Unit 2 - Anatomy and Histology of Periodontium Flashcards
1
Q
What are the four principal components of the periodontal (in order)?
A
- Gingiva
- Alveolar bone
- Periodontal ligament
- Cementum
2
Q
What does the word periodontium mean?
A
Tissues that invest and support the teeth
3
Q
What is the mucous membrane lines the oral cavity?
A
Oral mucosa
4
Q
What is a mucous membrane?
A
Lining of a body cavity that communicates with the external environment
5
Q
What are the four functions of the oral mucosa?
A
- Protection
- Sensation
- Synthesis/secretion
- Esthetics
6
Q
What is the distinguishing feature of orthokeratinized epithelium?
A
No nuclei are present within the keratin layer
7
Q
What is the distinguishing feature of parakeratinized epithelium?
A
Some pyknotic nuclei are present within the keratin layer
8
Q
What is the distinguishing feature of nonkeratinized epithelium?
A
No keratin layer on the epithelium
9
Q
What tissue is the papillary layer made of?
A
Loose connective tissue
10
Q
What tissue is the reticular layer made of?
A
Dense connective tissue
11
Q
Where structure does the lamina propria insert into?
A
Epithelial rete pegs
12
Q
Where is the submucosa located?
A
Located below the lamina propria, not part of the mucosa
13
Q
What layer contains structures such as adipose tissue, glands, pacinian corpuscles, blood vessels, and nerves?
A
Submucosa
14
Q
What structures does the masticatory mucosa cover?
A
Gingiva and hard palate
15
Q
What structures does the lining mucosa cover?
A
Vermilion, buccal mucosa, lips, ventral surface of tongue, floor of mouth
16
Q
What structures does the specialized mucosa cover?
A
Dorsum of the tongue
17
Q
What mucosa covers the alveolar processes of the jaws and surrounds the necks of teeth?
A
Masticatory mucosa
18
Q
What are the three functions of the gingiva?
A
- Mechanical barrier
- Chemical barrier
- Microbial barrier
19
Q
What are the three divisions of the gingiva?
A
- Marginal gingiva
- Attached gingiva
- Interdental gingiva
20
Q
What division of the gingiva can be separated from the tooth surface using a probe?
A
Marginal gingiva
21
Q
What division of the gingiva forms the tissue wall of the gingival sulcus?
A
Marginal gingiva
22
Q
What structure separates attached gingiva and the marginal gingiva?
A
Free gingival groove (aka marginal groove)
23
Q
What are the two boundaries of the gingival sulcus?
A
- Tooth surface
- Free gingival epithelium
24
Q
What is a normal probing depth?
A
1-3 mm
25
What structure roughly correlates to the bottom of the gingival sulcus in most healthy gingiva?
Free gingival groove (aka marginal groove)
26
Where is the attached gingiva located?
Tightly attached to the periosteum of underlying alveolar bone
27
The facial aspect of the attached gingiva attaches to what structure?
Mucogingival junction
28
What does the mucogingival junction separate?
Attached gingiva from the alveolar mucosa
29
Is the alveolar mucosa made of keratinized or non-keratinized epithelium?
Non-keratinized
30
Is the free gingiva made of keratinized or non-keratinized epithelium?
Keratinized
31
Is the attached gingiva made of keratinized or non-keratinized epithelium?
Keratinized
32
Does the mucogingival junction remain stationary in adults?
Yes
33
Where is the interdental gingiva located?
Fills in the inter proximal spaces
34
What epithelium is the facial interdental papilla made of?
Keratinized stratified squamous epithelium
35
What epithelium is the lingual interdental papilla made of?
Keratinized stratified squamous epithelium
36
What epithelium is the col space of the interdental papilla made of?
Non-keratinized stratified squamous epithelium
37
The shape of the interdental gingival papillae correlates with what?
The shape of the teeth and embrasures
38
What can attach at the frenums?
- Muscles
- Connective tissue
39
Does the lamina propria contain blood vessels and nerves?
Yes
40
What layer does the masticatory mucosa lack?
Submucosa layer
41
What is the cell renewal time of the oral outer epithelium?
10 days
42
The oral outer epithelium is made out of...
Orthokeratinized and parakeratinized epithelium
43
The sulcular epithelium is made out of...
Non-keratinized epithelium
44
What does the lamina propria contain in the sulcular epithelium?
Gingival fiber bundles and loose connective tissue
45
The junctional epithelium is made out of...
