Download 2016 Orofacial Development Path wtih CYSTS 1st Year

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The beginning thru week one
Woman’s ovum fertilized
by man’s sperm forming
a zygote
Zygote undergoes mitosis
to form a hollow mass of
cells called a blastocyst
The blastocyst becomes
implanted in uterus
Embryology
Development of the Head and Neck
Steps in tissue formation
Embryonic second week
Ectoderm
 Induction: The beginning
 Proliferation: multiply
 Histodifferentiation (cell type)
Endoderm
 Morphodifferentiation (shape)
Blastocyst becomes embryo
during this period, is an
embryo for eight weeks
During second week, cells proliferate
 Apposition
 Maturation
and the ball shaped embryo becomes a
flattened bilaminar disc of ectoderm and
endoderm (an oreo cookie with NO
filling)
Placenta is beginning to form
Embryonic third week
Things to Remember
 Ectoderm forms nerves, skin, hair, glands,
Ectoderm
Mesenchyme
(mesoderm)
Endoderm
Bilaminar disc becomes trilaminar when mesenchyme
is formed in between two layers (an Oreo cookie WITH filling)
Mesenchyme generates connective tissue forming cells
(fibroblasts, osteoblasts) as well as another germ layer
called mesoderm
enamel of teeth
 Mesoderm forms muscles, bones, blood
vessels, connective tissue, dentin and pulp of
teeth
 Endoderm forms respiratory and digestive
system, liver, pancreas
Predict what would occur if a person had the condition
ectodermal dysplasia?
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Ectodermal Dysplasia
Embryonic third week - Disc
Disc develops a depression called a
“primitive streak” dividing the disc
into left and right
Primitive streak
Caudal end
Disc also forms a caudal end (tail)
And cephalic end (head)
right now the
Embryo is the size
of a pinhead
Ectodermal dysplasia: complete or partial anodontia,
absence of hair, sweat glands, melanin
ectoderm
Cephalic end
Mesenchyme
(mesoderm)
endoderm
Congenital syphilis
Teratogens
 A teratogen is any substance, agent, chemical,
etc that causes abnormal fetus development
 Examples of teratogens are radiation, alcohol,
cocaine, microorganisms, tetracycline, etc
 Infective Teratogens-can cause cataracts, heart
defects, and deafness in embryo
 Ex. Rubella virus and Zika virus
Hutchinson’s incisors
 If several abnormal affects occur together, it’s
called a “syndrome”
Mulberry molars
PREDICT the term used to describe this underformation
of tooth structure.
hypoplasia
Neuroectoderm – third week
Neuroectoderm forms
neural crest cells that
migrate to mesoderm,
help form branchial
arches
Ectoderm differentiates
into neuroectoderm,
forms neural groove
(spine)
Somites – third week
Somites appear as bulges
beside neural groove, somites
will develop into bones,
muscles, blood vessels, etc
Mesenchyme is now
mesoderm
Mesoderm differentiates into 38
pairs of somites
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Fourth week – embryonic folding
Embryo – tube shape
At cephalic end, oropharyngeal membrane fills gut,
temporarily closes off foregut. This membrane is the
posterior boundary of the stomadeum (primitive mouth)
Neural tube
endoderm
somites
ectoderm
mesoderm
Alimentary canal (3 regions)-foregut (forms primitive pharynx or
throat) midgut and hindgut (forms rest of pharynx and rest of GI)
Face/neck development (during fourth week)
How the embryo actually appears at four weeks
Six pharyngeal (branchial) arches
appear- develop into part of face,
hyoid bone, pharynx
Stomodeum
Right now, embryo is about
the size of a small pea
Mandibular arch (1st branchial
arch) gives rise to mandible,
part of maxilla, upper lip, all
teeth
Branchial Arches
Mandibular arch starts off as
Meckel’s cartilage
5th cranial nerve (trigeminal)
associated with 1st branchial
arch structures
Face/neck development (during fourth week)
Face development (during fourth week)
2nd branchial arch starts as
Reichert’s cartilage
Stomodeum
Reichert’s cartilage gives
rise to muscles of facial
expression, others
Frontal (frontonasal) process
Maxillary process (develops from
Mandibular arch)
Cranial nerve 7 (facial
nerve) associated
with 2nd branchial arch
Branchial arches 3 – 6 form
hyoid bone, pharynx, etc.
hypoglossal, glossopharyngeal
nerves associated
1st branchial (mandibular) arch
2nd branchial arch
Frontal view
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Face development (during fifth week)
Frontal process growing downward,
will form middle of upper lip
(intermaxillary process or premaxillary segment)
Forms maxillary incisors, primary palate, and
nasal septum
Face development (during fifth week)
lens placodes forming, will
begin moving toward midline
Maxillary process growing toward
midline, will form sides of
upper lip, midface, max canines,
and posterior teeth
Nasal placodes form
Mandibular arch fused at midline
Otic placodes form internal
ear and related tissues
2nd branchial arch forming facial
muscles
Face development (during sixth week)
Medial nasal process (philtrum)
contacts maxillary process
(site of cleft)
Face development (during seventh week)
Median nasal process and
Maxillary process fully fused
Face taking on human
appearance
lateral nasal process forms ala
(side of nose)
Auricular hillocks form
Tongue forming and filling
common nasal and oral
cavity
Lip Pits
Nasolacrimal groove forms
PREDICT What would happen if
fusion of median nasal process and
maxillary process does not occur?
Cleft Lip
Median nasal processes
Intermaxillary segment
Maxillary process
PREDICT in which week of
development a disturbance
occurred that caused cleft lip?
