FUNCTIONAL MATRIX REVISITED
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Melvin moss 1997 • FMH R 1 • FMH R 2 • FMH R 3 • FMH R 4
Craniofacial growth •
Genomic P
•
• Craniofacial growthgenetically predetermined • Orthodontic calvinismwendell w •
•
•
Functional P Emphasis on functional factors Plasticity of craniofacial growth Concentration – not on skeletal tissues
Origin of the concept Functional cranial component Skeletal unit
Functional matrices
Macroskeletal Microskeletal
Periosteal
Capsular
eg-endocranial surface Of calvaria
eg-teeth and muscles
eg neural mass
eg-coronoid, angular
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
Why revisited FMH?? Constraints in the initial version... • Methodological • Hierarchical
Why revisited FMH?? Measurement techniques – eg – roentgenographic cephalometry Method specific – not structurally detailed
FEM – quantitative aspect of localized cephalic growth kinematics
Why revisited FMH?? • Hierarchical constraints
Downwards –cellular, subcellular or molecular upwards – multicellular processes “suspended” or “sandwiched” b/w two levels
Why revisited FMH?? • How epigenetic stimuli are transduced into signals by bone cells??
• How individual bone cell signal brings about a multicellular process??
Why revisited FMH?? Fundamental point • PFM – mechanical loading • Growth of SU – biologic process
How are they related??
Anatomic and conceptual basis • Epigenetic primacy
• PFM considered only cellular and molecular processes brings about the triad of active skeletal adaptation. Deposition Resorption maintenance
Anatomic and conceptual basis • The developmental origin of all cranial skeletal elements and all their subsequent changes in size, shape and location, as well as their maintenance in being, are always , without exception , secondary, compensatory and mechanically obligatory responses to the temporally and operationally prior demands of their related cephalic non-skeletal cells, tissues, organs and operational volumes.
FMH R1 • All vital cells – irritability Mechanosensation
Mechanoreception
Mechanotransduction Intracellular signal
Osseous mechanotransduction Loading static
dynamic deformation
Extracellular matrix Bone cells threshold
triad of bone cell adaptation
Osseous mechanotransduction Unique in 4 ways 1. Mechanosensory cells are cytologically specialized but bone cells are not 2. 1 stimulus – 3 adaptational responses 3. Osseous signal transmission is Aneural 4. Adaptational processes are independent
Osseous mechanotransduction • Important point mechanotransduction translates the informational content of PFM stimulus to skeletal unit cell signal
Hierarchically downward
Mechanotransductive Processes Ionic processes • Transport of ions through bone cell plasma membrane Stretch activated channels loading Ca++
Intracellular signal
Mechanotransductive Processes Electrical processes Electromechanical
Electrokinetic
Voltage activated Ion channels
Streaming potential
Transmembrane ion flow
Electric field strength exogenous electrical fields endogenous electrical fields (muscle activity)
Mechanotransductive Processes Mechanical processes • Macromolecular lever capable of transmitting information from strained matrix to bone cell nuclear membrane Organic matrix
………… ………… …………
Nuclear membrane
extracellular
………… ………… …………
Macromolecular collagen Transmembrane integrin Cytoskeletal actin
intracellular
Loading Dynamic
Static
Mechanosensing Mechanoreception (Input) Mechanotransduction Ionic / electrical S –Achannels
Electromechanical
Mechanical Electrokinetic
Field strength
Macromolecular lever
Skeletal unit cell signal CCN Response (output)
Deposition Resorption Maintainance
Bone as CCN • PFM stimulus
transduced
Intracellular signal
Intercellular communication
Bone adaptation
Multicellular level
Bone as CCN • All bone cells are interconnected – Gap Junctions • Exception - osteoclasts
Connexin 43
Plasma membrane of canalicular processes meet
Bone as CCN Gap jnc’ connects1. Osteons to interstitial regions 2. Superficial osteocytes – periosteal & endosteal osteoblasts 3. Laterally connected 4. Periosteal osteoblasts – preosteoblastic cells(interconnected)
Bone as CCN •
Important points
1. 2. 3. 4. 5.
Extensive communication CCN acts as a syncytium Gap jns acts as electrical synapses Permits bidirectional signal traffic No role of secondary messengers
Bone as CCN • Network theory Cells are arranged in 3 layers Initial input layer Final output layer Intermediate / hidden layer
Bone as CCN • Network theory Initial layer cells (loading);stimuli “Weighted”input
summation threshold
Intracellular signal (mechanotransduction) Hidden layer cells (adj. Osteocytes) Final layer cells (osteoblasts)
output
Bone as CCN
“The output determines the site, rate, direction, magnitude and duration of specific adaptive response i.e deposition, resorption or maintenance of the skeletal tissue�.
