Ten Cate's Oral histology - Development, Structure and function Flashcards
1
Q
According to Ten Cate’s Oral histology - Development, Structure and function, During which stage of development can the enamel organ be first identified?
A
Cap Stage
2
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What germ layer is the enamel organ derived from and what structure gives rise to it?
A
Ectoderm and dental lamina
3
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What is in the centre of the enamel organ?
A
The center of the enamel organ is termed the stellate reticulum.
4
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What is the enamel knot?
A
A group of non-dividing epithelial cells found in the cap stage of development within the stellate reticulum of molar teeth, may be important to developing the cusp pattern of molars, but unknown.
5
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What is morphodifferentiation? What phase of development does it occur during?
A
When the tooth crown assumes its final shape, bell stage
6
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What is the cervical loop?
A
Location where inner and outer enamel epithelium meet at the reflection of the epithelium
7
Q
According to Ten Cate’s Oral histology - Development, Structure and function, At what location of the enamel organ are cells dividing to give the tooth it’s full size?
A
Cervical loop
8
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What is the first layer of dentin laid down called?
A
Mantle dentin
9
Q
According to Ten Cate’s Oral histology - Development, Structure and function, Do ameloblasts make enamel first, or do odontoblasts make dentin first?
A
Odontoblasts, but ameloblasts secrete protein first, which may be inductive signal to odontoblasts
10
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What are the three components of the tooth germ?
A
Enamel organ, dental papilla, dental follicle
11
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What will the cells of the enamel organ produce, and eventually become?
A
Produce enamel (duh), many will be shed when tooth erupts but some will contribute to the junctional epithelium
12
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What will cells of the dental papilla eventually become, and what will they produce?
A
Eventually will become odontoblasts and cells of the pulp, produce dentin
13
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What will cells of the dental follicle become and what will they produce?
A
Cementoblasts, produce cementum, and PDL fibroblasts, produce and remodel PDL
14
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What is the purpose of hertwigs epithelial root sheath, what cells does it come from?
A
Epithelial cells that cause ectomesenchyme of the dental papilla to become root odontoblasts. Proliferation of the cervical loop of the enamel organ in an apical direction,
15
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What is the eventual fate of hertwigs epithelial root sheath?
A
Most of the root sheath breaks up, but leaves behind cell rests of mallasez
16
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What happens when hertwigs epithelial root sheath breaks up?
A
Cells of the dental follicle (sac) come into contact with the newly formed root dentin, causes them to differentiate into cementoblasts to begin forming cementum
17
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What is the chemical makeup of bone?
A
Organic 33% (mostly type I collagen) Inorganic (hydroxyapatite) 67%
18
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What is RANK, Where is it found?
A
receptor-activated nuclear factor κB, on osteoclasts and pre-osteoclasts. Membrane bound receptor
19
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What is RANKL, Where is it found?
A
receptor-activated nuclear factor κB Ligand, on Osteoblasts and pre-osteoblasts, membrane bound ligand for RANK (which is on the osteoclast)
20
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What is OPG, where is it found?
A
Soluble decoy ligand for RANK – binds to but does not activate RANK. Produced by osteoblasts and pre-osteoblasts
21
Q
According to Ten Cate’s Oral histology - Development, Structure and function, In bone homeostasis, what is a cutting cone?
A
A group of osteoclasts moving through bone and resorbing
22
Q
According to Ten Cate’s Oral histology - Development, Structure and function, In bone homeostasis what is a filling cone?
A
A group of new osteoblasts and pre-osteoblasts that are generating new bone along behind a group of osteoclasts
23
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What is the first layer laid down by osteoblasts during remodelling and what is it’s composition and purpose?
A
Cement or reversal line, non collagenous matrix proteins like bone sialoprotein and ostepontin. Acts as a cohesive, mineralized layer to stick new bone to old
24
Q
According to Ten Cate’s Oral histology - Development, Structure and function, What is the composition of enamel?
