plawue and calculus clincial aspects of structure and formation

Question 1

aeitiolgy of PDD

Answer 1

environemtnal and acquiired risk factors feed into host immune system CT and bone metabolism into clinical signs of disease initiation and progression

Question 2

plaque

Answer 2

• 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.

Question 3

types of plaqy

Answer 3

sub and supra gingival

Question 4

strucutre of plaqu

Answer 4

70% microorganism

30% inter bacterial matrix

Question 5

interbacterial matrix consisits of

Answer 5

• cuticle
• epithelial cells
• polymorphonuclear leucocytes
• carbohydrates, lipids (LPS), proteins, immunoglobulins, enzyme

Question 6

stages of plaque formation

Answer 6

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

Question 7

how is the pellicle formed

Answer 7

• 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

Question 8

stages (timeline) ofplaqu formatio

Answer 8

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

Question 9

subgingival plaque

Answer 9

low 02 levels favour anaerobes
nutrients from crevicualr fluid
organisms can exist without attatchement

Question 10

pathogenisiy of plaque is split into

Answer 10

endotoxin
enymes
cytotoxic metabolites

Question 11

calculus

Answer 11

calcified or calcifying deposits on teeth or other solid structures present in the mout

Question 12

types of calculus

Answer 12

supra and sub gingival

Question 13

detection of calculus

Answer 13

visual
radiography
tactile

Question 14

composition of calculs

Answer 14

80% inorganic crystalline

20% organic

Question 15

structure of calculus

Answer 15

• 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

Question 16

how does calculus attatche to tooth surface

Answer 16

calcification of pellicle

intimate contact of crystals in calculus between enamel cementum or dentine

Question 17

theroies of formation of calculus

Answer 17

co2 synthesis
ammononia production hyposynthesis
nucleation hypothesis

Question 18

co2 synthesis

Answer 18

• 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

Question 19

nucleation hypothesis

Answer 19

• nucleation of crystal formation by unknown compounds

Question 20

ammonia prodcution hyposynthesis

Answer 20

• research showed that rapid calculus formers had raised salivary urea
• increase in pH
• Ca and PO4 ions come out of solution