Dentin

Question 1

Dentin Composition

Answer 1

70% Inorganic hydroxy apatite crystals 20% collagen 10% water

Question 2

Types of Dentin

Answer 2

Primary Dentin- while tooth is erupting and forming Secondary dentin- after eruption and root is almost complete

Question 3

Mantle Dentin

Answer 3

First primary dentin formed Mantle bc serves as covering

Next to DEJ

Large collagen fibers

Question 4

Interglobular Dentin

Answer 4

Primary Dentin

Globules are calcified

Interglobular spaces are hypomineralized

Calcosphers- spheres that are highly calcified

Question 5

Circumpulpal Dentin

Answer 5

Primary Dentin

Bulk of dentin

smaller collagen fibers

Question 6

Secondary Dentin

Answer 6

Forms internal to primary dentin

Develops after tooth is in occlusion and roots nearly formed

Develops slower than primary

Question 7

Teritiary Dentin

Answer 7

Produced in response to stimuli

• Attrition
• Caries
• Dental restorations

Question 8

Odontoblasts Life and General

Answer 8

Odontoblasts remain functional for life, ride or die homies!

Unlike lazy ameloblasts

They are end cells

Question 9

Predentin

Answer 9

Unmineralized, newly formed band of dentin at pulpal border of dentin

Question 10

Phases of dentin formation

Answer 10

1) Predintin: organic matrix deposited
2) Inorganic mineral substance is added

Question 11

Odontoblast Movement

Answer 11

Move toward pulp as they lay down dentin

Cell free zone allows for their movement towards pulp

Odontoblast process extends through predentin into dentin and into enamel

Question 12

Relevance of Dentinal Tubules

Answer 12

Impart a porosity or permeability to dentin

Provide elastin quality

Nerves and fluid within tubules perceive pain

Question 13

Enamel Spindle

Answer 13

Extensions of odontoblast process

Pass across DEJ into enamel

Question 14

Intertubular Dentin

Answer 14

Primary product of odontoblast

Lies btw tubules

Question 15

Peritubular Dentin

Answer 15

Hypermineralized

Found throughout dentin except:

• near pulp
• interglobular dentin

Question 16

Circumpulpal Dentin Mineralization Patterns 2

Answer 16

Linear pattern

• Slow rate
• Mineralization front is uniform

Globular (Calcopheric) Pattern

• Quick
• Front is not uniform

Question 17

Mineralization of Predentin

Answer 17

Single crystals of calcium hydroxyapetite appear within matrix vessicles

Crystals grow rapidly, grow rapidly, spread as clusted of crystallites

Adjacent clusters fuse to form continous layer of mineralized matrix

Question 18

Dead Tracts

Answer 18

Odontoblasts die due to old age or trauma

Tubules are open

Question 19

Sclerotic Dentin

Answer 19

AKA Trasparent dentin

• Increases with age, attrition
• Normal process
• permeability to pulp is eliminated
• Possibly to protect pulp
• Tubules occlude with calcified material and denatured collagen
• Dentinal fluid in tubule crystalizes

Question 20

Lines of Von Ebner

Answer 20

Overlapping lines

Question 21

Granular Layer in Root Dentin (Tomes)

Answer 21

Serves as an interface of collagen and noncollagenous matrix proteins between cementum and dentin