CE: The Environment

Question 1

When can carries occur?

Answer 1

Only when acidity increases in the oral environment does demineralization of enamel & caries occur

Question 2

Impact towards prevention

Answer 2

Alteration in consumption of sugars, control dental plaque biofilm to reduce cariogenic bacteria quantity present, encouragement of remineralization processes to
maximize the potential for mineral repair

Question 3

Cariogenic bacteria is?

Answer 3

Streptococcus mutans

Question 4

High sucrose diets exhibits what?

Answer 4

Increases in S. mutans and caries

Question 5

Pathway of eating sugars -> carries

Answer 5

Frequent consumption of starch => caries

Starch => maltose by enzyme in saliva (amylase) => further metabolized to acids => demineralization

Question 6

Dietary restrictions of fermentable carbohydrates & cooked starches does what?

Answer 6

Reduces level of cariogenic organisms

Question 7

Physical traits

Answer 7

adhesiveness (stickiness) & clearance time/frequency of exposure of dietary carbs

• Diff foods cleared @ diff times/rates (compact in pits/fissures longer)
• Bacterial acid production can persist after carbs has cleared

Question 8

Frequency of intake or exposure

Answer 8

Frequency of eating/drinking increases episodes when pH of plaque falls below 5.5
- Restricting btw meal snacks & drinking non-sugared drinks reduces time that plaque pH falls below 5.5

Question 9

Vipeholm study

Answer 9

incidence of caries caused by diff amounts/types of dietary carbs

Question 10

What is the Stephan Curve?

Answer 10

Resting plaque pH, Decreasing plaque pH, increase plaque pH, salivary stimulation and plaque pH, and critical pH

Question 11

Resting plaque pH

Answer 11

• plaque not been exposed to fermentable carbs for ~2hr & generally has pH 6-7
• Stable and remain so for long periods of time
• Exception: antibiotics which may alter normal flora (less acidic); glutamate & proline more predominant, ammonia (pH neutralizer) – higher in plaque > saliva

Question 12

Decreasing plaque pH

Answer 12

• after exposure to fermentable carbs, the pH decreases rapidly
• Due to production of lactic acid
• If more acidogenic, aciduric bacteria is present in plaque, pH lower rapidly
• Decrease is dependent on speed which plaque bacteria are able to metabolize dietary carbs
• Sucrose would be metabolized quickly => more rapid decrease
  o Starch (larger) diffuse into plaque => more slowly (needs to be broken down before assimilated into plaque
• Buffering capacity of unstimulated saliva
• Density of plaque

Question 13

Increase plaque pH

Answer 13

• gradual recovery of plaque pH influenced by many factors—
  buffering capacity of saliva, time fermentable carbs stay in mouth, pH value, diffusion of acids from plaque into saliva/teeth
• Also influenced by base production in plaque
• Ammonia (deamination of aa) & breakdown of urea in saliva
• Bases neutralize acids & aide in removal of acids by bacteria

Question 14

Salivary stimulation & plaque pH

Answer 14

• Chewing gum or unflavored materials (paraffin wax) => increase in salivary flow with concurrent rapid rise in pH
• Rise in bicarbonate buffering capacity & increase supply of nitrogenous substrates (metabolized to basic end)

Question 15

Chewing of cheeses rich in nitrogenous compounds

Answer 15

• Strong sialagogue (agent that increases flow)

- Raising plaque concentrations of Ca & P => increasing chance of remineralization

Question 16

Critical pH

Answer 16

• pH @ which saliva & plaque fluid non-saturated w/ Ca & P => permitting hydroxyapatite in dental enamel to dissolve
• highest pH @ net loss of enamel from teeth @ 5.5 pH
• increasing concentration of Ca & P reduce effects of critical pH