Randomized in situ trial on the efficacy of Carbopol in enhancing fluoride/stannous anti-erosive properties

Objective: To evaluate if the bioadhesive polymer (Carbopol 980) could potentiate the protective effect of sodium fluoride with stannous chloride (FS) solution on the control of enamel erosive wear. Methods: Cylindrical bovine enamel specimens were polished and randomly allocated into three groups (n = 60): FS (500 ppm F- + 800 ppm Sn2+ - positive control), FS + Carbopol (0.1% Carbopol), and ultrapure water (negative control). A randomized double-blind cross-over in situ model with three phases was used. In each phase, volunteers (n = 15) used a palatal appliance containing 4 specimens: two were submitted to an erosion model (2 h of pellicle formation; immersion in 1% citric acid, pH 2.3, for 5 min, 4x/day; 1 h intervals of saliva exposure; and treatment with the WA solutions for 1 min, 2x/day). Besides erosion, the other two specimens were also subjected to abrasion (2x/day, 15 s) with active electric toothbrush, before the treatment with the solutions. After 5 days, enamel surface loss (mu m) was evaluated by profilometry. Data were analyzed by two-way RM-ANOVA and Tukey tests (5%). Results: There were significant differences for both challenge and treatment factors. Erosion/abrasion challenge resulted in significantly higher enamel loss than erosion only (p < 0.05). The surface loss values for the ero sion/remineralization model were (means +/- SL): C = 14.7 +/- 5.8b; FS = 9.0 +/- 7.5ab; FS + Carbopol = 5.9 +/- 3.8a; and for erosion/abrasion: C = 26.6 +/- 10.1c; FS = 15.0 +/- 8.8b; FS + Carbopol = 12.3 +/- 7.9ab. Conclusion: The association of Carbopol to the FS solution significantly protected the enamel against erosive wear, but it was not significantly superior to FS only. Clinical Significance: Under highly erosive and abrasive conditions, rinsing with solutions containing sodium fluoride plus stannous chloride, associated or not with the Carbopol polymer, is an effective approach to control enamel erosive wear.