Oral diseases such as periodontitis and gingivitis are inflammatory processes induced by bacterial biofilms. The bacterial factor lipopolysaccharide (LPS) is an important virulence factor of gram-negative bacteria, and plays an essential role in triggering periodontal inflammation. LPS activates macrophages and causes an inflammatory response including synthesis and release of cytokines – an important strategy utilized by the host to resist periodontal bacteria.
The Colony-Forming Unit (CFU) method can be used for identification of microorganisms and for testing the effect of antimicrobial substances and techniques. It is a sensitive and widely accepted method within microbiology. In this method, the number of living cells (cells able to reproduce) present in a suspension is counted on a nutrient agar surface.