2.
What kind of papilla is pictured?
Correct Answer
A. Circumvalate
Explanation
Section of circumvallate papilla (A). Serous glands (B) of von Ebner empty via ducts
into the base of the trench (C) surrounding the papilla, which is not raised above the surface
of the tongue. D = muscle of tongue.
3.
This photo is of an erupting tooth, with "C" and "B" fusing to make an epithelium lined pathway for the tooth. "D" is depicting enamel space.
Explanation
An erupting tooth (A) about to emerge into the oral cavity through an
epithelium-lined pathway as a result of fusion of the oral epithelium (B) and the reduced
enamel epithelium (C) D = enamel space
4.
True or false, this image is of keratinized epithelium of the soft palate
Correct Answer
false
Explanation
Section of the masticatory keratinized epithelium (A) of the hard palate. Note the
highly folded interface with the lamina propria (B).
5.
What kind of taste bud is pictured?
Correct Answer
A. Filliform
Explanation
Section showing dorsum of anterior two-thirds of tongue covered by keratinized
filiform papillae (A) with non-keratinized regions between (B)
6.
What kind of papilla is pictured?
Correct Answer
A. Foliate
Explanation
Section of foliate papilla showing taste buds (arrowed). Note the adjacent
lymphoid material characteristic of the posterior part of the tongue.
7.
What is enamel formation refferred to as?
Correct Answer
amelogenesis
Explanation
Enamel formation is referred to as amelogenesis. This term specifically describes the process by which enamel, the hard outer layer of the teeth, is produced and developed. During amelogenesis, specialized cells called ameloblasts secrete enamel matrix, which is composed of various proteins and minerals. This matrix then undergoes mineralization and hardening to form the durable and protective enamel layer. Understanding amelogenesis is crucial in studying tooth development, dental health, and potential treatments for enamel-related disorders.
8.
This photo depicts lining epithelium of the oral mucosa. Is there keratin present in this photo?
Correct Answer
no
Explanation
-Non keratinized epithelium , Lack of keratohylaine granules , Absence of filaggrin , less developed and dispersed tonofilaments present in lining epithelium.
-The outer layers are usually termed the intermediate (stratum intermedium) and superficial (stratum superficiale) layers.
9.
What transitionary structure is pictured?
Correct Answer
enamel knot
Explanation
– Localized mass of cells in the
centre of the internal enamel
epithelium.
– Forms a bulge into the dental
papilla, at the centre of the
enamel organ.
– It might play a role in the
formation of crown pattern
by outlining the central
fissure. However, it soon
disappears and seems to
contribute cells to the enamel
cord .
– The disappearance of the
enamel knot by the bell stage
may be associated with
apoptosis.
10.
This photo is showing interdental gingiva. "B" is showing the alveolar crest
Explanation
Demineralized section showing the interdental gingiva (A) between two cheek teeth
in the anteroposterior plane. B = alveolar crest; C = transseptal group of gingival fibres
11.
The periodontium is made up of specialized tissues that support and surround the teeth and
include the gingiva, alveolar mucosa, cementum, bone and periodontal ligament
Explanation
The periodontium refers to a group of tissues that provide support and protection to the teeth. These tissues include the gingiva (gums), alveolar mucosa (lining of the mouth), cementum (covering of the tooth root), bone, and periodontal ligament (connective tissue that attaches the tooth to the bone). Therefore, the statement that the periodontium is made up of these specialized tissues is true.
12.
This photo is picturing the vermillion "red-zone" of the lip
Explanation
Section of red zone of lip. A = keratinized epithelium; B = lamina propria. Note the
folded interface between epithelium and lamina propria bringing blood vessels (C) close to
the surface.
13.
What type of enamel prism structure is this?
Correct Answer
keyhole
Explanation
The three prism patterns seen in human enamel. In pattern I enamel the prisms
are circular. In pattern II enamel the prisms are aligned in parallel rows. In pattern III
enamel the prisms are arranged in staggered rows such that the tail of a prism lies between
two heads in the next row, giving a keyhole appearance.
14.
The Enamel Organ consists of 4 distinct layers. Which of these layers actually forms the enamel?
Correct Answer
A. Internal Enamel Epithelium
Explanation
Enamel organ shows four distinct layers:
- External enamel epithelium
- Stellate reticulum
- Stratum intermedium
- Internal enamel epithelium (forms enamel
whereas the first three layers provide support
to the developing tooth)
15.
What is the line pointing to in this image of a deciduous tooth?
Correct Answer
neonatal line
Explanation
The line in the image is pointing to the neonatal line. The neonatal line is a distinct line that forms in the enamel of deciduous teeth during the birth and early infancy period. It represents a temporary interruption in enamel formation and can be used to determine the age at which a tooth was formed.
