pH and the oral hard tissues

Question 1

What is the formula for hydroxyapatite

Answer 1

Ca10(Po4)6OH2

Question 2

What is the formula for the dissociation of hydroxyapatite

Answer 2

Ca10(PO4)6OH2 - 10Ca2+ + 6PO43_ + 2OH-

Question 3

Where is hydroxyapatite found

Answer 3

Rocks, geological formations and living tissues

Question 4

Composition of saliva

Answer 4

99% - water

1% - ions (rich in calcium and phosphate)

Question 5

Normal pH range of saliva

Answer 5

6.2-7.6

Average = 6.7

Question 6

Peak and low flow of saliva

Answer 6

Peak flow - 7.8
Low flow- 5.3

Low flow = demineralisation starts to occur - hydroxyapatite starts to dissociate

Question 7

Unstimulated whole saliva

Answer 7

Slightly more acidic = 0.3 - 0.4

Question 8

Stimulated whole saliva

Answer 8

Slightly more alkaline = 1.0- 2.0

Question 9

What does the Stephan curve show

Answer 9

What happens after the consumption of sugar (glucose challenge)
Sugar intake causes demineralisation to occur
After time the saliva buffers the pH and remineralisation will start to occur - returns pH back to normal level

Question 10

Critical pH level in the mouth

Answer 10

5.5

Below this point, your teeth start to demineralise or dissolve

Question 11

What affects the Stephans curve

Answer 11

How often you eat and drink
How long you eat and drink for
What you eat and drink etc

Question 12

Clinical significance of this reaction

Answer 12

Recalcification of the early carious lesion
Destructive carious lesion
Calculus deposition
Acid etch technique

Question 13

Low pH effects

Answer 13

Apatite dissolution, caries

Question 14

High pH effects

Answer 14

Apatite deposition, calculus