Reading 2/13 Histology of PDL Flashcards
1
Q
PDL forms from:
A
follicle
2
Q
PDL is made of:
A
CT ligament (PDL is specialized soft tissue)
3
Q
PDL embeds here:
A
cementum on tooth , alv bone
4
Q
When do PDL fibers first appear:
A
as root formation begins
5
Q
These cells begin to proliferate as root formation begins:
A
follicular cells
6
Q
What cells differentiate to cementoblasts?
A
innermost follicular cells near forming root
7
Q
What cells differentiate into osteoblasts?
A
outermost follicular cells
8
Q
Function of differentiated outermost follicular cells
A
make lining of bony pocket
9
Q
What cells differentiate into fibroblasts?
A
centrally located cells of the follicle
10
Q
Function of fibroblasts:
A
produce/ break down collagen
11
Q
What makes the cells that become embedded in the cementum and bone?
A
fibroblasts make the PDL
12
Q
original orientation of developing fibers of the PDL:
A
obliquely in coronal direction from tooth to bone
13
Q
TF? The coronal fibroblasts are the stem cells that proliferate and migrate apically.
A
F. apical, migrate cervically
14
Q
These form the first group of collagen fibers:
A
apical fibroblasts
15
Q
Stem cells of the PDL:
A
apical fibroblasts
16
Q
Initial orientation of the CEJ to the crest of the crypt:
A
CEJ apical to crypt, becomes coronal to alveolar crest
17
Q
TF? PDL doesn’t maintain support for tooth until it comes into functional occlusion.
A
F. erupting and functional support
18
Q
These remodel the PDL:
A
fibroblasts
19
Q
TF? Turnover only occurs in the metabolically active middle zone of PDL.
A
F. throughout whole thickness
20
Q
What is the intermediate plexus?
A
The metabolically active middle zone
21
Q
In which direction is the differential differentiation of the PDL fibers?
A
apicocervical direction
22
Q
Where is the highest turnover?
A
apical region, least in coronal
23
Q
When does maturation and thickening of the fiber bundles of the PDL occur>?
A
as teeth reach functional occlusion
24
Q
Functions of PDL:
A
formative, supportive, protective, sensory and nutritive
25
What serves as the periosteum to the bone proper?
PDL
26
What does the PDL serve to the cementum?
pericementum
27
TF? The periodontium is n extension of the gingival CT.
T
28
Range of thickness of PDL:
0.15 to 0.38
29
Is the PDL fairly consistent in size along its length or highly variable?
fairly consistent
30
Does the PDL increase or decrease in size with age?
dec
31
Thinnest part of PDL is located here:
midroot zone
32
PDL is composed of:
collagen fiber bundles connecting cementum and avl bone proper
33
PDL is aka:
periodontal membrane
34
What are principle fibers:
fiber bundles that exit cementum and alv bone proper to form the PDL
35
Name the groups of fiber bundles:
apical, oblique, horizontal, alveolar crest, and gingival fiber groups
36
Types of fibers int he gingival group:
circumferential, transseptal, free, and attached gingival fibers
37
Fibers of the mid-root:
horizontal
38
Fibers directly above apical fibers
oblique
39
Fibers of the cervical region:
alveolar crest fibers
40
FIbers directly below the horizontal fibers:
oblique fibers
41
FIbers that resist vertical forces:
Apical
42
FIbers that resist vertical and intrusive forces:
oblique, alveolar crest
43
FIbers that resist horizontal and tipping forces:
horizontal
44
FIbers that resist vertical and lateral movement::
interradicular
45
FIbers that resist tooth separation; mesial distal
transeptal
46
FIbers that resist gingival displacement:
attached gingival, free gingival, ircumferential
47
Location of attachment of apical fibers:
apex of root to fundic proper, extend perpendicularly
48
Location of attachment of oblique fibers:
apical 1/3 of root, extend upward, to adjacent alveolar bone proper
49
Location of attachment of horizontal fibers;
mid-root to adjacent alveolar bone proper
50
Location of attachment of alveolar crest fibers:
cervical root gingiva to alveolar crest of alveolar bone proper
51
Location of attachment of interradicular fibers:
extend perpendicularly bw roots to alveolar bone proper on multirooted teeth
52
Location of attachment of transeptal fibers:
cervical tooth to adjacent tooth, M or D to it
53
Location of attachment of attached gingival fibers:
cervical cementum to lamina propria attached gingiva
54
Location of attachment of circumferential fibers:
continuous around neck of tooth
55
Location of attachment of free gingival fibers:
cervical cementum to lamina propria attached gingiva
56
Appearance of circumferential fibers in a longitudinal section:
dots
57
Dentoalveolar fiber group consists of these:
apical, oblique, horizontal, alveolar crest, interradicular
58
Gingival fiber group consists ofa:
transseptal, attached gingiva, free gingival, circumferential
59
Fiber bundles that extend perpendicularly:
apical, interradicular
60
Spaces bw fiber bundles:
interstitial spaces
61
Content of interstitial spaces:
BV, lymph channels, and myellnated and unmyelinated nerves.
