Chapter 5 Midterm Questions

Question 1

What are the stages of tooth development?

Answer 1

bud, cap and bell stages

Question 2

True or False

Each stage of tooth development is defined according to the shape of the ectoderm ally derived enamel organ, which is a part of the developing tooth.

Answer 2

True

Question 3

What is the bud stage composed of?

Answer 3

rounded, localized growth of ectodermal cells surrounded by the proliferating mesenchymal cells, gains concave surface (begins cap stage)

Question 4

The mesenchyme forms the __ ______

Answer 4

dental papilla (which becomes dental pulp)

Question 5

What is the tissue surrounding the dental papilla and dental pulp?

Answer 5

dental follicle

Question 6

What is the name of the cells that the enamel organ have differentiated into?

Answer 6

outer enamel epithelial cells

Question 7

Ameloblasts form what substance on the tooth crown?

Answer 7

enamel

Question 8

After the odontoblasts elongate, become columnar and polarize, they form an extracellular matrix, that is what percent of type I collagen fibers and non collagenous proteins?

Answer 8

90% type I collagen fibers

10% noncollagenous proteins (predentin)

Question 9

When the cell moves pulp ward, what is the process called?

Answer 9

odontoblast process

Question 10

The dentinal matrix becomes calcified in how many hours?

Answer 10

24

Question 11

What is the name of the dentinal matrix before calcification and after calcification?

Answer 11

predentin before

dentin after

Question 12

The initial formation of dentin (yellow) at the cuspal tips and the vascularized pulp organ are characteristics of what stage of tooth development?

Answer 12

dentinogenesis stage (follicular cells are differentiating around enamel organ and alveolar bone proper is beginning to define the dental crypt)

Question 13

What are the two phases of dentinogenesis?

Answer 13

collagen matrix formation, deposition of calcium phosphate crystals in the matrix

Question 14

At the bell stage, cells of the inner enamel epithelium elongate and are ready to become what?

Answer 14

active secretory ameloblasts

Question 15

What are the five functional stages of ameloblasts?

Answer 15

morphogenesis
organization and differentiation
secretion
maturation
protection

Question 16

The inner cell layer of the root sheath forms from what ?

Answer 16

inner enamel epithelium or ameloblasts in the crown (enamel is produced)

Question 17

True or False

As the root sheath lengthens, it becomes the architect of the root. The length, curvature, thickness and number of roots are all dependent on the inner root sheath cells

Answer 17

True

Question 18

What is intermediate cementum?

Answer 18

thin layer of acellular cementum that covers the ends of the dentinal tubule and seals the root surface and is composed of keratin-like protein

Question 19

True or False

The outer root sheath cells disperse into small clusters and move away from the root surface as “epithelial” rests

Answer 19

True (root sheath bends at 45 degree angle , termed epithelial diaphragm)

Question 20

What is the origin of ameloblast cells?

Answer 20

epithelial cells

Question 21

What angle does the root sheath bend at?

Answer 21

45 degree angle