A
96% mineral and 4% organic material and water
25
According to Ten Cate's Oral histology - Development, Structure and function, What are the three phases of enamel production?
Pre-secretory
Secretory
Maturation
26
According to Ten Cate's Oral histology - Development, Structure and function, What is happening during the presecretory phase?
differentiating ameloblasts acquire their phenotype
change polarity
develop an extensive protein synthetic apparatus
prepare to secrete the organic matrix of enamel
27
According to Ten Cate's Oral histology - Development, Structure and function, What is happening during the secretory phase?
ameloblasts elaborate and organize the entire enamel thickness, resulting in the formation of a highly ordered, partially mineralized, tissue.
28
According to Ten Cate's Oral histology - Development, Structure and function, During which stage of tooth development does enamel form?
Bell stage
29
According to Ten Cate's Oral histology - Development, Structure and function, What is happening during the maturation phase?
ameloblasts "modulate" and transport specific ions required for accretion of mineral
30
According to Ten Cate's Oral histology - Development, Structure and function, What is different about the first layer of enamel produced?
Does not contain rods
31
According to Ten Cate's Oral histology - Development, Structure and function, What is the cytoplasmic extension of the ameloblast called?
Tome’s process NB Don’t confuse with Tomes Fibre – the odontoblast process
32
According to Ten Cate's Oral histology - Development, Structure and function, What is the difference between rod and interrod enamel?
Orientation of their crystals – chemically the same
33
According to Ten Cate's Oral histology - Development, Structure and function, Describe the formation of rod and interrod enamel?
Proximal portion of tomes process secretes enamel around the periphery of the process, which creates a pit in which tomes process resides. This creates the interrod enamel, which is continuous with that produced by adjacent ameloblasts.
Tomes process elongates as more interrod enamel is laid down, and the distal portion of the process makes enamel with crystals oriented in a different direction. This makes the rod.
As the rod grows it squishes the tip of the process out of existence and the thin space where it last was becomes filled with organic material to become the rod sheath. The ameloblast continues retreating as more enamel is laid down.
34
According to Ten Cate's Oral histology - Development, Structure and function, What is different about the last layer of enamel formed?
It has no rods.
35
According to Ten Cate's Oral histology - Development, Structure and function, What parts of enamel are thought to be continuous with one another?
Initial layer, interrod enamel and last layer – all deposited by the same proximal portion of Tomes process
36
According to Ten Cate's Oral histology - Development, Structure and function, When is enamel fully mineralized?
During the maturation phase
37
According to Ten Cate's Oral histology - Development, Structure and function, How much mineral is deposited initially when enamel is being laid down?
Approx 30%
38
According to Ten Cate's Oral histology - Development, Structure and function, When are most of the enamel proteins removed?
During the maturation phase
39
According to Ten Cate's Oral histology - Development, Structure and function, What is the mechanism for removing enamel protein?
Degradation by extracellular proteolytic enzymes and escape through leaky distal junctions of the smooth ended ameloblasts
40
According to Ten Cate's Oral histology - Development, Structure and function, What is modulation with respect to ameloblasts?
During the maturation phase of enamel secretion, they alternate back and forth between ruffle ended and smooth ended
41
According to Ten Cate's Oral histology - Development, Structure and function, Describe the cell:cell junctions of ameloblasts during modulation?
Smooth ended ameloblast – tight proximal junctions, leaky distal junctions Ruffle ended ameloblast – tight distal junctions, leaky proximal junctions
42
According to Ten Cate's Oral histology - Development, Structure and function, How does calcium get to the mineralizing enamel when the ameloblasts are in the ruffle ended morphology versus in the smooth ended morphology during modulation?
Ruffle ended ameloblasts - Goes through the ameloblast and secreted via the ruffles (this configuration has tight distal junctions); travels between ameloblasts in the smooth ended configuration (this configuration has leaky distal junctions)
43
According to Ten Cate's Oral histology - Development, Structure and function, What are Striae of Retzius?
