DH227 Board Review
Oral Histology & Embryology
LISA MAYO, RDH, BSDH
CONCORDE CAREER COLLEGE
General Embryology
 23 chromosomes in each germ cell (haploid)
 46 chromosomes after fertilization (diploid)
 Zygote: mitotic divisions
1.
Morula
2.
Blastocele
3.
Blastocyst
 3 periods of development
1.
Period of ovum (1st week)
2.
Embryonic Period (2-8 weeks): most congenital
malformations occur
3.
Fetal Period (3-9mo)
Gen Embryology
 Facial & Oral structures dependent on grp of neural
crest cells derived from ectoderm as neural tube
develops




Facial skeleton: Meckel’s cartilage
Neck skeleton: hyoid bone
Connective tissue components
Tooth development
Gen Embryology
 Neural crest cells migrate into each brachial arches
and surrounds existing mesoderm
1.
2.
3.
4.
Cartilage rod: 1st brachial arch
Muscular component: 2nd, facial muscles
Vasculature component
Nerve component: 1st, trigeminal nerve
 Internal brachial arches – corresponding pharyngeal
pouches that give rise to
1.
2.
3.
4.
External auditory meatus
Pharyngotympanic tube
Palatine tonsils
Parathyroid glands
5 Brachial Arches
 Five Pharyngeal (Branchial) arches develop
below the oral pit
 Each pharyngeal arch is associated with a
specific Cranial Nerve