16.
What kind of papilla is pictured?
Correct Answer
A. Fungiform
Explanation
Section of fungiform papilla on dorsal surface of anterior part of tongue
showing taste buds (arrowed). The papilla is keratinized (H & E; ×120). (b) High-power view
of surface of fungiform papilla seen in (a), showing taste buds (arrows) (×240).
17.
The submucosa layer consists of very tight connective tissue containing fat deposits and glands. Larger nerves and blood vessels also run through the submucosa.
Explanation
The submucosa layer consists of loose connective tissue containing fat deposits and glands. Larger nerves and blood vessels also run through the submucosa.
18.
What transitionary structure is pictured?
Correct Answer
enamel niche
Explanation
The enamel niche is seen
where the tooth germ
appears to have a double
attachment to the dental
lamina (the lateral and
medial enamel strands).
These strands enclose the
enamel niche, which
appears as a funnel-shaped
depression containing
connective tissue.
– The functional significance
of the enamel niche is
unknown.
Fig 21.21: The enamel niche (C). A = lateral
enamel strand; B = medial enamel strand
19.
What is "A"?
Correct Answer
cementum
Explanation
Cementum is a hard, mineralized tissue that covers the root surface of teeth. It provides support and attachment for the periodontal ligament, which connects the tooth to the surrounding bone. Cementum helps to anchor the tooth in its socket and protects the underlying dentin. It is an essential component of the periodontium and plays a crucial role in maintaining the stability and health of the teeth.
20.
The stages in tooth development consists of 1) Initiation, 2) Morphogenesis, 3) Histogenesis
Explanation
Initiation- the sites of the future teeth are established,
appearance of tooth germs along an invagination of the
oral epithelium called the dental lamina.
• Morphogenesis- the shape of the tooth is determined by a
combination of cell proliferation and cell movement.
• Histogenesis- differentiation of cells (begun during
morphogenesis) proceeds to give rise to the fully formed
dental tissues, both mineralized (i.e. enamel, dentine and
cementum) and unmineralized (i.e. dental pulp and
periodontium)
21.
What transitionary structure is pictured?
Correct Answer
enamel cord
Explanation
Strand of cells seen at the
early bell stage of
development extending from
the stratum intermedium into
the stellate reticulum.
– It overlies the incisal margin
of a tooth or the apex of the
first cusp to develop (primary
cusp).
– may be involved in the
process by which the cap
stage is transformed into the
bell stage (acting as a
mechanical tie) or that it is a
focus for the origin of stellate
reticulum cells.
Fig 21.20: The enamel cord (A). B = enamel navel
22.
Which of the following is not a type of oral mucosa?
Correct Answer
A. Keratinized
Explanation
Within the oral cavity about 60% of the mucosa is lining mucosa, about 25% of the mucosa is masticatory mucosa and the
remaining 15% specialized mucosa.
Masticatory mucosa is found where there is high
compression and friction, and is characterized by a
keratinized epithelium and a thick lamina propria. Eg :
gingiva and palate
• Lining mucosa is not subject to high levels of friction but
must be mobile and distensible. It is thus non-keratinized
and has a loose lamina propria. Within the lamina
propria, the collagen fibres are arranged as a network to
allow free movement, and the elastic fibres allow recoil to
prevent the mucosa being chewed. Commonly, lining
mucosa also has a submucosa. The lips, cheeks, alveolus,
floor of the mouth, ventral surface of the tongue and soft
palate have a lining mucosa.
• Specialized mucosa : the specialized gustatory mucosa of
the dorsum of the tongue and where the vermilion zone
forms a transition between the skin and the oral mucosa.
23.
The Transitionary Structures are which of the following
Correct Answer(s)
A. Enamel knot
A. Enamel cord
A. Enamel niche
Explanation
The transitionary structures mentioned in the answer are all related to the development of enamel in teeth. Enamel knot, enamel cord, and enamel niche are all structures that form during tooth development and play a role in enamel formation. These structures are involved in the differentiation and organization of the cells that produce enamel. Therefore, they are considered transitionary structures in the process of enamel development.
24.
What is the following SEM image depicting?
Correct Answer
A. Hunter-Schreger bands
Explanation
)
* Up to 100μm apart towards the cusp of the tooth
25.
What is "A" in the Photo
Correct Answer
Mucous cell
Explanation
elongated, cuboidal shape with flat nucleus
26.
What is this picture depicting represented by "A"?
Correct Answer
tertiary dentine
Explanation
A variety of outside stimuli including
caries, attrition, cavity preparation,
microleakage around restorations and
trauma lead to formation of tertiary
dentine.
