The study revealed positive correlation between bleeding on probing and teeth loss risk with periodontal hypercolonization by Porphyromonas gingivalis, Prevotella intermedia and Treponema denticola. Pathological tooth mobility was associated with hypercolonization by P. intermedia and Tannerella forsythensis. Expression of IL8, TNF-α, MMP8 and MMP9 genes was also assessed in patient groups divided according to the depth of periodontal pockets and-the severity of chronic periodontitis revealing IL8 as positive diagnostic marker.