Final answer:
The anti-caries effect of topical fluoride is determined by its conversion of hydroxyapatite to fluorapatite in tooth enamel and its bacteriostatic properties, which strengthen enamel and inhibit tooth-decay-causing bacteria.
Step-by-step explanation:
The anti-caries effect of topical fluoride is primarily determined by its role in the remineralization of tooth enamel and its antibacterial properties. Fluoride becomes incorporated into the hydroxyapatite of tooth enamel, converting it to fluorapatite, which is much less soluble and more resistant to the acidic by-products of oral bacteria.
This transformation not only fortifies the enamel, making it less prone to decay but also helps in promoting remineralization by enhancing the uptake of calcium and phosphate ions.
Furthermore, fluoride is bacteriostatic, which means it inhibits the metabolism of bacteria that form plaque and cause cavities by producing acid. This dual action makes fluoride a key ingredient in prophylactic dental care through toothpaste, mouthwashes, and community water fluoridation, which are important for maintaining oral health.