Don’t Overlook Prenatal Benefit of Fluoride

The "Quick Take" on water fluoridation states that "fluorideprevents caries primarily after tooth eruption" (CONSULTANT,March 2001, page 472). Certainly, toothpastes, rinses,and gels that contain 1000 to 1500 ppm of fluoride achievea temporary benefit as posteruptive topical treatments. However,the primary benefit of fluoridated water is the incorporationof fluoride into the enamel-a process that beginsbefore eruption and that lasts for the life of a tooth.
In infants and children, the 1 ppm of fluoride in fluoridatedwater can be absorbed without causing fluorosis inthe permanent teeth-which develop for 6 or more yearsbefore eruption. Human and animal studies have shownthat the amount of fluoride present during the earliestphase of tooth development primarily determines howmuch fluoride is incorporated into the enamel during thefinal phase of mineralization. The classic fluoridation trialsof the 1940s and 1950s in children showed that the earlierthe ingestion of fluoride began, the more resistant tocaries were the permanent teeth. The incorporation ofnear-maximum, subfluorosing amounts of fluoride resultsin teeth that have a smooth occlusal surface and enamelthat has a tight, dense crystallinity with high resistance toacid dissolution.
Six trials examined the effect of prenatal exposure tofluoridated water and found that resistance to caries wasimproved in the primary teeth that start to develop at thetwelfth week in utero and in the 6-year permanent molarsthat begin to develop around the fifth month.¹ Ten studiesdemonstrated that prenatal fluoride tablet supplementationcan virtually eliminate the "cavity-prone years of childhood."A once-a-day fluoride supplement better overcomesmaternal loss of fluoride, which was formerly believed notto cross the placental barrier.¹
The Food and Nutrition Board of the National Academyof Sciences recently recommended that pregnantwomen ingest a minimum of 3 mg/kg/d of fluoride andthat infants and children ingest 0.05 mg/kg/d.²
-William Darby Glenn III, MD
  South Miami, FlaREFERENCE:1. Glenn FB. Preeruptive effect of fluoride. JADA. 2000;131:1674-1676.
2. Food and Nutrition Board of the National Academy of Science. Dietary ReferenceIntakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride.Washington, DC: National Academy Press; 1997.

FOR MORE INFORMATION:
Glenn FB, Glenn WD. How to Have Children With Perfect Teeth. Miami:Children's Dental Research Society; 2000.