Cariology

Question 1

Enamel Organization

Answer 1

rods/prisms - run from the DEj –> surface

Question 2

Enamel Development

Answer 2

epithelial origin - ameloblasts extinct after deposition

Question 3

Dentin/Pulp Complex

Answer 3

mesenchymal origin - odontoblasts remain in pulp to make more dentin (repair)

Question 4

Enamel Organization

Answer 4

rods (4-8um) - interlocking prisms - rods surrounded by sheaths - made up of crystallites (HA) -

Question 5

Properties of enamel

Answer 5

very hard, brittle, stiff (parallel to rod direction) - low tensile strength (perp. to rod direction)

Question 6

Pulp/Dentin Complex

Answer 6

tubules extend from pulp chamber to DEJ -

Question 7

Dentinal Tubule Function

Answer 7

allows fluid movement and ion transport - remineralization, apposition of peritubular dentin, pain perception

Question 8

odontoblastic processes

Answer 8

cytoplasmic extensions of cell body (Tomes fibers)

Question 9

odontoblasts

Answer 9

cell bodies line the wall of the pulpal chamber

Question 10

Dentin Organization

Answer 10

not uniformly mineralized - peritubular dentin is more mineralized than intertubular dentin - principle organic component is collagen - long, rope like protein

Question 11

pre-dentin

Answer 11

unmineralized zone of dentin immediatel adj. to cell bodies of odontoblasts

Question 12

dentin types

Answer 12

Primary: forms up to 3 yrs after tooth rupture
Secondary: without any obvious stimulus - dentin direction changes & deposition shows

Question 13

Dentin vs. enamel

Answer 13

less mineral content - small tubules run throughout - ability to repair & regenerate - ductile - more tensile strength

Question 14

dental pulp function

Answer 14

1. development (odontoblasts)
2. nutrition
3. sensory/protection
4. reparative

Question 15

cementum

Answer 15

hard, avascular tissue covering anatomic roots - formed throughout life (cementoblasts) - mesenchymal cells - undergo self repair to some degree