seminar on development of face palate and jaw

1. DEVELOPMENT OF FACE,
PALATE AND JAWS
Presented by:
DR. KALPAJYOTI BHATTACHARJEE

2. CONTENTS
• General embryology
• Pharyngeal arches
• Development of head
• Development of skull
• Development of face
• Derivation of different parts of face
• Development of mouth
• Development of palate
• Development of mandible
• Development of maxilla
• Development of teeth
• Development of tongue
• Development of salivary glands

3. GROWTH
• Increase in size, change in proportion and
progressive complexity- Krogman
• An increase in size- Todd
• Change in any morphological parameter which
is measurable- Moss

4. DEVELOPMENT
• Development is the progress towards
maturity- Todd(1931)
• Differentiation is the change from a
generalized cell or tissue to one that is more
specialized. It is change in quality or kind.

5. INTRODUCTION
• Embryology is the study of the development
of an individual before birth.
• Fertilization is the fusion of male and female
germ cells to form a zygote. It takes place in
the ampulla of the uterine tube.
• During the first two months the developing
zygote is called an embryo and after that it is
called a fetus.

6. • The human embryo contains 46
chromosomes, called as diploid number. Out
of which 44 chromosomes are autosomes and
remaining 2 are sex chromosomes, designated
as X and Y chromosomes.
• The sex chromosome in female are XX
chromosome and in male XY chromosome.

7. THE PROCESS OF FERTILIZATION
• The male gamete (sperm) fuses with the
female gamete (ovum)

9. Prenatal development
 Embryonic stage:-
 1st four weeks- cellular proliferation and
differentiation.
 next 4 weeks- major external and internal
structures form.
 Fetal stage:- growth and maturation of embryo.

10. Formation of Blastocyst
Fertilized egg undergoes
rapid division
Morula
Fluid seeps into morula
Blastocyst

11. Bilaminar disc
 At about day 8 of
gestation, embyoblast
cells differentiate , into
a 2 layered disk called
bilaminar germ disk.
 ectodermal cells are
columnar and
reorganize to form
amniotic cavity.

12. Extraembryonic mesoderm
• Cells of trophoblast
give rise to mass of
cell called EEM.
• Lie between
trophoblast and the
flattened hypoblast
cells lining the yolk
sac.
• Does not give rise to
any tissue of the
embryo itself.

13. Prochordal plate
• During the time the axis
of the embryo is
established and is
represented by a slight
enlargement of the
ectodermal and
endodermal cells at the
head end of the embryo
in a region known as
prochondral plate.

14. Primitive streak
• Floor of the amniotic
cavity is formed by
ectoderm, and within it
primitive streak
develops along the
midline.
• The rostral end of
streak finishes in a
depression called
primitive node.
• Multiplying cells move
into the interval
between ectoderm and
endoderm to form
mesoderm.

15. Notochord
• Cells of ectoderm divide
at the node, migrate
between ectoderm and
endoderm to form a solid
column that pushes
forward in the midline as
far as the prechondral
plate.
• Through canalization of
this cord of cells,
notochord is formed to
support the embryo.

17. Somite

18. Neural Crest cells
• A group of cells separate from the neuroectoderm on
the lateral aspect of the neural plate.
• Undergo epithelial-mesenchymal interactions.
• BMP and FGF are the inducing agents.
• Embryonic CT derived from mesoderm- mesenchyme
• Head- neuroectoderm- ectomesenchyme
• Form all tissues of tooth except enamel.
• Treacher Collins syndrome.

20. Folding of the Embryo
• In 2 planes: rostrocaudal
axis and lateral axis.
• Head fold critical in
formation of oral cavity.
• Stomatodeum separated
from the gut by the
buccopharyngeal
membrane.

22. Sequence of events
• 8th day – bilaminar disc
• 14th day- prochordal plate and primitive streak
• 16th day- intraembryonic mesoderm
• 17th day- notochord
• 23th day- neural tube

23. PHARYNGEAL ARCHES
• Rod-like thickenings of mesoderm in the foregut.
• At first 6 arches. 5th arch disappear, only 5 remains.
• The ventral ends of the arches of the right and left sides
meet at the middle line in the floor of the pharynx.
• They bring about elongation of the region between the
stomatodeum and the pericardium forming neck.
• In the interval between any two adjoining arches,
endoderm extends outwards to form a series of pouches.
They are called endodermal or pharyngeal pouches..

