Growth and development of Maxilla and Palate

1. DEVELOPMENT OF
MAXILLA & PALATE
By B.A Abhinav

2. CONTENTS.
• Introduction
• Anatomy
• Prenatal development of maxilla
• Development of palate
• Postnatal development of maxilla
• Anomalies of the maxilla and palate
• Clinical implications
• Conclusion
• References.

3. Introduction
Definition:
Growth and development is a morphologic process
working toward a composite state of aggregate
structural and functional balance among all of the
multiple, regional growing and changing hard and soft
tissue parts.

4. Terminology Related To Growth:
Growth Fields : The outside & inside surfaces of a
bone are blanketed by a mosaic-like, pattern of soft
tissues,cartilage or osteogenic membrane called as
Growth Fields.There when altered are capable of
producing an alteration in the growth of the particular
bone.
Growth Sites : Growth sites are growth fields that have
a special significance in the growth of a particular
bone.
Eg. Mandibular condyle in the mandible,
Maxillary tuberosity in the maxilla.
The growth sites may process some intrinsic potential
to growth.

5. Remodeling : It is the differential growth activity
involving simultaneous deposition & resorption on all
the inner & outer surfaces of the bone.
Eg. Ramus moves posteriorly by a combination of
resorption & deposition.
Growth Centers: Growth centers are special growth
sites , which control the overall growth of the bone.
Eg. Epiphyseal plates of long bone.

6.  The maxilla is the largest of the facial bones excluding
mandible.
 It contributes a large share in the formation of the
facial skeleton.
 Maxillae are a pair of pneumatic bones and form
together the upper jaw.

7. Bone is a specialized tissue of mesodermal origin. It
forms the structural framework of the body.
Bone is calcified tissue that supports the body & gives
points of attachment to the musculature.
Normal bone contains between 32-36% of organic
matter.
-Bone deposition & deposition
-Cortical drift
-Displacement
Mechanism Of Bone Growth

8. Most bones grow by interplay of bone deposition &
resorption .
A combination of bone deposition & resorption
resulting in a growth movement towards the deposition
surface is called “Cortical Drift”.
If bone deposition & resorption on either side of a
bone are equal - the thickness of the bone remains
constant.
If in case more bone is deposited on one side & less
bone resorbed on the opposite side – the thickness of
the bone increases.
Cortical Drift:

9. It is the movement of the whole bone as a unit.
Displacement can be of two types.
Primary displacement: If a bone gets displaced as a result
of its own growth, it is called “Primary displacement”.
eg. Growth of the maxilla at the tuberosity region results in
pushing of the maxilla against the cranial base which results
in pushing of the maxilla against the cranial base which
results in the displacement of the maxilla in a forward &
downward direction.
Secondary displacement: If the bone gets displaced as a
result of growth & enlargement of an adjacent bone, it is
called Secondary displacement.
eg. The growth of the cranial base causes the forward &
downward displacement of the maxilla.
Displacement

10. Characteristics of Bone Growth
Bone formation occurs by 2 methods of differentiation
of mesenchymal tissues that may be of mesodermal or
ectomesenchymal origin.
Accordingly 2 types of bone growth is normally seen.
•Intra-membranous ossification : The transformation
of mesenchymal connective tissue usually in
membranous sheets, into osseous tissues.
.

11. • Endochondral ossification: The conversion of
hyaline cartilage prototype models into bone.

12. ANATOMY

13. • The body of the maxilla is roughly pyramidal
is shape.
• The anterior surface of the body of the
maxilla presents,
a} nasal notch medially.
b} anterior nasal spine.
c} infra orbital foramen.
d} canine fosse.

14.  In addition, three process of maxilla are,
a} frontal process of maxilla, it directed
upwards.
b} zygomatic process of maxilla articulates
with the zygomatic bone.
c} the alveolar process of maxilla.

15. FRONTAL PROCESS
• The frontal process
projects posterosuperiorly
between nasal and
lacrimal bones.
• It is a strong triangular
process projecting
upwards with a back tilt
and a truncated tip.

16. ZYGOMATIC PROCESS
 it projects laterally from
the junction of anterior,
posterior, and orbital
surfaces and bears a
triangular rough area on
its upper surface for
articulation with maxillary
process of zygomatic
bone.

17. ALVEOLAR AND PALATINE PROCESS
• Alveolar process is a
thick and arched wide
behind and socketed for
dental roots.
• Palatine process projects
as a thick horizontal
shelf from junction of
nasal surface of the body
of maxilla and its
alveolar process.

