dental caries

Question 1

dental caries definition

Answer 1

an infectious microbiological disease of the teeth that results in localized dissolution and destruction of the calcified tissues

Question 2

what causes caries?

Question 3

how can caries be prevented?

Question 4

how does decay alter tooth tissue?

Question 5

how can we diagnose caries?

Question 6

how can we treat early lesions without operative intervention?

Question 7

how can we treat advanced lesions by removing decayed tooth structure without damaging healthy tooth structure?

Question 8

dental diseases are related to:

Answer 8

tooth biofilm

Question 9

process of tooth biofilm build up

Answer 9

1. initial colonization by pioneer species
2. outgrowth: colonies form and grow up and out
3. secondary colonization and multiplication: increase diversity, plaque is invaded by bacteria, cell density decreases and replaced by polymers

Question 10

what does oral hygiene accomplish? does it remove all microorganisms?

Answer 10

• thins biofilm

Question 11

formation of a mixed microbial community

Answer 11

the plaque environment affects its development and the type of clinical condition it causes
- as time goes on and as conditions change, so does the bacterial population

Question 12

caries producing plaque

Answer 12

• the plaque builds up on the teeth
• proteins in saliva stick to enamel
• bacteria attach to the pellicle that is formed
• bacteria secrete carb matrix
• complex community forms plaque
  ** S. mutans colonizes teeth

Question 13

streptococcus mutans can

Answer 13

• transmit from mother to baby when first primary teeth erupt at 6 months
• attaches to teeth not mucus membranes

Question 14

how can transmission be prevented?

Question 15

how does S. mutans vary among individuals?

Answer 15

everyone has S. mutans but the difference is between caries-free and caries-active subjects
(levels vary)

Question 16

what is considered high count of S. mutans

Answer 16

10^6

Question 17

S. mutans can survive in what kind of environment?

Answer 17

acidic environment (virulence factor)
- S. mutans stores sugars

Question 18

How does S. mutans take over the plaque?

Answer 18

If you feed it

Question 19

effects of sugar consumption with S. mutans

Answer 19

• they ingest sugar and produce acid
• 6 carbon sugar to 3 carbon acid
• acid kills other bacteria
• S. mutans tolerates low pH
• it increases plaque

Question 20

saliva flow to protect enamel

Answer 20

• acts as pH buffer and presence of calcium and phosphate in saliva
• proteins attach to and stabilize pellicle

Question 21

low saliva states:

Answer 21

• radiation treatment
• many drugs that affect nerves and autoimmune diseases of the salivary glands
• must have low saliva when sleeping

Question 22

how do you prevent caries?

Answer 22

tell patient to avoid eating sugar and carbs before bedtime and must brush before going to sleep

Question 23

when is saliva secreted?

Answer 23

during meals, gustatory stimuli can cause very high flow rate

Question 24

what kind of medications influence salivary flow?

Answer 24

• some that impact nervous cardiovascular function reduce salivary flow:
• BP pills
• heart pills
• happy pills
• sad pills

Question 25

saliva

Answer 25

• water
• electrolytes including calcium and phosphate
• duct system pumps out NA
• saliva is hypotonic
• higher NA as secretion rate increases

Question 26

activation of the ANS ?

Answer 26

443

Question 27

secretory unit

Question 28

modification of saliva by duct cells

Question 29

2-stage hypothesis

Question 30

what biological properties of saliva influence the caries process?

Answer 30

1. mechanical washing
2. buffering
3. antibacterial activity
4. aggregation of bacteria
5. remineralization of enamel

Question 31

stephan curve

Question 32

stimulated saliva has a higher

Answer 32

buffer capacity than unstimulated saliva (neutralize acid better)

Question 33

calcium and phosphate

Answer 33

• help prevent dissolution of enamel
• pH down to 6 - hydroxyapatite is unlikely to dissolve
• increase of pH = precipitation of calcium salts = dental calculus

Question 34

calcium in saliva

Answer 34

1.4 mmol/1 (1.7mmol/1 in stimulated saliva)
- only around 50% in ionic form

Question 35

phosphate in saliva

Answer 35

6 mmol/1 (4mmol/ stimulated saliva)
- 90% ionic fomr