Chapter 20

Question 1

where does the ameloblasts lay down a matrix of mucopolysaccharide and organic fiber next to the dentin matrix?

Answer 1

Dental papilla

Question 2

Where is the CEJ formed?

Answer 2

Dental Papilla

Question 3

What has genetic control over the tooth shape?

Answer 3

Dental papilla

Question 4

What is the hardest structure of the body?

Answer 4

Enamel

Question 5

Enamel is generally what color?

Answer 5

White

Question 6

Enamel can appear what color at times and why?

Answer 6

yellowish because of the reflection of the underlying dentin

Question 7

Composition of enamel is

Answer 7

96% inorganic (Hydroxyapatite)

Question 8

Other 4% of enamel is composed of what

Answer 8

Water and fibrous organic material

Question 9

Enamel rod is made up of what?

Answer 9

Hydroxyapatite crystals.

Question 10

What is the primary unit of enamels structure?

Answer 10

Enamel Rod

Question 11

a column of enamel that runs from the Dentinoenamel Junction to the surface of the tooth

Answer 11

Enamel Rod

Question 12

Enamel rod is Perpendicular to

Answer 12

The DEJ and the surface of the crown

Question 13

Lays down matrix to form enamel

Answer 13

Ameloblasts

Question 14

where does Ameloblasts begin to lay down Matrix

Answer 14

At the tip of the cusp and then further toward the cervical line

Question 15

Ameloblast lying down matrix is referred to as

Answer 15

the mineralization stage of enamel rod calcification

Question 16

The second stage of calcification is called the

Answer 16

Maturation stage

Question 17

what happens in Maturation stage

Answer 17

Crystals should grow in size until they are tightly packed together

Question 18

When is there a change in development of the enamel rod

Answer 18

every 4 days

Question 19

when change in development of enamel rod occurs and a brownish line develops in the enamel it is called

Answer 19

Striae of retzius

Question 20

On the labial surface of the crown you can se horizontal lines on the crown due to

Answer 20

Striae of Retzius

Question 21

Horizontal lines that can be seen on crown of Anterior teeth are called

Answer 21

Imbrication lines.

Question 22

Imbrication lines are

Answer 22

surface manifestations of the striae of retzius

Question 23

The final job of ameloblasts is to

Answer 23

lay down a protective layer over the enamel

Question 24

Protective layer of the enamel created by ameloblasts is called

Answer 24

Primary enamel cuticle

Question 25

Another name for Primary enamel cuticle is

Answer 25

Nasmyths membrane

Question 26

Nasmyths membrane (Primary Enamel Cuticle) covers

Answer 26

the crown and remains there for many months after eruption until worn away by toothbrushing and other abrasion

Question 27

when spots or entire areas of the teeth appear white to whitish yellow in color

Answer 27

Hypocalcified enamel

Question 28

hypocalcified enamel the result of

Answer 28

insufficient growth of the enamel crystals or an insufficient number of crystals originally deposited in the matrix

Question 29

hypocalcification can be termed

Answer 29

Soft teeth

Question 30

soft teeth (hypocalcification) can decay

Answer 30

More rapidly

Question 31

Density is normal but enamel is thin in

Answer 31

Hypoplastic enamel

Question 32

teeth with hypoplastc enamel look what color

Answer 32

Enamel of tooth will have a yellow to gray hue

Question 33

Enamel will look thinner than normal radio graphically due to

Answer 33

hypoplastic enamel

Question 34

Cracks in the enamel

Answer 34

Enamel lamellae

Question 35

Enamel lamellae clinically appear

Answer 35

as hairline cracks in enamel that extend all the way through the enamel and even into the dentin

Question 36

small area of hypocalcified enamel seen at the DEJ

Answer 36

Enamel tuft

Question 37

enamel tuft is only foud

Answer 37

in the histologic section of the tooth

Question 38

Enamel spindle is an

Answer 38

odontoblastic process

Question 39

Cellular extension of the odontoblast that becomes trapped between ameloblasts in early developed