1st Pharyngeal Arch: Mandibular
2nd Pharyngeal Arch: Hyoid
3rd, 4th, and 5th Pharyngeal Arches are located respectively
below the other two arches and are separated down the
middle by the pericardial cavity (heart).
Developing Pharyngeal Arches
3½
Weeks
Pharyngeal (Branchial) Arches
 The cores of these arches will
differentiate into the blood vessels,
muscles, nerves, cartilages, and
bones that will form the human face
Mandibular Arch: (1st Pharyngeal Arch)
Gives
rise to the Maxillary Process
which forms the cheeks
Eventually forms the:
Mandible
Muscles of Mastication
Innervated
by V Cranial Nerve
(Trigeminal Nerve)
Hyoid: 2nd Pharyngeal Arch)
Forms
the:
Facial muscles
Vessels
Hyoid bone
Innervated by the VII Cranial Nerve
(Facial Nerve)
3rd and 4th Pharyngeal Arches
 Become the constrictor muscles of
the throat
 Innervated by other Cranial Nerves
of the muscles of the neck
Question
 Which of the following tissues derive from
ectoderm?
a.
b.
c.
d.
Bone
Nervous tissue
Dentin and pulp
Chewing muscles
Answer
 Which of the following tissues derive from
ectoderm?
a.
b.
c.
d.
Bone
Nervous tissue
Dentin and pulp
Chewing muscles
NBQ
The first brachial arch gives rise to the mandible,
and it innervated by the trigeminal nerve
a.
b.
c.
d.
Both statement are TRUE
Both statements are FALSE
The first statement is TRUE, the second statement is
FALSE
The first statement is FALSE, the second statement is
TRUE
NBQ
The first brachial arch gives rise to the mandible,
and it innervated by the trigeminal nerve
a.
b.
c.
d.
Both statement are TRUE
Both statements are FALSE
The first statement is TRUE, the second statement is
FALSE
The first statement is FALSE, the second statement is
TRUE
NBQ
With the exception of the ____, the oral and nasal
cavities develop from the first brachial arch and the
frontal process
a.
b.
c.
d.
e.
Lower lip
Lower border of the cheeks
Anterior portion of the hard palate
Base of tongue
Base of the nasal septum
NBQ
With the exception of the ____, the oral and nasal
cavities develop from the first brachial arch and the
frontal process
a.
b.
c.
d.
e.
Lower lip
Lower border of the cheeks
Anterior portion of the hard palate
Base of tongue
Base of the nasal septum
Pharyngeal Grooves
and
Pharyngeal Pouches
Development of Pharyngeal Arches
 Each arch is separated
 Internally
by
Pharyngeal pouches
 Externally by
Branchial clefts/grooves
Gill-like slits (pharyngeal arches) smooth to
form Neck
Disappearing “Gills”
 Tissues of the 2nd and 5th pharyngeal arches grow
over the other arch grooves and make contact with
each other
Pharyngeal Grooves & Pharyngeal Pouches
The 1st Pharyngeal Groove (covered by ectoderm)
deepens to form the external auditory canal.
The 1st Pharyngeal pouch forms into the middle
ear and Eustachian tube.
 The membrane at the deepest part of this tube
becomes the tympanic membrane.
Pharyngeal Grooves & Pharyngeal Pouches
2’nd Pharyngeal Pouch Becomes
Palatine Tonsils
3’rd Pharyngeal Pouch Becomes
Parathyroid Glands
Thymus
4’th Pharyngeal Pouch Becomes
Ultimobranchial Body
Prenatal Development
 Pre-implantation: 1-7 days
 Embryonic: 2-8 weeks
 Fetal: 9-38+ weeks
 Major developmental malformation occur in the
embryonic period
NBQ
The olfactory (nasal) pits appear on the lateral sides
of these
a.
b.
c.
d.
e.
Maxillary process
Olfactory process
Mandibular process
Frontal process
Globular process
NBQ
The olfactory (nasal) pits appear on the lateral sides
of these
a.
b.
c.
d.
e.
Maxillary process
Olfactory process
Mandibular process
Frontal process
Globular process
Prenatal Development
 3 primitive tissue precursors form
1.
Ectoderm: Form outer covering of body. Lining of oral
cavity. epithelium, salivary glands, nervous system,
ameloblasts (enamel)
2.
Endoderm: Epithelial linings of internal organs: GI tract,
resp system, urinary tract
3.
Mesoderm: connective tissues of skeletal, vascular, muscle,
dermis, dental pulp, periodontal attachment, cementum,
dentin
Derivatives of Ectoderm, Mesoderm,
and Endoderm layers
Ectoderm
 The
embryo is covered by a single
layer of ectodermal cells which
differentiate into multiple layers
 Epidermal
and dermal cells
develop and differentiate into
hair, teeth, nails and mammary,
sebaceous, and salivary glands
Mesoderm
 Medial somites in the mesoderm form the
skeleton that will surround the neural tube.
 Intermediate mesoderm forms the
striated/voluntary muscle of the body.
 Lateral mesoderm forms the dermis of
the epithelium of the body and the GI tract.
All peristaltic musculature is derived from
mesoderm.
Endoderm
 The endoderm forms into the
gastrointestinal tract, which elongates
and develops “outpouchings” that form
the pharyngeal pouches, lung buds,
liver, gall bladder, pancreas, and
urinary bladder.
Ectoderm forms Neural Crest
 Neural crest cells form the
sensory system of the dorsal root
ganglia of the cranial and spinal
nerves
Neural Tube Development: Week 3 - 9
Closing of Neural Tube
(3rd week of development)
Head and Neck Development
 Folding of the embryo at 3-4 weeks forms a space
(stomodeum) limited by a temporary barrier
(oropharyngeal membrane). It will become the oral
cavity
 Pouches form called brachial arches


FIRST MANDIBULAR ARCH: forms mandible, muscles of
mastication, nerve and blood supplies, Merkel’s cartilage
which is the precursor of the mandible
SECOND ARCH (HYOID): forms facial muscles and vessels,
hyoid bone
Head & Neck Development
 Face forms week 4-7 w/ formation of stomodeum
 Tooth enamel forms from ectoderm lining the stomodeum
 Upper Lip: complete within 6-8 weeks: Fusion of the median
nasal process and RT/LF maxillary processes
 Palate forms week 5-12



