A pH-cycling model has been used to examine the reactivity of fluoride dentifrices and rinses with subsurface carious lesions in vitro. Measured parameters included fluoride uptake, remineralization, surface hardening and the distribution of acquired fluoride. In the study, all fluoride treatment groups exhibited increased remineralization relative to placebo and demineralization-only controls. In general, remineralization paralleled the total fluoride uptake, but the relationship was not one to one. The rank ordered efficacy of the fluoride topicals was found to be NaF dentifrice > remineralization solution = NaF + MFP dentifrice > MFP dentifrice > placebo. Analysis of the acquired fluoride distributions suggested that fluoride was incorporated throughout lesions under dynamic conditions.