The microflora of the oral cavity

The microflora of the oral cavity represents more than a thousand different bacterial species: both in terms of variety and quantity of bacteria, the mouth can be considered as “the tropical forest” of our organism. Oral bacteria settle from birth by colonizing all surfaces of the mouth (tongue, gums, teeth, etc.) and persist throughout the life of the individual. The microflora of the mouth is intimately linked to the state of wellbeing of the individual and it may be responsible for a wide range of physiological processes essential to the oral health. Furthermore, some of the bacteria present in the oral microbiota are rich of enzymes, which are able, through their metabolic activities, to modulate the surrounding microenvironment.

On the surface of each tooth, more than a billion bacteria aggregate to form complex communities embedded in a biofilm commonly called dental plaque. Within this structure, the bacteria are protected against external insults and are able to establish a complex network of chemical and metabolic messages. Such intense signaling constantly monitors the surrounding environment by modifying gene expression in response to changes in the density of the microbe population. In a physiological state of wellbeing, the biofilm provides a protection mechanism that allows “friendly” bacteria to compete and effectively control the population of “harmful” bacteria. When for various reasons such as bad eating habits (excessive use of sugars), tooth loss, placement of orthodontic appliances, use of drugs (antibiotics, antidepressants that cause alterations in saliva, etc), head and neck radiation, the delicate balance of the oral microflora is disrupted, an increase of potentially pathogenic bacteria and some pathologies including caries, gingivitis, periodontitis, mouth ulcers, etc. may appear.