Fixation of Topically Applied Fluoride in Enamel

¹ Forsyth Dental Center, Boston, Massachusetts

It has been shown through in vitro experiments that the fluoride deposited in intact enamel after a 4-minute exposure to a topical solution can be washed away by a 24-hour washing procedure. Significant amounts of fluoride were retained when this washing procedure was begun several hours after the fluoride exposure, thus permitting the fluoride to react with the enamel for a prolonged period before washing. Application of polar and non-polar coating agents to the fluoride-exposed enamel significantly decreased the loss of fluoride from the washing. The most effective polar agent tested was polyoxyethylene soya amine, and the most effective non-polar agent was silicone grease. The possibility of increasing the effectiveness of topical fluoride treatments is discussed in the light of these findings.