Failure of components to fuse during these periods results in cleft lip,
palate or both. Unilateral or bilateral
Fusion of globular process with the LF/RT palatal shelves
Separates the stomodeum into an upper (nasal) and lower (oral) cavity
 Tongue forms weeks 4-8
 Body from tuberculum impar and lateral tissues, and base from copula
form and fuse at the sulcus terminalis
 Post 1/3 and hyoid bone develops from the 2nd and 3rd brachial arches
 Know the nerve and blood supplies for the tongue, other oral soft tissues,
facial skeleton, teeth
NBQ
The buccopharyngeal membrane at what week in
development?
a.
b.
c.
d.
2 weeks
3 weeks
4 weeks
6 weeks
NBQ
The buccopharyngeal membrane at what week in
development?
a.
b.
c.
d.
2 weeks
3 weeks
4 weeks
6 weeks
NBQ
A cleft lip occurs when maxillary process fails to fuse
with the
a.
b.
c.
d.
e.
Palatine process
Globular process
Lateral nasal process
Mandibular process
Opposing maxillary process
NBQ
A cleft lip occurs when maxillary process fails to fuse
with the
a.
b.
c.
d.
e.
Palatine process
Globular process
Lateral nasal process
Mandibular process
Opposing maxillary process
NBQ
Palatal closure occurs during which week in
embryonic development?
a.
b.
c.
d.
2
4
8-12
16
NBQ
Palatal closure occurs during which week in
embryonic development?
a.
b.
c.
d.
2
4
8-12
16
Head & Neck
 Most structures of oral cavity develop from 2
embryonic processes

Frontal process
Forehead, frontal bone
 Median nasal process: center and tip nose, nasal septum, globular
process (philtrum, premaxillary palate)
 Lateral nasal process: sides of nose, infraorbital area


1st brachial arch
Maxillary process: lateral palatine processes (palatal shelves),
upper parts of cheek, sides of upper lip
 Mand process: lower jaw, lower parts of the face and lower lip, ant
2/3 of tongue

