Orthodontics- growth and development

1. Dr .Imtiaz Ahmed B.D.S , F.C.P.S , M-Orth (Edin)
HEAD OF ORTHODONTIC DEPARTMENT
SUPERVISOR , FCPS,MDS POST GRADUATE PROGRAM
DIKHIOUS
DOW UNIVERSITY OF HEALTH SCIENCES

3. Why do we assess growth?
 To determine optimum time for treatment
(growth modification and surgery)
 to determine the amount of growth left
 to determine type of growth

4. Principles of Tissue Growth
 Hypertrophy
 hyperplasia
 increased production of
extracellular matrix (cell
independent)

5. Bone, muscle and soft
tissue growth
 All are dependent on each other to some
degree
 Growth of mineralized tissues = can be done
in the surface only (periosteum)= surface
apposition of bone
 Growth of the soft and cartilaginous tissues =
interstitial growth

6. Growth of Cartilage/
Endochondral Ossification
 Long bones
 Epiphyseal plate
contains dividing
cartilaginous cells
 Rate of growth and
maturation of cells
need to be equal for
growth to occur
Proliferating cartilage
Epiphyseal plate

7. Growth of the Maxilla
 Growth of maxilla are produced by two basic
mechanism
 Passive displacement : created by growth of
cranial base that pushes the maxilla forward
 Active growth : growth itself occurs in
maxilla.

8. Growth of the Maxilla
 Remodeling of the
palatal vault moves it
in the same direction
as it is being translated
 bone is removed from
the floor of the nose
and added to the roof
of the mouth

9. Growth of the Maxilla
 On the anterior
surface, bone is
removed, partially
cancelling the
forward translation.
As the vault moves
downward, the
same process of
bone remodeling
also widens it.

10. Growth of the Maxilla
 Growth of the
surrounding soft
tissues translates
the maxilla
downward and
forward, opening
spaces in the
sutures where
bone is added.

11. Growth of the Maxilla
 Midpalatal suture is opened until teenage years.
 Apposition of bone in the molar area accounts
for space for the third molars.

12. Growth of the Maxilla
Summary:
growth of the maxilla
occurs in 2 ways:
 by apposition of bone in
the sutures that
connect the maxilla to
the cranial base
 by surface remodeling.

13. Growth of the Mandible
 Remodeling is done by resorption in the anterior
part of the ramus and deposition in the posterior
part of the ramus

15.  Gonial angle changes after little muscle activity.
 Transverse dimension is mainly due to growth at
posterior border in an expanding V pattern.

16. Growth of the Mandible
 Overall growth
direction results in a
downward and
forward displacement
with most of growth
occurring in the
ramus.

18.  The two rami also diverge outward from below to
above so that additive growth at coronoid notch ,
coronoid process &condyle also increses the superior
inter-ramus dimension.
 Alveolar process of mandible grows upward &
outward on an expanding arc. This permit dental arc
to accommodate the larger permanent teeth.

19. Growth of the Mandible
Mandibular symphysis is closed by age of 1 year.
Late mandibular growth:
 can occur in the late teenage years or adulthood
 most often seen in asians and males
 can cause incisor crowding when there is a tight
occlusion (overbite/overjet)

20. When things go wrong
 Congenital craniofacial malformations: cleft
lip/palate, syndromes (Apert, Crouzon, etc..),
craniosynostosis
 Non-syndromic craniosynostosis
 Trauma
 Ankylosis
 Juvenile rheumatoid arthritis

21. When things go wrong
 Blow to one side of the
mandible may fracture
the condylar process on
the opposite side
 pull of the lateral
pterygoid muscle
distracts the condylar
fragment including all the
cartilage = resorption
occurs
Trauma

22. ROTATIONAL CHANGES OF JAWS

23. ROTATIONAL CHANGES OF JAWS

24. MANDIBULAR ROTATION WITH
RESPECT WITH CRANIAL BASE

25. NORMAL MANDIBULAR ROTATION
PATTERN

26. JAW ROTATION IN LONG FACE
PATTERN

27. JAW ROTATION IN SHORT FACE
PATTERN

28. JAW ROTATION IN MAXILLA