• It may resemble secondary dentine in
having a regular tubular structure; it
may have few and/or irregularly
arranged tubules; or it may be
relatively atubular.
• Also called irregular secondary
dentine, reparative dentine,
reactionary dentine, response dentine
and osteodentine.
27.
This image was taken during the 7th week of development. What is "A"?
Correct Answer
vestibular lamina
Explanation
The vestibular lamina (A) and dental lamina (B) seen at the 7th week of intra-uterine life.
the primary epithelial band divides into two processes: a
buccally located vestibular lamina and a lingually situated dental
lamina.
• The vestibular lamina contributes to the development of the vestibule
of the mouth, delineating the lips and cheeks from the tooth-bearing
regions. Cells of the vestibular lamina proliferate, with subsequent
degeneration of the central epithelial cells to produce the sulcus of
the vestibule.
28.
What are the 4 tissues that support the tooth in the jaw?
Correct Answer(s)
A. Cementum
A. Periodontal ligament
A. Alveolar bone
A. Gingiva
Explanation
The tooth is supported in the jaw by four tissues: cementum, periodontal ligament, alveolar bone, and gingiva. Cementum is a hard tissue that covers the root of the tooth, providing attachment to the periodontal ligament. The periodontal ligament is a connective tissue that connects the tooth to the alveolar bone. The alveolar bone is the bone that surrounds and supports the tooth socket. Lastly, the gingiva, also known as the gum tissue, surrounds the tooth and provides protection. These four tissues work together to support the tooth in the jaw.
29.
When this happens to enamel, it is called?
Correct Answer(s)
gnarled enamel
Explanation
When enamel becomes rough, uneven, and twisted, it is referred to as gnarled enamel. This condition can occur due to various factors such as genetics, poor oral hygiene, excessive consumption of acidic foods or drinks, or certain medical conditions. Gnarled enamel can make the teeth more susceptible to tooth decay and other dental problems. Regular dental care and proper oral hygiene practices are essential to maintain healthy enamel and prevent the development of gnarled enamel.
30.
The Late Bell stage is associated with the formation of hard dental tissues during Week 15
31.
What kind of cells are the arrows pointing at?
Correct Answer
myoepithelial
myoepithelial cells
Explanation
Lie between basal lamina and basal membranes of acini cells and duct cells.
• Dendritic cells with stellate shaped body,
• Also present in intercalated ducts.
• Have parasympatheic and sympatheitc
stimulation.
• Functions include: supporting parenchyma,
increasing initial flow of saliva, contributing to
secretory pressure and reducing luminal flow
32.
What is the following SEM image depicting?
Correct Answer
A. Perikymata grooves / ridges
Explanation
)
* Up to 100μm apart towards the cusp of the tooth
33.
What is this condition called?
Correct Answer
dentinogenesis imperfecta
Explanation
teeth are malformed and dark due to absence of pulp chambers (explains translucency). Enamel is weak and flakes off as it is only weakly attached to the dentine. Enamel from first molars is lost in photo
34.
What is this picture showing?
Correct Answer
enamel spindle
Explanation
Narrow (up to 8 μm in diameter, and extend up to 25 μm
into the enamel
* Common beneath cusps
* Result of some odontoblast processes
35.
What is the arrow pointing to in this image?
Correct Answer
enamel lamellae
Explanation
* Sheet-like, structural faults
* Hypomineralised, narrower, longer and less common than enamel tufts
* May arise developmentally due to incomplete maturation of groups of prisms
36.
In this photo of a resorbing tooth, what are the arrows pointing to?
Correct Answer
odontoclasts
Explanation
Buccolingual section through a resorbing deciduous tooth (A) and its erupting
successor (B). Arrows indicate multinucleated odontoclasts
Resorption of the hard tissues of the deciduous tooth
takes place by the activity of multinucleated osteoclastlike cells termed odontoclasts. The vascular, resorbing
tissue has been termed the resorbing organ of Tomes.
• Odontoclasts lie within resorption lacunae (Howship's
lacunae). Odontoclasts, like osteoclasts, differentiate
from circulating monocyte-like cells. They are
vacuolated and have long cytoplasmic processes, an
abundance of ribosomes and a large number of
mitochondria. Howship's lacunae in resorbing teeth
tend to be larger and more spherical than lacunae in
bone.
37.
This photo is of attached gingiva, what are the arrows indicating?
Correct Answer
stippling
Explanation
Section of the attached gingiva. The epithelium is a keratinized stratified squamous
epithelium. The lamina propria is dense and relatively avascular and the interface with the
epithelium is highly folded. The lamina propria is directly attached to the underlying alveolar
bone (A), forming a mucoperiosteum. Arrows indicate surface stippling.
38.