26. ARCH NERVE OF THE
ARCH
DERIVATIVES
First
(mandibular
arch)
Mandibular Muscles of mastication, anterior belly of digastric,
tensor tympani, tensor palati, meckels cartilage,
sphenomandibular ligament, anterior ligament of
malleus.
Second
(hyoid arch)
Facial Stapes, styloid process, stylohyoid ligament,
smaller cornu of hyoid bone, superior part of
body of hyoid bone, occipitofrontalis, platysma,
posterior belly of digastric, auricular muscle .
Third Glosso-pharyngeal Stylopharyngeus, greater cornu of hyoid bone,
lower part of hyoid bone.
Fourth Superior laryngeal Muscles of larynx and pharynx.
Fifth Recurrent laryngeal

27. Fate of endodermal pouches
• 1st pouch: ventral part obliterated by
formation of tongue.
dorsal part – tubotympanic recess
proximal – auditory tube, middle ear cavity,
tympanic antrum.
• 2nd pouch: tonsil, tubotympanic recess,
• 3rd pouch: inferior parathyroid glands, thymus.
• 4th pouch: superior parathyroid glands,
thyroid glands
• 5th pouch: ultimobranchial body.

28. Development of head
• Anterior portion of the neural tube expands
greatly as forebrain, midbrain & hindbrain
form but a small amount of mesenchyme
always remains between the developing brain
and the surface epithelium.
• Hindbrain forms 8 bulges - rhombomeres
• Paraxial mesoderm: lateral to neural tube
 7 Somatomeres - rostrally
Somites - caudally

29.  Craniofacial development-
migration of the neural crest
cells from the midbrain & first
two rhombomeres in 2
streams:-
 1st stream:
 Migrates forward.
 Intermingles & reinforces the
mesenchyme beneath the
expanding forebrain.
 Connective tissue of the face.
 2nd stream directed towards the
first branchial arch.

30. Development of the skull
 Skull can be divided into 3 components:
1)The cranial vault 2)the cranial base 3) the
face
 Membranous bone, formed directly in
mesenchyme with no cartilaginous precursor,
forms the cranial vault and face
 Cranial base → endochondral ossification.
 Membrane formed bones may develop
secondary cartilages to provide rapid growth.

31. DEVELOPMENT OF FACE
• The basic morphology of the face is created 24th and
38th day of gestation - development & fusion of the
prominences:-
– Frontonasal prominence
– Maxillary swellings
– Mandibular swellings
• At 24 days, maxillary process & mandibular
process are formed.

32.  Early development is dominated by proliferation
and migration of ectomesenchyme involved in
the formation of primitive nasal cavities.
 At about 28 days, localized thickening develop
within ectoderm of the frontal prominence
- olfactory or nasal placodes.
 Rapid proliferation of mesenchyme - Horse
shoe shaped ridge - nasal pits.

33. • Lateral arm of horse shoe - lateral nasal
process and middle arm - medial nasal
prosess.
• Region of frontal prominence where nose
develop - frontonasal process.
• The median nasal processes of both sides,
together with the frontonasal process, give
rise to the middle portion of the nose, middle
portion of the upper lip, anterior portion of
maxilla and the primary palate.

34. Maxillary process grows medially and
approaches the lateral and medial nasal
processes but remains separated from them by
distinct groove- naso-optic and bucconasal
groove.
Maxillary processes grow medially - pushing
the medial nasal process towards midline and
merges anatomic counterpart.

35. Upper lip - by maxillary process of each side &
medial nasal process.
Lower lip – merging of the ectomesenchyme of
the mandibular processes.

37. Derivations of the parts of the face

38. CHEEKS: After formation of upper and lower lips, the
stomatodaeum is very broad. On the lateral side it is bounded
above by maxillary process and below by mandibular process. The
maxillary and mandibular processes fuse to form the cheeks.
EYES: The eyes develop from the lens placode which are
ectodermal thickenings present lateral and cranial to the nasal
placode.
EYELID: Eyelids are derived from folds of ectoderm that are
formed above and below the eyes, and by mesoderm enclosed
within the folds.

40. PINNA: The pinna (auricle) is formed by the fusion
of the mesodermal thickenings on the mandibular and
hyoid arches.
NASOLACRIMAL DUCT: Nasolacrimal duct
is formed by fusion between the lateral nasal &
maxillary processes, separated by a deep groove.
The epithelium in the floor of the groove between
them forms a solid core that separates from the
surface and eventually canalizes to form
nasolacrimal duct.

