Oral Microbiology

The diversity of microorganisms that have been detected in the oral cavity is greater than at any other location in the human body. More than 700 bacterial phylotypes have been reported from oral sites, and estimates suggest that any individual harbors around 100-200 phylotypes. The presence of microorganisms on hard and soft oral tissues is fully compatible with health. However, inadequate control of the oral microflora can lead to disease. The major microbial pathologies in the oral cavity are dental caries and periodontitis. Dental caries refers to tooth decay caused by acids from bacterial metabolism of dietary sugars. Periodontal disease involves damage to gingival tissues surrounding teeth and results largely from an inappropriate immune response to anaerobic, proteolytic bacteria in biofilms at subgingival sites. Understanding oral health and disease requires multidisciplinary efforts. Specific genes and enzymes affect the properties of oral biofilms. Individual species can sometimes be correlated with health or disease. Interactions between microorganisms and between microbes and the host are critical for determining whether an individual's oral microflora remains harmless (commensal) or initiates disease. Oral microbiology is above all the study of multispecies microbial communities and their consequences on the host they inhabit.