Table 2.

Surface microhardness values

Group	VHNinitial (Mean ± SD)	VHNDay 5 (Mean ± SD)	ΔVHN Mean
Con	335.10 ± 39.11	272.61 ± 56.58	-18.93
PD	337.71 ± 16.49	288.56 ± 38.33	-14.73
NaF	340.90 ± 22.53	303.07 ± 27.64	-11.07*
Var	336.14 ± 15.90	310.93 ± 23.10	- 7.44*
PD/F	330.34 ± 31.54	318.45 ± 32.13	- 3.61*

^*Indicates a significant difference between changes in VHN compared to Con (P < 0.05)

$\mathrm{\Delta }\mathrm{VHN}=\frac{{\mathit{VHN}}_{Day5}-{\mathit{VHN}}_{\mathit{initial}}}{{\mathit{VHN}}_{\mathit{initial}}}\times 100(\%)$