Salivary Glands
 Major and minor, serous and mucous components,
major from 1st brachial arch
 PAROTID: Stenson’s duct, serous saliva, most
common site for tumors
 SUBMANDIBULAR: Wharton’s duct, serous mucous
 SUBLINGUAL: anterior floor of mouth, mucous,
several ducts along sublingual folds
Question
 The embryological origin of the face is largely from
the
a.
b.
c.
d.
Second brachial arch
Second and third brachial arches
Frontal process and first brachial arch
Frontal process and second brachial arch
Answer
 The embryological origin of the face is largely from
the
a.
b.
c.
d.
Second brachial arch
Second and third brachial arches
Frontal process and first brachial arch
Frontal process and second brachial arch
Tongue Development
Pharyngeal Arches:
1st forms the anterior
(moveable)
2nd , 3rd forms the immovable
base
The tongue is innervated by
the V, VII, IX, X, and XII
Cranial nerves for various
functions.
Tissues of the Tongue
 3 Parts:
Tuberculum
impar (central)
Both lateral lingual swellings (sides)
 As they grow, a U-shaped sulcus forms around the
anterior of the tongue to separate it from the jaw
tissues
 This allows free movement of the anterior tongue
 The 3 parts fuse completely to form the tongue
body
Tongue formation: 1st Pharyngeal Arch
Tongue Development
 The body and the base of the tongue are
separated by the terminal sulcus
 Behind the terminal sulcus the lingual
tonsil develops from the base on the dorsal
side
 Waldeyer’s Ring: (ring of tonsils in pharynx)
 Lingual tonsil
 Palatine tonsils
 Pharyngeal tonsils
Body and Base of the Tongue
Lateral lingual swellings and tuberculum impar have completely
merged and fused to form the body and base of the tongue.
Question
 What is the origin of “Rests of Malassez”?
 Junctional epithelium
 Reduced enamel epithelium
 Hertwig’s epithelial root sheath
 Cementoblasts in the PDL
Answer
 What is the origin of “Rests of Malassez”?
 Junctional epithelium
 Reduced enamel epithelium
 Hertwig’s epithelial root sheath
 Cementoblasts in the PDL
Question
 Rests of Malassez are composed of
 Calcified PDL
 Calcifications n the dental pulp
 Groups of epithelial cells attached t the enamel
 Groups of epithelial cells in the PDL
Answer
 Rests of Malassez are composed of
 Calcified PDL
 Calcifications n the dental pulp
 Groups of epithelial cells attached t the enamel
 Groups of epithelial cells in the PDL
Question
 Which structure marks the embryonic origin of the
thyroid gland?
a.
b.
c.
d.
Tonsillar pillar
Stenson’s duct
Foramen ovale
Foramen cecum
Answer
 Which structure marks the embryonic origin of the
thyroid gland?
a.
b.
c.
d.
Tonsillar pillar
Stenson’s duct
Foramen ovale
Foramen cecum
NBQ
What anatomic feature separates the root and the
body of the tongue?
a.
b.
c.
d.
e.
The lingual frenum
The fungifofrm papillae
The median groove
The third brachial arch
The circumvallate papillae
NBQ
What anatomic feature separates the root and the
body of the tongue?
a.
b.
c.
d.
e.
The lingual frenum
The fungifofrm papillae
The median groove
The third brachial arch
The circumvallate papillae
NBQ
Remnants of Hertwig’s epithelial root sheath sound
in the PDL of a functional tooth are called:
a.
b.
c.
d.
e.
Enamel pearls
Denticles
Rests of Malassez
Cementicles
Intermediate plexus
NBQ
Remnants of Hertwig’s epithelial root sheath sound
in the PDL of a functional tooth are called:
a.
b.
c.
d.
e.
Enamel pearls
Denticles
Rests of Malassez
Cementicles
Intermediate plexus
HISTOLOGY
Histology
 Cells parts reviewed during A&P lecture
 Tissues
 Epithelium
 Connective Tissue
 Muscle
 Nervous Tissue
Histology: Epithelium Tissues
 Simple and stratified (layered)
 Named by cell shape
 Avascular
 Basement membrane separates from underlying
connective tissue
 Review locations of different types
 Stratified squamous epithelium lines oral cavity
Histology: Connective Tissues
 Collagen fibers
 Loose and dense
 Calcified and non-calcified
 Cartilage: hyaline remodels into bone
 Elastic is flexible
 Fibrous lines boney surfaces
 Bone: form skeletal system
 Blasts: build
 Clasts: consume
 Cytes: just hang around different hard CT
Histology: Muscle Tissues
 Skeletal (voluntary)
 Smooth(GI and blood vessels)
 Cardiac (heart muscle)
Histology: Nervous Tissues
 Ectodermal origin
 Central: brain and spinal cord
 Peripheral components
 Afferent (sensory) signals to CNS
 Efferent (motor) signals from CNS to muscle and glands
 Somatic system carries signals to voluntary muscles
 Autonomic system carries signals from CNS to
involuntary muscles and glands


Sympathetic: causes activity, fight-or-flight
Parasympathetic: maintain status quo, decrease activity
Tooth Development
 Begins 7th weeks of embryonic life with 20 primary




teeth
Continue development until late teens
Enamel forms from ectoderm lining the sotmoduem
Dentin/pulp form from ectomesenchyme (derived
from embryonic ectoderm adjacent to the underlying
mesenchymal tissue
Each tooth is product of 2 tissues
1.
2.
Mesenchymal: derived from neural crest cells
Epithelium: oral epithelium derived from ectoderm
NBQ
What type of primitive tissue gives rise to the enamel
of a tooth?
a.
b.
c.
d.
Ectoderm
Mesoderm
Endoderm
None of the above
NBQ
What type of primitive tissue gives rise to the enamel
of a tooth?
a.
b.
c.
d.
Ectoderm
Mesoderm
Endoderm
None of the above
NBQ
The embryonic origin of all connective tissue is
d.
Mesenchyme
Endoderm
Fascia
Ectoderm
e.
Epithelium
a.
b.
c.
NBQ
The embryonic origin of all connective tissue is
d.
Mesenchyme
Endoderm
Fascia
Ectoderm
e.
Epithelium
a.
b.
c.
NBQ
Rathke’s pouch if the embryonic origin of the
a.
b.
c.
d.
e.
Thyroid gland
Palate
Globular process
Pituitary gland
Nasal septum
NBQ
Rathke’s pouch if the embryonic origin of the
a.
b.
c.
d.
e.
Thyroid gland
Palate
Globular process
Pituitary gland
Nasal septum
Tooth Development: 2 Events
 Morphodifferentiation
 Shaping of teeth
 Stages: Bud, Cap, Bell, Apposition
 Cytodifferentiation
 Epithelial
Outer
 Inner
 Stratum
 Stellate reticulum


