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Cybernetics /certified fixed orthodontic courses by Indian dental academy
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Cybernetics /certified fixed orthodontic courses by Indian dental academy



Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.



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Cybernetics /certified fixed orthodontic courses by Indian dental academy Cybernetics /certified fixed orthodontic courses by Indian dental academy Presentation Transcript

  • CYBERNETICS INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  • Greek word KYBERNETES (art of steering) Plato & Ampere Norbart Weiner 1948 “ Science of control & communication in animal & machine” ART OF ENSURING THE EFFICACY OF ACTION. Once regarded as pointless sophistication in accounting for www.indiandentalacademy.com biologic & biomedical findings.
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  •  Cybernetics is the science that studies the abstract principles of organization in complex systems. It is concerned not so much with what systems consist of, but how they function. The cybernetic theory postulates that everything affects everything & therefore organized living systems never operate in an open-loop manner www.indiandentalacademy.com
  • • Based on communication & information theory : particularly on feedback control system. • Has bought new concepts eg –ve & +ve feedback,self regulation,reference input ,open & close loop www.indiandentalacademy.com
  • CYBERNETICS The science of control and communication in biological, electronic and mechanical systems. This includes analysis of feedback mechanics that serve to govern or modify the actions of various systems. TABER’S CYCLOPEDIC MEDICAL DICTIONARY 16TH ED www.indiandentalacademy.com
  • • Permits display of qualitative and quantitative relationship between observed and experimental findings (what I see is what I report) • Broader understanding of orthodontic problems, and action of appliances • Rigorous language of cybernetics is the most app way to lead to the current use of computers www.indiandentalacademy.com
  • Cybernetic features: 1 Placing observations next to each other 2.diagram displaying qualitative relations b/w observations. 3.mathematical language to describe interactions among various parts of morphophysiologic system. 4.cybernetics based on communication & information theory : mainly on feedback control system is also a useful research approach www.indiandentalacademy.com
  • Cybernetics Transfer of Information • Cybernetic systems operate through transfer of information • Physical, Chemical, Electromagnetic www.indiandentalacademy.com
  • Black box concept Input Black Box Output Input Transfer function Output Black box is the physiologic system under study www.indiandentalacademy.com
  • Input Orthodontic, Functional, & orthopedic appliances Black Box Genetically determined & cybernetically organized biologic features of Phenomena characterizing, inducing, or controlling spontaneous & appliancemodulated growth relative To the following: •Max. lengthening & •Widening •Mandible lengthening •Teeth movements www.indiandentalacademy.com Output Correction of malocclusion & Intermax. malrelation
  • • Identification & analysis of feedback loops are among main tasks in craniofacial growth . • So far, cybernetic language has been the best tool to render accurately the intricacy & complexity of craniofacial morphogenesis & the means to influence it clinically. www.indiandentalacademy.com
  • Pavlovian concept of accommodation in biological systems  Conditioning  Reinforcement  Habituation Living animals respond passively to stimuli www.indiandentalacademy.com
  • Morphophysiologic system Open loop closed loop www.indiandentalacademy.com
  • Open Loop Output has no effect on the input www.indiandentalacademy.com
  • Refutations 1. Steiner & Brown “The North Carolina chain gang” www.indiandentalacademy.com
  • 2. Post retention Relapse www.indiandentalacademy.com
  • Principle of optimality Feedback controlled behavioral Pattern is assessed. Deviation b/w given state of system + desired optimal state of system is fed back as input : system then take action to reduce this deviation to a min. www.indiandentalacademy.com
  • Closed Loop Relationship maintained between input and output www.indiandentalacademy.com
  • Closed Loop systems Input Regulation of effect Measure of effect Return of modified information www.indiandentalacademy.com
  • Closed Loop www.indiandentalacademy.com
  • Morphophysiologic systems Open loop closed loop Regulator www.indiandentalacademy.com Servosystem
  • These concepts of cybernetics : 1.Mechanism of craniofacial Growth 2.Method of operation of orthopedic & orthodontic appliance. www.indiandentalacademy.com
  • • Theory of facial growth based on these concepts of cybernetics is servosystem www.indiandentalacademy.com
  • Control of maxillary growth • Direct effect : STH preosteoblast • Indirect effect : thr intermediaries www.indiandentalacademy.com
  • Types of Cartilage Primary www.indiandentalacademy.com
  • Types of Cartilage Secondary www.indiandentalacademy.com