Cause unknown, but they are horizontal dark bands in the enamel, usually seen on ground sections
44
According to Ten Cate's Oral histology - Development, Structure and function, What are hunter Schreger bands?
Optical phenomenon resulting in an appearance of alternating light and dark bands in enamel. Caused by different orientation of enamel rods
45
According to Ten Cate's Oral histology - Development, Structure and function, What are enamel tufts, what is their clinical significance?
Branching defects in the enamel beginning at the DEJ and radiating into the enamel, contain greater amount of enamel matrix protein No known clinical significance
46
According to Ten Cate's Oral histology - Development, Structure and function, What are enamel lamellae and how can they be distinguished from fractures?
Linear, longitudinally oriented defects in enamel, extending from the surface to a variable depth. Filled with organic material (this is how they are distinguished from fractures, as a fracture will not contain organic material.
47
According to Ten Cate's Oral histology - Development, Structure and function, What are enamel spindles?
Odontoblast processes that were sticking into the ameloblast layer when enamel formation began. Become trapped and become enamel spindles
48
According to Ten Cate's Oral histology - Development, Structure and function, What is the chemical composition of mature dentin?
Mature dentin is made up of approximately 70% inorganic material, 20% organic material and 10% of water. Most organic is type I collagen
49
According to Ten Cate's Oral histology - Development, Structure and function, During which stage of tooth development is dentin first produced in the crown?
Bell stage
50
According to Ten Cate's Oral histology - Development, Structure and function, Why is dentin production slightly later in the root than the crown?
Requires proliferation of hertwigs epithelial root sheath from the cervical loop first
51
According to Ten Cate's Oral histology - Development, Structure and function, What is predentin?
Dentin matrix which has been secreted but not yet mineralized, mineralization of dentin lags behind secretion of the matrix.
52
According to Ten Cate's Oral histology - Development, Structure and function, What is mantle dentin? What is different about it than primary or secondary dentin?
First dentin laid down by odontoblasts, and it is atubular and usually globular
53
According to Ten Cate's Oral histology - Development, Structure and function, What are Von Korff fibres?
distinct, large-diameter collagen fibrils which are the first sign of dentin formation
54
According to Ten Cate's Oral histology - Development, Structure and function, How does the initial mineralization begin in dentin?
Matrix vesicles are ruptured by growing crystals which fuse with other growing crystals to make the initial layer
55
According to Ten Cate's Oral histology - Development, Structure and function, What is a dead tract?
A dentinal tubule where the odontoblast has died and the process is gone, leaving an empty tunnel
56
According to Ten Cate's Oral histology - Development, Structure and function, What is peritubular dentin, what is different?
The layer of dentin surrounding the tubule space. It is more highly calcified than other types of dentin
57
According to Ten Cate's Oral histology - Development, Structure and function, What is sclerotic dentin?
Dentin where the tubules have become filled with calcified material
58
According to Ten Cate's Oral histology - Development, Structure and function, What is intertubular dentin?
Dentin located between the tubules
59
According to Ten Cate's Oral histology - Development, Structure and function, What is globular dentin?
Dentin that has arisen as a result of calcospheric deposition of dentin, as in the mantle dentin, which forms from matrix vesicles
60
According to Ten Cate's Oral histology - Development, Structure and function, What is the granular layer of Tomes?
A layer that appears between the root dentin and cementum that can only be seen on ground sections under transmitted light. May represent a special arrangement of collagen and non collagen proteins in this area.
61
According to Ten Cate's Oral histology - Development, Structure and function, What is interglobular dentin?
Areas of unmineralized and hypomineralized dentin in between areas of globular dentin. Usually seen in mantle dentin or circumpulpal dentin near the mantle dentin.
62
According to Ten Cate's Oral histology - Development, Structure and function, What are the 4 zones of the pulp?
