Oral microbial biofilms and plaque-related diseases: microbial communities and their role in the shift from oral health to disease

Abstract: many oral pathologies, such as dental caries, periodontal disease and peri-implantitis are plaque-related. Dental plaque is a microbial biofilm formed by organisms tightly bound to a solid substrate and each other by means of an exopolymer matrix. Bacteria exhibit difefrent properties when contained within a biofilm. Knowing the mechanism controlling the formation and deveopment of biofilms can help to understand the emergence and progression of such pathologies and to plan effective treatment. Most periodontal pathogens are common saprophytes of the oral cavity, expressing their virulence only in a sisceptible host or when some changes comw about in the oral envirnment. Physical, metabolic and physiological interactions may cause positive or negative effects among the various microbiota present.Such mechanisms of antagonisms/synergy select the bacterial population and alterations of its composition affect the balance with the host and may lead to pathology. The efefctivenes of antimicrobial agents, as measured trough in vitro tests, is dramatically reduced in vivo due to the properties of the microbial community: mature, intact biofilms are les sensitive to such agents, as the exopolymer matrix, bacterial enzymes and slow growth rate hinder the action of chemotherapeutic agents. The present literature review aims to examine the most representative sudies, focusing on the characteristics of the bacterial communities and the crucial shift from the oral health to plaque-related diseases. Keywords: Microbial film - Dental plaque - Periodontal disease - Peri-implantitis - Bacterial virulence - Host susceptibility