After a tooth erupts, how does fluoride continue to strengthen the enamel?

Fluoride plays a critical role in the post-eruption phase of tooth development by enhancing the structural integrity of enamel. Once a tooth has erupted, fluoride continues to exert its beneficial effects by entering the enamel and integrating into the hydroxyapatite crystals that make up the tooth structure. This process creates fluorapatite, a more resilient form of enamel that is less soluble than the original hydroxyapatite.

This incorporation helps to strengthen the enamel and make it more resistant to acid attacks from bacteria and dietary sugars, which are the primary contributors to tooth decay. By enriching the enamel crystals with fluoride, the overall mineral quality of the enamel improves, ultimately leading to a reduction in the susceptibility of the teeth to caries development.

Other options do not accurately reflect the role of fluoride after tooth eruption. For instance, fluoride does not form new teeth, and while it can reduce the rate of decay and influence the pH of saliva, its primary mechanism of providing ongoing protection involves the direct strengthening of existing enamel through mineralization processes.