Growth & DevelopmentGrowth & Development
Part IIPart II
www.indiandentalacademy.com
INDIAN DENTAL ACADEMY
Leader in contin...
Hypothesis of craniofacial
growth
• Genetic theory
• Sicher’s suturalHypothesis
• Scott’s cartilagenous hypothesis
• Moss’...
Genetic theory
• What we sometimes assume to be genetic
may be acquired and superimposed on a
genetic foundation comman to...
• There is evidence to support polygenic
inheritance greatly limiting our ability to
explain facial dimension from study o...
• The old argument about heredity versus
environment has changed from the question
of which is more important to how,and i...
• Even if the size of facial bones were
inherited in a medelian fashion,that
inherited pattern is altered by environmental...
Sicher’s Hypothesis
(Sutural dominance theory)
• Sicher deduced from the many studies using
vital dyes, that the sutures w...
• Replacement of the connective tissue was
necessary for functional maintenance of the
bones.
• He said sutures of the nas...
Disadvantages
• Primarily because translatory growth of the
bones continue normally either in the
absence of sutures or th...
Scott’s Hypothesis
(Cartilagenous theory)
• Scott noting the prenatal importance of
cartilagenous portions of the head ,na...
• Sutural growth ,Scott felt came in response
to the growth of the other structures
including cartilagenous elements,brain...
Cartilagenous growth
www.indiandentalacademy.com
Moss hypothesis
• Moss feels that the bone and cartilage lack
growth determination and grow in response
to intrinsic growt...
• He terms the associated tissues,
“Functional matrices” ,Each component of
a functional matrix performs a necessary
servi...
• Moss divides the skull into series of discrete
functional components each comprised of a
functional matrix and an associ...
• He stress the dominance of non osseous
structures of the craniofacial complex over
the bony parts. Moss claims that the ...
Functional cranial comp.Functional cranial comp.
Functional matricesSkeletal unit
Micro sk.unit Macro sk.unit
Periosteal M...
• Each functional cranial component has a
skeletal and functional matrices.
• Skeletal unit’s biomechanical role is to
pro...
• Functional matrix actually carries out the
function .Ex. Muscle,gland,teeth,etc.
Functional matricies are futher divided...
• Mandible is a Macro skeletal unit.Coronoid
process,condyle, angle of the mandible are
all micro skeletal units.
• Perios...
• Capsular matrices act on the macroskeletal
unit I.e whole mandible and they bring
about translation or passive growth. T...
www.indiandentalacademy.com
Anacephaly & Hydrocephaly
www.indiandentalacademy.com
Petrovic’s hypothesis
( Servosystem)
• Using the language of cybernatics,cybernatics,
Petrovic, reasoned that it is the in...
the secondary cartilages is comprised not only
of direct effect of cell multiplication but
also of indirect effects
• In h...
Petrovic’s Hypothesis
www.indiandentalacademy.com
Changing concepts of
craniofacial growth
www.indiandentalacademy.com
Van limbrough Hypothesis
• Intrinsic Genetic factors- Genetics factors
inherent to the skull tissues
• Local epigenetic fa...
• Local environmental factors- local non
genetic influences originating from the
external environment (local external
pres...
Van limbrogh Hypothesis
www.indiandentalacademy.com
• Growth of the cranium occurs almost
entirely in reponse to growth of the brain
• Growth of the cranial base is primarily...
• Growth of the maxilla and its associated
structures occurs from a combination of
growth at sutures and direct remodellin...
Thank you
For more details please visit
www.indiandentalacademy.com
www.indiandentalacademy.com
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Growth&dev ii /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078

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Growth&dev ii /certified fixed orthodontic courses by Indian dental academy

  1. 1. Growth & DevelopmentGrowth & Development Part IIPart II www.indiandentalacademy.com INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
  2. 2. Hypothesis of craniofacial growth • Genetic theory • Sicher’s suturalHypothesis • Scott’s cartilagenous hypothesis • Moss’ Hypothesis • Petrovic’s Hypothesis • Van limborgh Hypothesis www.indiandentalacademy.com
  3. 3. Genetic theory • What we sometimes assume to be genetic may be acquired and superimposed on a genetic foundation comman to parents and progeny. www.indiandentalacademy.com
  4. 4. • There is evidence to support polygenic inheritance greatly limiting our ability to explain facial dimension from study of parents. www.indiandentalacademy.com
  5. 5. • The old argument about heredity versus environment has changed from the question of which is more important to how,and in what we way does environment alter the original form laid down by heredity. www.indiandentalacademy.com
  6. 6. • Even if the size of facial bones were inherited in a medelian fashion,that inherited pattern is altered by environmental influences,some epigeniticepigenitic and some general to such an extent that in the patient the underlying genetic features cannot be easily detected. www.indiandentalacademy.com
  7. 7. Sicher’s Hypothesis (Sutural dominance theory) • Sicher deduced from the many studies using vital dyes, that the sutures were causing most of the growth, he said infact “ …. The primary event in the sutural growth is proliferation of the connective tissue between the two bones. • If the connective tissue proliferates it creates the space for the appositional growth at the borders of the two bones.www.indiandentalacademy.com
  8. 8. • Replacement of the connective tissue was necessary for functional maintenance of the bones. • He said sutures of the nasomaxiallary and vault produced forces which separated the bones ,just as the synchondrosis expanded the cranial base and the epiphyseal plates lengthened long bones. www.indiandentalacademy.com