18. PRENATAL DEVELOPMENT OF
MAXILLA
Growth and development of an individual can be
divided into PRENATAL & the POSTNATAL periods.
The pre-natal period of development is a dynamic phase
in the development of a human being. During this
period, the height increases by almost 5000 times as
compared to only a threefold increase during the post-
natal period. The pre-natal life can be arbitrarily divided
into three periods.
1. Period of the Ovum
2. Period of the Embryo
3. Period of the Fetus

19. Period of the ovum: This period extends for a period
of approximately two weeks from the time of
fertilization. During this period the cleavage of the
ovum and the attachment of the ovum to the intra-
uterine wall occurs.

20. Period of the embryo: This period extends from the
fourteenth day to the fifty sixth day of intra-uterine life.
During this period the major part of the development of
the facial & the cranial region occurs.

21. Period of the fetus: This phase extends between the
fifty sixth day of intra-uterine life till birth. In this period
,accelerated growth of the cranio-facial structures occurs
resulting in an increase in their size. In addition, a
change in proportion between the various structures also
occurs.

22. Prenatal Growth Of Maxilla
Around the fourth week of intra-uterine life, a prominent bulge
appears on the ventral aspect of the embryo corresponding to
the developing brain.Below the bulge a shallow depression which
corresponds to the primitive mouth appears called “
STOMODEUM”.The floor of the stomodeum is formed by the
buccopharyngeal membrane which separates the stomodeum
from the foregut.

23. By around the 4th week of intra-uterine life, five
branchial arches form in the region of the future head &
neck. Each of these arches gives rise to muscles,
connective tissue, vasculature, skeletal components, &
neural components of the future face.

24. The first branchial arch is called the mandibular arch &
plays an important role in the development of the
naso- maxillary region. The mesoderm covering the
developing forebrain proliferates & forms a downward
projection that overlaps the upper part of stomodeum.
This downward projection is called
“FRONTONASALPROCESS”.

25. The stomodeum is thus overlapped superiorly by the
fronto-nasal process. The mandibular arches of both
the sides form the lateral walls of the stomodeum.
The mandibular arch gives off a bud from its dorsal end
called the “MAXILLARY PROCESS”.

26. The maxillary process grows ventro-medio-cranial to
the main part of the mandibular arch which is now
called the “MANDIBULAR PROCESS”.
Thus at this stage the primitive mouth or stomodeum is
overlapped from above by the frontal process, below by
the mandibular process & on either side by the maxillary
process.

27. The ectoderm overlying the fronto-nasal process shows
bilateral localized thickenings above the stomodeum.
These are called the “NASAL PLACODES”. These
placodes soon sink and form the nasal pits.
The formation of these nasal pits divides the fronto-
nasal process into two parts:
a)The medial nasal process &
b)The lateral nasal process

28. The two mandibular processes grow medially & fuse to
form the lower lip & lower jaw.
As the maxillary processes become narrow so that the
two nasal pits come closer. The line of fusion of the
maxillary process & the medial nasal process
corresponds to the naso-lacrimal duct.

29. DEVELOPMENT OF PALATE
• The process of development of palate occurs at about 5-9 weeks of
embryo.
• It is basically formed by 3 elements that is premaxilla (or incisivum) and 2
lateral palatal shelves.
The palate is formed by the contribution of:
• Maxillary process.
• Palatal shelves given off
by the maxillary process
• Fronto-nasal process

30. PRIMARY PALATE
•By the fusion of the maxillary and nasal processes in the
roof of the stomodeum the primitive palate (or primary
palate) is formed, and the olfactory pits extend backward
above it. It consists of the maxillary process and medial
nasal process. The lip and primary palate close during the
4th to 7th weeks of gestation

31. The development of the secondary palate commences in the
sixth week of human embryological development. It is
characterized by the formation of two palatal shelves on
the maxillary prominences
SECONDARY PALATE

32. •As the palatal shelves grow medially their, their union is
prevented by the presence of tongue
•Initially the developing palatal shelves grow vertically toward
the floor of mouth.

33. •During 7th week of intrauterine life, a transformation in the
position of the palatine shelf occurs
•They change from a vertical to a horizontal position
•Various reasons are given to explain how this transformation
occurs. They are:
• Alteration in biochemical and physical consistency of the connective
tissue of the palatal shelves
• Alteration in vasculature and blood supply to the palatal shelves
• Appearance of an intrinsic shelf force
• Rapid differential mitotic activity
• Muscular movements

34. • The 2 palatal shelves, by 8 ½ weeks of intra uterine
life are in close approximation to each other
• Initially the 2 palatal shelves are covered by an
epithelial lining. As they join the epithelial cells
degenerate
• The connective tissue of the palatal shelves
intermingle with each other resulting in their fusion

35. • The entire palate does not contact and fuse at the
same time. Initially the contact occurs in the central
region of the secondary palate posterior to the
premaxilla
• From this point, closure occurs both anteriorly and
posteriorly

36. OSSIFICATION OF PALATE
•The ossification of palate proceeds during 8th
week from the
spread of bone into mesenchyme of fused palatal shelves and
from trabaculae appearing in primary palate as premaxillary
centres all derived from single primary ossification centres of
maxillae.
•The most posterior part of the palate does not ossify, this
forms the soft palate
•The mid palatal suture ossifies by 12-14 yrs

37. • Posteriorly the hard palate is ossified by trabaculae
spreading from single primary ossification centre of each
of palatine bone.
• Mid palatal suture is first evident at 10 ½ weeks, it is in Y
shape in coronal section and binds the vomer with palatal
shelves.
• In adolescene it become intedigitated and mechanically
interlocked.
• Ossification does not occur in the posterior part giving
rise to region of soft palate.