Mesenchymal
Dental sac: alveolar bone, PDL, Cementum
 Dental papilla: odontoblasts
 Pulp

Tooth Development
Initiation (Bud) stage
1.

Dental lamina (ectodermal thickening) grows into the
underlying mesenchymal (conncective) tissue at 20 places to
form the primary teetj
2. Proliferation (Cap) Stage
 Enamel organ develops from the dental lamina, and will
produce enamel
 Dental papilla arises and produces pulp/dentin
 The dental sac surrounds the developing tooth, and becomes
cementum, the PDL and alveolar bone
Tooth Development
3. Differentiation (Bell) Stage
 Enamel
1)
2)
3)
4)
organ develops 4 distinct layers
Outer enamel epithelium
Stellate reticulum
Stratum intermedium
Inner enamel epithelium: becomes enamel. IEE
becomes amelobasts which produce enamel,
odontoblasts from the dental papillae produce dentin
Tooth Development
 Tooth structure is produced layer by layer (appositional






growth)
Tooth matrix is initially soft, then mineralizes (hydroxyapatite
is crystalized calcium phosphate)
Root formation begins after the crown if complete, and ends 14yrs after eruption
Enamel organ layers condense to form the reduced enamel
epithelium
Hertwig’s epithelial root sheath (HERS), which develops from
the internal and external enamel epithelium, helps determine
outline of the root and dissolves
Remnants of HERS (knows as rests of Malassez) have the
potential to form cysts
Remnants of the dental lamina are known as Rests of Serres
Teeth: Enamel
 96% mineralized (hydroxyapatite)
 Composed of enamel rods perpendicular to surface
 Ectodermal origin from inner enamel epithelium
 Secreted by ameloblasts after dentin formation begins
 Inner and outer enamel epithelial areas combine to
form the Reduced Enamel Epithelium as enamel
formation is completed
 Hertwig’s root sheath forms
 REE combines with surface epithelium at eruption and
cervical area becomes junctional epithelium
 Ameloblasts have disappeared as formative cells
appear
Teeth: Dentin
 70% mineralized
 Composed of dentinal tubules extending from DEJ to pulp




