Remineralization Effect On Enamel Physicochemical Properties After Chlorine-Induced Erosion

To determine the effect of remineralizing agents on microhardness and mineral content of enamel exposed to chlorinated-water. Thirty-six enamel slabs retrieved from bovine incisors were allocated to 6 study groups (n=6): 1) Immersion in artificial saliva for 24h. 2,3) Immersion in acidic (pH=3) and neutral (pH=7) chlorinated-water for 2h, followed by 22 h in artificial saliva. 4,5,6) Application of remineralizing agents: fluoride varnish (Profluorid Varnish, VOCO), sodium fluoride containing toothpaste (Proenamel Daily Protection, Sensodyne) or CPP-ACP containing tooth mousse (MI Paste, GC) prior to immersion in acidic chlorinated-water for 2h, followed by rinsing with deionized water and storage in artificial saliva for 22h. Immersion was repeated for 24 days to simulate swimming sessions twice weekly for 3 months. Microhardness (MH) was evaluated using Vickers microhardness tester. Energy-dispersive X-ray spectroscopy (EDX) test was used to calculate mineral content (Ca, P, C, O, F, Cl) in weight%. Saliva, Profluorid, ProEnamel and MI Paste groups showed the highest MH values, with no significant differences among them. While acidic chlorinated-water produced the lowest MH value. Mineral levels did not vary significantly between all groups. However, acidic chlorinated-water group displayed the lowest Ca/P ratio. Application of remineralizing agents before swimming could improve surface hardness and protect enamel against chlorine-induced erosion.