The document discusses the growth and development of the mandible from prenatal through postnatal periods. It describes how during the fetal period, the alveolar plate lengthens more rapidly than the ramus and maintains a constant ratio of lengths. A number of structures influence mandibular growth including the inferior dental nerve, Meckel's cartilage, tooth germs and muscles. Remodeling occurs throughout life as the mandible adapts to functional forces, with deposition and resorption at growth sites. Logarithmic curves can model mandibular growth patterns.
4. PRE NATAL GROWTH OF
MANDIBLE
EMBRYONAL
FETAL
PERIOD
PERIOD
www.indiandentalacademy.com
5. FETAL PERIOD
The alveolar plate lengthens more rapidly than does the
ramus
The ratio of the alveolar plate length to total mandibular
length is reasonably constant
The width of the alveolar plate shows a more rapid
increase than does total width
The ratio of the width between the mandibular angle to
total width is relatively constant during fetal life
www.indiandentalacademy.com
33. CONDYLAR RESECTION IN RHESUS
MONKEY
Facial height is less in A than
in B
Accentuation of anti gonial
notch
Shorter,wide anteriorly
positioned ramus
Larger and heavier coronoid
process
Reduced facial height on
operated side
www.indiandentalacademy.com
35.
The chondroblasts issuing
from a progenitor
chondroblast produce a
pyramid-like structure that
is a component of the
primary growth cartilage
of the rib
www.indiandentalacademy.com
36. RIB TRANSPLANT EXPERIMENT
OBSERVATIONS
Intracellular concentrations of Na+ tended to decrease
Intracellular concentrations of Ca++ & H+ ions tended to
increase
Intracellular pH was lowered
Na+ & K+ -ATPase activity was intensified
Ca++, Mg++ - ATPase ,and H+ - ATPase activities were
diminished
The numbers of cell divisions declined slightly and
demonstrated a significant slowing of growth rate
Similar variations were observed in condylar cartilage of
rats and humans www.indiandentalacademy.com
37. Differentiation rate of the precursor chondroblast
into progenitor chondroblast is submitted not only
to the command represented by genetic,hormonal,
humoral factors but also to epigenetic biomechanic
factors
Also autologous osteochondral rib transplant is
preferable in treatment of TMJ ankylosis than
metatarsal cartilage transplant
www.indiandentalacademy.com
39. TRANSVERSE SECTION OF CONDYLAR
NECK
Lingual surface A has received
periosteal deposits
B is composed of endosteal
compacted cancellous bone
produced during condylar neck
reduction
C has received periosteal
depositsas post.border of neck
grows in post.direction
D buccal area growing in
endosteal direction lller to B
E is undergoing resorption as
ant.part of neck grows in a
www.indiandentalacademy.com
cephalic direction towards side
A
43. The posterior growth of the
tuberosity is accomplised
by continued new deposits
of bone on its posteriorfacing exposure.
Part of the ramus just behind
the tuberosity remodels
medially
www.indiandentalacademy.com
45. CONCLUSION
The spatial movements of the mandible, and of the mental
foramen, related to the “rotation” of this logarithmic spiral
are clear indications of the passive translation of the
macro-skeletal unit within the expanding oro-facial
capsule,which is a response to the primary morphogenetic
enlargement of the oro-nasal functioning spaces. The
posterior and upward movements of the mandibular
foramen ,on the other hand, accurately reflect the active
transformative growth changes of the several mandibular
microskeletal units due to deposition and resorption of
bone brought about www.indiandentalacademy.com periosteal matrices
by the action of