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

Abstract

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. 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 × 1h demineralization/day [pH = 5.0] and 3 × 3h Glandosane/day; 12h 100%humidity) were as follows: no treatment (NT), application (5min,2×/day) of 12.500ppmF- [pH = 6.04] (NaF-gel1), 12.500ppmF- [pH = 7.34] (NaF-gel2), 12.500ppmF- [pH = 5.82] (AmF-gel), 1450ppmF- [pH = 7.35] (KF-gel), and 5000ppmF- [pH = 8.14]; (NaF-TP) for 7days (E1). Subsequently, from each specimen, one lesion was covered, while the remaining lesion was cycled for another 7days (E2). Differences in integrated mineral loss (ΔΔZE1/ΔΔZE2) were calculated between values before and after pH cycling. 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. Under the in vitro conditions chosen, all fluoride agents could significantly hamper the adverse effects of a demineralizing saliva substitute. In combination with a demineralizing saliva substitute, slight mineral gain was only observed for neutral NaF-gel2 and 5000ppmF- toothpaste.