38. • The musculature of soft palate is derived from 1st
, 2nd
, and 4th
brachial arches.
a) Tensor veli palatini is the earliest of 5 palatal muscles to
develop at 40 days forming myoblasts.
b) Palatopharyngeous at 45 days.
c) Levator veli palatini at 8th
week.
d) Palatoglossus at 9th
week.
e) Uvular muscle at 11th
week.
• The growth at mid palatal suture ceases between 1&2 years
of age.
• Its growth in width is larger in its posterior than in its
anterior part

39. • The retention of syndesmosis in the midpalatal suture into
adulthood even after growth has normally ceased at this time
permits the application of expansion.
• The forceful separation of suture by an orthodontic appliance
reinstitutes compensatory bone growth at this site expanding
palatal growth.

40. • Cleft lip (cheiloschisis) and cleft palate (palatoschisis),
which can also occur together as cleft lip and palate, are
variations of a type of clefting congenital
deformity caused by abnormal facial development
during gestation.
• Cleft palate is a condition in which the two plates of
the skull that form the hard palate (roof of the mouth)
are not completely joined
• Palate cleft can occur as complete or incomplete (a 'hole'
in the roof of the mouth, usually as a cleft soft palate).
When cleft palate occurs, the uvula is usually split. It
occurs due to the failure of fusion of the lateral palatine
processes, the nasal septum, and/or the median palatine
processes (formation of the secondary palate)
APPLIED ANATOMY

41. POST NATAL DEVELOPMENT OF
MAXILLA
• Post natally maxilla develops by various processes
like
a) Displacement.
b) Sutural growth.
c) Remodeling.

42. Growth movements
Drift
•Cortical remodeling
•Selective apposition and resorption of cortical surfaces
Displacement
• Movement of entire bone
• Primary displacement
• Secondary displacement

43. Primary displacement
• In this type of displacement,
the maxilla is displacement
inferiorly by its own
enlargement.

44. Secondary displacement
• Here the growth of
cranial base displaces the
maxilla in downwards
and forwards.

45. Sutural growth
• The mechanism of growth are:
a) Connective tissue proliferation.
b) Ossification.
c) Surface apposition.
d) Resorption.
e) Translation.

46. Maxilla is related to cranium by
The maxilla is connected to the cranium and cranial base
by a number of sutures. These sutures include:
•Frontomaxillary suture.
•Zygomaticomaxillary suture.
•Zygomaticotemporal suture.
•Pterygopalatine suture.

47. According of weinman and sicher
Sutures are oblique and parallel to each other. This allows the downward
and forward repositioning of maxilla as growth occurs at these sutures. As
growth of surrounding soft tissue occurs, the maxilla is carried downwards
and forward. This leads to opening up of space at the sutural attachments.
New bone is formed on either side of the suture. Thus the overall size of
the bones on either side increases. Hence a tension related bone formation

48. All these changes does not occur simultaneously but
rather differentially and sequentially.

49. Remodeling occurs by bone deposition & resorption to
bring about:
a) Increase in size
b) Change in shape
c) Change functional relationship
SURFACE REMODELING

50. Bone changes in shape & size by two basic mechanisms, bone
deposition & bone resorption. The bone deposition &
resorption together is called “ BONE REMODELING”.
The changes that bone deposition & resorption can produce are:
•Change in size
•Change in shape
•Change in proportion
•Change in relationship of the bone with adjacent structures.
Bone deposition & resorption

51. Bone remodeling seen in the midfacial region
The floor of the orbit faces superiorly, laterally and anteriorly .
Surface deposition occurs here resulting in growth in a superior,
lateral and anterior direction.
Bone deposition occurs along the posterior margin of the
maxillary tuberosity causing lengthening of the dental arch and
enlargement of the A-P dimension of the entire maxillary body.
This helps in accommodating the erupting molar

52. Bone remodeling of the palate resulting in
its downward displacement
Bone resorption occurs on the lateral wall of the nose leading to
an increase in size of the nasal cavity. Bone resorption is seen on
the floor of the nasal cavity. To compensate this, there is bone
deposition on the palatal side. Thus a net downward shift occurs
leading to increase in maxillary height

