Structural Organization and Composition
In modern microbiology, dental plaque is viewed not simply as a bacterial accumulation, but as a fully developed biofilm. This is a symbiotic community that successfully functions under conditions of constant exposure to saliva (oral fluids).
The foundation of the biofilm is the matrix, a durable organic substance consisting of:
- Accumulations of various microorganisms;
- Polysaccharides;
- Specific proteins.
Practically all members of the normal oral flora can be found within this biotope. However, the specific microbial landscape and the number of microorganisms are not constant: they vary not only among different individuals, but even within the same person throughout their life.
The formation of this complex community is decisively influenced by the host organism and a number of environmental factors. These include diet, overall lifestyle, and occupational hazards.
Formation Mechanism and Microbial Succession
The process of dental plaque formation occurs in stages and is characterized by a strict sequence of shifting microbial communities.
- Initial Stage: It all begins with the formation of the pellicle—a soft, acellular protein layer covering the tooth surface that serves as a foundation for subsequent microbial attachment.
- Adhesion and Colonization: This stage takes only a few hours. A rapid increase in microbial biomass occurs. During this period, unique microscopic structures known as "corn-cob" formations appear. These result from coaggregation, where numerous microorganisms of completely different species tightly adhere to a single long, filamentous bacterium.
- Microbial Succession (Species Shift): Colonization of the biofilm proceeds strictly according to ecological succession rules:
- Primary colonizers: These are aerobes and facultative anaerobes (e.g., streptococci, corynebacteria, and actinomyces). Their main task is to consume oxygen and create anoxic conditions within the forming deposit.
- Secondary colonizers: Once the primary flora has prepared the environment, strict anaerobes invade the plaque, for whom the absence of oxygen is critical for survival.
Clinical Significance and Laboratory Diagnostics
Normally, the microorganisms of the biofilm are in equilibrium. However, disruption of the quantitative and qualitative balance of symbionts, as well as altered interactions with the host organism, triggers the pathogenesis of major dental diseases—caries and periodontitis.
Microbiological examination is used for precise pathogen identification and assessment of the biotope state. It consists of several strict stages:
- Sample collection: Performed very carefully using a dental explorer or metal spatula.
- Preparation: The collected mass must be weighed on analytical scales to precisely determine the biomass volume.
- Homogenization: To disrupt the tough matrix and separate bacteria for culturing, the material undergoes mechanical grinding or ultrasonic disintegration.
- Culturing: A quantitative method is applied. Given the predominance of strict anaerobes in the later stages of plaque formation, cultivation must be performed using anaerobic techniques.