Purpose: To evaluate whether increasing the frequency of its use can enhance the protective effect of AmF/NaF/SnCl2 solution against dental erosion. Materials and Methods: Sixty human enamel samples were obtained from sound human third molars, and after the formation of incipient erosive lesions (1% citric acid, pH 4.0, for 3 min), they were divided into five treatment groups (n = 12): G1 - deionised water (negative control); G2 - NaF solution (positive control) once a day; G3 - NaF solution (positive control) twice a day; G4 - AmF/NaF/SnCl2 solution once a day; G5 - AmF/NaF/SnCl2 solution twice a day. The samples were then subjected to 5 days of erosive cycling through 6 daily immersions (2 min each) in citric acid solution (0.05 M, pH 2.6). At the end of erosive cycling, surface wear was determined by means of optical profilometry. Results: One-way ANOVA showed that the surface wear was affected by surface treatments (p 0.001). Tukey's test showed no difference between the groups in which NaF was applied once or twice, but they showed limited reduction in wear compared to the deionised water group (G1). In the groups treated with the AmF/NaF/SnCl2 solution, there was a statistically significant difference between one and two application times (p 0.001). Although both demonstrated statistically significantly reduced tissue loss, increasing the frequency increased its anti-erosive potential. Conclusion: The AmF/NaF/SnCl2 solution proved to be effective in reducing dental enamel surface loss and its use twice a day potentiated its anti-erosive effect. Keywords: AmF/NaF/SnCl2 rinse, dental erosion, enamel, fluorides, tin