Table 2.

MMP-9 levels of crevicular and serum concentrations in RA, RA-CP, CP, and healthy groups and statistical significance comparison between groups.

Parameter (mean ± SD)	Control group (N = 21)	RA group (N = 16)	CP group (N = 14)	RA-CP group (N = 12)
Serum MMP-9 (ng/mL)	34.12 ± 15.4	498.12 ± 143.72   P < 0.001*	54.81 ± 25.93   P < 0.01**	640.18 ± 247.76   P < 0.001*** P < 0.001#   P > 0.05##
GCF   MMP-9 (ng/mL)	25.06 ± 11.9	44.16 ± 18.96   P < 0.001*	42.31 ± 19.92 P < 0.01**	58.67 ± 14.23 P < 0.001*** P < 0.05′′ P < 0.05′′ ′′

^*Significant statistical differences between RA and control group for serum and GCF MMP-9.

^**Significant statistical differences between CP and control group for serum and GCF MMP-9.

^***Significant statistical differences between RA-CP and control group for serum and GCF MMP-9.

^#Significant statistical differences between RA-CP and CP group for serum MMP-9.

′′Significant statistical differences between RA-CP and CP group for GCF MMP-9.

^{′′ ′′}Significant statistical differences between RA-CP and RA group for GCF MMP-9.

  ^##No significant statistical differences between RA-CP and RA group for serum MMP-9.