Dental plaque
Template:Infobox medical condition
Definition
[edit]Dental plaque is a complex, organized biofilm that forms naturally on the surfaces of teeth and other hard structures in the mouth (such as dental implants and dentures). It consists of a diverse community of microorganisms embedded in a self-produced matrix of extracellular polymeric substances (EPS).
Unlike a simple food debris or "materia alba," dental plaque cannot be removed by rinsing with water; it requires mechanical disruption through oral hygiene practices.
Composition
[edit]- Microorganisms (70-80%): Primarily bacteria, with over 700 species potentially present.
- Intercellular Matrix (20-30%): A "scaffold" composed of:
- Polysaccharides (e.g., glucans and fructans produced by Streptococcus mutans).
- Proteins (derived from saliva and bacterial products).
- Lipids and DNA.
- Inorganic components: Mainly calcium and phosphorus.
Formation Stages
[edit]The development of dental plaque is a dynamic process occurring in four distinct phases:
- Acquired Pellicle Formation: Within minutes of cleaning, a thin layer of salivary glycoproteins deposits on the enamel.
- Initial Colonization: Gram-positive facultative cocci (e.g., Streptococcus sanguinis) bind to the pellicle via specific adhesins.
- Secondary Colonization (Co-aggregation): Filamentous bacteria like Actinomyces and "bridge" organisms like Fusobacterium nucleatum allow late-colonizing anaerobes to attach.
- Maturation: The biofilm develops a 3D architecture with nutrient channels and reaches a state of homeostasis.
Classification
[edit]Dental plaque is clinically categorized by its location relative to the gingival margin:
Supragingival Plaque
[edit]Located above the gum line. It is predominantly aerobic and, if rich in saccharolytic bacteria, leads to the development of dental caries.
Subgingival Plaque
[edit]Located below the gum line within the gingival sulcus. It is dominated by anaerobic, proteolytic bacteria (the "Red Complex") which drive periodontitis.
Pathological Potential
[edit]If plaque is not disrupted, the microbial community undergoes dysbiosis.
- Acidogenesis: Bacteria ferment dietary sugars into lactic acid, causing demineralization of enamel.
- Calculus Formation: Over time, plaque can mineralize into dental calculus (tartar), which provides a rough surface for further plaque accumulation.
- Inflammation: Microbial toxins trigger an immune response in the periodontium.