Color Stability Of Enamel Exposed To Chlorinated Water After Remineralization

To evaluate remineralization effect on color stability of enamel exposed to chlorinated water. 36 bovine enamel slabs were assigned to 6 groups (n=6). Negative control 1 and Negative control 2: Immersion for 2h in acidic (pH=3) and neutral (pH=7) chlorinated water respectively, followed by 22h immersion in artificial saliva. Positive control: Immersion in artificial saliva for 24h. Three remineralizing groups: Application of fluoride varnish (Profluorid Varnish, VOCO), sodium fluoride containing toothpaste (Proenamel Daily Protection, Sensodyne) or CPP-ACP containing tooth mousse (MI Paste, GC), before immersion in acidic chlorinated water for 2h, followed by rinsing with distilled water and immersion in artificial saliva for 22h. Cyclic immersion was repeated in all groups for 24 days, to simulate 2 weekly swimming sessions over 3 months. Color parameters (CIE-L*a*b*) were measured using a spectrophotometer at baseline and after 24 days. Change in color (∆E), lightness (∆L*) and chromaticity (∆a*/∆b*) were analyzed using ANOVA/Tukey's tests. Acidic water showed the most noticeable ∆E and ∆b* changes. The least ∆E change was detected with saliva. A significant reduction in ∆L* was perceived with Proenamel and MI Paste. All groups shifted towards darker values, except for acidic water which resulted in brighter values. No significant difference in ∆a* values was found between groups with a tendency towards greener color. ∆b* values showed a decrease in yellow color saturation in all groups. Remineralization can improve color stability, yet reduce lightness and yellowness of enamel exposed to chlorinated water.