Bone as CCN Attributes of CCN 1. Developmentally – untrained, self- organized, epigenetically regulated 2. Operationally – stable, dynamic system – oscillatory behaviour 3. Structurally – non modular, i.e variation in organization permits discrete processing of signals
Bone as CCN Important points 1. Information is not stored discretely in CCN 2. CCN shows oscillations 3. Phenotypically similar osteoblasts – open gap jns 4. Dissimilar osteoblasts – sharp histological discontinuities
Bone as CCN Attributes of strain 1. Dynamic loadings – better response 2. Frequency – osteocytes are tuned to the frequencies of muscle function 3. Magnitude of the strain
Bone as CCN • conclusion New version – 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.
FMH R3 & FMH R4 The controversy • • • • •
Genetic Vs epigenetic Dichotomy How to solve dichotomy???? Dialectic analysis…. A method of examining and discussing ideas in order to find the truth
The controversy • Dialectic analysis Thesis Antithesis Resolving synthesis
Genomic thesis • The plan of growth – written down in nucleic acid message Jacob.F (Logic Of Life) • Within the fertilized egg, all information is present for growth Kessler and Melton • Genes make us, body and mind Dawkins ( The selfish gene)
Biologic bases for genomic thesis • Only 10% of genome is related to ontogenesis Housekeeping Genes
Structural Genes
• Regulate metabolic and resp activity of all cells • Regulate specific activity of special cell (neurons, osteoblasts)
Biologic bases for genomic thesis • Defect in the gene
Disorders….. Marfans syndrome O Imperfecta Achondroplasia
Physical analogy – construction of building
Genomic thesis in orofacial biology • Classic article on prenatal craniofacial dev Johnston. MC & Bronsky. PT Craniofacial development Initial regulatory homeobox gene activity
Subsequent activity of 2 mol. groups
Growth factor families
steroid/thyroid Retinoic acid Super family
Orthodontic implication of genomic thesis • Defect in the regulatory activity of genes or gene expression governing the size of the teeth and jaws
Malocclusion and dentofacial deformities
The other side of the coin • FMH supports the concept of epigenetic primacy • Epigenetic processes and mechanisms has the capability of regulating the genomic activity Epigenetic antithesis • Odontogenic eg. Of genomic / epigenetic dichotomy
The other side of the coin Mechanical forces Epigenetic signals
Dental papilla cells
Control of genetic expression of differential tooth form
To solve dichotomy… • Epigenetics • Hierarchy • Emergence • Causation
Epigenetics • All the extrinsic factors impinging on the vital structures – mechanical loadings / electrical signals
+
All intrinsic events occuring in the cell and between the cell
Hierarchy • Levels of organization • Sub atomic atom organism
organ
molecule tissue
Genomic thesis Epigenetic antithesis
subcellular cell
Emergence • Appearance of attributes at each successive higher level • Changes in attributes – cannot be predicted Osteocytes and bone tissue Emergence is not genomically controlled
Causation • How the attributes of a given biologic structural level cause (control, regulate and determine) the attributes of next higher level
Genomic thesis Epigenetic antithesis Coronoid and temporalis
Classification of causation Material (what is acted upon?) Intrinsic ;prior causes Formal (by what rules?) Efficient (what was the immediate preceding event?) Extrinsic ; proximate Final (why?)
