CAP 4

Question 1

What happens to hydroxyapatite below ph 5.5?

Answer 1

It dissolves

Question 2

How did the stephan curve come about?

Answer 2

Plaque on anterior tooth
§ Antimony electrode within plaque
§ Recorded pH
§ 2 minute rinse: 25ml of 10% glucose
§ Recorded pH every 10 mins

Question 3

What does the Stephan curve show?

Answer 3

The sudden ph drop on intake of sugar (sucrose) and going below the ‘critical ph’ 5.5. This is when enamel demineralises. The ph rises again slowly when no sugar is on the mouth.

Question 4

What is the rise in ph showing?

Answer 4

It is acid diffusing out and saliva buffering

Question 5

What would the Stephan curve be like for a caries free subject?

Answer 5

Start with a higher pH and end with a higher pH

Stays above the critical ph

Question 6

What would the Stephan curve be like for a caries active subject?

Answer 6

Start with a lower pH and finish with lower pH

Remained below critical pH for long period

Question 7

Name some nutritive sweeteners (3)

Answer 7

Sorbitol, xylitol, manitol

Question 8

Name some non nutritive sweeteners (3)

Answer 8

Saccharin, Aspartamine, Acesulfame K

Question 9

Name 4 host factors

Answer 9

food eating habbits, frequency of food intake, buffering capacity, fluoride in enamel

Question 10

What does saliva contain in terms of buffering?

Answer 10

HCO3

Question 11

When do saliva rates decrease?

Answer 11

At night and after radiotherapy (radiotherapy causes damage to saliva glands)

Question 12

Why is there not as much a pH drop at the FOM?

Answer 12

There is more saliva

Question 13

Why is sugar free gum good?

Answer 13

It promotes saliva flow and doesn’t cause a pH drop