Functional Matrix Theory

Basic about FMH

1. FUNCTIONAL MATRIX THEORY PRESENTED BY: ZYNUL JOHN DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPAEDICS

2. Learning objectives Various theories of growth Functional matrix theory Clinical implications

3. contents Introduction Various theories of growth Functional matrix theory Drawbacks Clinical implications Summary reference

4. Introduction Growth is strongly influenced by genetic factors, but it can also be significantly affected by the environment, in the form of nutritional status, degree of physical activity, health or illness and a no. of similar factors. Since a major part of the need for the orthodontic treatment is created by disproportionate growth of the jaws, it is necessary to learn how skeletal growth is influenced and controlled to understand the etiologic processes of malocclusion and dentofacial deformity

5. Theories of bone growth Bone remodelling theory(Brash) Genetic theory( Brodie ) Sutural theory( Sicher and Weinnman ) Cartilaginous theory(James Scott ) Functional matrix theory(Melvin Moss) Servo system theory( Alexandre Petrovic ) Neurotrophism ( Behrents ) Enlows V principle of growth .

6. FUNCTIONAL MATRIX HYPOTHESIS Van der Klaaw was a professor of descriptive zoology whose most important contribution is the introduction of new concept- functional cranial component. Influenced by this work, Melvin Moss in 1960s put forward the Functional Matrix Theory. The origin, growth and maintenance of all skeletal tissues and organs are always secondary, compensatory and obligatory to temporally and operationally prior events or process that occur in specifically related non-skeletal tissues, organs or functional spaces (Functional matrices).”

7. He theorizes that growth of the face occurs as a response to functional needs and is mediated by soft tissues in which jaws are embedded. In this conceptual view- the soft tissues grow and both bone and cartilage react. Operationally, the head is a region within which certain functions occur. Every function is completely carried out by certain hard and soft tissues: SKELETAL UNIT FUNCTIONAL MATRIX TOTALITY OF SKELETAL, SOFT TISSUES AND FUNCTIONAL SPACES NECESSARY TO CARRY OUT A FUNCTION IS “ FUNCTIONAL CRANIAL COMPONENT

8. Functional cranial component SKELETALUNIT FUNCTIONAL MATRIX MICROSKELETAL EG: CORONOID PROCESS, ANGULAR . MACROSKELETAL EG: MANDIBLE MAXILLA PERIOSTEAL MATRIX EG: TEETH MUSCLES CAPSULAR MATRIX EG: OROFACIAL

9. SKELETAL UNIT Bony structures that support functional matrix Skeletal unit provides necessary biochemical role of providing protection and support to soft tissue matrix MICROSKELETAL UNIT MACROSKELETAL UNIT

10. MICROSKELETAL UNIT A single bone may be composed of number of skeletal units, termed as microskeletal unit. Their growth is influenced by periosteal matrices. coronoid condyle ramus body alveolar

11. Macroskeletal unit When adjoining portion of number of bones are united to function as a single cranial component. MAXILLA MANDIBLE

12. Functional matrices Functional matrix refers to all the soft tissues and spaces that perform a given function. PERIOSTEAL MATRIX CAPSULAR MATRIX

13. PERIOSTEAL MATRIX All non skeletal functional unit adjacent to skeletal unit forms periosteal matrices. They act actively by means of osseous deposition and resorption . They act to alter the size and shape of the bones. The growth process is transformation.

14. TEMPORALIS MUSCLE CORONOID PROCESS LATERAL PTERYGOID CONDYLAR PROCESS MASSETER AND ANGULAR PROCESS MEDIAL PTERYGOID TEETH ALVEOLAR BONE INFERIOR ALVEOLAR NEUROMUSCULAR TRIAD BASAL BONE

15. Functional cranial analysis of coronoid process in rat 63 Columbia-Sherman rats were used . All were operated on the 11 th postnatal day & sacrificed from 2 – 43 days, postoperatively at intervals from 1 - 3 days. The middle & posterior fibers of left temporalis were removed. Source: Functional cranial analysis of coronoid process in rat: MELVIN MOSS AND MARY-ANN MEEHAN

16. results First five postoperative days - slight diminution in size, while form remained unchanged. - very slight reduction in trabeculae The 6 th post operative day - marked reduction in size - upper surface of process affected - trabeculae exposed In all later stages coronoid was markedly reduced, now seen only as a slight bump

17. In few cases, middle portion of muscle was not completely removed . Though it showed reduction in size and shape but it was recognisable.

18. The dependence of the coronoid process (skeletal unit) upon the demands of its functional matrix ( temporalis muscle) is shown in these alterations in size and shape following unilateral muscle resection 14 TH POST-OPERATIVE DAY 18 TH POST-OPERATIVE DAY 23 RD POSTOPERATIVE DAY

19. So, the point is the coronoid process does NOT grow first and thus provide a "platform" upon which the temporalis muscle can then alter its functions. The total growth changes in all aspects of coronoid process form (size and shape) are at all times a direct and compensatory response to the morphogenetically prior demands of the temporalis muscle function .