  9. 9. Disadvantages • Primarily because translatory growth of the bones continue normally either in the absence of sutures or through extirpation in experimental animals • In untreated cleft palates though suture is not present growth still takes place. www.indiandentalacademy.com
  10. 10. Scott’s Hypothesis (Cartilagenous theory) • Scott noting the prenatal importance of cartilagenous portions of the head ,nasal capsule ,mandible and cranial base feeling that this development is under the intrinsic genetic control • He specially emphasized how the cartilage of the nasal septum during its growth paced the growth of the maxilla. www.indiandentalacademy.com
  11. 11. • Sutural growth ,Scott felt came in response to the growth of the other structures including cartilagenous elements,brain, the eyes, and so forth.. www.indiandentalacademy.com
  12. 12. Cartilagenous growth www.indiandentalacademy.com
  13. 13. Moss hypothesis • Moss feels that the bone and cartilage lack growth determination and grow in response to intrinsic growth of associated tissues,noting that the genetic coding of craniofacial skeletal growth is outside the bony skeleton. www.indiandentalacademy.com
  14. 14. • He terms the associated tissues, “Functional matrices” ,Each component of a functional matrix performs a necessary service- such as respiration, mastigation, speech -while the skeletal tissues support and protect the associated functional matrices. www.indiandentalacademy.com
  15. 15. • Moss divides the skull into series of discrete functional components each comprised of a functional matrix and an associated skeletal unit,designing the functional matrices as a either periosteal or capsular. www.indiandentalacademy.com
  16. 16. • He stress the dominance of non osseous structures of the craniofacial complex over the bony parts. Moss claims that the growth of the skeletal components whether endochondral or intramembranous in origin is largely dependent on the growth of functional matrices. www.indiandentalacademy.com
  17. 17. Functional cranial comp.Functional cranial comp. Functional matricesSkeletal unit Micro sk.unit Macro sk.unit Periosteal M Capsular M www.indiandentalacademy.com
  18. 18. • Each functional cranial component has a skeletal and functional matrices. • Skeletal unit’s biomechanical role is to protect and or support its specific functional matrix.Each skeletal unit is further divided into microskeletal and macroskeletal. www.indiandentalacademy.com
  19. 19. • Functional matrix actually carries out the function .Ex. Muscle,gland,teeth,etc. Functional matricies are futher divided into periosteal matrices and capsular matrices. www.indiandentalacademy.com
  20. 20. • Mandible is a Macro skeletal unit.Coronoid process,condyle, angle of the mandible are all micro skeletal units. • Periosteal matrices includes muscles and teeth ; act on the microskeletal units directly and they bring about transformation or active growth. Their net effects is to alter the form (size and shape) of their respective units. www.indiandentalacademy.com
  21. 21. • Capsular matrices act on the macroskeletal unit I.e whole mandible and they bring about translation or passive growth. They do so by changing the volume of the capsule within which the functional cranial components Eg.oral cavity has inner oral epithelium and skin outside.Mandible is translated passively. www.indiandentalacademy.com
  22. 22. www.indiandentalacademy.com
  23. 23. Anacephaly & Hydrocephaly www.indiandentalacademy.com
  24. 24. Petrovic’s hypothesis ( Servosystem) • Using the language of cybernatics,cybernatics, Petrovic, reasoned that it is the interaction of a series of causal change and feed back mechanisms which determines the growth of the various crainofacial regions. • According to the servosystem theory of facial growth, control of primary cartilages takes a cybernatic form of command whereas in contrastwww.indiandentalacademy.com
  25. 25. the secondary cartilages is comprised not only of direct effect of cell multiplication but also of indirect effects • In his experiments petrovic detected no genetically predetermined final length for the mandible. • The direction & magnitude of condylar growth variation are perceived as quantitative responses to the lengthening of the maxilla www.indiandentalacademy.com
  26. 26. Petrovic’s Hypothesis www.indiandentalacademy.com
  27. 27. Changing concepts of craniofacial growth www.indiandentalacademy.com
  28. 28. Van limbrough Hypothesis • Intrinsic Genetic factors- Genetics factors inherent to the skull tissues • Local epigenetic factors- Genetically determined influences originating from adjacent structures(brain, Eyes etc) • General Epigenetic factors- Genetically determined influences originating from distant structures (Sex hormones) www.indiandentalacademy.com
  29. 29. • Local environmental factors- local non genetic influences originating from the external environment (local external pressure, muscle forces) • General environment factors -General non genetic influences originating from external environment (food, oxygen supply). www.indiandentalacademy.com
  30. 30. Van limbrogh Hypothesis www.indiandentalacademy.com
  31. 31. • Growth of the cranium occurs almost entirely in reponse to growth of the brain • Growth of the cranial base is primarily the result of endohondral growth and bony replacement at the synchondrosis and perphaps influenced by the growth of the brain www.indiandentalacademy.com
  32. 32. • Growth of the maxilla and its associated structures occurs from a combination of growth at sutures and direct remodelling of the surfaces of the bone. • Growth of the mandible occurs by both endochondral proliferation at the condyle and apposition and resorption of bone at surfaces. www.indiandentalacademy.com
  33. 33. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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