53. Enlow’s V principle
Growth of the palate exhibiting V pattern of growth

54. As the maxilla descends, transversely, additive growth on the free
ends increases the distance between them. The buccal segments
move outward and downward, as the maxilla itself is moving
downward and forward, following the principle of expanding
EXPANDING “V” PRINCIPLE OF MAXILLA

55. Lacrimal bone : A key growth
mediator.
• The lacrimal bone is a diminutive flake of a bony
island which is surrounded by sutural connective
tissue.
• The sutural system of the lacrimal bone provides for
the slippage of multiple bones along sutural interfaces
with the pivotal lacrimal as they all enlarge
differentially.
• The lacrimal sutures allow maxilla to slide downward
along its orbital contacts which facilitates inferior
displacement of the maxilla

56. Maxillary tuberosity
Maxilla grows horizontally by
remodelling of maxillary tuberosity.
Deposition occurs on the posterior
facing periosteal surface of the
tuberosity, Endosteal surface is
resorptive. Cortex moves posteriorly
and little laterally.
Maxillary tuberosity is major GROWTH
SITE of maxilla in posterior region.
Primary displacement of maxilla occurs
due to deposition at tuberosity. The
amount of forward movement is equal
and opposite to the posterior
lengthening . This functions to lengthen
the dental arch and to enlarge the
anterioposterior dimensions of the
entire maxillary body.

57. Key ridge.
• Major change in surface contour
occur along the vertical crest just
below the malar protruberace,
this is called key ridge

58. Timing and compensatory mechanism
• The adaptation is most dramatically seen in alveolar process.
When palate is narrow, the alveolar process compensates in
both height and width.
• Remodelling of alveolar process compensates nicely for palatal
displacement.
• The plane of occlusion is co-ordinated during growth with
overall morphologic pattern.
• It is due to adaptive and compensatory nature of alveolar
growth the occlusion is sometimes at variance with skeletal
relationship.

59. The para-nasal sinuses
4 sets of paranasal sinuses -maxillary -sphenoidal -frontal –
ethmoidal
Begins development at end of 3rd month i.u. as outpouchings
of mucous membranes of middle & superior nasal meatus &
sphenoethmoidal recesses.

60. Primary Pneumatization : Early paranasal sinuses expand into
cartilage walls & roof of nasal fossae by growth of mucous
membrane sacs into maxillary, sphenoid, frontal, ethmoid bones.
Secondary Pneumatization : Sinuses enlarge into bone from their
initial small outpocketings, retaining communication with nasal
fossae through ostia.

61. MAXILLARY SINUS
1st to develop at 10 wks from middle meatus by primary
pnumatization into ethmoid cartilage.
Secondary pneumatization into ossifying maxilla starts in
5th month i.u.
At birth it is large enough to be clinically imp. &
radiographically identifiable.
Sinus enlarges by resorption of cancellous bone except
on medial wall.

62. Rapid & continuous downward growth of sinus after
birth brings its wall in close proximity to roots of
maxillary cheek teeth.
As each tooth erupts ,vacated bone becomes
pneumatized by expanding sinus.
In adulthood, roots of molar teeth commonly project
into sinus lumen.

63. Absence of the development of frontal & spenoidal
sinuses is characteristic of down syndrome.
Diminution or absence of sinuses is also found in
Apert’s syndrome.
If a metopic suture persists ,the frontal sinuses are small
or even absent.

65. Developmental disturbances affecting
maxilla
• Cleft palate.
• Treacher collins syndrome.
• Cleidocranial dysostosis.
• Cruzons syndrome.
• Apert syndrome.
• Achondroplasia.

67. MAXILLARY HYPOPLASIA
Maxillary hypoplasia is the name that dentists have given to the
underdevelopment of the maxillary bones, which produces midfacial
retrusion and creates the illusion of protuberance of the lower jaw.

68. TREATMENT
• Prosthetic replacement
• Maxillary surgery
• Protraction headgear

69. Clinical implications
The articulation of maxilla with mandible gives the
classification of occlusion.
• Maxillary protrusion can be reduced and increased tonicity
of perioral soft tissue. E.g. functional appliance.
• Functional imbalances due to extrinsic factors can be
corrected if excess factors are removed. E.g
thumbsucking.
• Maxillary arch can be enlarged by the rapid expansion
appliances.

70. Conclusion
• It is important for the clinician to know the normal
and the abnormal ranges of growth for proper
diagnosis, treatment planning and selecting appropriate
clinical procedures.
• Orthodontic treatment irrespective of appliance
depends to a great extent on adaptive capacity of
alveolar process, growth and remodelling.

71. References.
• Enlow’s; Essentials of Facial Growth, 4th
Edition.
• Sperber; Craniofacial Embryology.
• Graber; Orthodontics, Current Principles and
Practice.
• Seminar on Development of Maxillary
Components by Dr. Pramod Shetty.

72. Thank You.