41. Developmental anomalies of the face
• Harelip
• Oblique facial cleft
• Macrostomia
• Lateral facial cleft
• Retrognathia
• Agnathia
• Mandibulofacial dysostosis
• Hypertelorism
• Congenital pits and fissure on lips
• proboscis

42. OBLIQUE FACIAL CLEFT HARELIP
PROBOSCIS

43. DEVELOPMENT OF MOUTH
• The mouth is derived partly from the stomatodeum
(ectodermal) and partly from the foregut (endodermal).
• After the disappearance of the buccopharyngeal
membrane the stomatodeum communicates with the
foregut.
• Epithelium lining the lips, cheek, palate; teeth and gums
are ectodermal in origin.

44. • Epithelium of the tongue is endodermal.
• In the region of the floor of the mouth; the
mandibular process forms the lower lip, lower
parts of cheek, lower jaw and tongue.

45. Development of palate
• From each maxillary process, a plate-like shelf
grows medially; called palatal process.
• The palate is formed from the 3 components:
The two palatal processes
The primitive palate formed from the
frontonasal process.

46. • The mesoderm in the palate undergoes
intramembranous ossification to form the
hard palate.
• Ossification does not extend into the posterior
portion; called as soft palate.
• The part of the palate derived from
frontonasal process forms the premaxilla;
which carries the incisor teeth.

48. • After the development of secondary palate
distinction between the oral and nasal cavity
is possible.
• Development 7-8 weeks and completes
around the 3rd month of gestation.
• 3 outgrowths appear one nasal septum
and two palatine shelves. They converge and
fuse in the midline.
• Displacement of tongue from between the
palatine shelves by the growth pattern of the
head is a contributing factor closure of palate.

50. Developmental anomalies of
lips and palate
• Congenital lips
• Commissural pits and fistulas
• Van der woude syndrome
• Cleft lip and cleft palate
• Chelitis glandularis
• Chelitis granulomatosa

51. Cleft lip and cleft Palate

52. DEVELOPMENT OF MANDIBLE
• Meckels cartilage forms the lower jaw in primitive
vertebrates.
• In humans, Meckel’s cartilage has a close positional
relationship to the developing mandible but makes no
contribution to it.
• At 6 weeks of development this cartilage extends as a
solid hyaline cartilaginous rod, surrounded by a
fibrocellular capsule, from the developing ear to the
midline of the fused mandibular processes.

53. • The two cartilages of each side are separated
in the midline by a thin line of mesenchyme.
• The nerve of first arch has a close relationship
to meckels cartilage.
• During 6th week; a condensation of
mesenchyme occurs in the angle formed by
the division of inferior alveolar nerve
• At 7th weeks; intramembranous ossification
begins in this codensation forming the first
bone of the mandible.

54. • From this centre of ossification, bone formation
spreads rapidly anterior to the midline and
posteriorly to a point where mandibular nerve
divides into its lingual and inferior alveolar
branches.
• Further growth of mandible till birth is under the
influence of the secondary cartilages:- Condylar,
Coronoid, Symphyseal cartilages

56. DEVELOPMENT OF RAMUS
• Rapid spread of
ossification posteriorly
into the mesenchyme
of the 1st arch.
• Point of divergence is
marked by the lingula
in the adult mandible.
• Spread of mandibular
ossification away from
meckels cartilage at the
lingula.

57. DEVELOPMENT OF MAXILLA
• The maxilla develops from a center of ossification in the
mesenchyme of the maxillary process of the first arch.
• Center of ossification is closely associated with the
cartilage of the nasal capsule.
• Bone formation spreads :
– From center Posteriorly below orbit towards forming
zygoma
– Anteriorly future incisor region
– Superiorly frontal process

58. • Bony trough forms for the infraorbital nerve and from
this trough downward extension forms lateral alveolar
plate.
• Ossification spreads to the palatine process and forms
hard palate.
• Median alveolar plate forms from the junction of the
palatal process & the main body of the forming maxilla.
• A secondary cartilage; zygomatic or malar cartilage
appears in the developing zygomatic process.

59. DEVELOPMENT OF MAXILLARY SINUS
• Forms around 3rd month of intra-uterine life.
• Develops by expansion of nasal mucous
membrane into maxillary bone.
• Later enlarges by resorption of internal wall of
maxilla.

