Effect of NaF, AmF, KF gels and NaF toothpaste combined with a saliva substitute on dentin lesions in vitro

OBJECTIVE: The aim of the present in vitro study was to evaluate the remineralizing effects of NaF, AmF, KF gels and NaF toothpaste in combination with a potentially demineralizing saliva substitute (Glandosane; pH = 5.1) being widely used in Germany.

METHODS: In each of 120 dentin specimens, three artificial lesions were created. One lesion was covered for analysis of pre-demineralization (ΔZB). Treatments during pH cycling (3 × 1 h demineralization/day [pH = 5.0] and 3 × 3 h Glandosane/day; 12 h 100%humidity) were as follows: no treatment (NT), application (5 min,2×/day) of 12.500 ppm F- [pH = 6.04] (NaF-gel1), 12.500 ppm F- [pH = 7.34] (NaF-gel2), 12.500 ppm F- [pH = 5.82] (AmF-gel), 1450 ppm F- [pH = 7.35] (KF-gel), and 5000 ppm F- [pH = 8.14]; (NaF-TP) for 7 days (E1). Subsequently, from each specimen, one lesion was covered, while the remaining lesion was cycled for another 7 days (E2). Differences in integrated mineral loss (ΔΔZE1/ΔΔZE2) were calculated between values before and after pH cycling.

RESULTS: Mean (95%CI) ΔZB was 3851 (3762;3939) vol% × μm. Except for NaF-gel2 and NaF-TP, specimens of all other groups further demineralized. Only NaF-gel2 induced a significant gain in mineral content (p ≤ 0.004; paired t test). Significant differences in the change of mineral loss were found between NT and all fluoride groups for both ΔΔZE1 and for ΔΔZE2 (p < 0.05, Bonferroni post hoc test). However, only NaF-gel2 and NaF-TP induced remineralization.

CONCLUSION: Under the in vitro conditions chosen, all fluoride agents could significantly hamper the adverse effects of a demineralizing saliva substitute.

CLINICAL SIGNIFICANCE: In combination with a demineralizing saliva substitute, slight mineral gain was only observed for neutral NaF-gel2 and 5000 ppm F- toothpaste.