Dental plaque Flashcards
Does plaque adhere to hard or soft surfaces
Hard
What is plaque associated with
Biofilm
Bacteria in the red complex
T. forsythia
P. gingivitis
T. denticola
Difference between supra and sub gingival plaque
Supra - at or above the gingival margin
Sub - below the gingival margin
Composition of plaque
70-80% bacteria
Water channels - acts as a circulatory system
Organic components: glycoproteins from saliva, polysaccharides, proteins, lipid material
Inorganic components:
Calcium and phosphorous
Phases of plaque formation
1) Acquired pellicle
2) Adhesion
3) Colonisation
How quick does the acquired pellicle form
Within seconds
Bacteria that adhere to tooth surfaces do not contact the tooth directly but interact with the acquired pellicle
What happens in the adhesion phase
Adhesin molecules on cell surfaces interact with receptors in the pellicle
Only a small amount of the bacteria have adhesion molecules so the ones that do that adhere to the pellicle are called primary colonisers
First 4-8 hours, 60-80% bacteria = streptococcus
What happens in colonisation phase
Coadhesion: primary colonisers provide binding sites for adhesion of new bacteria = secondary colonisers
Coaggregation: genetically distinct bacteria become attached to one another via specific molecules
Coadhesion and congregation lead to a biofilm
Early to mature plaque leads to a shift in gram +ve to gram -ve
Natural factors favouring plaque retention
Calculus, enamel projections, fissures
Iatrogenic factors favouring plaque retention
Overhanging restorations, open contacts, over contoured crowns
Materia alba vs calculus
Materia alba = soft accumulation of bacteria, food etc
Calculus = hard deposit that forms by the mineralisation of dental plaque
