Normal Microbial Flora of Oral Cavity

INTRODUCTION The normal flora can be divided into two groups Resident flora and Transient. Some organisms are almost always present in a normal oral cavity and constitute constant/normal microbial flora. It is further divided into two types: indigenous & supplemental. Comprise of those species that are almost always present in high numbers (> 1%) in a particular site, such as the supra gingival plaque, the surface of the tongue. There numerical dominance implies that they are compatible with the host and have entered into a stable relationship with the host.The supplemental flora comprises the species that are nearly present but are in low numbers (<1%). These organisms may become indigenous if the environment changes.Certain microbes tend to stay for a short time in the oral cavity of a few individuals. If the resident flora is intact, there is very little significance of the transient flora. However if the normal flora is disturbed, the transient flora may proliferate and produce disease. In addition to the normal & transient micro floras, a third or intermediate group, the supplemental (normal) flora has been designated it represents those microorganisms that may be detected in a significant percentage of individuals. Persons harboring supplemental normal flora generally possess them in moderate numbers & for long periods of time.