Monday, August 25, 2014

Keep Fluoride Toothpaste Out of Children's Reach, Expert Cautioned in 1980

The following is quoted from Gary M. Whitford, PhD, DMD, August 1981

“Some fluoride-containing products, however, have enough of the ion to be hazardous and should be handled and stored with caution.  For example, a 1.23 percent fluoride gel contains 12,300 ppm or 12.3 milligrams per gram [such as dentists' fluoride treatments]. Thus, one ounce (28.3) grams) contains 348 milligrams, a life-threatening dose for a 11.5 kilogram or a 25 pound child.  Even the popular fluoride toothpastes may be hazardous to small children. These products typically contain 0.1 percent fluoride or 1000 ppm.  Thus, an eight ounce tube containing 226 milligrams of fluoride, could endanger a 16 or 17 pound child…Therefore such products should be kept out of the reach of those who are at risk."

“Dental fluorosis, a disorder of enamel mineralization which can be produced only during the development of the enamel prior to tooth eruption, is generally regarded as a toxic manifestation of chronic intake of excessive fluoride.  Exactly, how much fluoride is too much is uncertain.”

                                                 Gary M. Whitford, PhD, DMD, August 1981

                                “Fluorides: Mechanism of Action Efficacy and Safety,”
                                      Dental Caries Prevention in Public Health Programs
                                        Proceedings of a Conference October 27-28 1980
                                            Sponsored By the National Caries Program
                                                 National Institute of Dental Research
                                           US Department of Health and Human Services
                                         Edited by Alice M. Horowitz and Hilah B. Thomas

Excerpts above and below by Gary M. Whitford, PhD, DMD

Dr. Nichols asks Dr. Whitford the following question:  "If I gave you two items, one a 9 ounce size of Crest toothpaste another a 7 ounce bottle of 0.2 percent sodium fluoride solution, could you discuss the toxicity of each in relation to a 20 kilogram child?"

Dr. Whitford answers "There would be 225 mg of fluoride in the tube. The 7 ounce bottle is about 0.1 percent fluoride so it would contain about 200 mg of fluoride...I think that the potential for toxicity, if ingested all at once, would be about equal.  Assuming that 30 mg of fluoride per kilogram of body weight is fatal, these doses would be dangerous for seven and nine kilogram children, respectively  [15 to 20 pounds]. I'm unaware of any report indicating that death has occurred from the ingestion of toothpaste or a 0.2 percent sodium fluoride solution.  It is, however, conceivable that it could happen. For that reason, when our children were younger, we purchased the 4 to 6 ounce tube of toothpaste and kept them out of their reach."

Fluoride is readily absorbed from the gastrointestinal tract. That which appears in the feces is mainly if not entirely, unabsorbed fluoride and usually accounts for only about 5 to 10 percent of the amount ingested daily. Some factors, however, decrease the absorption of fluoride, particularly divalent and trivalent cations such as calcium, magnesium and aluminum. If high concentrations of these ions are present with the fluoride at the time of ingestion, systemic absorption is reduced.

From the plasma, fluoride diffuses to the extra cellular and intracellular fluids of the soft tissues where it rapidly reaches a steady-state distribution.

As the plasma curve rises, so do the concentrations of fluoride in the muscle, the liver, the heart, and all soft tissues

The excretion pattern of fluoride, however, is not exactly this way in all people.  The age of the individual influences how much fluoride is removed from the body...  The excreted percentage of a fluoride dose generally varies as a direct function of age. The younger the individual, the less excretion.  The older the individual, the more of a given dose is excreted.  This result is attributable principally to the growth rate and age of the skeleton and the surface area of bone mineral available for fluoride uptake. In the growing individual, these factors favor enhanced fluoride uptake so that relatively less is excreted in the urine.

According the some findings that we made a few years ago, fluoride excretion is a function of the pH of the urine. At a low pH, fluoride excretion is also low and as the urine pH rises, the rate of fluoride excretion rises as well.

The diet of most infants is either mother’s milk or a formula based on cow’s milk.  The urine pH of  infants who are solely formula fed is generally lower, sometimes markedly so, then that of solely breastfed infants and the would be expected to excrete less of the fluoride delivered to the kidneys in the blood.  Such differences in excretion rate might or might not be desirable depending on the quantities of fluoride involved.

Thus, difference in diet, among several other important factors, will tend to produce urine pH values that approach one end or the other of the physiologic range. These factors influence the uptake of fluoride by developing teeth and the fluoride levels of the oral fluids. Therefore, they can affect the cariostatic efficacy of fluoride in certain individuals or perhaps the development of fluorosis in others.

Dental fluorosis, a disorder of enamel mineralization which can be produced only during the development of the enamel prior to tooth eruption, is generally regarded as a toxic manifestation of chronic intake of excessive fluoride.  Exactly, how much fluoride is too much is uncertain.”…Probably no single dose, or narrow range of doses can be determined because of several variables. The age and body weight of the child or fetus, the frequency of the doses, the peak plasma levels, the magnitude of the more sustained fasting plasma level, are among the factors to be considered.  Nevertheless, the early data provided by Dean are pertinent. 

According to his findings and classification system, when the community index of fluorosis exceeds 0.6, the incidence and severity of fluorosis begins to constitute a public health problem warranting increasing consideration.  This index value was reached in communities with water fluoride levels of 1.6 to 1.8 ppm.  Thus the margin of safety for avoiding a degree of dental fluorosis which may be of public health concern is rather low at somewhat less than two and is another reason for carefully monitoring fluoride levels in water.