INVESTIGATIONS OF THE ANTI-ENZYMATIC ACTION OF FLUORIDE AT THE ENAMEL SURFACE

¹ The Institute of Dental Research, United Dental Hospital, Sydney, and the Faculty of Dentistry, The University of Sydney, Sydney, Australia

1. Powdered enamel, synthetic hydroxyapatite and naturally occurring fluorapatite had no effect on the rate of acid formation from sucrose by salivary sediment.

2. Artificially fluorosed, powdered enamel, and synthetic hydroxyapatite inhibited acid production to a similar degree to that caused by calcium fluoride.

3. Washing powdered enamel and fluorosed enamel with distilled water increased their inhibitory action on acid formation. This effect could not be explained by the fluoride ion concentration in the system.

4. A similar increase in inhibition of acid formation on washing was found with either fluorosed or untreated tooth crowns.

5. These observations are discussed in relation to the possible fluoride content of enamel and its solubility. It is concluded that fluoride, in a concentration expected at the tooth surface, does not prevent acid formation.