Non-keratinized epithelium
46
What is the cell renewal time of the junctional epithelium?
4 days
47
Why is it important for the junctional epithelium to have a fast cell renewal time?
Important to heal quickly to keep the tooth attached to the gingiva
48
The junctional epithelium varies in length from...
0.25 to 1.35 mm
49
Cells of junctional epithelium immediately adjacent to the tooth are attached to the tooth surface by what two structures?
- Hemidesmosomes
- Internal basal lamina
50
Cells of the junctional epithelium adjacent to the lamina propria are attached by what structure?
External basal lamina
51
How many basal laminae does the junctional epithelium have?
2
52
Are the majority of epithelial cells of the gingiva keratinocytes, melanocytes, Merkel cells, or Langerhans cells?
Keratinocytes
53
What is the function of melanocytes?
Synthesis of melanin
54
What is the function of Merkel cells?
Tactile sensory
55
Where does mitosis of keratinocytes take place?
Basal layers of the epithelium
55
What is the function of Langerhans cells and lymphocytes?
Immune response
56
Where do "old" keratinocytes eventually go?
Migrate to the surface of the epithelium
57
When does differentiation of keratinocytes occur?
During cell migration
58
What does the differentiation of keratinocytes result in?
Keratinization
59
Starting where mitosis of keratinocytes occurs, what layers of the epithelium do they migrate through?
- Basal layer/stratum basale
- Prickle layer/stratum spinosum
- Granular layer/stratum granulosum
- Keratinized layer/stratum corneum
60
What structure do keratinocytes lose as they migrate towards the surface?
Nuclei
61
How quickly does keratinocyte cell renewal occur?
10 days
62
What is a desmosome?
Cell structure specialized for cell-to-cell adhesion
63
What is acantholysis?
Loss of intercellular attachments/desmosomes
64
What produces physical pigmentation?
Melanin from melanocytes
65
Where are melanocytes found?
Basal and prickle cell layers
66
What cells acquire antigens, transport to local lymph nodes, present to T-cells, and initiate immune response?
Langerhans cells
67
What are Merkel cells innervated by?
Mechanosensory neurons
68
What is the basement membrane?
Acellular layer between the epithelium and underlying connective tissue
69
What is the basement membrane made out of?
- Basal lamina
- Lamina reticularis
70
What is the basal lamina made out of?
- Lamina lucida
- Lamina densa
71
What is the primary cell in connective tissue?
Fibroblasts
72
What two layers of connective tissue is the lamina propria located in?
- Papillary layer
- Reticular layer
73
What 3 things is connective tissue composed of?
- Fibroblasts, 5%
- Collagen fibers, 60%
- Maxtix/blood vessels/nerves, 35%
74
What are the functions of gingival fibers?
- Holds marginal gingiva against tooth and prevents its deflection due to masticatory forces
- Connects marginal gingiva to cementum and to the attached gingiva
75
What are the four types of gingival fibers
- Gingivodental
- Circular
- Transseptal
- Alveologingival
76
What gingival fiber connects the gingiva to bone?
Alveologingival fibers
77
What is the supracrestal attached tissues defined as?
The dimension of the soft tissue which is attached to the portion of the tooth coronal to the crest bone
78
The supracrestal attached tissue is how many millimeters in a healthy periodontium?
2 mm
79
The apical coronal dimension of the supracrestal attached tissue is measured from the...
Coronal aspect of the junctional epithelium to the apical/base of the connective tissue attachment
80
What fluid is secreted from the gingival sulcus?
Gingival crevicular fluid
81
What is the composition of the gingival crevicular fluid?
Amino acids, plasma proteins, electrolytes, etc.
82
Is there a lot or a little gingival crevicular fluid in a healthy periodontium?
A little
83
Is the gingival crevicular fluid increased or decreased in inflamed gingiva?
Increased
84
What are six clinical features that sound be identified during a visual exam of the periodontal tissues?
- Color
- Consistency
- Contour and shape
- Surface texture
- Size
- Position
85
What color indicates a healthy periodontium?
Coral pink
86
What color indicates inflammation in the periodontium?
Red or magenta
87
What color indicates pathogenic lesions in the periodontium?
Bluish-red
88
What are two examples of endogenous pigmentation?
- Melanin
- Hemoglobin
89
What are three examples of exogenous pigmentation?
