Functional matrix theory- Revisited .pptx

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1. FUNCTIONAL MATRIX THEORY- Revisited Presented by : Dr. ADITI JAIN 1 ST Year PG Santosh Dental College Department of Orthodontics and Dentofacial Orthopedics

2. History: of Functional Matrix Theory Given By: MELVIN L. MOSS. (American Orthodontist)- 1962 C oncept of “ Form follows Function ” : C. J. Van der Klaauw (Dutch Zoologist) -1948-52. Article: Melvin L. Moss & Richard W. Young : A functional approach to craniology in American journal of physical anthropology- 1960. In the year 1981, Moss gave the classical statement Melvin L. Moss(1923-2006)

3. Definition “The origin, form, growth and maintenance of all skeletal tissue and organs are always secondary, compensatory and obligatory responses to chronological and morphological prior events or processes that occur in specifically related non-skeletal tissues, organs or functional spaces (functional matrices).”

4. Explanation: The theory considers the head and not the skull as the composite area. Head and neck region performs various functions : Digestion, respiration, speech, olfaction, balance, vision. Each of these functions is completely carried out by “Functional Cranial Component” . Totality of skeletal structure + Soft tissue + Functioning space = Functional Cranial Component .

5. Functional Cranial Component Functional Matrix Skeletal Unit Periosteal Matrix Capsular Matrix Neurocranial Capsule Orofacial Capsule Micro- skeletal Unit Macro- skeletal Unit Otic Capsule Orbital Capsule

6. Basic Concept of Growth Transformation: It is a change in shape and size. Osseous deposition and resorption. It is a direct response to primary morphogenic demand of specifically related function matrix. Translation: Change in spatial relation. It is without osseous deposition and resorption. It is Passive.

7. Periosteal Matrix Transformation Micro- Skeletal Unit Capsular Matrix Translation Macro- Skeletal Unit Directly; Actively Indirectly; Passively

8. Skeletal Unit When a bone is made up of several contiguous skeletal units they are termed as micro skeletal units. The maxilla and mandible is made of number of micro skeletal units. Micro- Skeletal Unit All the skeletal tissue associated with single function are called as skeletal unit The skeletal unit made up of bones, cartilage, tendinous tissue.

9. Macro Skeletal Unit When adjoining portions of a number of neighboring bone are united to function as single cranial component, is termed as macro skeletal unit Example:- endocranial system of calvarium maxilla & mandible.

10. Periosteal Matrix All non skeletal functional units adjacent to skeletal unit form the periosteal matrices. They act by bringing transformation of the related skeletal units. Alteration in periosteal matrices functional demands produce secondary, compensatory transformations of the size and or shape of the skeletal units. Such transformations are brought about by interrelated process of bone deposition and bone resorption.

11. Capsular Matrix Defined as the organ and space that occupy broader anatomical complex. T his class of matrix are those masses and spaces that are surrounded by capsules. All the functional cranial components (functional matrices together with the skeletal units) organize in the form of cranial capsules. Each of these capsules is an envelop containing functional cranial component.

12. Neurocranial Matrix Sandwiched between skin and dura matter. Consists of: 5 layers of scalp Bone 2 layers of dura matter. Volume of the neural mass is important whether or not it contains “normal” amount brain tissue.

13. Expansion of the enclosed capsular matrix volume Capsule enlarges The whole of the included and functional components are carried outwards in a totally passive manner.

14. Microcephaly Hydrocephaly

15. Orofacial Capsule Surround and protect oronasopharyngeal space. Surrounded by skin and mucous membrane on either side. Originates by process of enclosure. Primary function is maintaining airway this is accomplished by “AIRWAY MAINTENANCE SYSTEM”.

16. Volumetric growth of these spaces is the primary morphogenetic event in facial skull growth. Growth of functional spaces-increase in the size of capsule. The whole of the included and enclosed functional components are translated to a new position in space. AJO – May 1972, MOSS STATED THAT INVESTIGATIONS ARE STILL GOING TO FIND OUT VARIOUS MEANS AND PROCESS BY WHICH MORPHOGENETIC STIMULI ARE TRANSMITTED TO THEIR SKELETAL UNIT ,MODE OF TRANSMISSION,ITS RECEPTION AND TRANSLATION

17. Drawback Opposition By Various Authors MO s S 1972 JOHNSTON 1976 KOSKI 1977 WAYNE WATSON 1982 No clarification on as to how functional needs are transmitted to tissues.

18. FMH: Revisited The role of Mechanotransduction. The Role of an Osseous Connected Cellular Network. The Genomic Thesis. The Epigenetic Antithesis and the Resolving Synthesis. Orofacial Capsular Matrices Defined.

