1. growth & development


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1. growth & development

  1. 2. <ul><li>General concepts of growth </li></ul><ul><li>Growth Assessment </li></ul><ul><li>Bone formation and growth control </li></ul><ul><li>Growth of craniofacial complex </li></ul>
  2. 3. <ul><li>Growth Development </li></ul><ul><li>Increase in size - increase in </li></ul><ul><li>& number complexity </li></ul><ul><li>Anatomical - increase in </li></ul><ul><li>specialization </li></ul><ul><li>- phsiological or </li></ul><ul><li>behavioral </li></ul>
  3. 4. <ul><li>Pattern </li></ul><ul><li>Variability </li></ul><ul><li>timing </li></ul>
  4. 5. <ul><li>Reflects proportionality overtime </li></ul><ul><li>Allows predictability </li></ul><ul><li>Ex: changes in overall body proportions </li></ul><ul><li>- cephalocaudal gradient of growth </li></ul>
  5. 6. <ul><li>Not all tissues </li></ul><ul><li>grow at the same rate </li></ul>
  6. 7. <ul><li>Individuals are not alike in the way they grow </li></ul><ul><li>It is important to know if an individual is at the extreme of a normal variation or outside the normal range </li></ul>
  7. 8. <ul><li>The same events happen to different individual at different times ( biologic clock) </li></ul><ul><li>Some children grow quickly and mature early </li></ul><ul><li>Chronological age Vs Development age </li></ul><ul><li>CA is not a good indicator of growth status because of timing and variability </li></ul>
  8. 9. <ul><li>To determine optimum time for treatment(growth modification & surgery) </li></ul><ul><li>To determine the amount of growth left </li></ul><ul><li>To determine type of growth </li></ul>
  9. 10. <ul><li>“ Brachy”tends to grow horizantly </li></ul><ul><li>“ Dolicho” tends to grow vertically </li></ul><ul><li>Knowing the general pattern of growth and the expected direction can be helpful in orthodontics diagnosis and treatment planning . </li></ul>Vertical Growth Damages Faces (Dolicocephalic) Horizontal Growth Improves Faces (Brachycephalic)
  10. 11. <ul><li>Bone ,teeth,sometimes cartiladge </li></ul><ul><li>Hyperplasia </li></ul><ul><li>hypertrophy </li></ul><ul><li>Mineralized ECM </li></ul><ul><li>Interstitial growth is </li></ul><ul><li>Impossible after calcification </li></ul><ul><li>Direct or surface deposition </li></ul><ul><li>Everything including some cartiladge except bone and teeth </li></ul><ul><li>Hyperplasia </li></ul><ul><li>Hypertrophy and secretion of ECM occur in the surface </li></ul>
  11. 12. <ul><li>The sites of growth </li></ul><ul><li>Type of growth </li></ul><ul><li>Control of growth </li></ul>
  12. 13. <ul><li>Flat bones –intermembranous bone </li></ul><ul><li>Ossification center </li></ul><ul><li>Apposition of new bones at the cranial sutures ,periosteal activity (remodelling)-pressure from the growing brain </li></ul><ul><li>Bone resorption from the inner surface and bone deposition in the outer surface - remodelling </li></ul>
  13. 14. <ul><li>Bones of the base of the skull are formed by endochondreal ossification . </li></ul><ul><li>Centers of ossification appears leaving some cartilage called synchondroses in between </li></ul><ul><li>These are the growth sites </li></ul><ul><li>. Sphino-occipital </li></ul><ul><li>. Intersphenoid </li></ul><ul><li>. Sphenoethmoidal </li></ul>
  14. 15. <ul><li>Cranial base grows by endochondreal ossification that occurs at both margins of the synchondrosis. </li></ul>
  15. 16. <ul><li>Intermembranous </li></ul><ul><li>Growth occur by : </li></ul><ul><li>. Apposition of bone at the sutures that connect the maxilla to the cranium </li></ul><ul><li>. Surface remodelling </li></ul><ul><li>Downward and forward – anterior maxilla is the area of resorption </li></ul>
  16. 17. <ul><li>Growth of the surrounding soft tissue translates the maxilla downward and forward ,opening spaces in the sutures where bone is added </li></ul>
  17. 18. <ul><li>Remodelling of the palatal vault moves it in the same direction as it is being translated </li></ul><ul><li>Bone is removed from the floor of the nose and added to the roof of the mouth </li></ul><ul><li>On the anterior surface ,bone is removed ,partially cancelling the forward translation ,as the vault moves downward ,the same process of bone remodelling also widen it . </li></ul>
  18. 20. <ul><li>Intermembranous and endochondral </li></ul><ul><li>Cartridge-condyle </li></ul><ul><li>Growth sites : </li></ul><ul><li>. Chin inactice </li></ul><ul><li>.translated downward and forward by growth at the mandibular condyle along the posterior border of the ramus </li></ul><ul><li>. The body grows longer by periosteal apposition of bone on its posterior surface </li></ul><ul><li>. The ramus grows higher by endochondral replacement at the condyle accompanied by surface remodelling </li></ul><ul><li>. growth is upward and backward </li></ul>
  19. 21. <ul><li>Remodelling is done by resorption in the anterior part of the ramus and deposition in the posterior part of the ramus </li></ul>
  20. 24. <ul><li>Overall growth direction results in a downward and forward displacement with most of growth occuring in the ramus . </li></ul>
  21. 26. <ul><li>Orthodontics alternative Official Site for Natural Growth Guidance.flv </li></ul>