  • Double differentiating potential of skeletoblasts www.indiandentalacademy.com
  • Primary Cartilage: Epiphysis, Synchondrosis, Nasal Septum, Ethmoid Sphenoid Secondary Cartilage: Condyle, Coronoid, Mid Palatal Suture, Fracture Callus www.indiandentalacademy.com
  • Factors influencing Growth Primary Cartilage Secondary Cartilage Hormones Yes Yes Local Factors No Yes (Pre- (Chondroblasts surrounded by matrix) Orthopaedic appliances chondroblasts not surrounded by matrix) Only Direction Direction and Amount Charlier, Petrovic, Stutzmann www.indiandentalacademy.com Strasburg, France
  • Growth of the maxilla Growth in Length Growth in Height www.indiandentalacademy.com Growth in Width
  • Growth in Length: Traction SeptoPremaxillary ligament Induction Growth of Nasal Septum Biomechanical Labio narinary Muscles Release of STH Somatomedin Thrust Growth of Pre Maxillary extremity Anterior shift Of premaxillary bones Growth of PremaxilloMaxillary suture Protrusion of Upper Incisors Increased size Of Tongue Thrust Protrusion of Lower Incisors www.indiandentalacademy.com Direct Action Growth of Maxillo Palatine suture
  • Growth in Width: Growth of Lateral cartilaginous masses of Ethmoid Release of STH Somatomedin Transverse Separation of premaxillae Outward growth Of maxillary bones Growth of cartilage B/w greater wings & body of sphenoid Increased size Of Tongue Outward shift of Alveolus and molars www.indiandentalacademy.com Direct effect Growth of inter Pre Maxillary suture Transverse Separation of Horizontal Maxilla and Palatine plates Growth of mid Palatine suture Outward Appositional Bone growth
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  • Growth in height www.indiandentalacademy.com
  • Control of Mandibular Growth Role of Lateral Pterygoid & Retrodiscal Pad Two roles : •Blood Supply •Biomechanic www.indiandentalacademy.com
  • Metabolic role Increase • Blood & Lymph flow • nutritive factors Decrease • Cell catabolites • -ve feedback factors www.indiandentalacademy.com
  • Biomechanic role www.indiandentalacademy.com
  • Relationship Between Lateral Pterygoid, Retrodiscal Pad and Condyle MENISCUS LPM RDP www.indiandentalacademy.com
  • Somatomedin & LPM Interaction www.indiandentalacademy.com
  • • Definitions • Command : signals established independent of feedback system under scrutiny. • Reference input elements: establish r/lship b/w command & reference input • Reference input : signal established as a standard of comparison. • Controller : located b/w deviation & actualling signal www.indiandentalacademy.com
  • •Actuating signal :corresponds to output signal of the controller • Controlled system : b/w actualing signal & directly controlled variable. • control variable : output signal of the system. www.indiandentalacademy.com
  • Components of a Servosystem Reference Input Elements Reference Input COMMAND Actuator, Coupling System Controlled system (Controlled Variable) Performance Analyzing Elements Central Comparator (sensory engram) Output COMPARATOR Deviation Signal www.indiandentalacademy.com Performance
  • The Face as a Servosystem Input – Maxillary dental arch Output – sagittal position of the mandible. www.indiandentalacademy.com
  • The Face as a Servosystem Release of Hormones(Command) LPM & RDP (Coupling system) Actuating signal Hormones Growth at condyle (Controlled System) Position of Maxillary Dental arch (Ref Input) Output Actuator (Motor Cortex) Brain (sensory engram) Deviation Signal www.indiandentalacademy.com OCCLUSION (Comparator) Periodontium, Teeth Musculature Joint Mastication (Performance)
  • The Sensory Engram • Blueprint of ideal muscular function/position • Collection of feedback loops • CNS tends to operate along these feedback loops www.indiandentalacademy.com
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  • Other Terms Related to a Servosystem Gain = Output Input Amplification (Gain>1) Attenuation (Gain <1) www.indiandentalacademy.com
  • Attractor Cusp to fossa relation Repeller Cusp to cusp relation Disturbances Abnormal tooth position Occlusal interferences Arthritis Muscle Inflammation Periodontitis, Pulpitis www.indiandentalacademy.com
  • Peripheral Comparator Before development of Occlusion:•Sensory engram not developed •Servosystem does not operate •Genetic influence on mandibular growth •Anodontia After Development of Occlusion:•Sensory engram forms •Peripheral comparator controls growth www.indiandentalacademy.com
  • Discontinuities Stable Unstable Stable Catastrophe Theory So , a class II molar r/l will never spontaneously revert www.indiandentalacademy.com to class I
  • Bifurcation www.indiandentalacademy.com
  • Importance of Discontinuities Facial growth should be accounted for by using unpredetermined & discontinous models rather continous & deterministic ones. Stability of occlusion after it is established • Genotype does partially influence the phenotype www.indiandentalacademy.com
  • Cybernetics Dr.Rekha www.indiandentalacademy.com
  • The Face as a Servosystem Release of Hormones(Command) LPM & RDP (Coupling system) Actuating signal Hormones Growth at condyle (Controlled System) Position of Maxillary Dental arch (Ref Input) Output Actuator (Motor Cortex) Brain (sensory engram) Deviation Signal www.indiandentalacademy.com OCCLUSION (Comparator) Periodontium, Teeth Musculature Joint Mastication (Performance)
