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Post on 16-Jul-2015
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Dr .Imtiaz Ahmed B.D.S , F.C.P.S , M-Orth (Edin)
HEAD OF ORTHODONTIC DEPARTMENTSUPERVISOR , FCPS,MDS POST GRADUATE PROGRAMDIKHIOUSDOW UNIVERSITY OF HEALTH SCIENCES
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
Principles of Tissue Growth
Hypertrophy hyperplasia increased production of
extracellular matrix (cell independent)
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
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
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.
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
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.
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.
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.
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.
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
Gonial angle changes after little muscle activity.
Transverse dimension is mainly due to growth at posterior border in an expanding V pattern.
Growth of the Mandible
Overall growth direction results in a downward and forward displacement with most of growth occurring in the ramus.
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.
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)
When things go wrong
Congenital craniofacial malformations: cleft lip/palate, syndromes (Apert, Crouzon, etc..), craniosynostosis
Non-syndromic craniosynostosis Trauma Ankylosis Juvenile rheumatoid arthritis
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
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