Fluoride ions inhibit the bacterial enzyme enolase, which interferes with the production of phosphoenolpyruvate (PEP). PEP is a bacterial source of energy and a molecule that is necessary for the uptake of sugar, which provides bacterial nutrition. A dental biofilm that contains just 1 ppm to 5 ppm of fluoride (an amount that is reached by using fluoridated toothpaste) is found to inhibit the adhesion, growth, metabolism, and multiplication of caries-linked oral streptococci. The presence of higher concentrations of fluoride—10 ppm to 100 ppm, which can be attained after use of prescription fluoride preparations—has also been found to inhibit acid production by most plaque bacteria.10