chamber
Mesodermal origin and formed by odontoblasts (precedes
enamel formation initially)
 Odontoblasts remain viable and capable of forming dentin
after tooth formation is completed
Primary dentition forms before completion of the root apex
Secondary dentin forms after apex is completed
Tertiary (reparative) dentin forms in response to injury or
some irritations
Teeth: Dentin
 Peritubular dentin forms tubule walls
 Intertubular dentin forms between tubules
 Outerdentinal layer nearest DEJ formed 1st and is called
mantle dentin
 Cicrumpulpal dentin forms inner dentinal layer nearest
pulp chamber
 Tubules narrow with age
NBQ
The layer of dentin found adjacent to the pulp in
young teeth is called
a.
b.
c.
d.
e.
Tome’s granular layer
Predentin
Interglobular dentin
Dead tracts
Sclerotic dentin
NBQ
The layer of dentin found adjacent to the pulp in
young teeth is called
a.
b.
c.
d.
e.
Tome’s granular layer
Predentin
Interglobular dentin
Dead tracts
Sclerotic dentin
The last visible layer in Nonkeratinized stratified
squamous epithelium is the
a.
b.
c.
d.
Basal cell layer
Prickle cell layer
Granular layer
Corneum layer
The last visible layer in Nonkeratinized stratified
squamous epithelium is the
a.
b.
c.
d.
Basal cell layer
Prickle cell layer
Granular layer
Corneum layer
NBQ
Dentin is the product of
a.
b.
c.
d.
e.
Dental lamina
Dental organ
Dental papilla
Dental cuticle
Dental sac
NBQ
Dentin is the product of
a.
b.
c.
d.
e.
Dental lamina
Dental organ
Dental papilla
Dental cuticle
Dental sac
Teeth: Cementum
 Cementicles
 Calcified ovoid or round nodule found in the PDL
 May be found in grps or near the surface of the cementum
 More prevalent along the root in an aging person
 May be found at the site of trauma
Teeth: Cementum
 Mature Cementum: 3 grps fibers
1.
2.
3.
Grp I: collagen fibers produced by
cementoblasts, parallel to long axis of root
Grp II: fibers from cells of dental sac, form
fibers PDL
Grp III (external): coarser than internal,
Sharpey’s fibers
Teeth: Pulp
 Vascular tissue within pulp chamber
 Contains connective tissue, nerves, blood vessels,
odontoblasts at periphery
 Nerves only respond with pain to stimulation
 Derived from dental papilla
Pulp & Dentin Comparisons
 Closely related developmentally and functionally
 Pulp = loose, non-calcified ct, vascular
 Dentin=calcified ct, avascular
 Development
 Odontobasts
= form dentin
 Dental papilla = form pulp
Bone: Alveolar
 Formed during development & eruption of teeth
 Located in boney crypts of jaw bone
 Same histology as other bones in body
 Anatomy
 Each tooth in own alveolus (socket), inner cortical plate,
spongiosa
 Each socket has 3 parts: Outer cortical plate
 Alveolar bone proper: part of bone facing root of tooth, follows
outline of roots, sometimes called cribiform plate/lamina dura
Question
The cells that produce enamel derive from the
a.
b.
c.
d.
Stellate recticulum
Junctional epithelium
Inner enamel epithelium
Outer enamel epithelium
Answer
The cells that produce enamel derive from the
a.
b.
c.
d.
Stellate recticulum
Junctional epithelium
Inner enamel epithelium
Outer enamel epithelium
Question
Which of the following is a likely reaction to
destruction of a focal area of odontoblasts by injury?
a.
b.
c.
d.
New odontoblasts will differentiate from epithelial rests
of Malassez
New odontoblasts will form by division of vital
odontoblasts adjacent to the zone of injury
New odontoblasts will form by differentiation from cells
in the cell rich layer of the pulp
None of the above
Answer
Which of the following is a likely reaction to
destruction of a focal area of odontoblasts by injury?
a.
b.
c.
d.
New odontoblasts will differentiate from epithelial rests
of Malassez
New odontoblasts will form by division of vital
odontoblasts adjacent to the zone of injury
New odontoblasts will form by differentiation from cells
in the cell rich layer of the pulp
None of the above
PDL
 Specialized form of ct
 Derived from dental sac
 Made of fiber bundles
1.
2.
Gingival: dentogingival, dentoperiosteal, transeptal,
circumfrential
Principal: alveolar crest, horizontal, oblique, apical, interradicular
 Fast turnover rate
 Fibrous Matrix


Fibers are collagen & oxytalan with few elastic fibers assoc with
blood vessels
Sharepy’s Fibers: terminal portion of PDL that is embedded in bone
PDL
 Rich blood supply
 2 types nerves
1.
2.
Autonomic
Afferent sensory
 2 types nerve endings
1.
2.
Free, un-myelinated
Encapsulated
 Width varies




