Studies of the Effects of Dietary NaF on Dairy Cows

Abstract

The distribution of fluorine in the enamel and dentin of cows exposed to elevated dietary fluorine levels from 2 and 5 years of age through 8 years has been studied. Dentin from control cows of this age contained less than 1000 and enamel less than 500 ppm of fluorine. The level of fluorine in the dentin, much like bone, increased with added increments of dietary fluorine and with duration of exposure. The amount of fluorine in the dentin increased from the first to the 4th incisor, indicating a more rapid accumulation in younger osseous structures. Increasing the dietary level of fluorine resulted in increased enamel fluorine only if the teeth had not erupted prior to exposure. Dentin having an increased fluorine concentration was shown to also have a decreased solubility in acid. Incisors which were in the formative stage during the fluoridation period developed typical signs of dental fluorosis. However, dental fluorosis, which usually precedes other systemic symptoms of fluorine toxicity, is quite variable and should not in itself be used as a definitive index of fluorine toxicosis.