Table 3. Penetration depth of rhodamine B in micrometers (mean and standard deviation) .

Groups	Depth of penetration
Control	200.71 ± 45.95a
GSE	122.26 ± 33.57b
NaF	107.14 ± 30.26b
CPP-ACP	144.32 ± 43.82b
GSE + NaF	30.99 ± 22.52c
GSE + CPP-ACP	49.75 ± 23.28c

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

Different superscripts show statistical differences (P < 0.05).