- Amalgam
- Lead (Burton's line)
- Bismuth
90
What is a normal consistency of the periodontium?
Firm and resilient
91
What does an edematous consistency of the periodontium indicate?
Inflammation, allergic reactions, etc.
92
What does a fibrotic consistency of the periodontium indicate?
Smoking
93
What is a normal contour and shape of the periodontium?
Knife-edge
94
What are three factors that the contour and shape of the periodontium can depend on?
- Shape of the teeth/alignment in arch
- Location and size of proximal contact
- Dimensions of the embrasures
95
Is stippling a sign of healthy or unhealthy gingiva?
Healthy
96
What part of the gingiva would be stippled?
Attached gingiva, not the marginal gingiva
97
Microscopically, what is stippling produced by?
Alternate rounded protuberances and depressions in the gingival surface
98
Is stippling less common on the lingual or facial surfaces?
Lingual
99
The size of the periodontium correlates to what?
Sum total of the bulk of cellular and intercellular elements and their vascular supply
100
In heathy patients, the gingival margin is position how many millimeters coronal to the CEJ?
2 mm
101
What is type 1 recession?
Gingival recession with no loss of inter proximal attachment
102
What is type 2 recession?
Interproximal attachment loss less than or equal to the buccal site
103
What is type 3 recession?
Interproximal attachment loss more than the buccal site
104
What is the alveolar process?
Part of the maxilla and mandible that forms and supports the tooth sockets
105
Does the alveolar bone disappear when a tooth is loss?
Yes
106
What are the three parts of the alveolar process?
- Cortical bone
- Alveolar bone proper
- Cancellous bone
107
What is the technical name for the inner wall of the tooth socket?
Alveolar bone proper
108
Does cancellous bone have more or less density? What is inside it?
- Less density
- Has lots of bone marrow
109
What is the external plate of the alveolar bone?
Cortical bone
110
What two things form cortical bone?
- Haversian bone
- Compacted bone lamellae
111
What type of bone forms the alveolar process?
Thin compact bone
112
What does the alveolar process contain to allow neuromuscular bundles link to the periodontal ligament with the cancellous bone?
Cribiform plate
113
Is the alveolar bone proper radiolucent or radiopaque?
Radiopaque
114
What is in the center of cancellous bone?
Trabecular bone
115
What is the basal bone?
Portion of the jaw located apically but unrelated to the teeth
116
Most of the facial and lingual portions of the sockets are what type of bone?
Compact bone
117
Cancellous bone surrounds the...
Lamina dura
118
What are the two main inorganic components of alveolar bone?
- Calcium
- Phosphate
119
What percentage of alveolar bone is inorganic vs organic?
- Two thirds inorganic
- One third organic
120
What is the main organic component of alveolar bone?
Type 1 collagen fibers
121
Does the number of osteoblasts increase or decrease with aging?
Decrease
122
What is the function of osteoblasts?
Build new bone
123
What are osteoblasts derived from?
Mesenchymal stem cells
124
What is the function of osteoclasts?
Eat or reabsorb bone
125
Where are osteoclasts derived from?
Monocytes or macrophages
126
Remodeling is the...
Bony changes in shape, resistance to forces, repair of wounds, and calcium and phosphate homeostasis
127
128
What are howship lacunae?
Eroded bone surfaced created by osteoclasts
129
What is an osteoid?
Bone matrix that is laid down by osteoblasts
130
How is alveolar bone formed during fetal growth?
Intramembranous ossification
131
What are the spaces that enclose osteocytes?
Lacunae
132
What processes do osteocytes extend into?
Canaliculi
133
Why are canaliculi essential?
Bring oxygen and nutrients
134
What is the bundle bone?
- Bone adjacent to the PDL and contains a great number of Sharpy fibers
- Has thin lamellae
135
The trabecular pattern of cancellous is affected by...
Occlusal forces
136
Where is cancellous bone found predominantly in the....
Interradicular and interdental spaces
137
What is the periosteum?
Tissue that covers the outer surface of bone
138
What is the endosteum?
Tissue that lines the internal bone cavities
139
What are the borders of the interdental septum?
- Socket wall cribriform plates
- Facial and lingual cortical plates
140
If the interdental space is narrow, then the septum may consist only of the...
Cribriform plate
141
If the interdental space is wide, then the septum consists of the..
Cribriform plate with cancellous bone in the middle
142
The mesiodistal angulation of the crest of the interdental septum usually parallels a line drawn between what structures?
