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Flashcards in Chapter 20 Deck (76)
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1
Q

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

A

Dental papilla

2
Q

Where is the CEJ formed?

A

Dental Papilla

3
Q

What has genetic control over the tooth shape?

A

Dental papilla

4
Q

What is the hardest structure of the body?

A

Enamel

5
Q

Enamel is generally what color?

A

White

6
Q

Enamel can appear what color at times and why?

A

yellowish because of the reflection of the underlying dentin

7
Q

Composition of enamel is

A

96% inorganic (Hydroxyapatite)

8
Q

Other 4% of enamel is composed of what

A

Water and fibrous organic material

9
Q

Enamel rod is made up of what?

A

Hydroxyapatite crystals.

10
Q

What is the primary unit of enamels structure?

A

Enamel Rod

11
Q

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

A

Enamel Rod

12
Q

Enamel rod is Perpendicular to

A

The DEJ and the surface of the crown

13
Q

Lays down matrix to form enamel

A

Ameloblasts

14
Q

where does Ameloblasts begin to lay down Matrix

A

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

15
Q

Ameloblast lying down matrix is referred to as

A

the mineralization stage of enamel rod calcification

16
Q

The second stage of calcification is called the

A

Maturation stage

17
Q

what happens in Maturation stage

A

Crystals should grow in size until they are tightly packed together

18
Q

When is there a change in development of the enamel rod

A

every 4 days

19
Q

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

A

Striae of retzius

20
Q

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

A

Striae of Retzius

21
Q

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

A

Imbrication lines.

22
Q

Imbrication lines are

A

surface manifestations of the striae of retzius

23
Q

The final job of ameloblasts is to

A

lay down a protective layer over the enamel

24
Q

Protective layer of the enamel created by ameloblasts is called

A

Primary enamel cuticle

25
Q

Another name for Primary enamel cuticle is

A

Nasmyths membrane

26
Q

Nasmyths membrane (Primary Enamel Cuticle) covers

A

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

27
Q

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

A

Hypocalcified enamel

28
Q

hypocalcified enamel the result of

A

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

29
Q

hypocalcification can be termed

A

Soft teeth

30
Q

soft teeth (hypocalcification) can decay

A

More rapidly

31
Q

Density is normal but enamel is thin in

A

Hypoplastic enamel

32
Q

teeth with hypoplastc enamel look what color

A

Enamel of tooth will have a yellow to gray hue

33
Q

Enamel will look thinner than normal radio graphically due to

A

hypoplastic enamel

34
Q

Cracks in the enamel

A

Enamel lamellae

35
Q

Enamel lamellae clinically appear

A

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

36
Q

small area of hypocalcified enamel seen at the DEJ

A

Enamel tuft

37
Q

enamel tuft is only foud

A

in the histologic section of the tooth

38
Q

Enamel spindle is an

A

odontoblastic process

39
Q

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

A

Enamel spindle

40
Q

Enamel spindle is found only

A

histologically

41
Q

Hard yellowish substance

A

Dentin

42
Q

Composiion of dentin

A

70 % inorganic hydroxyapatite

30 % primarily organic (composed of collagen, mucopolysaccharide ground substance, and water)

43
Q

Three distinct areas of dentin

A
  1. ) dentinal tubule
  2. ) peritubular dentin
  3. ) intertubular dentin
44
Q

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

A

Dentinal Tubule

45
Q

an area of higher crystalline content immediately surrounding the dentinal tubules

A

Peritubular dentin

46
Q

the bulk of the dentinal material

A

Intertubular dentin

47
Q

Distinct areas of dentin are all

A

Microscopic structures

48
Q

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

A

Primary dentin

49
Q

Dentin that continues to be formed

A

secondary or reparative dentin

50
Q

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

A

secondary dentin

51
Q

secondary dentin starts forming when

A

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

52
Q

what happens as secondary dentin forms

A

it causes the overall sixe of the pulp chamber to decrease

53
Q

Newly erupted teeth have

A

prominent pulp horns and large pulp chambers

54
Q

Dentin formed in response to local trauma

A

Repairative dentin

55
Q

repairative dentin is located

A

immediately beneath the trauma

56
Q

Trauma that triggers repairative dentin can be

A

Occlusal Mechanical or chemical

57
Q

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

A

Occlusal Trauma

58
Q

The result of cavity preparations in the tooth

A

Mechanical trauma

59
Q

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

A

Chemical trauma

60
Q

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

A

Dead Tracts

61
Q

Dead tracts can only be seen

A

Microscopically

62
Q

Dead tracts provide

A

a pathway to the pulp for bacteria involved in decay

63
Q

Dentinal tubules become filled with dentin material

A

Sclerotic dentin

64
Q

Sclerotic dentin is related to

A

Occlusal trauma or decay

65
Q

Pulp consists of

A

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

66
Q

Nerves of the pulp are

A

Primarily sensory

67
Q

Nerves of the pulp transmit

A

only one type of sensation– Pain

68
Q

Primary abnormality seen in pulp

A

Pulp stones

69
Q

Small circular calcified areas found in the pulps

A

Pulp stones

70
Q

Pulp stones are found in about

A

about 80% of older persons age 70-80 years

71
Q

True pulp stones

A

originate from odontoblasts and are very rare

72
Q

False pulp stones

A

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

73
Q

What does a false stone look like under the microscope

A

resembles an onion cut in the cross section

74
Q

Free pulp stones are found

A

In the middle of the pulp

75
Q

Pulp stones may be seen as

A

Small globular radiopacities on the microscope

76
Q

the only problem that may occur with pulp stones

A

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