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Functional matrix revisited
- 1. FUNCTIONAL MATRIX THEORY REVISITED BY Dr.Gejo Johns Dept of orthodontics
- 2. contents Functional matrixtheory Constrains of FMH Functional matrix theory revisited Articles Reference
- 3. Functional Matrix Hypothesis-MelvinL. Moss 1962 Revisited –1997 FMH 1 FMH 2 FMH 3 FMH 4 ( Am J Orthod Dentofac Orthop 1997;112)
- 4. Functional matrix theory 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.
- 5. Functional cranialcomponent Skeletal unit Functional matrix Macroskeletal Eg:endocranial surface Of calvari Microskeletal Eg:coronoid, angular Periosteal E:-teeth and muscles Capsular matrix neurocranial orofacial
- 7. The periostealmatrices stimulation causes growth of the microskeletal unit .They act to alter the size or shape or both of the bones. The growth process that occurs due to periosteal matrix stimulation are called ‘Transformation” The capsular matrix act indirectly on macroskeletal unit or entire functional cranial component . They do not alter the size and shape of the skeletal unit they change their location in space this is called ‘Translation’.
- 9. Drawbacks of functionalmatrix theory No clarification on how functional needs are transmitted to tissues - PROFITT MOSS - Methodological constraints Hierarchical constraints
- 10. Methodological constraints FMHuses macroscopic measurements by using point mechanics and arbitary reference frames like cephalometric radiograph. Measurement technique and arbitary reference planes are now beeen replaced by continuum mechanics technique like –FEM
- 11. Hierarchical constraints Secondconstraint of FMH doesn’t explain how the extrinsic , epigenetic functional matrix stimuli are transduced into regulatory signals at the cellular, multicellular or molecular levels FMH versions were suspended or sandwiched as it were between these two hierarchical levels
- 12. Experimental andtheorical studies of bone adaptation consider only the unicellular , unimolecular or ,unigenomic levels not extensible to higher multicellular , tissue levels. The new version of FMH tries to bridge the gap between hierarchial constraints and explain the operation from genome to organ level
- 13. The newestFMH version includes two complementary concepts 1. Mechanotransduction occur in single cell 2. Connected cellular network
- 16. Mechanotransduction Mechanotransduction isthe process by which mechanical stimulus is converted into biological signal to alter a cellular response Mechanosensing processes enables a cell to sense and response to extrinsic loadings, a widespread biologic attribute by using the process of mechanoreception
- 18. Osseous Mechanotransduction Staticand dynamic loadings are continuously applied to bone tissue tending to deform both extracellular matrix and bone cells When an appropriate stimulus exceeds threshold values the loaded tissue responds by bone cell adaptation processes. Both osteocytes and osteoblasts are competent for intracellular stimulus reception and transduction and subsequent intracellular signal transmission.
- 19. Osteoblast directlyregulate bone deposition and maintenance and indirectly regulate osteoclastic resorption Osseous mechanotransduction is unique in four ways 1. Most other mechanosensory cells are cytologically specialized ,but bone cells are not. 2. One bone loading stimulus can evoke three adaptational response ,whereas non-osseous processes generally evoke one
- 20. 3. Osseous signaltransmission is aneural, whereas all other mechanosensational signals use afferent neural pathways 4. The evoked bone adaptational response are confined within each bone organ independently.
- 21. Types of mechanotrasnductive processes 1.IONIC-broughtabout transport of ions through plasma membrane resulting in creation of electrical signal. 2.Stretch activated channels loading S-A get activated passage of certain sized ions k+,ca2+, Na+ 3. Electrical processes Electromechanical Electro kinetic Electric field strength 4 Mechanical process
- 22. Mechanical process Thebasis of this mechanism is the physical continuity of the transmembrane molecule integrin This molecule is connected extracellularly with the macromolecular collagen of the organic matrix and intracellulary with cytoskeletal actin
- 23. • Macromolecular levercapable of transmitting information from strained matrix to bone cell nuclear membrane extracellular intracellular Macromolecular collagen Transmembrane integrin Cytoskeletal actin Nuclear membrane Organic matrix
- 25. The firstarticle implicate the ability of bone cells to carry out intacellular mechanosensation and transduction and intra cellular network communication
- 26. FMHR# 2 Therole of osseous connected cellular network (CCN) Bone as an osseous connected cellular network (CCN). All bones are extensively interconnected by gap junction and form an osseous connective cellular network Osteocytes have cytoplasmic processes which are oriented three dimensionally GAP JUNCTION- are found where plasma membrane of pair of markedly overlapping cannicular process meet
- 27. Canaliculi formextensive connection between osteons and interstitial region Gap junction connect Superficial osteocytes to periosteal and endosteal osteoblast Periosteal osteoblast with preosteblastic cells and these in turn are similarly interconnected
- 28.