19. Basis of Revision The developmental origin of all cranial elements and all their subsequent change in shape, size and location ,as well as their maintenance in being ,are always without exception secondary ,compensatory and mechanically obligatory response to the operationally prior demand of their related cephalic non-skeletal cells, tissues, organs and operational volumes.

20. Constraints Macroscopic measurements use the techniques of point mechanics and arbitrary reference frames. Roentgenographic cephalometry permitted only method specific descriptions that cannot be structurally detailed. This constraint was removed by continuum mechanics techniques of FEM. This version’s descriptions did not extend “downward” to processes at the cellular, subcellular or molecular structural domains or extend “upwards” to the multicellular process by which bone tissues respond to lower level signals. Lower attributes ≠ Higher attributes Methodologic Constraints Hierarchical Constraints

21. The Role of Mechanotransduction Cells are irritated. Mechanosensing Mechanoreception : It transmits an extracellular physical stimulus into a receptor cell. Mechanotransduction : It transduces or transform the stimulus’s energetic and/or informational content into an intracellular signal. 1

22. Osseous Mechanotransduction Unique in 4 ways: Most of mechanosensing cells are cytologically specialized, but bone cells are not. One loading stimulus evoke 3 adaptation. Osseous signal transmission is aneural. Responses are confined within “bone organ” independently.

23. Types of Mechanotransductive Processes 1.Ionic Or Electrical Processes Subsequent intercellular trasport of the created ionic or electrical signals through a plasma membrane. Electromechanical Electro kinetic Electric field strength (1-10 uV /cm) Stretch Activated Channels Loading (1k-3k ue ) S-A get activated passage of certain sized ions (K+, Na+, Ca2+) 2.Mechanical Processes Extracellular Collagen Intracellular Nuclear Membrane Integrin

24. Mechanical Process Stretch Activated Channels Ionic / electrical Process MECHANICAL PROCESSES

25. The role of an Osseous Connected Cellular Matrix Osteocytes have cytoplasmic processes which are oriented 3-Dimmensionally. Present laterally and vertically. All bone cells except osteoclast are interconnected with Gap Junctions. Gap Junctions are found where plasma membrane of a pair of markedly overlapping canalicular process meet. 2 Superficial Osteoblast Periosteal and endosteal Osteoblast Periosteal and endosteal Osteoblast Superficial Osteoblast Periosteoblastic Cell Periosteoblastic Cell BIDIRECTIONAL

26. The Network Theory Initial Cell Stimuli (weighted input) Summation Intercellular signal (mechanotransduction) Hidden Layer Cells (Adjacent osteocytes) Final Layer cells (osteoblast) Bone Responses - Output The CCN’s shows oscillation i.e. iterative reciprocal signaling (feedback) between layers.

27. Attributes Of CCN’s Developmentally, it is an untrained self-organized, self-adapting and epigenetically regulated system. Operationally, it is a stable, dynamic system that exhibits oscillatory behavior permitting feedback. Structurally, an osseous CCN is nonmodular, i.e., the variations in its organization permit discrete processing of differential signals. It is this attribute that permits the triad of histologic responses to a unitary loading event.

28. The Genomic Thesis The initial version of the functional matrix hypothesis (FMH), claiming epigenetic control of morphogenesis, was based on macroscopic experimental, comparative, and clinical data. Recently revised, it now extends hierarchically from gross to microscopic levels and identifies some epigenetic mechanisms capable of regulating genomic expression. 3 The genomic  thesis holds that the genome, from the moment of fertilization, contains all the information necessary to regulate. 

29. Orthodontic Implications Rigid Genomic control of odontogenesis:- Temporally sequential Spatially restricted Epigenetic regulation of odontogenesis E xperiments on polyphyodont chiclid fish. Poor co-ordination of form and size of structures(teeth and jaws) by regulatory genes result in malocclusion and dentofacial deformities.

30. The Genomic Thesis In orofacial Biology The Genomic Thesis claims that prenatal craniofacial development is controlled by two inter related processes: Initial regulatory (Homeobox) gene activity. Activity of the regulatory molecular groups: growth factor families and steroid/thyroid family. It is claimed that regulatory molecules can “ alter the manner in which homeobox genes coordinate cell migration and subsequent cell interactions that regulate growth”. And be involved in the “genetic variations causing, or contributing to, the abnormal development of relatively common craniofacial malformations”.

