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

    • Growth & DevelopmentGrowth & Development Part IIPart II www.indiandentalacademy.com INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
    • Hypothesis of craniofacial growth • Genetic theory • Sicher’s suturalHypothesis • Scott’s cartilagenous hypothesis • Moss’ Hypothesis • Petrovic’s Hypothesis • Van limborgh Hypothesis www.indiandentalacademy.com
    • 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
    • • There is evidence to support polygenic inheritance greatly limiting our ability to explain facial dimension from study of parents. www.indiandentalacademy.com
    • • 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
    • • 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
    • 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
    • • 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
    • 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
    • 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
    • • 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
    • Cartilagenous growth www.indiandentalacademy.com
    • 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
    • • 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
    • • 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
    • • 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
    • Functional cranial comp.Functional cranial comp. Functional matricesSkeletal unit Micro sk.unit Macro sk.unit Periosteal M Capsular M www.indiandentalacademy.com
    • • 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
    • • 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
    • • 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
    • • 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
    • www.indiandentalacademy.com
    • Anacephaly & Hydrocephaly www.indiandentalacademy.com
    • 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
    • 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
    • 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 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
    • • 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
    • 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 the result of endohondral growth and bony replacement at the synchondrosis and perphaps influenced by the growth of the brain www.indiandentalacademy.com
    • • 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
    • Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com