Resolving synthesis Materials
Formal
Cellular/intercell Genomic code ular materials “laws” “rules”
Efficient Epigentic factors
sufficient Morphogenesis
final
Conclusion • Morphogenesis is regulated by both genomic and epigenetic processes, mechanisms • Both are necessary causes, neither alone are sufficient causes. • Their integrated activities provide the necessary and sufficient causes for growth and development
References • Moss, Primary role of functional matrix in facial growth- Am J Orthod, 1969 June:(20-31) • James Scott, The doctrine of functional matrices- Am J Orthod, 1969 July:(56) • Moss, The capsular matrix- Am J Orthod, 1969 nov:(56) • Moss, Twenty years of functional cranial analysis- Am J Orthod, 1972 may:(61) • Moss, Genetics, epigenetics and causation- Am J Orthod, 1981oct: (366-75) • Moss, Functional matrix hypothesis revisited- Am J Orthod Dentofac Orthop, 1997 july-oct. • Lysle E.Johnston Jr - Factors affecting the growth of the midface – The functional matrix hypothesis : Reflections in a jaundiced eye • David S. Carlson – craniofacial biology as normal science
HUMAN TOOTH MOVEMENT IN RESPONSE TO CONTINUOUS STRESS OF LOW MAGNITUDE Laura R. Iwasaki James E. Haack Jeffery C. Nickel John Morton AJODO 2000
• Conventional orthodontic therapy
100 g for canine retraction
Lag phase
• Current project – • Translation can occur without lag phase • Low force magnitude • Translation can occur at velocities that are clinically significant
• • • •
7 subjects 84 day study 18 g and 60 g Compressive stresses on distal aspect of canine was 4 kPa and 13 kPa • M/F ratio – 9-13 • Tooth movement in 3 linear and 3 rotational dimensions was measured • Dental casts – at 14 day interval
Subjects and method • 7 Healthy patients from the graduate orthodontic clinic at the university of nebraska medical center • 2 males and 5 females (12y 3m to 16 y 3m) • Good oral hygiene • Maxillary 1st premolars extracted • NSAIDs avoided
Subjects and method • Each subject was scheduled for 9 appt • Day 0 , 1 , 3 and then after every 14 day for a total of 84 day • • • •
One week before day 0 – orthodontic appliance Chlorhexidine mouth wash Oral hygiene evaluated Impressions made
Subjects and method • Maximum posterior anchorage was required • Nance app or combination of nance/ transpalatal arch • Upper 2nd molars involved • Segments were made of 19 x 25 ss
Subjects and method • • • • •
Canine retraction 17x25 or 16x22 ss Vertical height – 9-13 mm Cres – 0.24(Lr) Activation of loop – NiTi closed coil spring
Subjects and method • 2 retraction forces • Distributed randomly to Rt and Lt canines • Force (spring)= k(ΔL) • Spring attachment
Subjects and method • Between appointments – canines moved • Springs adjusted or changed to maintain the desired force magnitude • The forces and countermoment delivered were measured with 2 calibrated clinical instruments
Subjects and method • Orthometer , ortho measurements
Battery operated 2 probes Transducer Electronic display
Subjects and method • •
The compressive stresses applied were 4kpa and 13 kpa These values were chosen for 3 reasons
1. 2 stresses were different enough to bring different rates of tooth movement 2. Both stresses were of low magnitude 3. Pilot work demonstrated sufficiency for canine retraction
Subjects and method • To produce the desired compressive stresses Distal root surface area Root morphology
Subjects and method • Impressions were made at each appt.
Posterior anchorage segment was stable
3 axis measuring microscope
Subjects and method • Results
2.41 mm
Canines retracted at low stresses Canines retracted at high stresses
3.52mm
Subjects and method
Subjects and method
Crown moving more lingual than the root
Distal in
• Conclusion • Effective canine retraction can be brought about, without a detectable lag phase and with minimal unwanted linear or angular tooth movements • Continuous stresses of 13 kpa (60g force) produced distal tooth velocity of 1.27mm/ month • 4kpa – 0.87mm/month • Segmental retraction showed controlled and determinate tooth movement
Optimum force magnitude for orthodontic tooth movement : A systemic literature review Yijin Ren Jaap C. Maltha Angle Orthod 2003
Materials and methods • Meta analysis of force magnitude • • • •
Medline was searched from 1966 – 2001 Over 400 articles collected Animal studies Human trials
Materials and methods • • • • • • • •
Exclusion criteria No quantification of orthodontic force magnitude No quantification of rate of tooth movement No control group or split mouth design Number of experimental sites </= 5 Use of extaoral or functional app Observation period </= 1 week Medication or surgical intervention.
Materials and methods • 161 articles on animal studies - 17 • 305 articles on human studies – 12 • Articles tabulated
Results
Results
Conclusion â&#x20AC;˘ It is not possible to perform a meta analysis of the relation between force magnitude and rate of tooth movement from current literature â&#x20AC;˘ No evidence based force level could be recommended for optimal efficiency in clinical orthodontics â&#x20AC;˘ Well controlled clinical studies with standardized set up are required for better understanding on optimal forces.
