Table 2. Microhardness reduction percentage (%) values compared to initial measurements at two intervals as mean and standard deviation .

Groups	Difference between the measurements (%) before and after demineralization	Difference between measurements (%) before and after remineralization +pH cycling
Control	77.17 ± 5.12a*	91.71 ± 3.11b*
GSE	75.83 ± 8.19a*	82.67 ± 3.67b^ +
NaF	75.43 ± 11.10a*	88.55 ± 5.15b*^
CPP-ACP	71.77 ± 15.28a*	86.79 ± 8.71b*^
GSE + NaF	74.56 ± 9.75a*	80.11 ± 5.64b +
GSE + CPP-ACP	78.07 ± 6.37a*	88.16 ± 6.07b*^

GSE, grape seed extract; CPP-ACP: Casein phosphopeptide-amorphous calcium phosphate.

a-b shows the differences between columns in the same row (differences between microhardness values in the same group).

*^ + show differences between rows in the same column (differences among groups in the same measurement period).