Functional appliances /certified fixed orthodontic courses by Indian dental academy

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The 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 provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
00919248678078

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Functional appliances /certified fixed orthodontic courses by Indian dental academy

  1. 1. GENERAL PRINICPLES OF FUNCTIONAL APPLIANCES AND MODE OF ACTION www.indiandentalacademy.com 1
  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com 2
  3. 3. Topics 1}History - Changing concepts Compressive 2}Forces - Shear Tensile 3}Treatment principles External Internal Force application Force elimination 4}Applications www.indiandentalacademy.com 5}Mode of actions of functional appliances 3
  4. 4. Myotonic & Myodynamic appliances Frankel Regulator Functional Space Head posture & Cranio-facial growth Construction Bite Cephalometric analysis for functional appliance therapy Cybernatic theory Functional matrix concept Functional analysis www.indiandentalacademy.com 4
  5. 5. Definition: Functional appliance refers to a variety of removable (fixed) appliances designed to alter the arrangement of various muscle groups that influence the function and position of the mandible in order to transmit forces to the dentition and the basal bone. Typically the mandibular position sagittaly and vertically, resulting in orthodontic and orthopedic changes. www.indiandentalacademy.com 5
  6. 6. In last 20 years, functional appliances therapy has become a generally accepted method to treat severe and moderate discrepancies of sagital jaw relations in children. Until now, functional appliance therapy had its greatest application and success in Class II malocclusions. (A variety of different functional appliances is available). The appliance selected for the treatment can be adapted to the type of anomaly and to the growth pattern. The growth direction, the growth amount and the timing are relevant to the ultimate success of the treatment. www.indiandentalacademy.com 6
  7. 7. The theoretical basis of functional treatment in general is the principle that a “new pattern of function” dictated by the appliance, leads to the development of a correspondingly “new morphologic pattern”. www.indiandentalacademy.com 7
  8. 8. The “new pattern of function” can refer to different functional component of the orofacial system  for eg, the tongue, the lips, the facial and masticatory muscles, the ligaments, and the periosteum. Depending on the type of appliance, its proponent puts more emphasis on one of these different functional components. www.indiandentalacademy.com 8
  9. 9. The “new morphologic pattern” includes a different arrangement of the teeth within the jaws, an improvement of the occlusion and an altered relation of the jaws. It also includes changes in the amount and direction of growth of the jaws, and differences in the facial size and properties. www.indiandentalacademy.com 9
  10. 10. The influences of natural forces and functional stimulation on form were first reported by Roux in 1883. He described the characteristics of functional stimuli as they build, mold, remold and preserve tissue. His working hypothesis became the background of both general orthopedic and functional dental orthopedic procedures. www.indiandentalacademy.com 10
  11. 11. Häupl in 1938 on the basis of Roux hypothesis applied his concepts to the correction of jaw and dental arch deformation using functional stimuli. He also explained the way functional appliances worked through the activity of the orofacial muscles. www.indiandentalacademy.com 11
  12. 12. It was also said that function is inherent in all cells, tissues and organs and influences these media as a functional stimulus. The goal of the functional dental orthopaedics is to use this functional stimulus, channeling it to the greatest extent the tissues, jaws, condyles and teeth allow. The mode of transmission is “passive” in the sense that the mechanical force producing elements are unnecessary. The forces that arise are purely functional and are intermittent in nature. www.indiandentalacademy.com 12
  13. 13. According to Häupl this is the only mode of force application that can build up tissue, since with continuous active forces bone remodeling cannot take place. Because of the ability of the passive appliances to transfer muscle forces from one area to another, functional orthopedic appliances were called “Transformators”. Schwarz in 1952 indicated that activators worked by not only intermittently transmitting functional force stimuli but by also applying light, compressive forces such as those achieved with removable plates. www.indiandentalacademy.com 13
  14. 14. Forces: Types of forces employed in orthodontic and orthopedic procedures are: • Compressive • Tensile • Shearing www.indiandentalacademy.com 14
  15. 15. Tensile forces are forces which are acting in the opposite direction and are collinear whereas shearing forces are forces acting in the opposite direction and are non-collinear. Tensile forces are the ones which cause stress and strain in functional appliance therapy. www.indiandentalacademy.com 15
  16. 16. They also alter the stomathognathic muscle balance both external (primary) and internal (secondary) forces can be observed in each force application. External forces are the primary motivating influences harnessed by functional appliances. They include various forces acting on the dentition such as occlusal and muscle forces from the tongue, lips and cheeks. www.indiandentalacademy.com 16
  17. 17. Note the primary objective of functional appliances is to take advantages of natural forces and transmit them to selected areas to produce the desired change. www.indiandentalacademy.com 17
  18. 18. Internal forces are the reactions of the tissues to primary forces. They strain the cartilaginous tissues, leading to the formations of an osteogenetic guiding structure (i.e. deformation and bracing of alveolar process). This reaction is important for secondary tissue adaptation. The strain and deformation of the tissues results in remodeling, displacement and all other alterations that can be achieved by orthodontic therapy. www.indiandentalacademy.com 18
  19. 19. Wolff’s Law : Bone- connective tissue-Responds to mild degree of pressure & tension- Changes in its form resorption or deposition This may take place on the surface of bone under periosteum or in cancellous bone on the surface of trabaculae or the walls of marrow spaces or air sinus The architecture of a bone is such that it can best resist the forces brought to bear upon it with use of little tissue as possible www.indiandentalacademy.com 19
