plaque and biofilm Flashcards
sterile when born?
yes, bac colonize after birth and establish normal flora (2 weeks for gut flora and 2 yrs for whole flora)
how to bac maintain themselves in a host? exceptions?
With the exception of microorganisms that are present in feces and in secretory fluids, all bacteria
maintain themselves within their host by adhering to a surface
most bac can survive in the oropharynx only when?
when they adhere to either soft tissues or the hard
surfaces
how can bac in the oropharynx be removed if not adhered
- Swallowing, mastication, or blowing the nose
- Tongue and oral hygiene implementation
- The wash-out effect of the salivary, nasal, and crevicular fluid outflow
- The active motion of the cilia of the nasal and sinus walls
What ability/virulence factor of a bacterium tis crucial for the induction of infectious diseases such as
gingivitis or periodontitis?
The ability of a bacterium to adhere to its host is crucial for the induction of infectious diseases such as
gingivitis or periodontitis. Oral bacteria have a large battery of virulence factors, one of which is the ability to adhere to hard intraoral surfaces and the oral mucosa
the oral cavity can be divided into 6 major ecosystems
which may also be referred to as niches. They are as follows:
- The intraoral and supragingival hard surfaces (teeth, implants, restorations, and prostheses)
- Subgingival regions adjacent to a hard surface, including the gingival sulcus
- The buccal palatal epithelium and the epithelium of the floor of the mouth
- The dorsum of the tongue
- The tonsils
- The saliva
biofilm composition
Biofilms are composed of microbial cells encased within a matrix of extracellular polymeric substances,
such as polysaccharides, proteins, and nucleic acid
interactions within biofilm
Bacteria that grow in multispecies biofilms interact closely with neighboring cells. Sometimes, these
interactions are mutually beneficial, as is the case when one organism removes another’s waste
products and uses them as an energy source.
diversity of biofilm contents
similarities?
Biofilms are diverse in their content: variations in biofilm structure exist within individual biofilms, between different types of biofilms, and between individuals. However, some structural features that
are common to many biofilms have been noted.
oral example of biofilm
plaque
Intercellular Plaque Matrix
composed of?
major components?
minor components?
Matrix that surrounds the bacteria within the plaque biofilm
• Composed of inorganic and organic components that originate from the bacteria, GCF and saliva
• Major components: polysaccharides derived from bacterial metabolism of CHO
• Minor components: salivary glycoproteins
fluid channels within plaque
how are nutrients delivered?
evidence of open fluid-filled channels running through the plaque mass.
Nutrients make contact with the attached microcolonies by diffusion from the water channels to the microcolony, rather than from the matrix.
biofilm matrix functions as?
barrier
The intracellular
matrix consists of?
organic and inorganic materials derived from saliva, gingival crevicular fluid, and
bacterial products.
Organic constituents of the matrix include:
polysaccharides, proteins, glycoproteins, lipid material, and
DNA.
salivary components of the biofilm
Glycoproteins from the saliva are important components of the pellicle that initially coat a clean tooth
surface, but they also become incorporated into the developing plaque biofilm.
Polysaccharides
produced by bacteria also contribute to?
Polysaccharides
produced by bacteria also contribute to the organic portion of the matrix. They play a major role in maintaining the integrity of the biofilm.
The inorganic components of plaque are:
The inorganic components of plaque are predominantly calcium and phosphorus, with trace amounts of
other minerals such as sodium, potassium, and fluoride.
The source of inorganic constituents of
supragingival plaque is?
as mineral content increases?
The source of inorganic constituents of
supragingival plaque is primarily saliva. As the mineral content increased, the plaque mass becomes calcified to form CALCULUS.
Calculus is frequently found?
in areas of the dentition adjacent to salivary ducts
lingual of mandibular incisors and buccal of maxillary 1st molars
why would calculus be associated with salivary ducts
reflects the high concentration of minerals available from saliva in those regions.
how does sungingival plaque get inorganic components
GCF, can form subgingival calculus
Subgingival calculus color? why?
Subgingival calculus is typically dark green or dark
brown, which probably reflects the presence of blood products that are associated with subgingival
hemorrhage.
Dental plaque is clinically defined as?
Dental plaque is clinically defined as a structured, resilient, yellow-grayish substance that adheres
tenaciously to the intraoral hard surfaces, including removable and fixed restorations.
why cant plaque be removed with rinsing or sprays?
The tough extracellular matrix makes it impossible to remove plaque by rinsing or with the use of sprays.
how is plaque removed
mechanical forces such as brushing and flossing
Materia alba:
app?
consists of?
lacks?
displaced with?
White, cheese-like accumulation
Consists of: salivary proteins, bacteria, desquamated epithelial cells/disintegrating food debris
Lack organized structure/not complex
Easily displaced with water spray
non mineralized deposits
• Dental plaques
• Acquired pellicle
• Plaque biofilm
• Materia alba
• Food particles
mineralized deposits
calculus
common forms of calculus formation
functions of the pellicle
what forms first? 2hrs? multiply? protective layer? 2 days? circ sys?
Plaque Formation Timeline
plaque composition by mass %