This is a developing root, what is "B"?
Correct Answer
dental papilla
Explanation
The developing root. A =epithelial root sheath, B= dental papilla; C = primary
apical foramen; D = dental follicle; E = developing root dentine; F = odontoblast layer
39.
What is this condition refferred to as?
Correct Answer
amelogenesis imperfecta
Explanation
front teeth have normal appearance, molars have had most of the enamel stripped exposing dentine. Restorations can usually help the dentition ie. crowns.
40.
What is "A" and what is "B"? (separate answers w/ comma)
Correct Answer
acellular cementum, cellular cementum
Explanation
The distribution of acellular (A) and cellular (B) cementum.
Cellular cementum has cells (cementocytes),acellular cementum does not.
– Acellular cementum covers the root adjacent to the dentine, whereas
cellular cementum is found mainly in the apical area and overlying the
acellular cementum. Being formed first, the acellular cementum is
sometimes termed primary cementum and the subsequently formed
cellular variety secondary cementum. Common in interradicular areas.
– Many of the structural differences between cellular and
acellular cementum are thought to be related to the
faster rate of matrix formation for cellular cementum
41.
This photo is depicting orthokeratinized oral epithelium characterized by the presence of small and shrunken nuclei.
Explanation
In some areas such as the gingiva the nuclei may be retained, although small and shrunken. These cells are described as parakeratinized (in contrast to the more usual orthokeratinized cells without nuclei)
42.
This photo was taken during the 6th week of development. What is the arrow point to?
Correct Answer
primary epithelial band
Explanation
Oral epithelium thickens
and invaginates into the
mesenchyme to form a
primary epithelial band.
• The first sign of tooth
development is the
condensation of
mesenchymal tissue which
are ectomesenchymal
(neural crest) in origin,
having migrated into the
jaws from the margins of
the neural tube.
43.
What stage of morphodifferentiation is this image?
Correct Answer
cap stage
Explanation
Early cap stage of tooth development (arrows). A = Meckel's cartilage; B = developing tongue
11th week
morphogenesis- the
deeper surface of the
enamel organ
invaginating to form a
cap-shaped structure.
• Poorly
histodifferentiated.
• External and internal
dental epithelium
forming.
44.
What is "B" in this photo?
Correct Answer
secondary dentine
Explanation
Change in direction of tubules bw
primary and secondary dentine.
• The same odontoblasts continue to
lay down dentine and the tubules of
primary and secondary dentine are
continuous.
• Secondary dentine formation begins
at the completion of root formation
as the tooth comes into occlusion.
• Secondary dentine formation
continues throughout life leading to
smaller pulp chambers and narrower
root canals in older patients.
45.
What is this picture showing? What is represented by "B' (separate answer with a comma)
Correct Answer
oral mucosa, lamina propria
Explanation
• Lining of the oral cavity
• Epithelium with an
underlying connective
tissue (the lamina
propria).
• Third layer (the
submucosa) is found
between the lamina
propria and the
underlying bone (palate)
or muscle (cheeks and
lips).
2 LAMINA PROPRIA LAYERS =
Superficial, papillary layer between the
epithelial ridges, in which the collagen fibres are thin
and loosely arranged.
-Deep, reticular layer dominated by thick,
parallel bundles of collagen fibres.
Section showing regions of oral mucosa. A = stratified squamous epithelium; B =
lamina propria; C = submucosa; D = bone
46.
What layer is this?
Correct Answer
prickle cell layer
Explanation
Characterized by desmosomes between cells that look 'prickly"
47.
What is "B" in this photo?
Correct Answer
periodontal ligament
Explanation
Fig 11.21: Attachment of the periodontal ligament fibres to cementum. The fibres of the periodontal
ligament (B) are seen to run into the organic matrix of precementum (A)
In the teeth, Sharpey's fibres are
the terminal ends of principal fibres
(of the periodontal ligament) that
insert into the cementum and into
the periosteum of the alveolar
bone
48.
What is being show in this picture?
Correct Answer
sclerotic dentine
Explanation
Dentinal tubules fill in
due to age, external
stimuli (caries,
attrition).
• Type of dentine that
lacks structure and
appear transparent.
49.
This image is occurring during dentine mineralization, what are the arrows pointing to?
Correct Answer
interglobular dentine
Explanation
Dentine mineraliztion -starts
as globules or calcospherites
which fuse to form a
uniformly calcified tissue.
– Sometimes the fusion may be
incomplete and viewed in
transmitted light, the
uncalcified, interglobular
areas appear dark.
– Dentinal tubules pass through
interglobular areas and since
these areas remain
uncalcified, peritubular
dentine is also absent from
the tubules as they pass
through interglobular
dentine