  20. 20. Basett has modified Wolff’s law: Bone elements place or displace themselves in the direction of function and increase or decrease their mass to deflect the amount of functional forces. If Wolff’s law and its modification are accepted then it follows according to woodside, Altuna and Metaxas, that “moving a bone to a new position within a muscle system results in rearrangement of the stress distribution and reorganization of the shape and the internal structure. 20 www.indiandentalacademy.com
  21. 21. Depending on the force applied 2 treatment principles can be differentiated: 1. Force Application 2. Force Elimination www.indiandentalacademy.com 21
  22. 22. 1. Force Application: * Compressive stress and strain act on the structures involved resulting in primary alteration in form with a secondary adaptation in function. * All active fixed or removable appliances work according to this principle. * It stimulates neuromuscular response by sensory stimulation. * Success of functional appliance therapy depends on the neuromuscular response. www.indiandentalacademy.com 22
  23. 23. 2. Force Elimination: * Abnormal and restrictive environmental influences are eliminated. * Lip bumper, Fränkel buccal shield etc. work on the following principle. * Function is reliabilitated and followed by secondary adaptation in form. * During the elimination pressure a tensile strain can arise as a result of the viscoelastic displacement of periosteum and the bone forming response in affected areas. www.indiandentalacademy.com 23
  24. 24. * Tension can be more effective man pressure because most bony structures are designed to resist pressure but not tension. * These appliances can guide stomathognathic function or work solely by elimination of unwanted muscle influences to permit undisturbed development of dentition. * The application of protective barriers, or screens, in the path of abnormal muscle forces has also been called as “incubatory treatment”. www.indiandentalacademy.com 24
  25. 25. * Normal function leads to normal structure and proportions whereas abnormal function leads to malformation and malocclusion. * Expectation is that subsequent development will correct the transient environmental assault on the integrity of the dentition. * Disturbing the environmental influences also lender the hereditary traits. www.indiandentalacademy.com 25
  26. 26. * However to give a normal hereditary pattern the best chance to express itself is to correct the effects of environmental assaults, interceptive therapy must start early so that it has the greatest adaptive opportunity and the most amount of growth on which to work. * With the use of either of these principles it is possible to perform tooth movement. Alveolar bone is purely membranous thus, by its nature is responsive to slightest change in balance. 26 www.indiandentalacademy.com
  27. 27. To be continued www.indiandentalacademy.com 27
  28. 28. Mode of action of the functional appliance Functional appliance Increased contractile activity of the lateral pterygoid muscle Intensification of the retrodiscal pad Increase in the growth stimulating factors Enhancement of local mediators Reduction of local regulators www.indiandentalacademy.com 28
  29. 29. Change in condylar trabacular origin Additional growth of condylar cartilage Additional subperiosteal ossification of the posterior border of the mandible. Supplementary lengthening of the mandible. www.indiandentalacademy.com 29
  30. 30. Increased contractile activity of the lateral pterygoid * Mandibular protrusion causes alteration in the function of the two jaw protrusor – lateral pterygoid superior masseter muscle. * Increased tonic activity of LPM * Leads to increased condyler growth and its stimulation. www.indiandentalacademy.com 30
  31. 31. Intensification of retrodiscal pad repetitive activity * Meniscotemporomandibular frenum is a mediator of LPM activity in the control of condylar cartilage activity. * Increase blood and lymph flow with decreased cell catabolic concentration and negative feedback factors. * Stutzmann and Petrovic showed that surgical resection of TMF result in significant reduction of growth of condylar cartilage. www.indiandentalacademy.com 31
  32. 32. Enhancement of local mediators Stimulating effect on the cell multiplication i.e. growth homone, testosterone, somatomedin, glucagons, parathormone, calcitonin etc. Growth promoting factors also operate by canceling effects of agents that complify the intercellular signal restraining skeletoblast or pre osteoblast multiplication. www.indiandentalacademy.com 32
  33. 33. Classification of Views: 3 main groups. I. Petrovic, McNamara substantiate the Andressen – Häupl concept * Myotactic reflex activity and isometric contraction induce musculoskeletal adaptation by introducing a new mandibular closing pattern. * Muscle function with kinetic energy and intermittent forces. * Grude suggests that such adaptation is possible only with a small bite opening. * Stimuli from the activator and muscle receptors and periodontal mechanoreceptors promote displacement of mandible. * LPM play the most important role in adaptations. www.indiandentalacademy.com 33
  34. 34. II. Selmer-Olsen, Herren, Harvold and Woodside * Viscoelastic properties of the muscles and stretching of the soft tissues are decisive for activator action i.e. skeletal adaptation. * During each application of the force, secondary forces arise in the tissues, introducing a bioelastic process. www.indiandentalacademy.com 34
  35. 35. Depending on the magnitude and duration of the applied force, the viscoelastic reaction can be divided into the following stages: * Emptying of vessels. * Pressing out of interstital fluid. * Stretching of fibers. * Elastic deformation of bone * Bioplastic adaptation www.indiandentalacademy.com 35
  36. 36. Skeletal adaptation in the vertical plane alone according to Woodside Eliciting a stretch of the soft tissues primarily requires dislocating the mandible antenorly or opening beyond the postural rest vertical dimension. * Appliance works using potential energy * Herren overextends the mandible anteriorly into incisal crossbite. www.indiandentalacademy.com 36
  37. 37. III. Applies mode of action of the above two called transitional type. * Alternately uses muscles contraction and viscoelastic properties of soft tissues. * Appliance of this group have a greater bite opening. * Function appliance activates the muscles, various types of forces are thus created – static, dynamic and rhythmic. www.indiandentalacademy.com 37
  38. 38. Thank you www.indiandentalacademy.com Leader in continuing dental education www.indiandentalacademy.com 38

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