The most effective practical measure for the control of dental caries is the administration of fluoride in drinking water and toothpaste. One possible consequence of the widespread use of fluoride is the selection and maintenance of a fluoride-resistant population of oral bacteria. Fluoride-resistant mutants of Streptococcus mutans GS-5 have been isolated in vitro at a number of different pH values. There is evidence indicating that the fluoride-resistance may be associated with mutations in the sugar transport system. These fluoride-resistant mutants will be tested for alterations in their sugar transport systems, and attempts will be made to identify the specific mutation. An understanding of the nature of these mutations may lead to an understanding of the control mechanisms that govern sugar transport in this organism. Additionally, fluoride-resistant mutants will be examined for acid production levels and nature of metabolic end products. If the mutants produce greater quantities of acid than the parental strain, then these mutants would be undesirable in the oral cavity. If, on the other hand, they produce less acid, then their presence in the oral cavity may very well be desirable.