60. Developmental anomalies of jaws
• Agnathia
• Micrognathia
• Macrognathia
• Facial hemihyperatrophy
• Facial hemiatrophy

61. Development of teeth
• Primary epithelial band is a band of epithelium
that has invaded underlying ectomesenchyme
along each of the horseshoe shaped future dental
arches.
• At 7th week the PE band divides into Dental
lamina and vestibular lamina.
• The dental lamina shows a series of local
thickenings- enamel organ.

62. • The dental lamina is established in the sixth week
of intrauterine life.
• The dental lamina serves as primordium of the
ectodermal position of the deciduous teeth.
• Permanent molars arise directly from a distal
extension of the dental lamina.
• Dental lamina extends over a period of atleast 5
years.

65. Anomalies of teeth
• One or more teeth are absent.
• Supernumerary teeth.
• Individual tooth abnormality.
• Gemination.
• Malocclusion.
• Precocious eruption.
• Delayed eruption.
• Improper formation of enamel and dentin.

66. DEVELOPMENT OF TONGUE
• Develops at about 4 weeks.
• Pharyngeal arches meet at the midline
beneath the primitive mouth.
• Local proliferation gives rise to a number of
swellings in the floor of the mouth.
• 2 lateral lingual swellings enlarge and merge
with each other and the tuberculam impair to
form a large mass, from which anterior 2/3rd
of the tongue is formed.

67. • Root of the tongue arises from a large midline
swelling developed from the mesenchyme of
the 2nd 3rd & 4th arches.
• Swelling consists of copula and large
hypobranchial eminence.
• As tongue develops, hypobranchial eminence
overgrows the copula.
• Posterior part of the fourth arch marks the
development of the epiglottis.

69. Anomalies of tongue
• Macroglossia, microglossia, aglossia
• Bifid tongue
• Ankyloglossia
• Persistence of tuberculum impar
• Thyroid tissue within the muscles
• Remnants of thyroglossal duct
• Fissured tongue

70. Development of Paranasal Sinuses
• Paranasal sinuses appear as diverticula from nasal
cavity.
• The diverticula gradually invades the bones.
• Enlargment of paranasal sinuses is associated with
the overall enlargement of the facial skeleton
including the jaws.
• This provide space in the jaws for growth and
eruption of teeth.

71. Development of Salivary Gland
• The salivary glands develop as outgrowths of the
buccal epithelium.
• The outgrowths are at first solid and are later
canalized.
• They branch repeatedly to form the duct system.
• The terminal part of the duct system develop into
secretory acini.

72. • The outgrowths of the parotid gland arise in relation
to the line along which the maxillary and mandibular
processes fuse to form the cheek. It is ectodermal.
• The outgrowths for the submandibular and
sublingual glands arise in relation to the linguo-
gingival sulcus. They are endodermal in origin.
• One or more salivary glands may sometimes be
absent.

73. 4TH WEEK
5TH WEEK
6TH WEEK
7TH WEEK
8TH WEEK
10TH WEEK
• Frontonasal, maxillary and mandibular
process can be identified. Lens and nasal
placodes are also present.
• nasal pits are established
• Tubercles of the developing pinna, on
each side palatal process appear.
• Eyelids are established. Maxillary
process fuse with median nasal process.
• Eyes shift from lateral to frontal position.
Bucconasal membrane ruptures.
• The palatal process and nasal septum
fuse with each other.

74.  Tongue starts forming
 Hypobranchial eminence becomes visible
 Dental laminae of upper and lower jaws are
established
 Salivary glands starts developing
 Enamel organs are formed
 Enamel organ becomes cup- shaped
 Formation of tonsil begins
 Tonsil is infiltrated by lymphatic tissue
 Enamel amd dentine have formed
considerably, tongue complete.
 Cementum is formed
 PDL formed before eruption of teeth.
4th week
5th week
6th week
7th week
8th week
10th week
3 months
5 months
6 months
Just after
birth
After birth

75. REFERENCES
• Inderbir Singh; G.P. Pal- human embryology-
seventh edition.
• Nanci A. Tencate’s Oral Histology- Development,
Structure and Function, 8th Ed, Mosby Missouri.
• Kumar GS, Orban’s Oral Histology and Embrology,
13th Ed, Elsevier Mosby.

76. • S.l Bhalajhi, orthodontics the art and science,
3rd edition.
• Berkovitz BKB, Holland GR, Moxham BJ, Oral
Anatomy, Histology and Embryology, 4th Ed,
Mosby, Missouri.
• Shafers, textbook of oral pathology, 7th
edition.

77. THANK
YOU