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4 Types of Cleft Lips
2) Bilateral
 Same but on
both sides
 1) Unilateral failure
 Both
of maxillary process
on 1 side to meet &
fuse w/ medial nasal
process, which results
in a division of lip.
Nasal distortion results
4 Types of Cleft Lip (cont)
3) Median Cleft Lip
unilateral &
bilateral
may/or may
not be
associated
w/cleft palate
4) Median Cleft of Mandible
 Rare condition
 Failure of mesenchymal masses of
mandibular processes to merge
together at 5 wks
 Extremely rare; partialcomplete failure of medial
nasal processes to merge.
 Dimple of chin is slightest form of
incomplete merging of the 2
mandibular processes
 Only one that can be
called a “hare lip”.
Derived from rabbits-have
a cleft in middle of lip
Neck development (during seventh week)
Only 1st branchial groove
forms
a structure, external auditory
meatus
Phrayngeal pouches develop in
conjunction with arches, grow
toward midline, form many
neck structures
Palate development – eighth to twelfth week
Primary palate (premaxilla)
From intermaxillary segment,
contains maxillary incisors
Palatal shelves from
maxillary process grow
across, fuse at midline,
Form the secondary palate
PREDICT what would happen if palatal shelves
did not fuse?
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Cleft Palate
Primary palate formed
(no cleft lip)
Palatal shelve fusion
forming secondary palate
did not occur
Nasal cavity
PREDICT in which week of development a
disturbance occurred that caused cleft palate?
8th-12th week
Classifications of Clefts
 Class 1- Cleft of the tip
of the uvula
Classification of Clefts
 Class 3- Cleft of the
soft palate
 Class 2- Cleft of the
uvula (bifid uvula)
Classification of Clefts
Classification of Clefts
 Class 5- Cleft of the
 Class 4- Cleft of
the soft and hard
palate
soft & hard palates
that continues through
alveolar ridge on one
side of premaxilla;
usually associated
with cleft lip of same
side
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Classifications of clefts
 Class 6- Cleft of soft
& hard palates that
continues through
alveolar ridge on both
sides, leaving a free
premaxilla; usually
associated with
bilateral cleft lip
Classifications of Cleft Palate
 Class 7- Submucous cleft in which muscle union is imperfect
across soft palate. The palate is short; uvula is bifid; a
groove is situated at midline of soft palate; and closure to
pharynx is incompetent.
Repair of Cleft Lips and Palate
 When usually have first surgery performed
 Rule of 10, Lip repair by 6 months, Palate repair by 18 months or
earlier
 Goals for surgeries
 Aid in feeding, Encourage development of premaxilla, Help partial
closure of palatal cleft, Speech, Esthetic and oral function
 Other therapies required
 Airway, breathing, speech, hearing loss therapy
 Appliances
 Orthodontic and dentofacial orthopedics to reduce protrusion and
stabilize maxilla
Cleft Lips and Palates
Obturators and Speech Aid
Prosthesis
 Clinical Considerations
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Be kind!
Patients are “clinic tired”
Low self esteem
Careful to not damage surgery results
Missing and supernumary teeth
Oral care difficult
Periodontal disease in areas of cleft
Higher caries risk
3-4 month recall
Personal daily care, fluoride, and how to care for prosthesis
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Tongue development
The Tongue
Body of tongue
Base of tongue
Body of tongue forms from three
parts, two laterals and central
tuberculum impar (mesenchyme
from 1st brancial arch)
Base of tongue formed from
mesenchyme of 2, 3rd and 4th
arches (precursor is called the
copula).
Body of tongue
separated from base by
terminal sulcus
Tongue development
Body of tongue
Base of tongue
Thyroid tissue forms at foramen
caecum, migrates to location
in neck following thyroglossal
duct
ankyloglossia
Taste buds innervated by 7th
nerve (2nd Branchial arch)
Motor supply from XII
Hypoglossal nerve from
branches 3-6
Macroglossia
Developmental
Cysts
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Cysts
During embryonic development if clumps of epithelial cells
(epithelial rests) get trapped and left behind, they may later
grow to form cysts
Lymphoepithelial
(Branchial cleft) cyst
Nasopalatine cyst
Thyroglossal track cyst
Median cysts
Globulomaxillary cyst
Median Mandibular cyst
At midline in mandible
• Occurs where chin meets
• Rare
Median palatal cyst
• possible posterior nasopalatine cyst
• midline of hard palate
• Tx: surgical enucleation
• Recurrance is rare
Dermoid cyst
Always occurs between maxillary lateral and canine (the suture
between premaxilla and secondary palate)
Nasolabial Cyst
• Where median and lateral processes form
• Swelling in mucolabial fold (maxillary canine area)
Found in floor of mouth, cyst wall contains hair, sweat glands
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Pseudocyst – traumatic bone cyst
Pseudocyst – Stafne bone cyst
VOID
“Simple Bone Cyst”
“Static Bone Cyst”
Pseudocyst - Aneurysmal bone cyst
At what weeks did
disturbance occur?
 Cleft lip?
 Cleft palate?
 Cleft uvula?
• Blood filled, spaces containing giant cells
• Described as “honeycombed” or “soap bubble”
• Associated with trauma
Extra Resources
 Embryonic development (week by week)
 http://emedicine.medscape.com/article/1289057-overview
 Development of Face and oral cavity
 http://www.slideshare.net/meloymacainag/developmentof-face-and-oral-cavity?next_slideshow=1
 Human tooth development
 https://en.wikipedia.org/wiki/Human_tooth_development
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