Implant as absolute orthodontic anchors Dr. Chetan V. Jayade
Implants â&#x20AC;˘ Preserving anchorage in total is a major problem â&#x20AC;˘ Conventional orthodontics
IOA Anchor loss
EOA Patient compliance
Implants • Treatment options start getting limited or the end results compromised • Pioneering studies by Dr. Branemarke on Osseo integrated implants • Implants – Absolute anchors Indirect anchorage True stationary anchorage True skeletal anchorage
Implants • Definition • Implants are alloplastic devices which are surgically inserted into or onto the jaw bones
• Osseo integration – an intimate structural contact at the implant surface and adjacent vital bone devoid of any intervening fibrous tissue
Implants • Types Screw type Plate type
• Parts Head Body
Implants â&#x20AC;˘ Classification â&#x20AC;˘ Depending on the location of the implant
Subperiosteal Transosseous Endosseous
Implants
Subperiosteal
Transosseous
Endosseous
Implants â&#x20AC;˘ Based on configuration design Root form implant Blade / Plate implant â&#x20AC;˘ Based on surface structure Threaded or Non Threaded Porous or Non Porous
Implants • Based on the composition SS Ti Co - Cr – Mo Ceramic Miscellaneous – Vitreous carbon and composites
Implants â&#x20AC;˘ Early reports of implant usage â&#x20AC;˘ Grainesforth and Highely (1945)
Vitallium screws in Ramal area Immediately loaded For canine retraction
Implants â&#x20AC;˘ Linkow (1970) â&#x20AC;˘ Conducted a human trial to retract the anterior segment using molar implant
Implants • Orthopedic changes Maxillary protraction Maxillary expansion
• Shapiro and kokich (1984) used ankylosed teeth as pseudoimpant • Intentional ankylosis of deciduous canines
Implants â&#x20AC;˘ Smalley et al (1988) Insertion of titanium implants into maxilla, zygoma, orbital and occipital bones of monkeys 12-16mm widening of sutures with 5-7mm increase in overjet
Implants • Andrew , Parr et al (1997) • Conducted experiments on nasal expansion using endosseous Ti screws • Sample – 3 groups • 1 N and 3 N force force applied • 5.2 mm and 6.8 mm expansion
Implants • Orthodontic changes • Creekmore (1983) • Unloading period of 10 days • Within 1 yr – 6 mm of intrusion and 25ºof lingual root torque
Implants • Southard (1995) compared the efficacy of Ti implants with that of teeth in dogs • Unloading period of 3 months • Intrusive force of 50 – 60 g
Implants â&#x20AC;˘ Eugene Roberts: use of retromolar implants for space closure Size of implant: 3.8mm width and 6.9mm length
Implants â&#x20AC;˘
Drawbacks of Retromolar implants
1. 2. 3. 4. â&#x20AC;˘
Bulky Long waiting period Anatomic limitations Expensive Since 1995 , around 10 implant systems have evolved
Implants • Onplants • Block and Hoffman in 1995
3mm height
Unloading period 3-4 months
Implants • Osseous implants • Placed in dense bones – zygoma, body or ramus, mid palatal area Skeletal anchorage system Orthosystem implant Graz implant supported system Zygoma anchor system
Implants • Skeletal anchorage system (SAS) • Developed by Umemori and Sugawara • Ti miniplates stabilized using screws (2 - 2.5 mm in dia) • Design – L type T type
Implants Placement
Unloading period of 3 â&#x20AC;&#x201C; 4 weeks
Implants • • • • •
Orthosystem implant Developed by wehrbein Ti screw (3.3mm dia) 4mm or 6mm length 8 weeks of waiting period • Surface treatment
Implants • Graz implant supported system • Karcher and Byloff • Modified Ti miniplate
Implants • Zygoma anchor system • Hugo De Clerck and Geerinckx (2002) • Curved Ti miniplate with provision of 3 screws • Lower end projects outward and has a vertical slot • Placed in zygomaticomax buttress area
Implants Osseous implants • Advantage • Molar intrusion
• Limitation • Involves complex surgical procedure • Removal - difficult
Implants â&#x20AC;˘ Interdental implants â&#x20AC;˘ Rely on mechanical retention rather than Osseo integration â&#x20AC;˘ Simple to place under LA
Mini implant Aarhus implant Micro implant anchorage
Implants • Mini implant • Ryuzo kanomi (1997)
6 – 7 mm in lenth 1.2 mm dia
Implants â&#x20AC;˘ Aarhus implant â&#x20AC;˘ Birte melson
Implants • Microimplant anchorage (MIA) • Dev by a team of korean orthodontists • Maxillary implants are longer • Ti implants • Drill – 0.2 mm smaller than the implant size
Implants • Newer interdental implant system • Spider screws • OMAS
Implants • Stability of the implant • Miyawaki et al analyzed the stability of screw and plate implant • Sample – 51 patients • 134 screw implants(1,1.5, 2.3 mm dia) • 17 miniplate
Implants • Results • 1mm dia – high failure rate • 1.5 and 2.3mm dia – success rate of 84%and 86%respectively • Miniplates – showed best stability • Peri implant hygiene major criteria for success
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