Answer 39

Enamel spindle

Question 40

Enamel spindle is found only

Answer 40

histologically

Question 41

Hard yellowish substance

Answer 41

Dentin

Question 42

Composiion of dentin

Answer 42

70 % inorganic hydroxyapatite | 30 % primarily organic (composed of collagen, mucopolysaccharide ground substance, and water)

Question 43

Three distinct areas of dentin

Answer 43

1. ) dentinal tubule 2. ) peritubular dentin 3. ) intertubular dentin

Question 44

A long tube running from the DEJ to the pulp containing odontoblastic process

Answer 44

Dentinal Tubule

Question 45

an area of higher crystalline content immediately surrounding the dentinal tubules

Answer 45

Peritubular dentin

Question 46

the bulk of the dentinal material

Answer 46

Intertubular dentin

Question 47

Distinct areas of dentin are all

Answer 47

Microscopic structures

Question 48

dentin that has formed by the time the tooth has ruptured into the oral cavity

Answer 48

Primary dentin

Question 49

Dentin that continues to be formed

Answer 49

secondary or reparative dentin

Question 50

layer of dentin formed inside the regular dentin and positioned closest to the pulp

Answer 50

secondary dentin

Question 51

secondary dentin starts forming when

Answer 51

About the time the tooth erupts and comes into contact with the opposing tooth

Question 52

what happens as secondary dentin forms

Answer 52

it causes the overall sixe of the pulp chamber to decrease

Question 53

Newly erupted teeth have

Answer 53

prominent pulp horns and large pulp chambers

Question 54

Dentin formed in response to local trauma

Answer 54

Repairative dentin

Question 55

repairative dentin is located

Answer 55

immediately beneath the trauma

Question 56

Trauma that triggers repairative dentin can be

Answer 56

Occlusal Mechanical or chemical

Question 57

the condition that exists when one tooth or part of a tooth is subjected to more occlusal stress than normal

Answer 57

Occlusal Trauma

Question 58

The result of cavity preparations in the tooth

Answer 58

Mechanical trauma

Question 59

brought about by the acids produced by the bacteria that cause dental caries

Answer 59

Chemical trauma

Question 60

dentinal tubules that are empty because of the death of the odontoblasts that originally occupied them

Answer 60

Dead Tracts

Question 61

Dead tracts can only be seen

Answer 61

Microscopically

Question 62

Dead tracts provide

Answer 62

a pathway to the pulp for bacteria involved in decay

Question 63

Dentinal tubules become filled with dentin material

Answer 63

Sclerotic dentin

Question 64

Sclerotic dentin is related to

Answer 64

Occlusal trauma or decay

Question 65

Pulp consists of

Answer 65

Blood vessels, lymphatic vessels, nerves, fibroblasts and collagen fibers.

Question 66

Nerves of the pulp are

Answer 66

Primarily sensory

Question 67

Nerves of the pulp transmit

Answer 67

only one type of sensation-- Pain

Question 68

Primary abnormality seen in pulp

Answer 68

Pulp stones

Question 69

Small circular calcified areas found in the pulps

Answer 69

Pulp stones

Question 70

Pulp stones are found in about

Answer 70

about 80% of older persons age 70-80 years

Question 71

True pulp stones

Answer 71

originate from odontoblasts and are very rare

Question 72

False pulp stones

Answer 72

The most common type and probably originate from dead cells with concentric layers of calcium phosphate around them.

Question 73

What does a false stone look like under the microscope

Answer 73

resembles an onion cut in the cross section

Question 74

Free pulp stones are found

Answer 74

In the middle of the pulp

Question 75

Pulp stones may be seen as

Answer 75

Small globular radiopacities on the microscope

Question 76

the only problem that may occur with pulp stones

Answer 76

Would be in the endodontic treatment of a tooth with pulp stones (RCT- root canal therapy. )