(1) the odontoblastic zone at the pulp periphery;
(2) a cell-free zone of Weil beneath the odontoblasts, which is prominent in the coronal pulp;
(3) a cell-rich zone, where density is high, which again is seen easily in coronal pulp adjacent to the cell-free zone;
(4) the pulp core, which is characterized by the major vessels and nerves of the pulp
63
According to Ten Cate's Oral histology - Development, Structure and function, Which cells are most numerous in the pulp?
Fibroblasts
64
According to Ten Cate's Oral histology - Development, Structure and function, What is the subodontoblastic plexus of Raschkow?
Extensive plexus of nerves in the cell free zone, composed of sensory fibres
65
According to Ten Cate's Oral histology - Development, Structure and function, What are the major nervous components that enter the apical foramina?
Sympathetic branches from the superior cervical ganglion (provide autonomic control of blood vessels) sensory branches of CN V
66
According to Ten Cate's Oral histology - Development, Structure and function, What are the three theories of dentin sensitivity?
1) The dentin contains nerve endings that respond when it is stimulated,
(2) the odontoblasts serve as receptors and are coupled to nerves in the pulp,
(3) the tubular nature of dentin permits fluid movement to occur within the tubule when a stimulus is applied, a movement registered by pulpal free nerve endings close to the odontoblast
67
# According to Ten Cate's Oral histology - Development, Structure and function,
What is they type of joint that supports the tooth?
Gomphosis
68
# According to Ten Cate's Oral histology - Development, Structure and function,
What are the components of the periodontium
Alveolar bone, gingiva cementum, PDL
69
# According to Ten Cate's Oral histology - Development, Structure and function,
What is the chemical composition of cementum?
45-50% hydroxyapatite, 50-55% organic, (90% Type I collagen)
70
# According to Ten Cate's Oral histology - Development, Structure and function,
What is the difference between cellular and acellular cementum? Where is each found?
Acellular cementum has no cementocytes in lacunae, cellular cementum has cementocytes in lacunae, acellular cementum found more coronally and acellular cementum found more apically
71
# According to Ten Cate's Oral histology - Development, Structure and function,
What is the difference between intrinsic fibre cementum and extrinsic fibre cementum?
Intrinsic fibre cementum has colalgen produced by cementoblasts arranged parallel to the root surface. Since fibres made by cementoblasts they are 'intrinsic' to the cementum. Extrinsic fibre cementum has no discernable fibres made by cementoblats, only fibres are the PDL fibres entering the cementum made by PDL fibroblasts, or 'extrinsic' to the cementum.
72
# According to Ten Cate's Oral histology - Development, Structure and function,
What 3 histological configurations are there for the CEJ?
butt joint where enamel and cementum abut, overlap, where a small amount of acellular afibrillar cementum overlaps the enamel, gap where there is a small amount of exposed dentin because cementum terminates apical to enamel.
73
# According to Ten Cate's Oral histology - Development, Structure and function,
What is the alveolar process?
the bone of the jaws that contains the tooth sockets
74
# According to Ten Cate's Oral histology - Development, Structure and function,
What is bundle bone?
the inner aspect of the alveolus, where PDL fibres are embedded
75
# According to Ten Cate's Oral histology - Development, Structure and function,
What are the predominant collagen types in PDL fibres?
I, III, XII
76
# According to Ten Cate's Oral histology - Development, Structure and function,
What are principle fibre bundles?
Spliced ropes of collagen that run from the tooth to the bone
77
# According to Ten Cate's Oral histology - Development, Structure and function,
Where does the alveolar crest group attach?
attached to the cementum just below the cementoenamel junction and running downward and outward to insert into the rim of the alveolus
78
# According to Ten Cate's Oral histology - Development, Structure and function,
Where do the horizontal group of fibres attach?
horizontal group, just apical to the alveolar crest group and running at right angles to the long axis of the tooth from cementum to bone just below the alveolar crest
79
# According to Ten Cate's Oral histology - Development, Structure and function,
Where do oblique fibres run?