Wider in younger adults than older
Greater near cervical/apical areas
Greatest movements occur apical/cervical
Related to amt of function
Oral Mucosa
 Composed of stratified squamous epithelial layer and a ct




lamina propria, separated by a basement membrane
It includes the masticatory, lining, and specialized
mucosal tissues
Masticatory mucosal tissue is keratinized and protects
the gingiva and hard palate. The keratinization of the
attached gingiva ends at the free gingival margin
Lining mucosa is not keratinized and includes the
alveolar, vestibular and buccal mucosa, floor of the
mouth
Specialized mucosa refers to the papillae of the tongue
NBQ
In the oral cavity, one way in which lining mucosa
differs from masticatory mucosa is that
c.
Lining mucosa contains more muscle fibers
Masticatory mucosa contains glands
Lining mucosa has no submucosa
d.
Lining mucosa is not keratinized
a.
b.
NBQ
In the oral cavity, one way in which lining mucosa
differs from masticatory mucosa is that
c.
Lining mucosa contains more muscle fibers
Masticatory mucosa contains glands
Lining mucosa has no submucosa
d.
Lining mucosa is not keratinized
a.
b.
Anatomy of Gingiva
 Stratified squamous epithelium with a basement
membrane between the epithelium and connective
tissue
 Stratum corneum outside layer
 Keratinized=no nuclei, tough

Attached Gingiva
 Non-Keratinized=have nuclei, more flexible, lining
mucosa

Sulcular & Junctional Epithelium
Anatomy of Gingiva
 No blood vessels
 Nutrients from connective tissue vasculature
 Desmosomes connect epithelial cells to each other
 Hemidesmosomes connect epithelial cells to
connective tissue
 Gingival Fibers: 9 groups based on orientation,
insertions, structures, involved
 Gingival connective tissue


Lots collagen matrix
Few cells: fibroblasts, macrophages, lymphocytes, neutrophils
3 Gingival Epithelium Areas
Oral Epithelium
 Outer surface of free and attached gingiva from
gingival margin to mucogingival junction
 Keratinized or partially keratinized
 Orthokeratinized= thicker granular layer
 Rete pegs connect to connective tissue inside
2. Sulcular Epithelium
 Lining of gingival sulcus
 Nonkeratinized=allows for crevicular fluid in and out
 No Rete pegs, just smooth interface
1.
3 Gingival Epithelium Areas
3.
Junctional Epithelium
 Seals and protects
 Forms base of sulcus and attaches to tooth surface
 0.75-1.35mm long
 Nonkeratinized
 Attached by hemidesmosomes to enamel or an
implant surface in health, dentin or cementum in
disease
Oral Epithelium
 Melanocytes
 Langerhans cells
 Merkle cells
 Inflammatory cells
 Stratified squamous (3 types)
1.
Orthokeratinized
a.
b.
2.
Nonkeratinized
a.
3.
Less common
Cell layers: Basal (deepest), Prickle, Granular, Keratinized outer layer
Cell layers: Basal, prickle, nonker. outer layer
Parakeratinized: between #1&2
a.
Cell layers: Basal, prickle, keratinized outer layers
Oral Epithelium
 Connective Tissues: Lamina Propria
 Layers: Papillary & Reticular
 Submucosa: between lamina propria & muscles
 Interface
 Area between oral epithelium & ct
 Rete Pegs: epithelial extension into lamina propria
 Basement Membrane
 2 layers: Basal lamina (densa) & Reticular lamina (lucida)
 Epithelial cells for hemidesmosome attachments to basal
lamina
Question
 Where are Von Ebner’s glands located?
 In submucosa of the pharynx
 In the submucosa of the cheek
 Beneath the floor of the mouth
 Beneath circumvallate papillae in the tongue
Answer
 Where are Von Ebner’s glands located?
 In submucosa of the pharynx
 In the submucosa of the cheek
 Beneath the floor of the mouth
 Beneath circumvallate papillae in the tongue
Question
 During which time of fetal development will cleft
palate form?
a.
b.
c.
d.
Second trimester
Week 1-3
Weeks 6-11
Early in the 3rd trimester
Answer
 During which time of fetal development will cleft
palate form?
a.
b.
c.
d.
Second trimester
Week 1-3
Weeks 6-11
Early in the 3rd trimester