DOES ASSESSMENT OF MICROBIAL COMPOSITION OF PLAQUE SALIVA ALLOW FOR DIAGNOSIS OF DISEASE-ACTIVITY OF INDIVIDUALS/

Microbiological tests are limited in their applicability in the assess ment of caries activity and in caries prediction, They can be effectiv e in groups of persons with high or low caries experience. The reasons for the limitation of microbiological tests rests with unique charact eristics of the microflora and local environments of the oral cavity, which will modify the cariogenicity of plaque in an individual, Thus, high numbers of S. mutans may be associated with the development of a lesion at a site, while a second susceptible site with high levels of this organism in the same subject will remain caries free, This paper identifies some aspects of oral bacteria which can contribute to the u nique nature of the microflora associated with plaque in an individual , Firstly, the range of bacteria potentially involved in caries has wi dened and now includes, for example, 'low pH' non-mutans streptococci. The presence of such organisms in plaque in an individual may influen ce early enamel demineralization. Most significantly, Streptococcus mu tans, Streptococcus mitis and Actinomyces naeslundii have been shown t o be comprise many distinct clones, with different distribution among subjects. Little is known of the impact of clonal diversity on caries activity but in some bacterial diseases particular clones are associat ed with virulence, Therefore, possession of a particular clone or clon es by an individual could be related to caries activity. Also. the ext ent of clonal diversity may reflect the nature of the oral environment , Recent studies suggest that cells are released from biofilms during adherence and growth, i.e., the early phases of development, Thus, det ermination of the numbers of a given species in non-stimulated saliva may indicate whether it is actively growing in plaque, Microbiological tests on the oral flora should perhaps be used to monitor the status of the oral cavity, after establishing a norm for the individual patie nt, Research on species and clonal diversity of oral bacteria among hu man populations: diversity and its role in the caries process; and the liberation of biofilm cells could provide data to allow better apprec iation and evaluation of the results of microbiologiocal testing.