by far the most numerous in the PDL and running from the cementum in an oblique direction to insert into bone coronally
80
# According to Ten Cate's Oral histology - Development, Structure and function,
Where do the apical group of fibres run?
radiating from the cementum around the apex of the root to the bone, forming the base of the socket
81
# According to Ten Cate's Oral histology - Development, Structure and function,
Where do the interradicular fibres run?
found only between the roots of multirooted teeth and running from the cementum into the bone, forming the crest of the interradicular septum
82
# According to Ten Cate's Oral histology - Development, Structure and function,
What are Sharpies fibres?
mineralized embedded portions of PDL fibres
83
# According to Ten Cate's Oral histology - Development, Structure and function,
Where do all principle fibres of the PDL span?
All the way from bone to cementum
84
# According to Ten Cate's Oral histology - Development, Structure and function,
Where does the dentogingival group of fibres run?
These are the most numerous fibers, extending from cervical cementum to lamina propria of the free and attached gingivae
85
# According to Ten Cate's Oral histology - Development, Structure and function,
Where do the alveologingival fibres run?
These fibers radiate from the bone of the alveolar crest and extend into the lamina propria of the free and attached gingivae
86
# According to Ten Cate's Oral histology - Development, Structure and function,
Where do the circular fibres run?
This small group of fibers forms a band around the neck of the tooth, interlacing with other groups of fibers in the free gingiva and helping to bind the free gingiva to the tooth
87
# According to Ten Cate's Oral histology - Development, Structure and function,
Where do the dentoperiosteal fibres run?
Running apically from the cementum over the periosteum of the outer cortical plates of the alveolar process, these fibers insert into the alveolar process or the vestibular muscle and floor of the mouth
88
# According to Ten Cate's Oral histology - Development, Structure and function,
Where do transseptal fibres run?
These fibers run interdentally from the cementum just apical to the base of the junctional epithelium of one tooth over the alveolar crest and insert into a comparable region of the cementum of the adjacent tooth. Together these fibers constitute the transseptal fiber system, collectively forming an interdental ligament connecting all the teeth of the arch
89
# According to Ten Cate's Oral histology - Development, Structure and function,
What are the three phases of eruptive movement?
Pre-eruptive, eruptive and post-eruptive
90
# According to Ten Cate's Oral histology - Development, Structure and function,
What is the pre-eruptive stage?
Made by the deciduous and permanent tooth germs within tissues of the jaw before they begin to erupt.
91
# According to Ten Cate's Oral histology - Development, Structure and function,
What is eruptive tooth movement?
Made by a tooth to move from its position within the bone of the jaw to its functional position in occlusion. This phase sometimes is subdivided into intraosseous and extraosseous components.
92
# According to Ten Cate's Oral histology - Development, Structure and function,
What is post-eruptive tooth movement?
Maintaining the position of the erupted tooth in occlusion while the jaws continue to grow and compensate for occlusal and proximal tooth wear.
93
# According to Ten Cate's Oral histology - Development, Structure and function,
on which aspect of the deciduous tooth buds do the permanent buds develop?
lingual
94
# According to Ten Cate's Oral histology - Development, Structure and function,
What is the gubernacular cord?
remnant of the dental lamina that connects the successional tooth to the oral lamina propria
95
# According to Ten Cate's Oral histology - Development, Structure and function,
During orthodontic tooth movement, what is hyalinization?
In the PDL area under compression, the loss of cells from an area of ligament because of trauma/pressure
96
# According to Ten Cate's Oral histology - Development, Structure and function,
What process during orthodontic tooth movement allows movement to continue and resolves hyalinization?
Arrival of new cells which remodel the previous tissue, (osteoclasts and fibroblasts)
97
# According to Ten Cate's Oral histology - Development, Structure and function,
What is undermining resorption in orthodontic movement?
