Periodontal Anatomy Flashcards
1
Q
What does “periodontal” mean?
A
Perio = around odontos = tooth
2
Q
What structures make up the periodontal structures?
A
Gingiva
Periodontal ligament
Root Cementum
Alveolar bone
3
Q
Periodontal ligament
A
Attaches to the root cementum and the alveolar bone
4
Q
Sharpey’s Fibers
A
Projections that attach the PDL to cementum
5
Q
What makes up the alveolar bone?
A
Outer cortical plate, inner cortical plate, and cancellous bone in between them
6
Q
Outer cortical plate
A
The portion of the alveolar bone that the gingiva attaches to
7
Q
Inner cortical plate
A
Portion of the alveolar bone that the PDL attaches to
8
Q
What is the functions of periodontal structures
A
Attach the tooth to the bony tissue of the jaw
Maintain the integrity of the masticatory mucosa
9
Q
What happens if you don’t have a good PDL?
A
Teeth would move whenever you chew or did almost any mouth movement
10
Q
What type of cells do the periodontal structures originate from?
A
Neural crest cells beneath the stomodeal epithelium
11
Q
What structure in development gives rise to the periodontal ligaments
A
Dental follicle
12
Q
Why doesn’t a tooth bleed when it erupts?
A
It erupts through an epithelial passage - and there is no blood supply in epithelium
13
Q
What is the first tooth structure to erupt?
A
Crown
14
Q
What cells form dentin?
A
Odontoblasts
15
Q
What type of cells secrete enamel-related proteins?
A
Amelogenins
16
Q
What happens when the root sheath fenestrates?
A
Ectomesenchymal cells of the dental follicle contact the root surface, and amelogenin induces differentiation into cementoblasts
17
Q
What does the PDL form from?
A
Fibroblasts that are differentiated from the dental follicle lateral to the cementum
18
Q
Gingia definition
A
Part of the masticatory mucosa which covers the alveolar processes and surrounds the cervical portions of the teeth
19
Q
What are the 3 macroscopic anatomical parts of the gingiva?
A
Free gingiva
Attached gingiva
Interdentinal papilla
20
Q
Free gingiva
A
Extends from the free gingival margin to the free gingival groove
Made of keratinized epithelium
21
Q
Free gingival margin
A
Coronal end of the gingiva
Located 1.5-2.0 mm coronal to the CEJ
22
Q
Free gingival groove
A
Junction between the free and attached gingiva
Corresponds to the CEJ
only seen in 30-40% of adults
23
Q
What microscopic anatomical structures can be seen on the gingiva
A
Oral epithelium
Oral sulcular epithelium
Junctional epithelium
24
Q
Oral epithelium
A
Microscopic structure of the gingiva that faces the oral cavity
25
Oral sulcular epithelium
Microscopic structure of the gingiva that faces the tooth surfaces without actually conacting
26
Junctional epithelium
Microscopic structure of the gingiva that provides contact between the gingiva and the tooth
27
What are the macroscopic limits of the free gingiva?
Extends from the free gingival margin to the free gingival groove
28
What are the microscopic limits of the free gingiva?
Extends from the free gingival margin to the junctional epithelium
29
Why do we care about the limits of the free gingiva?
Because how these landmarks change from health to disease will determine the accuracy of probe readings
30
Attached gingiva description
Firm texture
Coral pink
Immobile
Width varies
31
How and why does the width of attached gingiva change?
It increases with age due to passive eruption
32
What teeth have the widest and narrowest attached gingiva?
```
-Buccal Side-
narrowest = premolar
widest = incisors
-Lingual Side-
narrowest = incisors
widest = molars
```
33
Stippling of attached gingiva
Present in 40% of adults
An indicator of health, but absence is not necessarily an indicator of them being unhealthy - if a patient had stippling previously, but lost it, then it's a sign of poor gingival health
34
Why isn't there a muco-gingival junction on the palate?