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  • Failure of Servosystem to Control Growth • Peripheral comparator faulty – Caries, Mutilated dentition. •Discrepancy between rotation pattern (Anterior or Posterior) and location of comparator. www.indiandentalacademy.com
  • Action of Functional Appliances www.indiandentalacademy.com
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  • Mode of action of functional Appliances Functional appliance LPM Retrodiscal Pad Growth stimulating factors Lengthening of mandible www.indiandentalacademy.com
  • Two Types of Functional Appliances 1) Activator, Postural hyperpropulsor, Frankel appliance, Twin block, Bionator, Class II Elastics(?) ) Herren activator, LSU activator, Harvold-Woodside activator, Extra oral traction on the mandible. www.indiandentalacademy.com
  • FIRST GROUP: Forward Position mandible: Increased activity of LPM and RDP LPM “helped to contract more” by Functional appliances. i.e myotactic reflex & isometric contractions www.indiandentalacademy.com
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  • CELLULAR LEVEL 1. Precursor Skeletoblast – pleuripotent, fibroblast like. 2. Prechondroblast – faster cell cycle, matures into Chondroblast www.indiandentalacademy.com
  • Chondroblasts lost removed) (hypertrophy, surgically Increased multiplication of prechondroblasts Local control over multiplication of prechondroblasts Originates from chondroblastic layer •Stutzmann and Petrovic (1982, 1990) www.indiandentalacademy.com
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  • Functional appliances (especially Class II elastics) Increased activity of RDP Increased nutrients and growth factors inhibitors removed. Increased mitoses and earlier hypertrophy of chondroblasts. www.indiandentalacademy.com
  • Cytoplasmic junctions between skeletoblasts reduce. Transmission of inhibitory factors reduce. Increased mitotic rate and rate of differentiation into prechondroblasts. www.indiandentalacademy.com
  • Reduced negative feedback signal reaching prechondroblasts Increased growth at the condyle www.indiandentalacademy.com
  • SECOND GROUP: Position mandible forward , open in beyond rest position. Viscoelastic property of muscle is imp No increase in activity of LPM •Herren (1953) •Auf der Maur (1978) •Yet there was an increase in growth www.indiandentalacademy.com
  • • Proponents contend that the use of myotactic reflex should be largely ignored. • Alveolar remodelling is obtained from the inherent elasticity of muscle,tendinous tissue, skin without motor stimulation. www.indiandentalacademy.com
  • wo steps: )While appliance is worn:Forward position increase in length of LPM New sensory engram )While appliance is not worn:New sensory engram Functioning in anterior position Increased activity of RDP www.indiandentalacademy.com
  • Action of first group while appliance is worn Action of second group while appliance is not worn www.indiandentalacademy.com
  • A New Parameter for estimating condylar growth direction • Growth direction of condyle coincides in general with the axes of individual trabeculae ,located just inferior to the central part of the condylar cartilage. • Stutzmann’s angle : trabecular alignment with mandibular plane. www.indiandentalacademy.com
  • Stutzmann’s angle increases at the beginning of treatment(only a transient remedial event). Closes: horizontal growth pattern. Opens : vertical growth pattern. www.indiandentalacademy.com
  • CLINICAL IMPLICATIONS 1)Principle of optimality of function : Less relapse tendency if post orthodontic treatment muscular activity produces a lower deviation signal. www.indiandentalacademy.com
  • 2) Removal of functional appliance – when growth is complete. 3) If removed when growth not complete – Proper intercuspation. www.indiandentalacademy.com
  • 4) Understanding of when, and for how long a particular functional appliance should be worn. First group – Full time Second group – Part time www.indiandentalacademy.com
  • 5) Proper functioning of LPM and RDP important for growth – Proper parent counseling. 6) Sensory engram poorly developed in younger children. 7) Utilization of high hormonal activity at puberty. www.indiandentalacademy.com
  • Drawbacks Lot of importance on condyle: Fracture? )Peripheral comparator (occlusion) itself is unstable. discrepancies may be overcome by Dentoalveolar changes rather than growth of Mandible. www.indiandentalacademy.com
  • ) Occurrence of Class II end on relation is seen often? ) Action of reverse pull headgear on maxilla (primary cartilage) www.indiandentalacademy.com
  • References Dentofacial Orthopedics with Functional Appliances Graber, Rakosi, Petrovic Craniofacial Growth Series – Monograph (Craniofacial Growth Theory and Orthodontic Treatment – Edited by Carlson) www.indiandentalacademy.com
  • Treatment objectives and case retention: Cybernetic and myometric considerations 1970 R.M. Jacobs Am J Orthod, 58:552-564, Grant’s Atlas of Anatomy www.indiandentalacademy.com
  • www.indiandentalacademy.com Leader in continuing dental education www.indiandentalacademy.com