
Full text loading...
Category: Bacterial Pathogenesis
Dental Plaque, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555818104/9781555811594_Chap21-1.gif /docserver/preview/fulltext/10.1128/9781555818104/9781555811594_Chap21-2.gifAbstract:
The salivary pellicle is an organic film derived from the saliva and deposited on the tooth surface. It is, however, rapidly colonized by bacteria which make up the dental plaque. Based on the dental plaque's relationship to the gingival margin, it has been separated for microbiological studies into two different communities: supragingival and subgingival plaque. Saliva plays two roles: it limits colonization of most surfaces in the oral cavity by a variety of mechanisms, and it provides these surfaces with colonizing microorganisms shed primarily from the tongue, dental plaque, and other mucosal surfaces. The presence of the normal supragingival oral flora generally results in oral health. Dental caries and periodontal diseases are conditional diseases, requiring both the presence of critical numbers of certain indigenous species and the response of the host. Dental plaque is a structurally organized community, and the response in planktonic or monospecies cultures is not necessarily applicable to their behavior within a biofilm. The role of glucans in human plaque formation is only now beginning to be understood through in vivo studies. Changes in species numbers and metabolic activities of these microbes are influenced by the environment, which affects the expression of virulence genes.
Full text loading...
Adherent S. gordonii strain S7 on in vitro saliva pellicle-coated enamel; density of bacteria is low, similar to that seen initially in vivo ( 5 , 30 ).
Adherent S. gordonii strain S7 on in vitro saliva pellicle-coated enamel; density of bacteria is low, similar to that seen initially in vivo ( 5 , 30 ).
Structure of a natural microbial dental plaque biofilm. Electron micrograph o f a serial section o f a sample from a subject with gingivitis. The most apically located microbial mass consists o f a mixture of coccoid and filamentous bacteria, details of which are shown in the insert. Magnification, × 4,050 ( 34 ). (Reprinted with permission of the Journal of Periodontology.)
Structure of a natural microbial dental plaque biofilm. Electron micrograph o f a serial section o f a sample from a subject with gingivitis. The most apically located microbial mass consists o f a mixture of coccoid and filamentous bacteria, details of which are shown in the insert. Magnification, × 4,050 ( 34 ). (Reprinted with permission of the Journal of Periodontology.)
Microcolonial forms seen in an in vitro mixed-species biofilm grown in flow cells ( 44 ). The inoculum was whole saliva, and perfusion was done with sterile glucose-supplemented (1 mM) saliva. Staining was done with negative fluorescein, with imaging by fluorescein exclusion using scanning confocal laser microscopy. Four distinct morphologies were documented after 48 h of incubation in sterile saliva. (Reprinted with permission of the Journal of Microbiological Methods.)
Microcolonial forms seen in an in vitro mixed-species biofilm grown in flow cells ( 44 ). The inoculum was whole saliva, and perfusion was done with sterile glucose-supplemented (1 mM) saliva. Staining was done with negative fluorescein, with imaging by fluorescein exclusion using scanning confocal laser microscopy. Four distinct morphologies were documented after 48 h of incubation in sterile saliva. (Reprinted with permission of the Journal of Microbiological Methods.)