Microhardness of Artificial White Spot Lesions Treated With Resin Infiltrant and Amorphous Calcium Phosphate

Abstract

This study was conducted to compare the effect of three different surface treatments on the microhardness of artificial white spot lesions. A total of 60 bovine specimens were prepared for microhardness testing. Specimens were assigned to three main groups (n = 20 each) according to the surface treatment performed (artificial saliva, resin infiltrant, CPP-ACP). Each group was divided into four subgroups (n = 5 each) according to time of measurement (immediate, after 2 weeks, after 4 weeks, and after 8 weeks). An additional 5 specimens of ground enamel surface served as a positive control. Microhardness of all specimens was measured using Vickers’s microhardness tester. A representative specimen from each group was evaluated under an environmental scanning electron microscope. Mean and standard deviation for microhardness of all specimens were calculated. Two-way ANOVA revealed that different surface treatment and time of measurement had no significant effect on microhardness of artificial white spot lesions. Different types of surface treatment showed a significant effect on artificial white spot lesion microhardness. Resin infiltrant (ICON®) showed the highest significant effect on microhardness followed by CPP-ACP then artificial saliva. Different times of measurement also showed a statistically significant effect on microhardness of artificial white spot lesion. After 4 and 8 weeks, mean microhardness were statistically significantly higher compared to immediately and after 2 weeks. CPP-ACP demonstrated comparable results to resin infiltrant after 4 and 8 weeks, but performed less at immediately and after 2 weeks. Also, artificial saliva performed the least at immediately, after 2 and 4 weeks, and achieved comparable results to both resin infiltrant and CPP-ACP after 8 weeks.