Chapter 29 - Oral biofilms: Architecture and control

Abstract

Human oral cavity is a composite microbial environment, hosting around 700 different microbial species belonging to 15 phyla. Oral diseases are considered as one of the predominant microbial infectious diseases among humans, as they collectively affect 60%–90% of the world population. The Global Burden of Disease Study 2016 estimated that oral diseases affected at least 3.58 billion people worldwide, with caries of the permanent teeth being the most prevalent of all conditions assessed. Oral health status of an individual affects three aspects of their living, namely systemic health, quality of life, and economic productivity. Dental caries is one of the most prevalent chronic infectious diseases among people worldwide. Almost every individual is subjected to any of the oral infections at least once in their lifetime. Microorganisms inhabiting the oral cavity have substantial prospects of spreading on to neighboring sites alongside the epithelial surfaces. Hence, persistent oral unhygienic condition may lead to several systemic conditions such as cardiovascular disease, chronic kidney disease, stroke, preterm low birth weight, pneumoniae, etc. A group of bacteria collectively known as mutans Streptococci is considered a major human cariogen. In addition, human oral flora comprises large proportion of anaerobic bacteria allied with periodontal disease. Besides this, oral candidiasis is an opportunistic fungal infection in the oral cavity caused by Candida species. Oral infections may globally affect all age groups and populations, posing a major health threat to the human community. Poor oral health may attribute negative impact on individual’s lifestyle, physical health, and other social and psychological well-being. Biofilm formation and quorum sensing are imparted as primary etiopathogenic mechanisms responsible for these infectious oral diseases. These diverse organisms adhere to the surface of the teeth/oral tissues firmly. Biofilm along with quorum sensing facilitates the cooperative response, which can resist environmental threats such as use of antibiotics, mechanical cleaning, etc., and thereby increase the persistence. Ineffectiveness of antibiotics and/or prevailing antibiotics resistance in the microorganisms suggests the search of alternatives to the conventional antimicrobial agents.