20. CAPSULAR MATRIX Organs and spaces that occupy a broader anatomic complex. Each capsule is an envelope that contains series of functional cranial component, skeletal unit and their related functional matrices. Capsular matrix do not act by process of active resorption and deposition. They act passively on macroskeletal unit by producing its secondary translation in space. Eg : neurocranial space orofacial space

21. OROFACIAL CAPSULE CORONOID CONDYLAR ALVEOLAR PROCESS BASAL BONE ANGULAR LATERAL PTERYGOID TEMPORALIS MEDIAL PTERYGOID MASSETOR TOOTH BUD ENLARGING CAPSULE

22. NEUROCRANIAL CAPSULE As the capsule enlarges, whole of included and enclosed periosteal matrices and microskeletal units are carried outward in a passive manner.

23. OROFACIAL CAPSULE OROFACIAL CAPSULE GROWS PERIOSTEAL MATRIX RESPONDS TO THIS VOLUMETRIC EXPANSION THIS THEN ELICITS CHANGES IN MICROSKELETAL UNIT The growth of all orofacial skeletal units is a combination of the two types of growth process discussed above – periosteal and capsular, transformative and translative , changes in size and shape, and changes in spatial position. GROWTH IN RESPONSE TO FUNCTIONAL NEEDS

24. Functional cranial analysis of maxilla Head is a composite structure, operationally consisting a no.of independent functions : Olfaction, Respiration, Vision, Digestion, Speech, etc . The facial bones are passively carried outwards by the primary expansion of the enclosed matrices.this causes adaptive fill in response. ( e.g. : orbital, nasal, oral matrices ) .

25. Orbital, nasal and oral space

26. There are three types of bone growth changes to be observed in the maxilla : First, those associated with passive motions of bone associated with primary expansion of the orofacial capsule. Secondly , changes in bone morphology associated with alterations in the absolute volume, size, shape or spatial position of maxillary functional matrices, such as the orbital mass. Finally there are bone changes associated with the maintenance of the form of the bone itself.

27. Functionalcranial analysis of mandible The mandible is not a unitary biological object, but rather a composite of several unitary & relatively independent functional cranial components. The skeletal units corresponding to these mandibular functional components include : Alveolar process Coronoid process Condylar process Angular process Body Chin

28. The mandibular cranial components arise & exist completely embedded within the capsule, they all are passively & secondarily translated in space to a new position as the capsule expands. Such passive translations of mandibular functional cranial components as a whole, also alters the individual periosteal matrices. This causes direct changes in the size &/or shape of their various skeletal units. A longitudinal series of cephalometric radiographs were taken by Moss & the following structures were traced: Anterior cranial base External surface of mandible Mental foramina

29. First , 2 tracings were superimposed on the cranial base, Moss observed the total growth changes of the mandibular complex during this period. Moss termed this is a Inter-Osseous Growth , i.e total growth relative to fixed anterior cranial base.

30. Similarly a second tracing was made superimposing the mandibular tracings on the mental foramen. We now observe the changes in shape or size of several mandibular units which occur independently of the changes in spatial position of these same units with time. This is termed as Intra-osseous Growth .

31. Finally a third composite tracing was made in which both the previous composite tracings were taken & superimposed on the outlines of the oldest mandibles. Downward and forward motion of the mandible primarily is passive translation, active transformation produces minor changes anteriorly and inferiorly and the posterior and upward compensatory growth of the condylar process.

32. 3 important concepts in mandibular growth - Moss Constancy of relative growth of mandible

33. Absolute migration of dention through alveolar bone- the migration is pronounced during eruption of permanent dentition

34. Change in direction of mental foramen

35. Periosteal Matrix ------------ > Skeletal Unit [Teeth] [Alveolar Bone] CLINICALIMPLICATIONS Capsular Matrix ------------- > Multiple Skeletal Units [Functional Appliances] [Jaw Bones]

36. FRANKEL APPLIANCE The Frankel Regulator buccal shields prevent the pressure of the buccinator being exerted on the dento alveolar area both during deglutition and at rest. The net effect is outward expansion to the “ought-to-be” acrylic shield functional matrix.

37. Drawbacks. No clarification on as to how functional needs are transmitted to tissues - PROFFITT In 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.

38. How the functional matrix is involved in its own growth and development on how it is controlled. That is, how much genome and how do the provocative ideas of complexity and self-organization play into this? – Donald Enlow

39. Functional Matrix Hypothesis - Revisited 1997 FMH 1- Role of Mechanotransduction FMH 2 - Role of Osseous Connected Cellular Network FMH 3 - The Genomic Thesis FMH 4 - The Epigenetic Antithesis and the Resolving Synthesis Am J Orthod Dentofac Orthop 1997;112

40. summary According to functional matrix hypothesis, apart from initiating the process of development, heredity and genetics play no active role in growth of skeletal structures. Bones do not grow, bones are grown. Expansion of soft tissue matrix is the primary response

41. reference Textbook of craniofacial growth- Sridhar Premkumar Text book of orthodontics-T.M Graber The capslar matrix- melvin moss The functional cranial analysis of mandible The primary role of functional matrices in facial growth- melvin moss

42. Thank You