- 29. Bone as CCN Network theory Cells are arranged in 3 layers Initial input layer Final output layer Intermediate / hidden layer
- 30.
- 31. FNH#2 CONCLUSION TheFMH concept of mechanotransduction and of computational bone biology offers an explanatory chain extending from the epigenetic event of skeletal muscle contraction, hierarchically downward , through the cellular and molecular levels to the bone cell genome and then upwards again through histologic levels to the event of gross bone form adaptational changes
- 33. The initialversion of FMH claiming epigenetic control of morphogenesis. Current – genomic regulation of growth
- 34. The Genomic thesis The genomic thesis holds that from the moment of fertilization all the information necessary for the regulation is determined by the DNA It includes regulation of intranuclear formation and transcription of mRNA. It is the genome of an individual which determines the overall phenotype
- 35. APPLICATION OF GENOMIC THESISIN OROFACIAL BIOLOGY 10%-of the genome is related to the phenotypic ontogenesis Prenatal craniofacial development is controlled by two processes- 1.Initial Regulatory gene activity. 2.Subsequent activity of the regulatory molecular groups such as growth factory families and steroid/ thyroid/retinoic acid super family.
- 36. CAUSATION There iscontinuing controversy concerning the role of genomic and non genomic processes in the regulation of growth this is resolved by several types of causation.
- 37. CLASSISAL CATEGORISATION OF CAUSATION Thereare four principle causes of ontogenesis MATERIAL(what is acted upon?) FORMAL(set of rules?) EFFICIENT(immediate preceding event?) FINAL( why)
- 38. MATERIAL: Cellularand extracellular substance, extrinsic and intrinsic FORMAL: Genomic regulation EFFICIENT: Epigenetic event FINAL : Teleology
- 41. The genomicthesis is denied because it is reductionist and molecular Descriptions of the causation of all hierarchically higher and structurally more complex morphogenetic processes are reduced to explanation of mechanisms at the molecular (DNA) level.
- 42. THE EPIGENETIC ANTITHESIS Refersto to the entire series of interaction among cells and cell products which lead to morphogenesis and differentiation THESE INCLUDE- 1. All extrinsic, extraorganismal, macroenvironment factors 2. All intrinsic, intraorganismal, microenviromental factors
- 43. COMPLEXITY AND SELF ORGANISATION Complex adaptive system ensembles of several tissues and organs, and not as clusters of individual cells and extracellular substances Ontogeny is a nonlinear process. Spontaneous self organizing ontogenic processes and mechanism can create phenotypic variability under constant genetic and other extra organisimal epigenetic condition.
- 44. “Environmental factors playa decisive role in all ontogenetic processes. But it is the organism itself that ,as an integrated system ,dictates the nature of each and a very developmental response. The living organism self organizes on the basis of its own internal structuring, in continuous interaction with the environment in which it finds itself
- 45.
- 49. References The functionalmatrix hypothesis revisited.1. The role of mechanotransduction – Moss; Am J Orthod Dentofac Orthop 1997; 112:8-11 The functional matrix hypothesis revisited. 2.The role of an osseous connected cellular network – Moss; Am J Orthod Dentofac Orthop 1997;112:221-6
- 50. The functionalmatrix hypothesis revisited.3.The genomic thesis – Moss; Am J Orthod Dentofac Orthop 1997; 112:338-42 The functional matrix hypothesis revisited.4.The epigenetic antithesis & the resolving synthesis – Moss; Am J Orthod Dentofac Orthop 1997; 112:410-17 Moss ML. The functional matrix. In: Kraus B, Reidel R, editors. Vistas inorthodontics. Philadelphia: Lea & Febiger, 1962:85-98.
- 51. Moss ML.The primacy of functional matrices in orofacial growth. Trans Br Soc Study Orthod and Dent Pract 1968;19:65-73. Moss ML. Twenty years of functional cranial analysis. Am J Orthod 1972;61:479-85. Moss ML, Salentijn L. The primary role of functional matrices in facial growth.Am J Orthod 196%;55:566- 77. Moss ML, Salentijn L. The capsular matrix. Am J Orthod 1969b;56:474-90. Moss ML. The functional matrix hypothesis revisited. 1. The role of mechanotransduction.Am J Orthod Dentofac Orthop 1997;111:8-11.