All of the palate is keratinized gingiva
35
What is the importance of attached gingiva?
Supports marginal/free gingiva
It's a base for movable elements (cheeks, lips, tongue)
Can withstand frictional and functional stress
Barrier for inflammation
36
What helps the attached gingiva withstand frictional and functional stress?
It has a thick connective tissue layer
| and is firmly bound to the periosteum and bone
37
Why should we care about the attached gingiva?
If the patient has great oral hygiene, the thickness of attached gingiva doesn't matter
But thickness is important in patients with poor gingival health
38
What are some gingival landmarks?
Keratinized gingiva
Free gingival groove
Mucogingival junction
39
Keratinized gingiva
The combination of the attached gingiva and the free gingiva
40
Mucogingival junciton
Border between the attached gingiva and alveolar mucosa
41
What is the keratinized gingiva minus the sulcus?
Attached gingiva
42
What is the marginal gingiva?
Sulcus
43
When we say the "width" of the gingiva, what are we talking about?
The height occluso-cervically
44
When we say the "thickness" of the gingiva, what are we talking about?
Thickness bucco-lingually
45
What is the interdentinal papilla?
The part of the gingiva that comes together in a concave shape between the teeth
46
What does the shape of the interdentinal papilla depend on?
The contact relationships between adjacent teeth (concave because teeth are contacting...if teeth are missing, they will be flat)
Width of approximal tooth surfaces
Course of CEJ
47
What is the Col?
The concavity seen in contact areas of premolar and molar regions
48
Is interdentinal papilla keratinized or non-keratinized? Why?
Non-keratinized because it has no stimulus to become keratinized. It could be if it were stimulated
49
The bottom of the gingival sulcus in a healthy mouth is positioned apical to the CEJ. When is this most likely to occur?
A. Prenatally
B. 10-20 years of age
C. Before the roots of the primary teeth are resorbed
D. 40-60 years of age
E. Just after a permanent tooth has erupted
D. 40-60 years of age
50
Describe oral epithelium
Keratinized, stratified squamous epithelium in layers
51
What are the layers of the oral epithelium?
Basal layer
Prickle cell layer
Granular cell layer
Keratinized cell layer
52
Orthokeratinized
No nucleus
53
Parakeratinized
Has some nuclear remnants
54
Clinically, how do orthokeratinized and parakeratinized cells differ?
They don't
55
What changes occur from the basal layer to the granular layer of oral epithelium?
Cytoplasmic tonofilaments and the number of desmosomes increase
The number of organelles decreases
Function decreases, but attachment increases
56
What is the major cell type in the oral epithelium?
Keratinocytes (90%)
57
What are some "other" cells in the oral epithelium?
Melanocytes (synthesize melanin pigment)
Langerhans cells (defense cells)
Merkel's cells (sensory)
58
Basement membrane
Present between the basal layer of the oral epithelium and the CT
1-2 um wide
Rich in glycoproteins
Contains protein-polysaccharide complexes
59
What are the 2 layers of the basement membrane?
Lamina lucida - adjacent to basal cells
| Lamina densa - adjacent to CT
60
Hemidesmosomes
Dense plaques that attach epithelium to the basement membrane
Two of them make up a desmosome
61
What microscopic features describe the macroscopic stippling?
CT projects into epithelium by CT papillae
Inbetween the papilla are rete pegs
When rete pegs are fused, it seen as stippling
When rete pegs are missing at the junctional epithelium site, papilla depressions are seen clinically
62
Biologic width definition
Where attached gingiva is not attached to the alveolar bone, but enamel and cementum
63
Where do the cells of the junctional epithelium originate before tooth eruption?
Reduced enamel epithelium
64
Where do the cells of the junctional epithelium originate after tooth eruption?
Cells of the OE possess the ability to differentiate into cells of JE
65
At what portion is the JE thickest and what portion is the thinnest?
