What is the primary action of fluoride in caries prevention?

The primary action of fluoride in caries prevention is that it promotes remineralization of enamel. Fluoride has a key role in the process of strengthening enamel and reversing early signs of tooth decay. When fluoride is present, it enhances the reabsorption of minerals like calcium and phosphate back into the tooth structure, which helps to repair and reinforce the enamel that has been weakened by acid attacks from bacteria in the mouth.

This process is particularly important because it can help to reverse early carious lesions before they progress to cavities. Fluoride alters the structure of hydroxyapatite, the mineral found in enamel, making it more resistant to acid dissolution. Thus, the primary mechanism for fluoride's efficacy in caries prevention centers around its capability to promote the remineralization of enamel, which is vital for maintaining tooth integrity in the presence of caries-causing factors.