MMP9 and gingivitis: In the present study, a positive mean correlation of MMP-2 with the oral hygiene status (OHI-S) and a positive mean correlation of MMP-9 and its inhibitor TIMP-1 with the gingivitis (GI) in the entire examined group were obtained, whereas in the control group, the oral hygiene level and the presence of gingival inflammation did not influence the MMP level.