Dental Plaque Flashcards
What are some general properties of biofilm? (4)
- Protection (ie moisture, predators)
- Slow growth rate
- Get their physical characteristics from surface
- The variation of biofilm leads to their metabolic interactions
Define dental plaque
A complex microbial community on a tooth surface, embedded in a matrix of polymers of bacterial and salivary origin (BIOFILM)
Define biofilm
Biofilms are a collective of one or more types of microorganisms that can grow on many different surfaces
How are the properties of micro-organisms growing in microfilm different to ones growing from planktonic growth? (2)
- Microfilm grows slower
- Microfilm much more resistant to antimicrobial agents
Give some examples of synergistic interactions between organisms in a biofilm (5)
- Enzyme sharing
- Food chains
- Co-adhesion
- Cell-to-cell signalling
- Gene transfer
Give some examples of antagonistic interactions between organisms in a biofilm (6)
- Bacteriocin production
- H2O2 production
- Organic acid production
- Bacteriophage release
- Competition for nutrients
- Predation
Name some different types of dental plaque (5)
(Think location)
- Fissure plaque
- Approximal plaque
- Gingival crevice plaque
- Denture plaque
- Calculus
What are the 5 steps of the development of dental plaque
- Acquired enamel pellicle is deposited on clean tooth surface about 1μm thick
- Pioneer species of bacteria will adhere to the acquired pellicle
- Pioneering species multiply and form a confluent layer
- Accumulated bacterial growth leads to a decrease in oxygen tension which cultures additional anaerobic bacteria
- Plaque maturity
After brushing your teeth how long does it take for the acquired enamel pellicle to form?
2 Hours
What is the acquired enamel pellicle composed of? (5)
{3 Molecules + 2 fluids}
- Proteins
- Lipids
- Glycoproteins
- Saliva
- Gingival crevicular fluid
What components of the enamel pellicle are bacteria derived? (4)
- Glycosyl transferase
- Glucans
- Fructans
- Bacterial cell fragments
What components of the enamel pellicle are host derived? (5)
- Acidic, proline-rich proteins
- Amylase
- Lysozyme
- Albumin
- Immunoglobulins
What are the interactions that attract pioneer bacteria to the pellicle?
Van der Waals
What are the interactions that repel pioneer bacteria to the pellicle?
Electrostatic repulsion between negatively charged bacterial cell and pellicle surface.
Explain the molecular interactions between bacteria and pellicle
Bacteriums have adhesive molecules that are complementary to the pellicle surface receptors
During the multiplication stage of the pioneer species, co-aggregation occurs, what is this?
Cell-to-cell interactions leading to distinctly different bacterial species becoming predetermined ‘partners’ in forming plaque.
Mature plaque is a _____ community
Mature plaque is a climax community
Are there any benefits of dental plaque for the host?
Small amount of dental plaque can help exclude exogenous organisms
How can dental plaque help in the exclusion of exogenous organism from entering the mouth? (3)
- Competition for adhesion receptor sites
- Competition for nutrients and co-factors
- Production of inhibitory substances, eg acids, H2O2
What is calculus?
Calcified dental plaque
What is calculus composed of? (3)
- Mineral deposits
- Proteins
- Carbohydrates
Where is the most predominant supra gingival location for calculus?
Near salivary ducts
