Enamel, Dentin, Cementum

Question 1

What is the main component of enamel

Answer 1

Inorganic matter (NOT collagen)

Mainly hydroxyapetite a crystalline calcium phosphate

Question 2

Enamel rods positioning in primary (decidous) vs permanent teeth in the cervical third

Answer 2

• Decidous teeth- rods are more vertical
• Permanent- rods in gingival direction
• Rods are typically perpendicular to the Dental-Enamel-Junction

Question 3

What germ layer does enamel come from?

Answer 3

The ectoderm

All other dental tissues come from the mesoderm (mesenchyme)

Question 4

Perikymata and Striae of Retzius

Answer 4

• Perikymata
  
  • Depressed furrows on enamel surface as a result of enamel spposition
• Striae of retzius
  
  • Point incisally from DEJ, form concentric circles

Question 5

For multi rooted teeth dentin continues to form most rapidly at the ____ and ____

Answer 5

Floor and roof of the pulp chamber

Question 6

Dentin composition

Answer 6

70% Inorganic hydroxyapetite

20% Collagen

Question 7

What is the PRIMARY function of the dental pulp

Answer 7

Form dentin

Its secondary function is to nourish and provide sensation

Question 8

Dentin is formed by

Answer 8

Dental papilla and dental pulp

Question 9

Which dentin is most mineralized

Answer 9

Intra or peritubular dentin

This is the dentin that is wrapped around the odontoblastic process

Question 10

The softest dental tissue is

Answer 10

Cementum

Question 11

What are the 2 types of cementum

Answer 11

• Acellular
  
  • Coronal 2/3
• Cellular
  
  • Apical 1/3
  • Near the blood supply

Question 12

Cementum functions

Answer 12

Seals the tubules of root dentin

Attachment for periodontal fibers

Question 13

Cementum Composition

Answer 13

50% Inorganic hydroxyapetite calcium

50% Organic (water, type I collagen, proteins)