Remodelling of bone from the endosteal surface
98
# According to Ten Cate's Oral histology - Development, Structure and function,
What are the rete pegs?
interdigitations between the oral epithelium and the underlying lamina propria. Most pronounced in the attached gingiva
99
# According to Ten Cate's Oral histology - Development, Structure and function,
What is the epithelial turnover time in the gingiva? In the cheek?
epithelial turnover time is 41-57 days in the gingiva, 25 days in the cheek
100
# According to Ten Cate's Oral histology - Development, Structure and function,
What regions of oral mucosa are keratinized?\>
Gingiva, hard palate, some parts of the dorsal surface of the tongue
101
# According to Ten Cate's Oral histology - Development, Structure and function,
List the epithelial layers in the keratinized oral mucosa from the bottom up?
Basal, prickle/spinosum, granular, keratinized
102
# According to Ten Cate's Oral histology - Development, Structure and function,
What is parakeratinization?
When the superficial layer of epithelium maintains pyknotic nuclei
103
# According to Ten Cate's Oral histology - Development, Structure and function,
What regions of oral mucosa are non-keratinized?
lining mucosa: lips, buccal mucosa, alveolar mucosa, underside of the tongue and soft palate
104
# According to Ten Cate's Oral histology - Development, Structure and function,
Aside from keratinocytes, wht other cells are commonly found in oral epithelium?
pigment-producing cells (melanocytes), Langerhans cells, merkel cells, and inflammatory cells (e.g., lymphocytes), that together make up as much as 10% of the cell population in the oral epithelium
105
# According to Ten Cate's Oral histology - Development, Structure and function,
What are langerhans cells?
likely have an immunologic function, processing antigen in the epithelium and presenting it to T lymphocytes
106
# According to Ten Cate's Oral histology - Development, Structure and function,
What are Merkel cells?
probably touch receptors in the epithelium, closely associated with nerve fibres
107
# According to Ten Cate's Oral histology - Development, Structure and function,
What is the mechanism of gingival overgrowth in response to drugs like cyclosporine and amlodipine?
Fibroblasts of the lamina propria are overactive, and secrete more ground substance than is normal.
108
# According to Ten Cate's Oral histology - Development, Structure and function,
What (sensory nerves) innervates the hard palate?
greater, lesser and sphenopalatine nerves
109
# According to Ten Cate's Oral histology - Development, Structure and function,
What (Sensory nerves) innervates the soft palate?
lesser palatine nerve, tonsillar branch of glossopharyngeal
110
# According to Ten Cate's Oral histology - Development, Structure and function,
What sensory nerves are responsible for taste innervation in the rostral 2/3 of the tongue?
lingual branch of the mandibuar nerve carries fibres, but they originate in the facial nerve and pass via chorda tympani to the lingual nerve
111
# According to Ten Cate's Oral histology - Development, Structure and function,
What is responsible for taste and general sensation in the caudal 1/3 of the tongue?
glossopharyngeal nerve
112
# According to Ten Cate's Oral histology - Development, Structure and function,
Which tongue papillae contain taste buds?
fungiform, foliate, circumvallate, NOT Filiform
113
# According to Ten Cate's Oral histology - Development, Structure and function,
Why do different sections of the tongue have different innervation?
Rostral 2/3 derived from the first pharyngeal arch, caudal third derived from the third pharyngeal arch
114
According to Ten Cate's Oral histology - Development, Structure and function,
Name the PDL fibre bundles shown here
Apical group
oblique group
horizontal group
alveolar crest group
interradicular group
(Transseptal group - doesn't attach to bone, but shown here)
115
According to Ten Cate's Oral histology - Development, Structure and function,
Name the gingival fibre bundles shown here:
Dentogingival group
dentoperiosteal group
alveologingival group
circular group
(Transseptal not shown)
116
According to Ten Cate's Oral histology - Development, Structure and function,
Name the gingival fibres show here, from the vantage between teeth:
Circular fibres,
dentogingival,
alveologingival
Dentoperiosteal
(Transeptal not shown)
