Pre and post natal growth of maxilla

2. • Maxilla form from the tissues of the first branchial arch.
• Maxilla develops intramembranously.
• Around fourth week of intra utrine life a prominent bulge appears on ventral aspect of the
embryo corresponding to the developing brain. Below the bulge the shallow depression
which corresponds to the primitive mouth appears called stomatodeum.
2

3. 3
• Floor of stomatodeum is formed by buccopharyngeal membrane. Which separates it from
foregut
• Mesoderm covering the developing forebrain proliferates, and forms a downward projection
that overlaps the upper part of stomatodeum this downward projection is called frontonasal
process.
• Then mandibular arch forms the lateral wall of the stomatodeum. This arch gives off a bud
from its dorsal end, the bud forms the maxillary process.
• Reference: Chapter # 3 Ten cate’s Oral histology

4. • Begins week 6, up till week 12
• Develops from 2 structures:
• Primary palate (premaxilla)
• From fusion of two medial nasal prominences
• Secondary palate
• develops into hard and soft palate posterior to incisive foramen
• arises from paired lateral palatine shelves of maxilla
4

5. • Lateral palatine shelves of maxilla oriented in a superior-inferior plane with tongue interposed
• Later, palatine shelves elongate, and tongue moves inferiorly
• Shelves become oriented horizontally, approach one another and fuse in midline
• The median palatine raphe is a clinical remnant of fusion between the palatine shelves
• Lateral palatine shelves also fuse with primary palate and nasal septum, beginning in 9th week in
Anterio-posterior direction
• Reference: Chapter# 18 Oral anatomy, Histology and Embryology by B.K.B Berkovitz
5

6. • The maxilla develops postnatally entirely by intramembranous
ossification.
• Since there is no cartilage replacement, growth occurs in two
ways
• 1) by apposition of bone at the sutures that connect the maxilla to
the cranium and cranial base.
• 2) By surface remodeling.
6

7. • Growth of nasomaxillary area is produced by two basic mechanisms.
• 1) Passive displacement: Created by growth in the cranial base that pushes the
maxilla forward.
• 2) Active growth at the sutures
• The maxilla grows downward and forward as bone is added in the tuberosity area
posteriorly and at the posterior and superior sutures, but the anterior surfaces of
bone are resorbing at the same time.
• Reference: Chapter# 4 Contemporary Orthodontics by William R.Proffit
7

8. 8

9. • BONE AS THE PRIMARY DETERMINANT OF GROWTH CONTROL
• CARTILAGE AS THE PRIMARY DETERMINANT OF GROWTH CONTROL
• FUNCTIONAL MATRIX THEORY OF GROWTH CONTROL
9

10. • This theory implies that genetic control is expressed directly at
the level of the bone.
• This theory was rejected as when an area of the suture between
two facial bones is transplanted to another location the tissue
does not continue to grow.
• Secondly growth at sutures will respond to outside influence under
a number of circumstances.
10

11. • This theory suggests that genetic control is expressed in cartilage,
while bone responds passively to being displaced.
• Has some innate potential for growth
• Transplanting the nasal and spheno-occipital synchondrosis cartilages
show some growth and removing the nasal cartilage results in mid
face discrepancy
• But the condylar cartilage does not show any growth on
transplanting.
• So it was concluded epiphyseal cartilages and the cranial
synchondrosis can and do act as independently growing centres and
nasal septum perhaps to a lesser extent and condyle can not act as
growing centre.
11

12. • It proposes that "the origin, development and maintenance of all skeletal units are secondary,
compensatory and mechanically obligatory responses to temporally and operationally prior
demands of related functional matrices.
• The growth of cranium is a direct response to the growth of the brain
• Enlarged eye or small eye causes a corresponding change in the orbital cavity
• major determinant of growth of maxilla and mandible is enlargement of nasal and oral
cavities, which grow in response to functional needs
• Reference: Chapter# 2 Contemporary Orthodontics by William R.Proffit
12

13. References: 13