Pharmacology Which of the following is the primary mechanism of action of fluoride on topical application? A Forming a reservoir in saliva B Inhibition of plaque bacteria C Improvement in tooth morphology D Conversion of hydroxyapatite to fluorapatite by replacing the OH- ions 💡 Explanation Which of the following is the primary mechanism of action of fluoride on topical application? ✓ Correct Answer: D. Conversion of hydroxyapatite to fluorapatite by replacing the OH- ions