31. Critical Definitions Epigenetics : All of the extrinsic factors impinging on vital structures and intrinsic events occurring inside and outside of a cell. Hierarchy : The structural and functional complexity is increasing “upwards”. Atoms Molecules Cells Tissue Organ Organism. Emergence : The integrated activities of all the attributes in a given hierarchical level self organize to produce the next higher level of complexity. “ Bones do not Grow, they are Grown” Causation : How the attributes of a given biological structural level “cause” (control, regulate, determine) the attributes of the next higher level.

32. Classification Of Causation Principle Causes of ontogenesis Intrinsic / Prior (Molecular Level) Extrinsic / Proximate (Regulate) Material With , What? Cellular & intercellular Formal By what rules? Genomic Code Efficient How? Epigenetic Factors Final Why? Development Creation of new state Sufficient

33. Drawback of genomic Thesis The genomic thesis passes directly from molecules to morphogenesis: directly from DNA molecules to adult morphology, ignoring the roles of the many epigenetic processes and mechanism. The epigenetic antithesis is integrative & details the processes and mechanisms seeking to clarify the casual chain between genome & phenotype. Reductionist and Molecular

34. The Epigenetic Antithesis & the Resolving Synthesis Process : Series of action or operation that lead towards a particular result. Mechanism : Fundamental physical or chemical process(es) involved in, or responsible for an action, reaction or other natural phenomenon. Epigenetics : The entire series of interactions among cell and cell products which leads to morphogenesis and differentiation. 4

35. Loading Chains of intracellular molecular levers begin deformation. Epigenetic Cell signaling processes. Extracellular matrix deformation. Cell shape Changes. Other processes and mechanisms. (DNA methylation) Epigenetic Regulation of functional matrices.

36. A resolving Synthesis The morphogenesis is regulated by the activity of both epigenetic and genomic processes and mechanisms. Complex Adaptive system(CAS) Epigenetic Input (Minor Change) Morphological output (High Fluctuation) Complexity Theory

37. Loading At cellular/tissue level Static (Muscle Contraction) Dynamic (Gravity) Mechanosensing Mechanoreception Mechanotransduction Ionic/ Electrical Mechanical Process S-A Channels Electromechanical Electrokinetic Field Strength Macromolecular Lever Skeletal Unit Cell Signal Connected Cellular Network Bone Response

38. Orofacial Capsular Matrices Defined Carbonated hydroxyapatite + protein + water = Human Enamel 5 Timothy G. Bromage 95% 3-4% 1-2% Hard and tough food Following Perturbations exists- Purpose = Hard & tough food Soft Diet Enamel is 2mm thick and more on molars. Molar HSB’s originate at the Enamel Dentine Junction, dispersing into a zone of parallel rods. Enamel Prism discontinuity serves to resist the propagation of cracks. Dentine side of DEJ itself is graded too. Enamel Crystallites are hexagonal offering resistance to strain in bulk enamel. Ameloblast secretory behavior renders incremental lines.

39. Functional matrix of nasal Cavity: Air Obligatory Nasal breathing is to promote normal facial growth and function. The diet (chewing hard and tough food) causes stresses and strains called as Bernoulli’s forces which are the primary cause of nasal cavity development. Perturbations exist due to breathing through mouth which has led to current suboptimal health of the human industrialized population.

40. THANK YOU In the words of Sir Arthur Keith “Civilization is antievolutionary in it’s effects; it works against the laws and conditions which regulate the earlier stages of man’s ascent.”

41. References Dubbeldam JL. An annotated bibliography of C.J. van der Klaauw with notes on the impact of his work. Acta Biotheor . 2007;55(1):1-22. doi : 10.1007/s10441-007-9006-9. Epub 2007 Mar 9. PMID: 17347784; PMCID: PMC2781101. Melvin L. Moss,Twenty years of functional cranial analysis, American Journal of Orthodontics, Volume 61, Issue 5,1972,Pages 479-485,ISSN 0002-9416,https://doi.org/10.1016/0002-9416(72)90152-2.( https://www.sciencedirect.com/science/article/pii/0002941672901522 ) Moss ML, Young RW. A functional approach to craniology. Am J Phys Anthropolgy . 1960 Dec;18(4):281-92. doi : 10.1002/ajpa.1330180406. PMID: 13773136. The functional matrix revisited 1. The role of mechanotransduction AJODO –1997 ; 112 :8-11. The functional matrix revisited 2. The role of an osseous connected cellular network AJODO -1997; 112:221-6 The functional matrix revisited.3 .The genomic thesis AJODO-1997;112:338-42 The functional matrix revisited.4 .The epigenetic antithesis AJODO-1997;112:410-7