The CEJ of approximating teeth
143
The distance between the crest of the bone and the CEJ should be between how many millimeters?
1-2 mm
144
What is osseous topography?
The bone contour normally conforms to the prominence of the roots, with innervating vertical depressions that taper towards the margin
145
Is the marginal bone intact in a fenestration?
Yes
146
Is the marginal bone intact in a dehiscence?
No
147
Are fenestrations and dehiscences more common of the facial or lingual bones?
Facial
148
Are fenestrations and dehiscences more common on the anterior or posterior?
Anterior
149
What are four predisposing factors for fenestrations and dehiscences?
- Prominent root contours
- Malpositioning
- Labial protrusion of the root
- Thin bony plate
150
the number, density, and alignment of cancellous trabeculae is influenced by what?
Forces exerted on the tooth
151
What is trauma from occlusion defined as?
Forces that exceed the adaptive capacity of the periodontium and produce injury
152
What is the PDL?
Complex vascular and highly cellular connective tissue that surrounds the tooth
153
What does the PDL connect?
The tooth to the inner wall of the alveolar bone
154
What are the main fibers of the PDL?
Principal fibers
155
What are principal fibers mainly composed of
- Type 1 collagen fibers, 80%
- Type 3 collagen fibers, 20%
156
What are Sharpey's fibers?
Terminal portions of principle fibers that are inserted into bone and cementum
157
Where are the interradicular principle fibers located?
In furcations
158
What do transseptal principle fibers connect?
One adjacent tooth to another
159
What are the most abundant type of principle fibers?
Oblique fibers
160
What is the difference between PDL fibers and gingival fibers?
Gingival fibers hold the marginal gingiva against the tooth
161
What is the function of alveolar crest PDL fibers?
Prevent the extrusion of the tooth and resist lateral tooth movements
162
Where do horizontal PDL fibers extend from?
Extend at right angles from the long axis of the tooth from the cementum to the alveolar bone
163
Where do oblique fibers extend from?
Cementum in a coronal direction obliquely to the bone
164
What PDL fibers bear the brunt of vertical masticatory stress?
Oblique fibers
165
What fibers are not present in incompletely formed roots?
Apical fibers
166
What are the three components of ground substance?
- Glycossaminoglycans (GAGs)
- Glycoproteins
- Water
167
What are two significant PDL functions?
- Transmission of occlusal forces to bone
- Resistance to the impact of occlusal forces/shock absorption
168
Is cementum vascular or avascular?
Avascular
169
Is cementum neural or aneural?
Aneural
170
What is the definition of cementum?
Calcified mesenchymal tissue that forms the outer covering of the anatomical root
171
What color is cementum?
Yellow, darker and less shiny
172
Is cementum harder or softer than dentin?
Cementum is softer than dentin
173
What are the three organic components of cementum?
- Extrinsic collagen fibers/Sharpey's fibers
- Intrinsic collagen fibers
- Interfibrillar ground substance
174
What are the two inorganic components of cementum?
- Hydrozyapatite
- Floride
175
What type of cementum does not contain cells?
Acellular cementum
176
What type of cementum contain cells?
Cellular cementum, contains cementocytes
177
When does acellular cementum form?
First to form, before the tooth reaches the occlusal plane
178
Acellular cementum is mainly composed of...
Sharpey's fibers
179
What type of cementum is formed after the tooth reaches the occlusal plane?
Cellular cementum
180
What does acellular cementum cover?
Cervical half of root
181
What does cellular cementum cover?
Apical third/half and furcation areas
182
Is cellular cementum more or less calcified?
Less calcified
183
Where do cementocytes reside at?
Lacunae
184
How do cemntocytes communicate with each other?
Through a system of anastomosing canaliculi
185
What is the cementodentinal junction?
Terminal apical area of the cementum where it joins the internal root canal dentin
186
What three ways can blood vessels reach the PDL space?
- Apical vessels
- Transalveolar vessels
- Gingival vessels
187
The deep cervical lymph nodes drain what areas?
- Palatal gingiva
- Tissue around 3rd molars
188
The submental lymph nodes drain tissues around what areas?
Mandibular incisors
189
The submandibular lymph nodes drain tissues around what areas?
All other areas besides the palatal gingiva, tissue near 3rd molars, and mandibular incisors
190
What nerve innervates the periodontium?
Trigeminal nerve
