coat, seal, drill and fill for a living (
Glenn FB, Glenn WD III. Optimum dosage for prenatal fluoride supplementation [PNF]: part IX. ASDC J Dent Child 1987;54[6]: 445–50[Medline]
.
Leverett DH, Adair SM, Vaughan BW, Proskin HM, Moss ME. Randomized clinical trial of the effect of prenatal fluoride supplements in preventing dental caries. Caries Res 1997;31[3]:174–9[Medline]
).
The cult’s attack on systemic F is bad enough just considering teeth, but Dr. Featherstone is unaware of the growing body of literature concerning the "medical" benefits that accrue to the infant, child and adult as a result of supplying nutritional F (
Glenn FB, Glenn WD III, Burdi AR. Prenatal fluoride for growth and development: part X. ASDC J Dent Child 1997; 64[5]:317–21[Medline]
).
Here, there is cause for optimism as the Food and Nutrition Board in November 1999 published in final form its new dietary reference intakes for mineralized tissue nutrients. Fluoride garners 35 pages as an essential nutrient, with recommendations as the minimum for adequate intakes, or AI, of 0.05 mg/kg/day for infants and children over six months and 3 mg/day for women, including during pregnancy. Men’s AI is 4 mg/day. Adult upper limit, or UL, is 10 mg/day (Standing Committee on the Scientific Evaluation of Dietary Reference Intakes, Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. Washington, D.C.: National Academy Press; 1999).
I do not agree with all their numbers exactly, but the cream of our academic nutritionists are so many light years ahead of Dr. Featherstone and his antifluoridationist colleagues that it permits hope that science, unselfish interest in the well-being of one’s fellows and preventive nutrition may yet carry the day.
