Fluoride and the caries lesion: interactions and mechanism of action.

AIM: To review the mechanisms of action of fluoride (F). METHODS: Narrative review of the literature. FINDINGS: Fluoride can reduce tooth mineral solubility by exchanging for hydroxyl groups and reducing carbonate content. Thus its presence in solution facilitates mineral precipitation or reprecipitation by lowering solubility products of precipitating calcium phosphates. While sound enamel tends to lose fluoride with age, it accumulates at stagnation sites where caries lesions develop indicating this as a site of action. Fluoride in the lesion will encourage remineralisation [Robinson et al., 2000] such that penetration of the lesion by fluoride is pivotal. Access from plaque, however, is limited due to restricted penetration. CONCLUSIONS: Maintaining a very thin plaque layer is thus important in delivering fluoride to the lesion.