Effect of Fluoride and Calcium Phosphate on Enamel White-Spot Microhardness

Methods: 45 human incisor teeth (with no enamel defect) were collected. Initial hardness (Vickers), as baseline, was measured with 300 gr force on 3 longitude dots on polished facial surface (V0). Samples were randomly divided into 3 groups of 15(G1, G2 and G3). White spot lesions were induced on facial surfaces of teeth by PH-cycling model and microhardness of samples was measured again (V1).G1 teeth were put in 0.05% fluoride solution for one minute per day. G2 were kept in 0.05% amorphous calcium three phosphate solutions for one minute a day. G3 were only kept in artificial saliva. All samples were kept in 37° C incubator in artificial saliva as storage matrix. After 10 weeks microhardness re-assessed (V2). One-way ANOVA test and Tukey test as post hoc analyze were used with SPSS version 11.5 software.

Results: The mean V0 microhardness were 401.13±18.69, 394.20±33.65, 409.00±50.40 and V1 microhardness were 360.80±93.25, 388.53±24.20, 383.00±31.76 and V2 microhardness were 410.60±26.18, 417.00±23.54, 392.86±30.13 in G1, G2, and G3 respectively. The results showed significant differences in fluoride and amorphous calcium phosphate groups between V1 and V2 (P-value<0.05). There were no significant changes in artificial saliva. The results also showed significant differences between amorphous calcium phosphate and control groups (P-value<0.0.5) but no significant differences were found between fluoride and amorphous calcium phosphate group as well as fluoride and control groups.

Conclusions: According to the results of this study 0.05% amorphous calcium phosphate and 0.05% fluoride solutions could enhance the microhardness of enamel white spot lesions. However, amorphous calcium phosphate solution is more effective than fluoride solution on microhardness.