Method: 77 subjects participated in a randomized, examiner and laboratory analyst blinded, placebo controlled, five period, crossover, exploratory study. There was a one-week washout period between each test leg which included a 2-3 day lead-in with a dental prophylaxis followed by the use of non-fluoride dentifrice. Subjects' mandibular partial dentures were modified to hold four partially demineralized enamel specimens, two shallow and two deep lesions, in the buccal flange. Each test dentifrice was used for a four-week period. The dentifrices used were: experimental (MFP+CSPS); positive control (927ppm F-as-MFP); F dose-response controls (250ppm F-as-MFP and 0ppm F-as-MFP); control (0ppm F-as-MFP+CSPS). The surface microhardness (SMH) test was used to assess changes in the mineral status of shallow lesions after three weeks. Changes in mineral content in deep lesions were quantified using transverse microradiography after four weeks. Enamel fluoride and calcium uptake of all lesions was determined using the microdrill enamel biopsy technique.
Result: No statistically significant differences with respect to %SMH Recovery (p=0.6788), changes in integrated mineral loss (p=0.5908), lesion depth (p=0.6622) or calcium and fluoride uptake to enamel were observed between experimental and positive control dentifrices, with both providing significantly greater remineralization of shallow (p<0.0002;SMH) and deep lesions (p<0.0001;integrated mineral loss) than F-free controls. A good F dose-response was observed for all tested parameters. The experimental dentifrice demonstrated a significantly greater change in surface mineral density (ΔSZmax) compared to the positive control dentifrice in deep lesions (p=0.0114).
Conclusion: CSPS did not negatively impact on the ability of fluoride to remineralize shallow or deep lesions in situ. The change in ΔSZmax may indicate a potential additive effect for CSPS which warrants further investigation.