Cariology (Sharples) Midterm

Question 1

Enamel (hydroxyapatite) pH critical level

Answer 1

5.5

Question 2

Dentin pH critical level

Answer 2

6.2

Question 3

Enamel (hydroxyfluorapitite) critical pH level

Answer 3

4.5

Question 4

A caries lesion in any surface of the anatomical tooth crown

Answer 4

Coronal Caries

Question 5

A caries lesion not adjacent to an existing restoration or crown

Answer 5

Primary Caries

Question 6

Enamel Composition

Answer 6

90-92% inorganic (HA- hydroxyapatite)

4-12% Water

1-2% protein

Question 7

Enamel origin

Answer 7

Epithelial origin, built by ameloblasts which die after deposition

Question 8

Enamel at cervical and incisal/occlusal areas; harder to cleave

Answer 8

Gnarled Enamel

Question 9

Structural properties depend on direction force is applied (ex: enamel)

Answer 9

Anisotropic

Question 10

Same structural properties regardless of force direction (ex: composite)

Answer 10

Isotropic

Question 11

Dentin composition

Answer 11

50% inorganic (HA; 75% wt)

25% collagen (20% wt)

25% water (5% wt)

Question 12

Dentin development

Answer 12

Mesenchymal origin; built by odontoblasts which remain in pulp

Question 13

Dentinal Tubule function

Answer 13

Allow fluid movement and ion flow

->Remineralization, apposition of peritubular dentin, pain perception

Question 14

Dentin Properties

Answer 14

20% less hard than enamel

Higher tensile strength, lower stiffness

Isotropic

Question 15

Unmineralized zone of dentin immediately superior to cell bodies of odontoblasts

Answer 15

Predentin

Question 16

Dentin that forms up to 3 yrs after eruption

Answer 16

Primary Dentin

Question 17

Dentin in which direction changes and deposition slows

Answer 17

Secondary Dentin

Question 18

Formed dentin in response to stimulus (bacteria); often forms into pulp

Answer 18

Reparative Dentin

Question 19

Calcification in dentin tubules due to injury/increasing age

Answer 19

Sclerotic Dentin

Question 20

Cementum (Periodontium) composition

Answer 20

45-50% inorganic (HA)

50-55% organic (water)

5-10% mineral

(Highest fluoride content of all mineralized tissue)

Question 21

Sudden dryness in mouth (from radiation, medication, etc.)

Answer 21

Xerostomia

Question 22

Diet effect on caries process

Answer 22

Sucrose -> promotes highly acidogenic bacteria growth

Acidic food -> caries

Question 23

Hypocalcified Caries

Answer 23

Developmental white spot

Same wet or dry

Do not restore unless for esthetics

Question 24

Non-cavitated Caries (White Spot lesion)

Answer 24

• Demineralized but not cavitated
• Disappear when wet
• Don’t restore
• Proximal lesions in enamel

Question 25

Active Caries

Answer 25

• Surface disturbed/missing
• Soft, chalky surface found with explorer tip
• Proximal lesions into dentin
• Can’t remineralize, must restore

Question 26

Inactive Caries

Answer 26

• Calcium and phosphate in saliva help remineralize
• Remineralized more resistant, looks discolored (brown/black)
• Don’t restore unless for esthetics