62
Function of the contents of the interstitial spaces of PDL:
vitality of periodonteum
63
Relation of BV's & nerves to the tooth:
encircle, connect w others that extend vertically from toothapex to gingiva
64
Vessels enter the ligament via:
alveolar bone
65
In which direction does the vascular plexus run?
in the center, longitudinally in the ligament
66
What is directly adjacent to the alveolar plexus?
clear zone (dentin)
67
What is adjacent to the clear zone on the opposite side of the alveolar plexus?
BV"s in the pulp
68
Function of circular and longitudinal vessels of PDL:
nutrition and dampening the change in shape of the PDL that occurs when the teeth are occluded
69
TF? Longitudinal vessels are arranged with great regularity in the periodontium.
T
70
These are a communicating branches of vessels:
longitudinal plexus
71
TF? Nerve trunks run in the interstitial space.
T
72
Larger nerve trunks traverse here:
central zone
73
Type of receptor that may be found int the interstitial space of the PDL:
pacinian receptor
74
Arrangement of some organized nerve endings:
enclosed in a delicate CT capsule
75
Fibers that make up the bulk of the PDL:
principle fibers
76
Function of principle fibers:
support
77
Name of the supporting fiber system:
indifferent fiber plexus, fine fibers supporting the principal collagen fibers
78
Main cell type found in the dense population of principal collagen fibers of the PDL:
fibroblasts
79
Elastic like fibers found in the PDL, around vessel walls, parallel to long axis of tooth:
oxytalan fibers
80
These surround oxytalan fibers:
a fibrillar and an amorphous zone
81
Arrangement of oxytalan fibers:
in parallel, function unknown
82
TF? A single cell can both build up and break down collagen.
T (fibroblast/ fibroclast - lysosomal system one end, active procollagen chain synthesis other)
83
What do procollagen chains form?
superhelix of the collagen molecule.
84
What is required for the hydroxylation of proline and lysine within the superhelix collagen molecule?
vitamin C
85
Cells found in the alveolar bone proper:
osteoblasts, cementoblasts
86
TF? osteoblasts, cementoblasts carry out the same function.
T
87
What is the collective name of osteoblasts and cementoblasts?
osteoclasts
88
Osteoclasts arise from:
circulating monocytes
89
Describe the osteoclast cells:
Large multinucleated, resorption lacunae
90
Which are more rare, cementoclasts or osteoblasts>
cementoblasts
91
When are cementoclasts seen?
only during exfoliation of teeth, traumatic occlusion, or possibly w tooth movement
92
TF? Cementum is prone to resorption and req very active turnover because of this.
F. not prone to resorption
93
Function of cementum being resistance to resorption:
allows orthodontic tooth movement w reluctant remodeling of alveolar bone
94
When are epithelial rests present in the PDL.
Throughout life
95
Epi rest cells originate from:
root sheath
96
Appearance of epi cells of root sheath;
lacy strands, networks, or isolated nests of active or inactive cells
97
Types of epithelial rest cells:
proliferating , resting, or degenerating
98
Cause of periodontal disease:
bac + specific host inflammatory response
99
Possible cause of individual differences in susceptibility to periodontitis and disease progression:
polymorphic nature of the immune system components, alleles may predispose to infectious disease or an unusual disease severity
100
What allows for tooth movement throughout life?
PDL, alveolar bone, cementum, and gingiva
101
TF? Tooth buds move spontaneously before eruption at times.
T
102
How are late growth changes and tooth wear compensated for?
passive eruption and migration
103
What allows for the movement of teeth via ortho:
alveolar bones and gingiva modifications
104
How are cells activated to remodel?
mechanical load
105
How to move implants and ankylosed teeth endodontically.
You can't, no PDL
106
What is remodeled in ortho moevent?
PDL, surrounding bone, entire surface of socket
107
What is created on the opposite side of the tooth movement direction?
stretching of PDL, tension, ligament narrower on compression side
108
Arrangement of PDL fibers on the compressed side before movement:
disorganized and compacted
109
Affects on compressed side:
blood flow dec, cell death, osteoclasts appear
110
Affects on the tension side:
fibroblasts become more spindle-shaped and appear oriented with long axis in direction of fiber bundle
111
How many zones of tension/ stretching does a 2-rooted tooth have?
2+ zones
112
Zones of compression/ tension in bifurcation area of a 2 rooted tooth:
tension zone toward L root, compression zone toward R
113
Where is there a transition zone from tension to compression?
apical area
114
Vulnerable area during tooth movement:
apical area, too much P --> death of pulp tissue by blood flow blockage
115
Initial response to physical force:
displacement of tooth, then permanent structural changes
116
Histo changes w tooth movement:
cell type/ number, vascular, ECM
117
The conversion of physical force to biologic response:
transduction
118
Type of osteocyte found on the compression side:
osteoclast
119
Non-destructve tooth movement:
Direct or frontal resoption
120
How long after tooth movements begin do osteoclasts appear?
a few hours after
121
From where are osteoclasts recruited?
circulating monocytes
122
Osteoclast and blasts stain w:
oxidative enzymes
123
Histological appearance of the resorption sites:
large, multinucleated, black stained osteoclasts w highly cellular, fibrous zone
124
Fibroblasts proliferate and synthesize new matrix in these sites:
tension sites
125
Cells that participate in the degradation of ligament on the compression side:
fibroblasts, osteoclasts, macs
