functional matrix theory1 / orthodontic courses by indian dental academy

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”


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”


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


Stress trajectories


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


Development of a concept

10 yrs – extensive study

1960 – 1st paper – YOUNG – American journal of physical anthropology

1962 – 2nd major paper - orthodontic community


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’


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


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


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


Concepts and components

Head and neck region carry out number of functions

-Respiration-Olfaction-Vision-Hearing-Balance

-Chewing-Digestion-Swallowing-Speech-Neural integration


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


Skeletal unit

Microskeletal unit– bone composed of several contiguous skeletal units eg . Mandible – alveolar angular condylar coronoid basal


Skeletal unit

• Maxilla- nasalorbitalpneumaticbasalalveolar


Skeletal unit•Macroskeletal unit - adjoining portions

of number of neighbouring bones carrying out a single function

eg-endocranial surface of calvaria


Functional demands

• Coronoid --------------temporalis

• Angular---------------- masseter & medial pterygoid

• Alveolar---------------presence of teeth

• Basal-------------------inferior alveolar neuromuscular triad matrix


Periosteal matrix• These are non-skeletal functioning units

adjacent to the skeletal unit.

• Produce secondary – compensatory transformation

• Best eg:- role of temporalis – coronoid process


Periosteal matrix

• Removal,denervation – postinfectively/post-traumatically - decrease in the size or total disappearance

• Functional hypertrophy/hyperactivity- increase in size and change in shape


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


Capsular matrix


Capsular matrix

4 such cranial capsules exist

Neurocranial capsuleOrofacial capsuleOrbital capsuleOtic capsule


Capsular matrix

• Capsular matrices exist in volumes

• volumetric capsular matrix – expansion of capsule

• Translation of embedded bones


Neurocranial capsule• Calvarial bones sandwiched b/w the skin & duramater


Neurocranial capsule

• Composition--5 layers of the scalp

outer table

--bone inner table

diploic space

--2 layers of duramater



• Contents--brain

--leptomeninges volume of NCC

--CSF



• 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



• Hydrocephaly-- passive , non – periosteal translative

growth produced by capsular matrices

--The expansion of the NCC is always proportional to the increase in neural mass


Orofacial capsule

• Sandwiched b/w skin & mucosa

• Surrounds and protects oronasopharyngeal functioning spaces

• These 3 spaces (oral,nasal & pharyngeal)are unitary spaces


Orofacial capsule


Orofacial capsule

• Patency – functional unit

• Related to the general metabolic demands of the body

• Respiratory functional space volume – dominant cranial functioning space


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


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


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

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


CLINICAL ASPECTS

• Palate splitting – adjustive and compensatory reactions of sutural connective tissue and the immediate sensitive response of membranous bone to tensional forces


Shortcomings

• No clear explanation of how functional needs are transmitted to the tissues around mouth and nose – Proffit

• Does not suggest unitary mechanism



Thank you

For more details please visit www.indiandentalacademy.com

functional matrix theory1 / orthodontic courses by indian dental academy

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