In Situ Anti-erosive Effect of Sodium Fluoride/Propylene Glycol Alginate

Objectives: The aim of this study was to evaluate the anti-erosive effect of solutions containing sodium fluoride (F: 225 ppm F^-), sodium fluoride + stannous chloride (F+Sn: 225 ppm F^- + 800 ppm Sn²⁺), sodium fluoride + propylene glycol alginate (F+PGA: 225 ppm F^- + 0.1% PGA), and distilled water (DI, negative control), using a single blind, split mouth, four-arm crossover in situ trial.
Methods: Twelve subjects participated after signing a written informed consent. In each study arm, the subjects wore removable mandibular appliances containing four enamel specimens, which were subjected to erosion-abrasion or erosion cycling model of five days. The erosion-abrasion cycling consisted of 5 min extra-oral immersion in 1% citric acid (pH=2.6), followed by 120 min remineralization in situ. This procedure was repeated 4x/day. Treatment with test solutions was performed 2x/day, for 2 min, 60 min after the first and the last erosive challenges. Before treatment, brushing was performed with electric toothbrush and toothpaste slurry (1450 ppm F) for 5 s, in a total of 2 min exposure to the slurry. For the groups subjected to erosion only, the same cycling protocol was performed but the specimens were only exposed to the toothpaste slurry for 2 min, without brushing. At the end, enamel surface loss (SL, in µm) was evaluated using optical profilometry. Data were analyzed with repeated-measures 2-way ANOVA and LSD Fisher’s test (α=0.05).




Results: For both conditions (erosion-abrasion and erosion), F+Sn application resulted in the lowest SL, followed by F+PGA, F, and DI, which did not differ from each other. Groups subjected to erosion-abrasion presented higher SL in comparison to erosion only.




Conclusions: In conclusion, only the solution F+Sn presented a protective effect against erosive wear. PGA was not capable of improving the protective effect of F in situ.