plawue and calculus clincial aspects of structure and formation Flashcards
aeitiolgy of PDD
environemtnal and acquiired risk factors feed into host immune system CT and bone metabolism into clinical signs of disease initiation and progression
plaque
- plaque is a soft, concentrated mass consisting mainly of a large variety of bacteria, together with cell debris which develops within short time of refraining from tooth brushing.
types of plaqy
sub and supra gingival
strucutre of plaqu
70% microorganism
30% inter bacterial matrix
interbacterial matrix consisits of
- cuticle
- epithelial cells
- polymorphonuclear leucocytes
- carbohydrates, lipids (LPS), proteins, immunoglobulins, enzyme
stages of plaque formation
1) passive transport of microorganisms
2) adhesion receptors provide reversible adhesion
3) VDW forces act on the dental pellicle which holds the plaque onto the tooth surface
4) can also be involvement of primary and secondary colonisers(may have irreversible adhesion
5) can also have tertiary colonisers, can act in unison
how is the pellicle formed
- formed by opposite charges in salivary macromolecules
- large amounts of acidic amino acids, and glycoproteins from saliva
- small amounts of basic and sulphur containing amino acids
stages (timeline) ofplaqu formatio
1) 1-2 days
- formation of dental pellicle
2) 2-4 days
- primary colonisation
- formation of ECM, provides attachment to the tooth surface and protection
3) 4-7
- succession
- increase in bacterial load, no organisms
- thickening of biofilm
- colonisation of gram - organisms
4) 7-14
- secondary colonistion and proliferation
- more gram + bacteria
- increased number of anaerobes
- increased expression of virulence factors by bactera
- formation of well organised biofilm colonies
- can see clinical effects of gingival inflammation
5) 14 onwards
- maturation of biofilm
- gram – organisms proliferating
- densly packed within biofilm
- well organised
- clinical signs will be more profound
subgingival plaque
low 02 levels favour anaerobes
nutrients from crevicualr fluid
organisms can exist without attatchement
pathogenisiy of plaque is split into
endotoxin
enymes
cytotoxic metabolites
calculus
calcified or calcifying deposits on teeth or other solid structures present in the mout
types of calculus
supra and sub gingival
detection of calculus
visual
radiography
tactile
composition of calculs
80% inorganic crystalline
20% organic
structure of calculus
- layers (Resting lines in histlogical sections)
- various amounts of calcification throughout the layers
- random arrangement of crysals
- outline of calcified microorganis
- plaque on the surface
how does calculus attatche to tooth surface
calcification of pellicle
intimate contact of crystals in calculus between enamel cementum or dentine
theroies of formation of calculus
co2 synthesis
ammononia production hyposynthesis
nucleation hypothesis
co2 synthesis
- high levels in salia as it leaves the glands
- CO2 leaves saliva,gives a rise in pH, Ca and PO4 ions come out of solution
- precipitiation into plaque
nucleation hypothesis
- nucleation of crystal formation by unknown compounds
ammonia prodcution hyposynthesis
- research showed that rapid calculus formers had raised salivary urea
- increase in pH
- Ca and PO4 ions come out of solution