```
Widest coronally (15-20 cells)
Thinnest towards CEJ (3-4 cells)
```
66
T/F - JE is continually renewed
True - and the turnover rate is faster than the oral epithelium
67
Does the JE or OE have larger cells? Why?
JE - it has many functions to carry out, so it has many contents to do so
68
Does the JE or OE have larger interstitial space? Why?
JE - allows for neutrophils and other defense cells to get out to the sulcus and kill pathogens
69
Does JE or OE have more desmosomes?
OE
70
At what tooth level will the JE be at in healthy adult sulcuses?
At or just apical to the CEJ
71
What will occur to the JE in diseased adult teeth?
There will be attachment loss of the JE
72
Necrotizing Ulcerative Periodontitis
Necrosis of junctional epithelium, leading to pocketing
| Marginal epithelium falls away and the bone is exposed
73
What cells are found in the gingival connective tissue?
```
Fibroblasts (synthesize matrix and fibers)
Mast calles (vasoactive substances)
Macrophages (phagocytosis and synthesis)
Neutrophilic granulocytes
Lymphocytes
Plasma cells
```
74
What fibers are found in the gingival connective tissue?
Collagen
Reticulin
Oxytalan
Elastic
75
What is the role of collage in gingival connective tissue?
Characteristic cross-banding
Produced by fibrobasts, cementoblasts, and osteoblasts
The most abundant fiber
76
What is the importance of reticulin in gingival connective tissue?
Numerous adjacent to basement membrane
| Around blood vessels
77
What is the importance of Oxytalan in gingival connective tissue?
They are mostly in the pdl
| Run parallel to the long axis of the tooth
78
What is the importance of elastic fibers in the gingival connective tissue?
They are around the blood vessels like a cuff
79
What is the function of Gingival fibers?
Reinforce the gingiva
Provide resilience and tone
Maintain architectural form and integrity
80
What are the types of Gingival fibers?
Circular fibers
Dentogingival fibers
Dentoperiosteal fibers
Transseptal fibers
81
Circular fibers
Gingival fibers that encircle the tooth like a cuff
82
Dentogingival fibers
Gingival fibers that fan out from the supracrestal cementum to the free gingiva
83
Dentoperiosteal fibers
Gingival fibers that run from supracrestal cementum to the attached gingiva
84
Transseptal fibers
Gingival fibers that run from tooth to tooth and embed in the cementum of each
Maintains the M-D demensions
85
What is the richly vascular and cellular CT that surrounds the roots and joins the cementum and alveolar bone?
PDL
86
What is the function of the PDL?
Permits forces to be distributed
| Essential for the tooth's mobility - otherwise teeth would chip much more than they do
87
What are the fibers of the PDL?
Alveolar crest fibers
Horizontal fibers
Oblique fibers
Apical fibers
88
Cementum
Mineralized tissue covering the root surface, and occasionally small portions of the crowns of the teeth
89
What is the difference between bone and cementum?
Their makeup is similar
| Cementum lacks blood vessels, lymph, innervation, and physiologic remodeling/resorption
90
Intrinsic cemental fibers
Produced by cementoblasts
| Composed of fibers oriented parallel to root
91
Extrinsic cemental fibers
Sharpey's fibers
| Produced by PDL fibroblasts
92
What are the different forms of cementum?
Acellular, extrinsic fiber cementum
Cellular, mixed stratified fiber cementum
Cellular, intrinsic fiber cementum
93
Acellular, extrinsic fiber cementum location
At the coronal or middle portion of the root
94
Cellular, mixed stratified cementum location
At the apical third of the root and in the furcations
95
Cellular, intrinsic fiber cementum location
In the resorption lacunae
96
T/F - Cementum thickness increases by gradual aposition through out life
True
97
What is the thickness of cementum in the cervical portion of the root?
20-50 um
98
What is the thickness of cementum in the apical portion of the root?
150-250 um
