Functional matrix hypothesis
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Initial formulationForm and function are intimately related
1867 – Effect of function on bone – femur- Anatomist Meyer & mathematician Culmann – Theory of “Trajectory of bone formation”
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Initial formulation
• 1870 – Julius Wolff – stated that the external morphology & internal architecture of bone is directly proportional to the functional forces acting upon it
• Modern restatement – WILHELM HIS –1874 – “physiology of the plastic”
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Initial formulation• Wilhelm Roux & Hans Driesch –
ENTWICKLUNGMECHANIK (developmental mechanism)
• Benninghoff showed that the stress trajectories obeyed no individual bone limits but rather the demands of the functional forces
• “Functional cranial component” – Vander Klauuw
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Stress trajectories
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Development of a conceptDept of anatomy – university of columbia (1948-51)
“problems of cranial growth in general and the role of sutures in particular”
Books –“The development of the vertebral skull – Gaven de beer“on growth and form” - Thompson
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Development of a concept
10 yrs – extensive study
1960 – 1st paper – YOUNG – American journal of physical anthropology
1962 – 2nd major paper - orthodontic community
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Point of view
• ‘If neither bone or cartilage were the determinants for craniofacial growth , it would appear that the control would have to be in the adjacent soft tissues’
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Classic statement – 1981• The functional matrix hypothesis claims
that the origin , growth & maintenance of all skeletal tissues and organs are always secondary , compensatory and obligatory responses to temporally and operationally prior events or processes that occur in specifically related non-skeletal tissues, organs or functioning spaces
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Basic concept of growth
• Transformation (remodelling)-change in size and shape-osseous deposition and resorption
• Translation (displacement)-change in spatial position-without osseous deposition and
resorptionwww.indiandentalacademy.com
Basic concept of growth
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Functional cranial component
Skeletal unit Functional matrices
MacroskeletalEg-endocranial
surface Of calvaria Microskeletal
Eg-coronoid,angular
PeriostealEg-teeth and
muscles
CapsularEg-orofacial,neurocranial
Components & concepts
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Concepts and components
Head and neck region carry out number of functions
-Respiration-Olfaction-Vision-Hearing-Balance
-Chewing-Digestion-Swallowing-Speech-Neural integration
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Components & concepts• Functional cranial component (FCC) – The
tissues, organs, spaces & skeletal parts necessary to carry out a given function
• Functional matrix – non-skeletal tissues of a FCC eg-muscles, glands, nerve ,vessels, teeth
• Skeletal unit – skeletal tissues which protect or support the functional matrix eg-bone,cartilage & tendinuous tissue
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Skeletal unit
Microskeletal unit– bone composed of several contiguous skeletal units eg . Mandible – alveolar angular condylar coronoid basal
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Skeletal unit
• Maxilla- nasalorbitalpneumaticbasalalveolar
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Skeletal unit•Macroskeletal unit - adjoining portions
of number of neighbouring bones carrying out a single function
eg-endocranial surface of calvaria
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Functional demands
• Coronoid --------------temporalis
• Angular---------------- masseter & medial pterygoid
• Alveolar---------------presence of teeth
• Basal-------------------inferior alveolar neuromuscular triad matrix
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Periosteal matrix• These are non-skeletal functioning units
adjacent to the skeletal unit.
• Produce secondary – compensatory transformation
• Best eg:- role of temporalis – coronoid process
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Periosteal matrix
• Removal,denervation – postinfectively/post-traumatically - decrease in the size or total disappearance
• Functional hypertrophy/hyperactivity- increase in size and change in shape
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Capsular matrix
• FCC (skeletal + functional matrices) capsules
• Each capsule is a envelope sandwiching the FCC in b/w its layers
• Arise , grow, exist , operate & maintained
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Capsular matrix
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Capsular matrix
4 such cranial capsules exist
Neurocranial capsuleOrofacial capsuleOrbital capsuleOtic capsule
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Capsular matrix
• Capsular matrices exist in volumes
• volumetric capsular matrix – expansion of capsule
• Translation of embedded bones
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Neurocranial capsule• Calvarial bones sandwiched b/w the skin & duramater
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Neurocranial capsule
• Composition--5 layers of the scalp
outer table
--bone inner table
diploic space
--2 layers of duramater
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Neurocranial capsule
• Contents--brain
--leptomeninges volume of NCC
--CSF
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Neurocranial capsule
• Two important factors volume of the neural massTotal neural mass – morphologically significant – than amount of brain tissue
Expansion of the neurocranial capsulePrimary event – expansion of capsular matrices – compensatory expansion of capsule – translation of FCC
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Neurocranial capsule
• Hydrocephaly-- passive , non – periosteal translative
growth produced by capsular matrices
--The expansion of the NCC is always proportional to the increase in neural mass
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Orofacial capsule
• Sandwiched b/w skin & mucosa
• Surrounds and protects oronasopharyngeal functioning spaces
• These 3 spaces (oral,nasal & pharyngeal)are unitary spaces
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Orofacial capsule
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Orofacial capsule
• Patency – functional unit
• Related to the general metabolic demands of the body
• Respiratory functional space volume – dominant cranial functioning space
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Orofacial capsule
WORK OF BOSMAPrimary function – maintenance of patent
airway
Dynamic musculoskeletal postural balance – “Airway Maintenance Mechanism”
Airway maintained throughout range of motion of head & neck
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Orofacial capsule
• Embryonic development--originate by process of enclosure
--formation of palate – nasal & oral portions
--Volumetric growth of these spaces is the primary morphogenetic event in facial skull growth
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Support for the hypothesis mandibular growth
--bilateral condylectomy – does not effect growth or spatial movement of acondylar contiguous structures
Hydrocephaly
Microcephaly
Size of eye and orbit
Teeth and alveolar bonewww.indiandentalacademy.com
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CLINICAL ASPECTS• Etiology of m o due to deficient functioning
eg – mouth breathing, tongue thrusting, digit sucking
• Growth modulation is based upon this theory
• Appliances are used to either transmit, eliminate or guide the natural forces of musculature
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CLINICAL ASPECTS
• Palate splitting – adjustive and compensatory reactions of sutural connective tissue and the immediate sensitive response of membranous bone to tensional forces
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Shortcomings
• No clear explanation of how functional needs are transmitted to the tissues around mouth and nose – Proffit
• Does not suggest unitary mechanism
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Thank you
For more details please visit www.indiandentalacademy.com